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The Challenges of Avian Medicine

Since I've been doing consulting, I have come to the realization that with age comes wisdom. Well, I have passed my 20-year vet school reunion, so I needed to find some positive spin on getting older, okay? Actually, I think I have learned a few things along this pathway that I have chosen, and I would like to share the common-sense, nuts-and-bolts information that will help you in the day-to-day practice of avian veterinary medicine. I will also present some cases that astounded, confounded, confused and surprised me.

I have had the privilege of working with facilities breeding some of the most rare and endangered parrots on this planet. I have worked with a dedicated group of bird breeders who wanted to offer to the pet trade the finest baby parrots anywhere, so they practiced excellent preventative flock medicine, maintained superior nurseries and vaccinated all of their offspring. I have worked with top pet retailers selling psittacines into the pet trade. I have a wonderful client base of committed, caring pet parrot owners who allow me to practice the kind of avian medicine that I want to. I have visited aviaries in other countries, and had the privilege of spending time in the Republic of South Africa, lecturing and traveling to some of the most amazing aviaries I have ever seen.

Listen to Your Clients

My first words of wisdom for you are these: It always pays to listen to your clients. They live with their birds and they will often pick up on subtle clues that you won't see during the stress-filled (hopefully, just for the bird) office exam. If they think their birds are sick, then they probably are! One referral client of mine insisted that her Amazon swallowed a sliver of wood and it was stuck somewhere in the oropharynx or esophagus, and she went to half a dozen avian vets, all of whom insisted that that was an impossibility. Well, guess what? A piece of wood had pierced the oropharynx and had caused a derangement of the TMJ on one side due to the abscess and fibrous tissue that resulted. The astute owner had observed that the bird had begun making choking motions, rubbing its beak and yawning immediately after chewing on a wooden toy. That began a six-month period of frustration for the owner as she tried to get an answer about her bird's illness. She visited five or six vets in her area, drove five hours to a veterinary school and began making calls to set up phone consultations. That's how she found me. When I told her that if she thought the bird had a splinter of wood in its throat, then it probably did, the woman burst into tears. I was the first vet to take her seriously about what she thought was wrong! Please, please listen to your clients when you are taking the history and signalment, and don't form any preconceived ideas about what the problem is (or is not, as the case may be), as that might color your diagnostic impression. First and foremost, listen to your clients.

Be Sensitive to Clients and Patients

One client told me that she would never return to a certain veterinary hospital, because when she went to the ward to visit her hospitalized bird, she was horrified to see that her darling child-substitute was housed in a cage right next to a large boa constrictor, which was in plain view to her Eclectus hen. The owner was very distraught, seeing a large snake in a cage right next to her beloved pet bird, considering that the snake would think that her bird was just a brightly-colored meal waiting to be consumed. Even though the owner was assured that the snake could not escape or harm her bird, the damage had already been done in the owner's mind. She felt very uncomfortable about the situation, and elected to remove her bird from that hospital for treatment elsewhere. She was afraid that her bird, already ill, had been further stressed by being housed next to this predator snake.

I think it behooves us all to pay attention to how our clients perceive us, as veterinarians, and how they perceive that their birds are being cared for. This includes paying attention to other hospitalized patients housed near ill birds.

It can also be dangerous to board or hospitalize certain predatory species in the same building as avian patients. I have heard of one case where a boarding raccoon escaped from its cage during the night, and managed to knock over the cages of several birds boarding in the same room, allowing them to escape from their cages. The raccoon then killed and partially ate two pet birds, a cockatoo and an African Grey, both child-substitutes for a childless couple who were unable to have children (the human kind). This kind of horror story could have been avoided by paying attention to where specific animals are boarded or hospitalized, never putting predators/prey in the same room.

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Certificate of Examination

I highly recommend that you purchase (from the Association of Avian Veterinarians) the AAV Certificate of Veterinary Examination and use them for every patient. It has a place to mark down any tattoos, band numbers, microchip number, etc. Most of the vets that I consult with through Antech do not even know if a specific patient of theirs is banded or not, and they certainly have not written it down anywhere. This becomes of vital importance in regards to necropsies and histopath. Many of my aviculturists would have been happy to replace a young bird that had died, IF the vet who performed the necropsy had written down the band number, identifying the bird as originating from their aviary. If histopathology is performed, again, make sure that the band or microchip number appears on the paperwork. It will save everyone a pile of headaches and legal wrangling, should there ever be questions as to the origin and ownership of the bird. Also, many birds are bred in Florida and shipped all over the country as babies. This brings me to my next point.

Prophylactic Deworming

I have been saying this for years (because I have been seeing this for years!) and here it is: Many young and adult birds can be harboring ascarids (especially if they were parent-raised for any length of time) and you can run fecals all day, and guess what? The fecals will almost always be negative. A paper out of the Univ. of Georgia a few years back confirmed this. Many a time I have been a hero when I have dewormed a bird during a second or third opinion, when it passes a pile of ascarids and shocks the owner after being repeatedly told by other vets that "the fecal was negative." Well, deworm it anyway, with something safe. I routinely use pyrantel pamoate, since you can't hurt a bird with it, unless you aspirate it! Don't use fenbendazole, as it can cause idiosyncratic liver problems or death. In my experience, ivermectin works for mites and lice, but not very well for ascarids or capillaria. My point is, if a bird has a band indicating that it was bred in Florida, you might be better off deworming it unless it was dewormed according to paperwork that came with the bird (an AAV Certificate of Examination with my name on it, for example!)

Another reason that I like giving owners the AAV Certificate of Examination is because it gives the owner a complete record of the office visit, including weight (in grams, please, not ounces or portions of a kilogram!), ID, results of the physical exam, any treatments administered, and any tests performed. I think owners should have this information. I practice in Florida (I might have mentioned that before) and we have hurricanes, tornadoes, and serious thunderstorms, all which might result in power outages and phone lines being down. Should owners need to evacuate with their birds, it would be great for them to have copies of their medical records.

Identification of Species

One bit of advice that has served me well over the years is this: every morning, check your list of the day's appointments and then take a few minutes to get out your avian atlas to look up any species that you are unfamiliar with. (Make sure to ask your receptionist to always get the species of bird and write it in the appointment book, if the client knows what kind of bird they own). When you enter the exam room, instead of having to ask the owner what kind of bird it is, you will appear knowledgeable about the species. You will also know the scientific name, what country the bird is native to, the number of sub-species and all sorts of interesting information that will impress your client. It is always a good idea to learn the scientific names of birds you see in practice, as some owners will know them, and so should you. Also, some owners will have misidentified their pet bird (or they might have been told the incorrect name by a pet store or private individual). By having looked it up in an avian atlas, you might even find that the bird is not the species the owner thought he had.

Cloacal Examination

Every physical examination should include dipping a cotton-tipped applicator in 5% acetic acid (white vinegar), inserting it into the cloaca to evert the cloacal mucosa for visual examination (in appropriate species). You can learn a lot from looking at the mucosa. If it is angry red, the bird might have enteritis. If it is pale, the bird might be anemic. If there are white lesions, the bird might have papillomas, although the 5% acetic acid will turn other lesions white, as well. Amazons, macaws and mini-macaws are most likely to have internal papillomas, although I have also seen them in Jardine's parrots and African Greys. Lesions may be seen anywhere from the oropharynx through to the cloaca. Biopsy is diagnostic, but a presumptive diagnosis can be made based on the appearance of the lesions.

Determining Age

Regarding the age of a parrot, unless the bird was purchased as a baby, it is best to not take the owner's word for it. For example, an owner might say that their Double Yellow-headed Amazon is 26 yrs. old. Remember that, while some people were breeding these birds in captivity in the United States over 25 years ago, at that time birds were still being imported into this country. The bird may have been imported as a baby (as many Blue-fronted Amazons were) or it may have been imported as an adult. So, while an owner might have owned a bird for 26 yrs. (and was probably told by a pet store that the bird was one or two years old at the time), in reality, it could be a lot older. This can change your differential list for diagnosis. Also, I have seen many imports with tapeworms (that passed segments 20 plus years after importation!) Papillomas are a lot more common in imports, as well. Imported birds (that came into the country legally through quarantine) all had a stainless steel band applied to one leg. The band would be open, meaning it would have a gap where it was clamped on. Each band would be stamped with three letters and three numbers. The first letter would indicate which quarantine station it came in through (I for the Chicago, Illinois station, F for the Miami, Florida station, and C for the California stations, as there were two). The band will not give any other information other than which shipment it came in with, and which station it was quarantines through.

Use of Magnification and a Light Source for Avian Examination

Unless you have Superman-like vision, I recommend that you use a good quality magnifying loupe for examination of birds. This will greatly help you observe the choanal slit and choanal papillae and evaluate eyes, ears, skin, feathers, follicles, etc. I also recommend that you use a good quality light source to illuminate those orifices. You are doing your smaller patients a major disservice if you are not using magnification. Magnification is also very helpful for reading the numbers and letters on bird leg bands.

Examination of Ears and Related Structures

While performing the physical examination, make sure that you examine the ears. Part the feathers and wet them, if necessary, with a little rubbing alcohol, to better view the external acoustic meatus, which is nearly always circular. The external ear canal may be examined with a small otoscope or a small telescope attached to a fiber-optic cable. Ceruminous debris may accumulate in the canal, and can be a sign of otitis externa, which is most common in lovebirds, and the occasional conure, macaw, Amazon or Eclectus. It is usually possible to visualize the tympanic membrane. I have examined a hyacinth macaw, purchased by my client, as the third owner, and not one of the other vets who had examined this bird during the course of its life had noted that it only had one external acoustic meatus, the right one being completely sealed over! Don't let this happen to you! Also, make sure that you closely examine the infundibular cleft, a midline slit caudal to the choanal slit. The pharyngotympanic tube connects the cavity of the middle ear to the oropharynx, and is analogous to the Eustachian tube, for equalizing pressure on either side of the tympanic membrane.

Speculum Choice

If you need to swab the choanal slit, for a Gram's stain or for a culture, cytology or other types of staining (Acid-fast, for example), don't use a metal speculum to keep the beak open, as this can injure the delicate tissues of the beak. I recommend using a dog NylaboneTM (in the color of your choice, no less) with a hole drilled through the center, which will allow a moistened cotton-tipped applicator to fit through it. The NylaboneTM has a bit of give, which is better for a bird's beak. While we're on the subject of Gram's staining, I always recommend that you swab the choana and cloaca. If it's a baby bird, swab the crop, as well. I put all the swabs onto one slide, always in the same order, choana, crop, cloaca. For me, it helps in interpreting what's going on by looking at both ends.

Giardiasis

If you have a feather-picking cockatiel, chances are that is suffering from giardiasis. I would estimate that 75-80% of cockatiels that feather-pick have Giardia, even if you have run a fecal wet-mount that was negative. Giardia isn't shed in every dropping, and the trophozoites disintegrate quickly, so fresh, steaming, right-out-of-the-bird droppings must be examined. If you want to confirm a presumptive diagnosis, use preserved feces, and send them off to a lab that does special stains for Giardia. A high percentage of feather-picking budgies, lovebirds and other small birds, as well as occasionally large birds, will be suffering from giardiasis.

Treatment of Giardiasis

Everyone seems to think that metronidazole is the most effective drug to treat giardiasis. It isn't. It is effective in less than 50% of the cases, substantiated by a specialty lab that does extensive parasitology (Parasitology Research Lab, LLC. The only drug that I have ever found that works in clearing Giardia is ronidazole. This drug is available as a water-soluble powder that is available from Global Pigeon Supply (phone: 912-356-1320). It is mixed, 1 tsp. per gallon (10% powder, Ridzol, Merck, 100-200 mg/L) of drinking water, for 5-7 days. Oral dosing is: 6-10 mg/kg PO q24 hr.x 6-10 days. It is very safe and efficacious in treating giardiasis. I recommend that birds be treated in a water bottle, to prevent reinfestation. Most birds learn to use a water bottle in no time, as they stick their beak into the tube, and water comes out.

Water Bottles

Along those lines, I do recommend that all pet and breeder birds be converted to water bottles, anyway. It has been my experience that birds will have a higher level of sub-clinical bacterial infections from drinking out of water bowls, since they tend to dunk food and also to defecate into the water, increasing levels of bacteria rapidly. Studies have shown that the addition of vitamins to the drinking water will cause bacterial levels to rapidly rise.

Water Soluble Doxycycline

Global Pigeon Supply also sells water-soluble doxycycline (20% powder), which is a great treatment for those little psittacines going to live in nursing homes or in homes with immunocompromised owners. They also sell Ronidazone Plus, for birds (like those little pet store budgies) with Giardia and secondary enteritis.

Importance of the CBC

While we are on the subject of CBCs, I truly believe that the CBC is the single most important test to run on a bird. While Gram's stains are helpful, the CBC gives you the most bang for your buck. Amazon parrots are somewhat unique in that it is normal for them to be lymphocytic, meaning that they usually have more lymphocytes than heterophils when healthy. Some Eclectus also tend to have a higher percentage of lymphocytes normally, which is why it is so important to have baseline normals as a basis of comparison. A sick Eclectus may have a shift to an increased number of heterophils, which might be overlooked as a problem, unless you had another differential to compare it to, showing that the bird was initially lymphocytic.

Eclectus Toe Tapping

Eclectus sometimes present with a strange complaint of toe tapping, foot stomping, foot clenching or unilateral wing flipping. This usually occurs sporadically. The cause of this is unknown, but I believe that it is a neuritis secondary to something else going on. Some colleagues believe that it has to do with hypovitaminosis A, hypocalcemia or protein deficiency (or excessive protein in the diet!) I think that it may occur after a bout with polyomavirus, which can be fatal in unvaccinated adult Eclectus, or maybe even chlamydiosis (which can cause neurological signs), aspergillosis or a toxin. We definitely need to do a lot more work on this problem.

Steroids

If you do have bird with feather picking problems, please do not use topical preparations with steroids, especially betamethasone or dexamethasone. Research has shown that inflamed follicles rapidly absorb steroids, resulting in systemic effects. Preening birds will also ingest topical preparations. Even worse, oral or injectable steroids, including prednisone and prednisolone, can be very dangerous. All steroids are immunosuppressive. I have seen African Grey parrots develop aspergillosis after five days of topical eye drops with steroids, or after two weeks on a canine ear preparation with betamethasone. In addition to the immunosuppression, it usually causes a persistent hyperglycemia, with resultant polyuria/polydipsia and weight loss. This will usually resolve once the steroids are discontinued. If a bird does have Giardia, I'm sure that using an immunosuppressive steroid is not a beneficial thing to do.

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Venipuncture

When it comes to drawing blood on birds, since I have a housecall practice, I often must do all of my testing in front of the clients. They usually have strong feelings about not liking jugular venipunctures. My favorite vein for drawing blood for testing is the medial metatarsal vein. It runs diagonally across the medial aspect of the hock. Pluck the feathers just proximal to the scaled portion of the leg. (If you perform the venipuncture in the scaled area, you will have problems with hemostasis). The big mistake everyone makes when attempting venipuncture of the medial metatarsal vein is using a plunger in the syringe. I usually use a 27 ga. needle, without the plunger. Wet the skin with alcohol to better visualize the vein. If you can use your index and middle finger of the hand you are using to restrain the leg, to hold off the vein around the stifle, the vein will raise. Gently cannulate the vein, bevel up, and the back-pressure that develops by holding off the vein will begin to fill the syringe by capillary action. Since avian blood clots more slowly than mammal blood, you should have plenty of time to draw enough blood for a CBC, chemistry panel and any other blood tests necessary.

Prior to transferring the blood to the microhematocrit tubes, cut the needle off to prevent hemolysis, then insert the plunger, and gently transfer the blood into the appropriate tubes. I recommend using B+D Microtainer green top tubes with lithium heparin for the CBC. B+D also makes a green top tube with a separator gel. Use this for the chemistries, after spinning down the blood. While you can use a red top tube with separator gel for the chemistries, you will get a greater volume of plasma than serum. This can be of great importance when dealing with small patients. The general rule is that you can draw 1 cc from a 100 gram healthy bird (which is a good weight for a large cockatiel). You can draw 10 cc from a 1000 gram macaw, but that is almost never necessary. For most CBC and chemistry panels run 1 cc of blood should be all we need. So, for a budgie weighing 34 grams, if it is healthy, you can draw 0.34 ml. In cases like that, I recommend that to maximize testing, you make two good blood smears (for the estimated white blood cell count and differential) and fill two hematocrit tubes for PCVs. Put the rest of the blood into a GTT with a separator gel and spin it for the chemistries.

I never recommend using any of the wing veins, as venipuncture will result in a huge hematoma and it is possible to fracture a wing in a struggling bird. Regardless of the method of venipuncture that you choose, it should not be necessary to anesthetize a bird for a physical exam, venipuncture and testing in most cases. If you have someone who is comfortable with birds and knows how to perform gentle restraint, anesthesia is unnecessary unless you are performing a painful procedure. However, if you choose to use anesthesia, please be sure to completely inform the client prior to doing so, and don't just whisk the bird into the back room and gas it down.

Hemostatis

For injuries to the beak or inside the oropharynx, where it is dangerous to use clotting agents, try ice. For small injuries inside the oropharynx, try keeping some cotton-tipped applicators that have been moistened in sterile saline inside a plastic bag in the freezer that can be applied inside the mouth, on the beak or around the eyes to help achieve hemostasis. These frozen q-tips also work well when applied to the palatine vein of large snakes after venipuncture.

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Sinusitis Related to Low Ambient Humidity

Birds housed indoors, in air conditioning in the summer, or in dry heated homes in the winter, may suffer from sinusitis. Chronic sinus problems seem to occur most often in Amazons. While it is possible to treat the infections, the sinusitis will usually reoccur unless husbandry changes are made. I usually recommend that the owners take the bird into the bathroom with them when they are showering, so that the bird will benefit from the increased humidity. (Make sure the commode lid is down and it is not flushed while the bird is in the bathroom, as flushing aerosolizes all sorts of nasty bacteria). If possible, the bird should be kept in a room with plenty of living houseplants, which will also increase the humidity. Running a humidifier or vaporizer to increase humidity is also helpful (but make sure that the water tank is clean and free of bacteria and fungi). Some owners will be able to mist their bird with water, which may also help. If possible, having an owner flush the nostrils periodically with sterile saline to mechanically remove debris is very helpful.

Flushing Nares

While on the subject of flushing nostrils, it is usually not necessary to add antibiotics or antifungals to the flushing solution. I have heard of cases where medications have caused serious chemical burns to the delicate mucous membranes. It is probably best to just use sterile saline, which works quite well on its own.

Nebulization

For serious sinusitis, I usually also nebulize birds, using the same antibiotic that I am using systemically. You can purchase (slightly) used nebulizers from human respiratory companies at a great discount. If a nebulizer is delivered to a patient for in-home use, and the patient dies prior to it being used, or if was only used a few times, it can no longer be sold as new. These companies are often willing to sell them to vets. I have a half dozen that I rent out to my clients so that they can nebulize their pets at home. In most cases, the bird is much less stressed by home treatment.

Vitamin A Vs. Beta-Carotene

In cases where birds have blunted choana papilla, or the Gram's stain shows sheets of epithelial cells, these are usually signs of hypovitaminosis A. Injectable vitamin A can be hard to find in a concentration acceptable for avian patients, although it can be compounded by a pharmacist. Vitamin A, if overdosed, is toxic. However, beta-carotene is non-toxic. When beta-carotene is ingested, the body converts what it needs to vitamin A, and the rest is excreted unchanged. So this is much safer to administer to pet birds. I usually recommend that the owner purchase beta-carotene capsules, available in drug stores and health food stores, and puncture the end, in order to give a bird a drop or so orally or on a yummy food. Red-factor canary supplements also contain lots of beta-carotene.

Compounded Medications

While most pharmacists are willing to compound drugs for veterinarians, until recently, I was unaware that it is possible for pharmacists to acquire additional training in compounding. You may want to seek out such a specialist in order to develop a good working relationship with someone well-versed in concocting the strange medications that we often need. However, please don't have long-acting injectable doxycycline compounded, as European injectable doxy that can be given IM and will give blood levels for 7 days is available. I have heard anecdotal information of compounded doxy causing massive tissue necrosis and even death.

Cockatiels and Pellets

Many of my colleagues, myself included, have noted over the years, that a high percentage of cockatiels fed primarily pellets have developed renal disease. Most of these birds are 5-10 years of age. It is my opinion that the pellets originally manufactured for cockatiels were too high in protein and/or vitamin D3 for cockatiels that are primarily seed-eaters in the wild. While the bird food companies that I have spoken with have assured me that they have changed the formulas of the pellets to correct this, only time will tell. It may be better to recommend that our cockatiel patients be fed a percentage of pellets, a percentage of seed, some sprouted, plus whole-wheat bread, vegetables, fruits and table foods. The same may be true for budgies, and other small birds that are primarily seed-eaters in the wild.

Chlamydophila

Many cockatiels and budgies can be asymptomatic carriers of chlamydiosis. Testing in these small birds can be problematic. It is recommended that the EBA titer be run on cockatiels suspected of harboring the Chlamydophila organism. A pooled choanal/cloacal swab can also be run on birds suspected of shedding the organism. If a bird is already on antibiotics, do not run DNA PCR tests, as the antibiotics will usually prevent shedding, and may actually interfere with testing of the blood for the DNA PCR tests. Make a note in the chart that you have discussed chlamydiosis with the owner and note if you have given the owner a hand-out on it to read.

Client Education

The AAV has excellent hand-outs for client education on diseases, nutrition, signs of illness, children and pets, grooming, permanent identification, etc. I recommend that you purchase these to give out to your clients. Winger's Publishing also has excellent brochures about the different species of birds, their personalities, husbandry requirements and statistics. Providing your clients with this type of information is invaluable (and will save you a lot of repetitive discussions about disease, nutrition, etc.)

Biliverdin Vs. Melena

Ill birds that have not eaten for 24 hours or more will usually develop, dark, dark green, sticky droppings. This is often mistaken for melena, but it is actually biliverdin, from the liver. This is a commonly made mistake. If in doubt, add a drop of saline and smear the feces onto a white paper. Biliverdin will appear green. If a bird is passing these tarry droppings, it is vital that you begin administering parenteral fluids and gavage feedings. I hardly ever use IV or IO fluid administration anymore, as I have discovered using hyaluronidase (Wydase, Ayerst Labs). If you add 75-150 units of hyaluronidase to 1 liter of fluids, this will greatly facilitate absorption of SQ fluids. I think IO catheters are very painful and may actually impede recovery on occasion. Lafeber Company makes a critical care formula for gavage-feeding ill birds. If that is not available, you can always use a baby parrot hand-feeding formula. Do not crush up dog food to feed to ill birds. It is well-known that dog foods have allowable levels of bacteria that are not dangerous to dogs, but can be pathogenic, especially to debilitated birds. Monkey biscuits are also not appropriate for birds. Monkey biscuits are for monkeys, and also contain allowable levels of certain bacteria.

Bread in the Diet

From time to time, I hear a client or vet tell me that a bird cannot have bread, due to a previous diagnosis of candidiasis. I have never understood the connection. Any brewer's yeast found in bread-making is killed during the baking process. Candidiasis is usually secondary to hypovitaminosis A or from "swapping spit" with pet birds, and not from consuming bread products. My only rationale that I could come up with regarding not feeding bread, is because the glutens and sugars in bread could support Candida. I think there are much worse foods to feed than bread.

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Polyomavirus Vaccination

When it comes to vaccination for polyomavirus, I do recommend that all babies receive vaccines (administered SQ) at 5 and 7 weeks of age, especially if they are going into a pet store, or into a multiple pet bird household. The only adult birds that should be vaccinated are those that are going to be boarded or will be attending bird shows. Adult caiques, Eclectus and grass parakeets may die if exposed to polyoma, so they should be vaccinated every six months. The vaccine is available from Biommune, 8906 Rosehill Rd, Lenexa, KS 66215, phone: 913-894-0230.

Injectable Doxycycline

Injectable doxycycline: it's not just for chlamydiosis. If you have access to the German or Dutch intramuscular doxy, it is a great choice for treatment of many different types of infections, except for really nasty, antibiotic-resistant bacteria (like hot Pseudomonas). Many avian vets think that the injectable doxy is only useful for treating chlamydiosis. I use it often: for those little budgies that belong to ancient owners who are in no way are ever going to treat their little darling with an oral medication every 12 hrs. for two weeks. I use it for those nasty, related-to-pit-viper breeding Amazons that will exsanguinate their owner before treatment is finished. I use it for those particularly difficult to medicate turtles and tortoises (using the same doses that I would for birds, even though pharmacokinetic studies have not been performed in reptiles. It works very well clinically!)

Water Soluble BaytrilTM

While we are on the subject of antibiotics, most people don't know that Bayer has had a water-soluble enrofloxacin, BaytrilTM, available for several years in the United States. It is a 3.23% oral solution, labeled for use in poultry. Unfortunately, Bayer has no plans to try to promote this for small animals or exotics. It comes in quart containers, but you cannot purchase it directly from Bayer, as you must buy a zillion gallons at a time. It can be used as a water treatment for individual birds or for flock treatment, and the label gives dosages for 50 ppm and 100 ppm dosages. It can also be given orally, but it does taste somewhat bitter (but so does the injectable BaytrilTM, which people use orally in patients). I usually have the owners draw up the dose, then draw up some fruit juice to cut the taste. The good news is that birds have only about a tenth of the number of taste buds of those found in mammals. The best way to acquire this product at this time, is to make friends with someone raising poultry commercially or someone with an egg farm, and buy some off of them. Hello, Mr. Perdue?……But, it might help to put pressure on Bayer by telling your reps that carry Bayer products that you really want the water-soluble enrofloxacin solution. Bayer has said that since it would be an extra-label use, they are not interested in selling it to us. But, if enough vets ask for it, they might relent and at least make it easy for a distributor to sell it to us!

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Dealing With Broken Feathers

If a bird keeps breaking tail feathers (and baby Greys commonly do this) check and see if the bird is being kept in a round cage. Birds that hang on the sides of a round cage will often break tail feathers. If you must pluck some primary or secondary remiges or retrices, always tell the owners that plucking will cause some degree of damage to the follicle. In most cases, the feather(s) will regrow normally, but on occasion, a feather may grow in abnormally, or develop a feather cyst, after plucking (especially repeatedly). If a bird plucks feathers long enough, there may be enough damage to the follicle that feathers will cease growing. If a bird has broken tail feathers, to help them grow in, put the tail into an appropriate sized envelope, which can be stapled to the remaining feathers, or taped in place, to prevent damage to blood feathers, so that hopefully they will grow in normally. If a young bird continues to break blood feathers on the wings, it may be necessary to splint the wings to the body until all of the blood feathers are grown out (this usually takes about 2-3 weeks).

Grooming

Grooming is a very necessary skill for avian veterinarians. I guarantee that more bad-will is generated by vets who do a poor job of trimming wing feathers than any other reason. It is vital that you learn how to safely and gently restrain pet birds for grooming, and that you learn how to properly trim the different kinds of birds. Make sure that you and your staff can restrain a macaw, mini-macaw or African grey so that you don't leave bruises on the bare skin of the face. Owners really resent that and it implies that you were rough with their bird (even if you weren't!)

I perform and recommend the type of wing clip where I trim each feather individually, all the way at the base (where it is a quill, termed calamus) with cat or bird claw trimmers. I start at the tip of the wing, with the last primary (12) and clip five feathers on each wing, being careful no to cut the overlying covert and to avoid cutting a blood feather. Primaries are numbered from medial to distal. After clipping, then test fly the bird, to make sure that it glides to the ground and does not gain horizontal or upward flight. If necessary, clip additional feathers. I do not like the type of clip where the primaries are cut in half at the level of the coverts. This leaves sharp quills that poke the bird in the ribs when the wings are folded at rest. May birds, especially Eclectus, Greys and cockatoos, will chew on those cut feather ends trying to soften them. This may actually predispose a bird to becoming a feather picker.

The Association of Avian Veterinarians offers a laminated wall-chart on proper wing trimming methods that is available for sale, and can be displayed in the exam room. You may contact the Publications Office, AAVPubs@aav.org for practice materials.

It is important that you learn the normals for the different species so that you will know when to intervene and correct abnormalities. Many times, Amazon parrots will develop cranial growth of the beak, leaving a kind of ridge near the tip. Flaking is normal for Amazons and conures, especially. But if a ridge develops, you can use a grinding tool to shape the beak back to normal. Some birds will grow an excessively long beak, and while it is true that this can be a sign of liver disease, often it just means that the bird is not chewing enough to naturally grind down the beak normally.

Always check the maxillary tomium (the cutting edge) of the rhinotheca to ensure that it is straight across. It often becomes irregular in the Jardine's parrots, and the abnormal pressure on the two sides of the upper beak (gnathotheca) will often lead to the beak curving to one side. To shape and straighten out the tomium, manipulate the upper beak INSIDE of the lower beak, which will give you a way to grind the beak easily, out of reach of the rhinotheca and tongue. As you grind the beak, you will see little white dots, which are the sensitive nerves found there. Stop grinding when you visualize the dots because if you keep going, you will reach the blood vessels embedded in the beak, as well. Many vets overlook examination of the tomium. The gnathotheca can really overgrow in macaws and may need to be shortened.

For trimming nails, I often use a grinding tool, then I shape the nails with a nail file made for acrylic nails. If I manage to hit the quick and the nail bleeds, I toss out the grinder head and put on a new one.

Hypothyroidism

Thyroid testing is controversial in birds. You should never base a diagnosis of hypothyroidism on one thyroid test, nor should you rule it out based on one test. Technically, you should always do a THS-stimulation test for diagnosis. Measurement of T4 is the most logical choice for diagnosing hypothyroidism. However, normal T4 levels are much lower than those in mammals, and you must make sure that the lab you are using is actually able to measure the level with their assay, and that the level is not below the detection limits of the test. Stress can significantly lower T4 concentrations. Hypothyroidism is very over-diagnosed (incorrectly) in pet birds.

Diet and Weight Loss Tips

For overweight birds that are not hypothyroid, reducing caloric intake will be necessary for weight loss. Offering Harrison's Bird Diet High-Protein pellets as a nutritional base is recommended. Consult the HBD website or call them for specific information on what to offer, and how much to offer, as well. For seed-eating birds, sprouting the seeds is often beneficial, as the process of sprouting metabolizes the fat in the seed, making the seed more nutritious and less fattening. Sprouted seed also begins to resemble vegetables as they sprout, and this may be one way to entice a stubborn bird to begin eating vegetables. It has been my experience that caloric restriction is usually not enough for the bird to reach its target weight. In almost all cases, it is very important for the owner to commit to providing the overweight bird with some sort of exercise program. It is not enough for the overweight bird to sit on a play-gym, the bird must be forced to flap its wings, walk on the floor (away from pet dogs, cats, ferrets, etc.) or climb up and down stairs or a wooden ladder designed for birds. To encourage an overweight bird to move around, the owner must usually interact with it, or another bird may also motivate a bird to exercise.

I have seen overweight budgies with hepatic lipidosis, overgrown beaks and nails, and having severe exercise intolerance, lose weight quickly by placing them on play-gyms, and having another budgie encourage play time with it. Playing, falling off the perch, and climbing back up to the gym perch is a great exercise for little birds. I have seen some return to a normal weight, no longer huff and puff and cease having overgrown beaks and nails from the addition of exercise to the bird's life, with very little modification to the diet.

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Bloody Tears in African Birds

When you catch up an African grey parrot (either sub-species) make sure that you observe the eyes very carefully. Many greys with sub-clinical respiratory infections or sinusitis will have bloody tears, either unilaterally or bilaterally. I have also rarely seen this occur in African Poicephalus. Never ignore this sign. If the owner will allow you to work up the bird, then do so. Often, on the CBC, you may see a shift from heterophils to lymphocytes, indicating chronicity of infection, and you may see an increase in basophils, which also indicates a chronic problem. This is usually a bacterial infection that usually responds to enrofloxacin or the doxycycline that is the weekly injectable (from Europe).

Hypocalcemia in African Grey Parrots

Regarding calcium levels, especially in African grey parrots: don't rule out hypocalcemia problems based on one blood test showing a calcium level in the normal range. Calcium levels dip and rise according to circadian rhythm. If a grey is feather picking, or is clumsy, or has had a seizure, try treating with calcium in the drinking water, supplementing with TumsTM (calcium carbonate) and having the owner offer more high calcium food (cottage cheese, cheese, yogurt and almonds). Running an ionized calcium level may be diagnostic, however reference ranges for the different species are not currently worked out.

Also, make sure that the uropygial gland is functioning properly (test this by gently rolling the wick through your fingers, and then checking your fingers for a greasy spot). If no secretion is seen, then gently massage the gland (bilobed, heart-shaped) and then check the wick again. The normal uropygial gland produces vitamin D3 precursors that are preened onto the feathers. Upon exposure to ultraviolet light (particularly UVB), the precursors will be converted to active D3, which will then be ingested when the bird preens again. For activation, a bird needs exposure to natural, unfiltered sunlight (not through glass or plastic) or exposure to a full-spectrum fluorescent light (changed regularly and within 18 inches of the cage). While formulated diets should contain adequate amounts of vitamin D3, any bird, especially greys, with calcium problems should always have the uropygial gland evaluated, and it should be recommended that they receive some sunlight or full-spectrum artificial lighting. Some species of psittacines do not possess an uropygial gland (including Amazon parrots, hyacinth macaws) and emus, ostriches, cassowaries, bustards, frogmouths, many pigeons and woodpeckers do not possess one, either.

Visual Sexing African Birds

Most African parrots can be easily sexed after they have molted once. (See Appendix for photographs) While it is not advisable to determine the sex visually for breeder pairs, identifying the sex of a pet for an owner (without DNA sexing or surgical sexing) will make owners happy. African grey parrots (Psittacus erithacus erithacus) are usually easy to sex. Males have a solid red tail on the underside (the secondary retrices), while those of the hen are tipped in silver. While examining proven pairs, this has proven to be accurate in over 95% of the pairs. Also, with male greys, the underside of the wings is very dark, while those of the hen are lighter grey. This only holds true for the nominate species, and not for the Timneh grey (P. e. timneh).

Among Meyer's parrots (Poicephalus meyeri), males have bars (striping) on the blue chest feathers, while hens have a more solid blue. Senegals (P. senegalus) are easy to sex. Tip the bird over, and examine the V of feathers behind the vent on the tail. In males, these feathers are bright yellow, and in hens, they are green. Jardine's (P. gulielmi) hens have more orange on the crown, but since males also have orange feathers, this is more subjective. Red-bellied Poicephalus (P. rufiventris) are dimorphic. Male has red breast (actually more orange), and the female has a brownish lower breast and abdomen. It is possible to make an educated guess regarding the sex of the Cape parrot (P. robustus). All young leave the nest with forehead and part of the crown orange, which is gradually lost by 6-7 months of age. At about 9 months, the hen will regain the orange, but the head will remain silver in males. Males also have a relatively larger beak.

Uropygial Gland

The uropygial gland secretion helps to keep the feathers, scales and beak supple and waterproof. It is also important in preventing the growth of microorganisms. Examination of this gland (when present) should be a part of every avian examination. The uropygial gland is principle cutaneous gland of birds. In the domestic fowl, the gland is drained by a pair of ducts, one duct for each lobe, each duct opening through a single narrow, median, nipple-like papilla. Other species have up to eighteen orifices. The papilla is usually bare, except for a tuft of down feathers at the tip in most species, and this tuft is usually called the uropygial wick. The secretion of the gland is a lipoid sebaceous material, holocrine in type, and consisting of sudanophilic secretory granules and fragments of cells.

Dimethyl Glycine

There is a nutritional supplement, DMG, which can prove helpful in many cases of avian disease. It was studied extensively in the former USSR, as one effect is to remove lactic acid from muscle tissue. This was thought to be valuable for athletes. It has many benefits for the avian patient. It increases the threshold for seizures, which may be one way of treating African Greys with refractory seizures. It provides support to the central nervous system. It may also have other benefits that we do not yet understand, so I use it in cases of PDD, renal disease and for non-specific disease when antibiotics are not warranted, yet the owner wants you to "do something" for their bird.

Proventricular Dilatation Disease

PDD, a viral disease, is becoming a very common disease among psittacines of all ages, sizes and species. While it is known for causing weight loss, GI signs and birds passing whole seeds in the droppings, it is primarily a neurological disease, affecting the splanchnic nerves to the GIT. It can also present as an ascending paresis/paralysis. Some birds with PDD are ataxic, as well as thin. Some regurgitate, some do not. Some have whole seeds in the droppings, others do not, but most have malodorous droppings from maldigestion. It is a disease of many presentations. Biopsy of the crop, making sure to include a large blood vessel, can be diagnostic, but a negative biopsy does not rule out PDD. Treatment with CelebrexTM, dosed at 10 mg/kg PO q24 hr. may cause a reduction of clinical signs, but will not eradicate the virus from the bird's system and may be useful for treating the pet bird diagnosed with PDD.

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Gram's Stain Interpretation

Gram's stain results should not be relied upon solely to make a diagnosis of any disease or condition in an avian patient. While the Gram's stain can often be a valuable diagnostic screening test in both well and ill birds, the Gram's stain results must be interpreted in light of the history, age and condition of the bird, the bird's diet, culture results (if applicable), CBC results (especially the WBC and differential), and other diagnostic tests.

Where To Procure Gram's Stains From:

If a bird is showing upper GI signs, such as regurgitation or crop stasis, it may be valuable to perform a Gram's stain of the choanal slit and crop, as well as a fecal or cloacal Gram's stain. Fresh regurgitated material is also acceptable for Gram's staining and cytology. If a bird is showing upper respiratory signs, or if there are lesions present in the choanal slit, infundibular cleft or oropharynx, a Gram's stain of the choanal slit or lesions should be performed. Cytology of the area may also be diagnostic. If there is discharge present or excessive mucus in the choanal slit or oropharynx, consider performing a Gram's stain as well as cytology of the area. If lesions in the oropharynx are suspicious for Trichomonas, it is best to remove a lesion and swab the tissue underneath, or swab epithelium to cause a small amount of excoriation and bleeding, to have the best chance of diagnosing this disease.

Choanal Gram's Stain and Cytology Interpretation

Greater than 10% Gram-negative bacteria may be abnormal. Normal flora should consist of predominantly Gram-positive rods and cocci (approx. 90%.) Gram-negative spirochetes are abnormal and may cause pathology. Budding yeast or pseudohyphae may indicate an infection with Candida albicans. Non-budding yeast or a small percentage of budding yeast may be considered normal flora and may occur from additives to hand-feeding formulas. Rarely, very large Gram positive bacteria (megabacteria) may be found in a choanal Gram's stain. Gram negative rods may not always indicate disease, and may result from contaminated water, unwashed produce or bacteria that are just "passing through."

In addition to the observation of blunted choanal papillae as a clinical sign, sheets of epithelial cells on cytology or Gram's stain may indicate hypovitaminosis A, as will squamous metaplasia. Budding yeast and/or pseudohyphae from the choana, oropharynx or crop may also indicate hypovitaminosis A and secondary candidiasis. Inflammatory cells may indicate infection or trauma (from feeding syringes, hot formula, etc.) Trichomonads may be found intracellularly in psittacines, which may make diagnosis difficult.

Crop Gram's Staining and Cytology

With regurgitating birds or those with crop stasis, it may be valuable to gently swab the crop for Gram's staining and/or cytology. Normal flora should consist primarily of Gram-positive rods and cocci (approx. 90%.) Greater than 10% Gram-negative rods may indicate infection. Very large, Gram-positive rods may be megabacteria, Actinomyces virginiasus. Candida or trichomonads may be identified in crop swabs or regurgitated material. If a large number of similar Gram negative rods are seen, these are indicative of bacterial ingluvitis. Cytology from the crop may show inflammatory cells, bacteria within cells, epithelial cells, trichomonads, pseudohyphae, Candida or squamous metaplasia.

Cloacal or Fecal Gram's Stain Interpretation

Less than 20 bacteria per 1000-x field are considered a reduced number of bacteria in adult psittacine birds. Gram-positive rods and cocci should make up at least 90% of the total bacterial population. Generally, Gram-negative rods should account for less than 10%. However, some Gram-negative rods can be found as normal flora in some species of psittacines (for example, some strains of E. coli can be considered normal in cockatoos). If the Gram's stain shows an increased amount of abnormal bacteria, it is recommended that bacterial culture and sensitivity be performed to identify potential pathogens. The presence of budding yeast may be abnormal (check to see if the diet contains active brewer's yeast, for example). Neonates may normally have a higher percentage of Gram-negative rods. Passerine birds normally have low numbers of bacteria.

Gram-positive rods with spores present may indicate infection with Clostridium sp. and related toxins. An anaerobic culture may help in making a diagnosis in these cases. If a choanal Gram's stain has been performed in conjunction with a cloacal Gram's stain, it is possible to compare the relative amounts of bacteria and yeast between the two locations. Increased levels of Gram-negative rods in the choana compared to the cloaca may indicate an upper respiratory or upper GI bacterial infection. Increased levels of Gram-negative rods in the cloaca, when compared to the choana, may indicate bacterial enteritis. C+S is helpful in these cases, as is evaluation of the WBC. Isolation of a bacterial organism in an almost pure culture (approximately 80% of the colonies present) may indicate that the bacteria is a component of a disease process.

Black stools are often mistaken for melena, but usually indicate a bird that has not eaten for at least 24 hours, and is passing biliverdin. This stool might show decreased levels of bacteria. A bird passing black droppings should be gavage fed for a period of time and it is suggested that a Gram's stain of the cloaca should be performed again once the bird is passing more normal droppings.

Mycobacterium cannot be diagnosed on a Gram's stain. An acid-fast stain of the stool may test positive when lesions are associated with the GI tract. However, false-negatives can occur when lesions are found in the lungs or are walled-off as granulomas. Avian TB, due to Mycobacterium sp., is most commonly found in Grey-cheeked parakeets, Red-hooded siskins, geriatric macaws or Amazons, and in birds with access to the ground. A newer DNA PCR for Mycobacterium is available and can be helpful in procuring a diagnosis.

A Gram's stain of the feces in a bird with true diarrhea may be helpful in diagnosing the cause. Warm saline wet-mounts may help by demonstrating motile bacteria or Giardia. Bacterial C+S may be helpful, as may the WBC and differential.

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Avian Plasma Proteins

The accurate interpretation of avian plasma proteins is very important as a diagnostic tool in avian medicine. Understanding the uses of avian protein electrophoresis will enhance your practice of avian medicine and will help you hone your diagnostic skills. Protein electrophoresis is a practical and useful test in psittacines. Dramatic changes in protein fractions are evident in several diseases, and may help in procuring a diagnosis when other tests are equivocal. Serial electrophoresis is valuable in monitoring response to therapy, as well. We recommend the use of protein electrophoresis as a diagnostic air in evaluation of the health status of psittacine birds.

At the lab that I am associated with, determination of total plasma proteins is performed by the biuret methodology, which is also known as a colorimetric test. This is regarded as being the most accurate way to measure total avian proteins. Avian total proteins consist of albumin and globulins. All plasma proteins, except immunoglobulins, are manufactured in the liver. Albumin is the largest single fraction in the healthy patient. It serves as the major reservoir of protein, it is the main contributor of colloidal osmotic pressure, it is involved in acid-base balance, and it acts as a transport carrier for small molecules such as vitamins, minerals, hormones and fatty acids. Increases in albumin concentration are associated with dehydration or hemoconcentration. Decreases occur with decreased synthesis (chronic liver disease, dietary protein deficiency or chronic inflammation), increased loss (renal disease, intestinal parasitism or gastrointestinal disease), or sequestration (decreased oncotic pressure or increased hydrostatic pressure). Decreases can also occur with blood loss, severe inanition and chronic infection.

Pre-albumin is a separate and distinct fraction that precedes albumin in electrophoresis. The only known function of this fraction is the transportation of thyroid hormones. Pre-albumin has also been identified in the sera of laying hens, embryonic sera and neonatal sera.

The globulins are composed of three fractions, designated alpha, beta and gamma. In birds, one or two subfractions of the alpha globulin are identified and there is a single fraction for each beta and gamma globulins.

Alpha globulins are a group of proteins manufactured almost entirely by the liver. These proteins usually elevate during the acute phase of inflammatory disease, and therefore are helpful in the diagnosis and monitoring of many infectious diseases and other causes of chronic inflammation. Alpha globulins increase with acute nephritis, severe active hepatitis, active, usually systemic inflammation, malnutrition and in nephrotic syndromes. Decreases can occur with hepatic insufficiency, severe inanition, blood loss and protein-losing GI diseases.

Beta globulins include carrier proteins, complement, ferritin, C-reactive protein, lipoproteins and fibrinogen, and many are also acute phase proteins. In mammals, the beta-2 globulins contain much of the immunoglobulins IgM and IgA, in addition to IgG. Increases in beta globulins occur with acute inflammation, inflammatory liver disease, malnutrition, lipemia artifact, systemic mycotic disease, protein losing enteropathies and the nephrotic syndrome. Decreases occur with hepatic insufficiency, severe inanition, blood loss and protein-losing GI diseases.

Unlike those found in mammals, in birds, the gamma fraction contains most of the immunoproteins, including IgM, IgA, IgE and IgG. Gamma globulins usually elevate with ongoing antigenic stimulation, usually from infectious agents. Broad increases (polyclonal gammopathies) in gamma globulins occur with acute or chronic inflammation, infection, chronic hepatitis and immune mediated disorders. Sharp increases (monoclonal gammopathies) occur with tumors of the reticuloendothelial system and plasma cell dyscrasias. Deficiencies can occur with immunodeficiency states, blood loss, overwhelming infection, protein-losing GI diseases and severe inanition. The half-life of gamma globulins in birds is relatively short. In some species, some nonimmunoglobulin proteins, including transferrin, complement and fibrinogen, are found within the gamma globulins fraction.

Panhypoproteinemia, which occurs when all fractions on the electrophoresis are decreased, occurs with severe inanition or malnutrition, severe hepatic insufficiency, overwhelming infection, protein-losing states (especially GI or kidney), blood loss or third space loss (blood loss into the body cavity or effusion into the body cavity).

There is wide species variation in the accuracy of albumin levels measured by routine wet or dry biochemical methods used on an avian chemistry panel. While generally lower, the albumin levels tend to parallel the results found on protein electrophoresis. Because of this, for the most accurate measurement of albumin, always rely on the electrophoretic results as the most accurate.

Serum proteins include all plasma proteins except the coagulation proteins, principally fibrinogen, which are eliminated by clot separation. In most cases, the difference between avian plasma and avian serum protein concentration is small, and the electrophoretic patterns are not noticeably different between plasma and serum. Since lithium heparinized blood samples are preferred for avian chemistry analysis, this plasma can also be used for protein electrophoresis, although serum can also be used.

Protein electrophoresis has been demonstrated to be a very effective diagnostic tool in avian medicine. Once the total protein level has been determined by the biuret method, the electrophoretic fractions are calculated based on the total protein level.

There are some instances when interpretation of the electrophoretic pattern may be difficult to interpret. Avian neonates and juveniles likely show age-related differences in serum proteins, but this has not been fully investigated. Thus, caution is advised when interpreting electrophoretic patterns in young birds. If possible, age-matched samples from a healthy juvenile of the same species should be run for comparison. In some psittacine species, there may be a monoclonal spike in the beta fraction during periods of egg-laying, when there is a transport of egg proteins to the ovary. This increase in an egg-laying hen has been attributed to transferrin, and to increases in estrogen-induced yolk protein precursors, vitellogenin and lipoproteins. In raptors, there are normal variations that differ from those found in psittacines.

A unique electrophoretic pattern has been reported for acute chlamydiosis. Expect to see a moderate to sever hypoalbuminemia, mild to moderate elevation in beta globulins, and moderate to sever hypergammaglobulinemia. In chronic chlamydiosis, there may be no changes in the inflammatory proteins, or only a mild hyperbetaglobulinemia. In mycotic diseases, especially aspergillosis, expect an increase in the beta fraction during the acute phase. There may be beta or gamma elevations during the chronic phase of aspergillosis. Eventually, chronically infected birds may lose the inflammatory protein response altogether, becoming hypoproteinemic. Mycobacterial infections may show increases in either beta or gamma globulins. Sarcocystis infections usually show an elevation in both beta and gamma fractions. Birds with hepatitis or nephritis often show a decrease in albumin and increases in beta globulins. Gross hemolysis may show a severely restricted (usually gamma) spike composed of hemoproteins that can be misinterpreted.

Avian protein electrophoresis can provide important information that can help the practitioner in diagnosing avian diseases. It is also very helpful in assessing therapy and monitoring progress. Protein electrophoresis is a versatile and simple test that can greatly aid the avian practitioner in avian diagnosis and therapeutic management. The use of this tool in avian diagnostics has both prognostic and therapeutic value.

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Exotic Newcastle's Disease

There has been an outbreak of Exotic Newcastle's Disease virus in Southern California recently. A press release was sent out on October 3, 2002 to notify the public about this very serious outbreak. Because poultry in this country are very susceptible to Exotic Newcastle's Disease, it is important that the public be made aware of how to potentially identify this disease, to prevent its spread. This virus has the potential to cause devastating losses in commercial poultry facilities.

Newcastle's Disease is caused by a paramyxovirus, called PMV-1, one of nine serotypes of this virus identified. There are four large groups based on how dangerous they are and the type of disease that they cause in chickens. PMV-1 can infect a broad range of animals, including many species of mammals (including humans) and most species of birds.

Two strains of Newcastle's Disease virus (NDV) are common in domestic fowl in the United States, called lentogenic and mesogenic. There are two foreign strains, called velogenic strains that do not naturally occur in this country, VVND (velogenic viscerotropic Newcastle's Disease) and VNND (velogenic neurotropic Newcastle's Disease). To prevent the introduction of VVND and VNND, as well as avian influenza, the USDA restricted the importation of birds in the early 1970's, setting up quarantine stations to monitor imported birds for these viruses. Birds being imported to the United States must be quarantined in a USDA-controlled facility where they will be monitored and tested for PMV-1. Most recently, VVND and VNND have been classified as Exotic Newcastle's Disease.

In parrots, the signs may vary greatly. Some birds may remain completely normal while infected, others may develop the disease and recover, or they may die acutely with no premonitory signs, or they may die after a long illness. Infected birds can have a combination of mild to severe signs involving the respiratory system, gastrointestinal system or nervous system. Birds with nervous system signs that are severe usually results in death.

Signs in infected psittacine birds may include depression, anorexia, eye and nasal discharge, conjunctivitis, sneezing, coughing, difficulty breathing, diarrhea, unsteadiness, abnormal positioning of the head, convulsions, circling, tremors and paralysis of the legs and wings. Neurologic signs may intensify when infected birds are excited or disturbed. It is thought that lovebirds, Amazon parrots, Psittaculidae, Plum-headed parakeets and Eclectus are very susceptible. Some cockatoos are more susceptible than others. Cockatiels are moderately susceptible. Budgies appear to be relatively resistant to natural infection.

VVND is the most virulent form of PMV 1 affecting poultry. Smuggling of birds is considered the only route by which VVND virus could enter the United States. However, once here, it can spread to any susceptible bird. Poultry that are infected usually die rather quickly. Among exposed poultry, a very high majority will succumb to the virus and die. This could have very serious repercussions for commercial poultry facilities, as they may sustain extremely high losses among their birds.

The incubation period can vary from three to 28 days, depending on the strain, the quantity of virus and susceptibility of the host bird. In psittacines, the incubation period ranges from five to 16 days. In chickens, the incubation period averages about five days.

The disease is transmitted when the virus is shed from an infected bird (in all secretions, but primarily in respiratory secretions) and a susceptible bird either ingests or inhales virus particles. Aerosolized fecal dust and contaminated bedding are considered potential sources for infection. NDV is very stable outside of an infected bird, so insects, rodents and humans can disseminate the virus to other susceptible birds. The virus has also been demonstrated to be transmitted from chicken to chicken by feather mites. Free-ranging wild birds should be of minimal importance in spreading the virus and migratory birds appear to have no impact on the spread of the virus. Infected birds may appear normal and shed the virus in their feces.

VVND should not be a concern for professional psittacine breeders and pet owners who avoid birds that have entered this country illegally.

In this outbreak which began in Southern California, the birds so far identified to be infected with Exotic Newcastle's Disease are all poultry species, according to Dr. Prassad, an avian veterinarian with the Exotic Newcastle's Disease Task Force in California. The disease has already spread to several other states.

If you will be around birds suspected of being infected with NDV, you should shower, change clothes, remove shoes and disinfect any items that were also exposed, prior to handling your own birds. However, prevention is best. Try to avoid any sick birds to prevent the possible spread of the virus. Sound hygiene is necessary to prevent the spread of the virus. Insects and rodents must also be controlled to prevent spread of the virus.

Since NDV is stable in the environment, the virus is resistant to many common disinfectants. The virus has been found to remain active in moist soil for 22 days, on feathers at 20 degrees C for 123 days and in lake water for 19 days. The virus can be inactivated by extremes in pH (less than 2, greater than 11), high temperatures (56 degrees C), sunlight, detergents, chloramines (1%), bleach, phenols and 2% formalin.

PMV 1 can cause disease in humans. Healthy people who are exposed may develop mild signs of infection (malaise) or conjunctivitis. Infected people will shed the virus in secretions for a period of time after exposure, and they will be technically able to pass the virus to other humans or birds, but this is unlikely, as practicing good hygiene should prevent this. The risk of human disease is confined primarily to poultry workers however, any human exposed could develop signs of infection.

If you are concerned about NDV or suspect that you might have, or have seen an infected bird, in California, contact California Department of Food and Agriculture, 916-952-1595. E-mail: cdfapublicaffairs@cdfa.ca.gov. If you are concerned that you might have contracted this virus from being around infected birds, contact your own physician, hospital epidemiologist physician or your local health department.

For in-depth information on PMV-1, consult Avian Viruses, Function and Control, by Branson W. Ritchie, DVM, PhD, 1995, Wingers Publishing Co, Lake Worth, FL. Much of the information presented here is from this valuable resource.

Commercial poultry facilities in the US vaccinate their birds against lentogenic and mesogenic NDV. However, they are not vaccinated against Exotic Newcastle's Disease, VVND and VNND. Prevention of these diseases is accomplished by strict control of birds imported into this country. Psittacine birds are not vaccinated against lentogenic and mesogenic NDV, as some vaccines contain modified live virus and could possibly cause the disease. This is because the vaccine was not developed for psittacine birds. In general, modified live vaccines and killed virus vaccines should not cause disease in the species that they were developed to protect. Since Exotic NDV is a reportable and notifiable disease, government regulations may restrict vaccination of avian species other than commercial fowl. Vaccination against VVND and VNND is performed in some other countries.

PMV-1 can be diagnosed in both live birds and dead specimens. Most commonly, in live birds, swabs of the pharyngeal area and/or cloaca (or feces) maybe tested at appropriate diagnostic laboratories, using virus isolation. These swabs are then tested for the presence of virus by attempting to grow PMV-1. The feces may also be examined under an electron microscope to look for PMV-1 virus particles. Blood may be drawn to test for an increase in antibody titer (which requires paired serum samples drawn two weeks apart). These tests, called serology, are less effective than virus isolation in diagnosing infections. In live birds, swabs of the pharynx, cloaca or feces, to attempt virus isolation, are the tests used to screen birds in quarantine and those suspected of being infected. Post-mortem samples for virus isolation should include trachea, lung, spleen, liver and brain.

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West Nile Virus

WNV is one of a group of viruses known as flaviviruses. It is believed that the virus was introduced to the United States in the early summer of 1999, or perhaps earlier. The virus is commonly found in Africa, West Asia, Eastern Europe and the Middle East. The virus has been able to establish itself in the US and is transmitted primarily by the bite of an infected mosquito (usually the Culex species).

When a mosquito bites an infected bird or mammal, the virus then is taken into the mosquito where the virus will incubate for 10-14 days. If an infected mosquito then bites a susceptible person or animal, the virus will then be transmitted to that individual. Not every person or animal bitten by an infected mosquito will come down with WNV. People and animals with a strong immune system may be able to effectively eliminate the virus. The disease seems most devastating to horses, crows and jays. At this time, over 110 species of birds are known to have been infected with WNV. Although birds, especially crows and jays, infected with WNV can die or become very ill, it appears that most other birds do survive.

Signs of infection

In birds, there may be no clinical signs at all. Many birds will be infected and show no outward signs. While psittacine and passerine birds are susceptible to WNV, it appears that they are often resistant to the serious effects of this disease. Pet birds infected with WNV may mount an effective immune response and fight off the infection without becoming very ill. However, birds already infected with psittacosis, viruses such as Psittacine Beak and Feather Disease (PBFD) or those with debilitating illness, such as cancer, may be more likely to succumb to WNV.

Several tests are currently available for ante-mortem diagnosis of WNV. A serum neutralization titer can be performed, measuring IgG. As with other titers, paired titers drawn two weeks apart are most diagnostic. A DNA PCR can be performed on blood, CSF or tissue (brain, spinal cord, kidney). Virus isolation can also be performed on brain, spinal cord or kidney tissue.

A parrot seriously ill from WNV is likely to become ill very quickly, and will either be found down on the floor of the cage or it might be discovered dead with few or no signs ahead of time. Birds with viral infections often have low white blood cell counts (WBC). An infected bird might have neurological signs, such as tremors, seizures, abnormal posture, neck flexion, muscle weakness, stupor, disorientation or paralysis.

Considering the number of psittacine birds exposed to WNV, the number of them diagnosed with WNV is very low. A few cockatiels, cockatoos, one macaw and one conure have been diagnosed post-mortem as reported in the literature. I'm sure other psittacines have succumbed to this infection, but they may not have been diagnosed. But considering the number of psittacines being raised outdoors in the Southeastern United States, no large die-offs have occurred, as have in crows and jays.

Precautions

It is vital that humans and birds be protected from mosquito bites. This means that you should be diligent in preventing mosquitoes from entering your home. Make sure that window screens are in good shape and properly seal windows. Enter and exit your home quickly to prevent mosquitoes from sneaking indoors. Some perfumes and fragrances attract mosquitoes so be judicious in your use of these items. Wear long-sleeved shirts, long pants, socks and a hat when outdoors during times mosquitoes are most active (dawn, dusk and early evening). If possible, stay indoors during peak mosquito times. Wear insect repellant containing DEET. Clothing may also be treated with DEET or permethrins, as mosquitoes can bite through thin clothing.

Make sure that you have no standing water in your yard. Turn over buckets, check outdoor flower pots, and be diligent in removing standing water. You can purchase disks that can be placed in water outside that will kill mosquito larvae (check your local hardware store). Or you can purchase mosquito-larvae-eating fish called gambusia that can be placed in ponds.

Birds housed outdoors should be protected from mosquitoes by placing mosquito netting around cages, if possible. Birds living outdoors can be protected from mosquitoes by the use of a product that is safe for birds that reduces the mosquito population. SonicWeb is such a product. It attracts biting insects and then traps them onto the unit.

Foggers utilize insecticides that are not very effective. Do not apply insect repellants directly on to birds or their cages. Mosquitoes often have a difficult time biting birds, since they have feathers and scales that offer some protection. Birds with bare skin on the face or around the eyes are more likely to be bitten in these areas. Please note that according to the CDC, vitamin B and "ultrasonic" devices are not effective in preventing mosquito bites.

Humans are definitely susceptible to this viral infection. However, you cannot catch the disease by handling dead or ill birds. Even so, it is wise to wear gloves and double bag any dead birds found on your property. Because the disease is transmitted by mosquito bites, an infected bird should not be a risk for human infection, nor will an infected human transmit the virus to a pet bird.

Many humans will likely be sub-clinically infected, meaning that while they will have the virus in their systems for a period of time, they will not become very ill from WNV. They will recover completely and then be immune to the virus, probably for life. One report recently stated that it is estimated that over 300,000 humans have now been infected with WNV. The elderly and those people with problems with their immune systems may become very ill from WNV and may even die. Prevention is the key.

It appears that the WNV can also be transmitted through blood transfusions or organ transplantation, if the donor was actively infected with the virus. Tests are currently underway to screen blood collected for transfusions to ensure the safety of our blood supply.

Access the Centers for Disease Control website.

For specific information regarding the disease in humans, contact your physician, hospital epidemiologist or local health department.

There is an approved vaccine for horses. This vaccine has proven to be very effective in preventing WNV in horses. The vaccine should be administered prior to exposure to the virus. The equine vaccine has been tested in limited trials in psittacines. However, results have shown that, while the vaccine proved safe, it did not stimulate vaccinated birds to develop a protective titer. This means that the killed virus vaccine did not stimulate the immune system enough for the birds to produce a protective titer. For falcons, eagles, hawks, kestrels and other raptors that appear very susceptible to the virus, the vaccine can be used in an attempt to save valuable or rare birds, however the vaccine should not be routinely used on pet birds. Because the vaccine contains killed virus particles, it cannot cause disease in vaccinated animals.

Several avian specialists, university researchers, members of the CDC, zoo veterinarians and industry leaders are working together in an attempt to develop a safe and effective vaccine for psittacines and other avian species. But at this time, no vaccine is licensed for use in any bird species. There is also no vaccine approved for humans in the US at this point.

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Conclusions

Well, those are the most important things that I wanted you to know. As my parting thought, I wanted to make a suggestion. In addition to attending continuing education and purchasing textbooks on birds, do me a favor and buy Birds: Their Structure and Function, by A. S. King and J. McLelland and actually read it. I did for my board exams, but I find myself referring to it all the time now. It is packed with all sorts of interesting and useful information about birds; how their eyes can see light in the ultraviolet range, the way feathers grow and how molting occurs and how eggs are formed. It's really neat stuff and goes to show just how unique birds are, and why we love them so much.

This presentation is a "kitchen sink" grouping of information gleaned from over 20 years of clinical private practice in avian medicine. Some is information that you won't find in standard textbooks, other information is practical, based on observations of birds, both in health and illness. Grooming is demonstrated, as this procedure can literally make or break you as an avian veterinarian. How to perform a thorough physical examination is demonstrated, including the often overlooked infundibular cleft, uropygial gland and even the band information and number. Odd and unusual clinical presentations such as bloody tears in African greys, Amazon sinusitis and Eclectus toe-tapping are discussed. Common techniques including, Gram's staining, venipuncture and nasal flushing are demonstrated. Effective medications, often different from those used in canine and feline practice, are discussed, along with sources for procuring them. This information and these skills should make you a better avian practitioner.

Suggested Reading

King AS, McLelland J. Birds: their structure and function. .Bailliere Tindall, London, England, 1984.
Carpenter JW, Mashima TY, Rupiper DJ. Exotic Animal Formulary. 2nd Edition, WB Saunders Co, Philadelphia, PA, 2001.
Rupley AE, Manual of avian practice. WB Saunders Co, Philadelphia, PA, 1997.
Sakas PS, Avian medicine: a guide for practitioners, 2nd Edition, AAHA Press, Lakewood, Co, 2002.

Cadeusus
Copyright 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
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