Aviary disease

Aviculture is my passion. Approximately 85% of my avian practice is devoted to avicultural medicine, and some of my professional breeders produce over 500 baby birds every year. Of course, some of my avicultural clients are stewards for just a few pairs of breeders. Some breed only passerines (finches and canaries), some breed the smaller birds (budgies, lovebirds and cockatiels), and some have varied collections of different psittacines (although I encourage specialization). Personally, my husband and I also maintain a collection of approximately 50 pairs of parrots. So, I feel that I have an excellent perspective when it comes to aviary management and disease.

Before I jump in and begin describing the most common diseases that I see in aviaries, let me preface my remarks by explaining that most diseases seen in aviaries are the result of poor management techniques, inadequate sanitation or diet, improper quarantine, lack of appropriate veterinary care, improper housing or nesting equipment, improper water or food delivery systems, incompatible birds housed in close proximity or other problems. It is not enough to just diagnose a disease in a flock bird, but it is vital to determine the underlying management problem that precipitated the disease entity.

And being a Trekker, I find Mr. Spock's words of wisdom he spoke as he was dying in Star Trek, "The needs of the many take precidence over the needs of the one." This holds true for the practice of avicultural medicine, as well. One must always ensure the health and safety of the flock over that of the individual bird. That's not to say that if a bird becomes ill, it should immediately be culled, but if it has an incurable, contagious disease that is of threat to the flock, then careful consideration should be given as to the disposition of the bird.

The best way to diagnose problems (and prevent them, as well) in an aviary is by actually having an avicultural veterinarian perform a thorough examination of the entire facility periodically. This means evaluating the areas of the aviary, including the cages and nest boxes, including their placement, traffic flow, species locations, food storage facility, nursery, incubation room, clean-up areas, food and water delivery systems including placement, water quality, ventilation, lighting, sanitation and vermin control. Prior to catching up each and every bird for examination and appropriate lab testing, the aviary records must be examined. Breeding pairs with problem babies, decreased hatchability, decreased fertility, or other problems should be noted, so that when the birds are examined, these problem pairs will receive special consideration in diagnosing their reproductive problems.

In many aviaries, especially the smaller ones, sub-clinical bacterial infection is the most commonly diagnosed disease. I attribute this to the fact that many facilities have water delivery systems that encourage bacterial growth. Water bowls are the worst choice of a method for watering birds. We all know that birds dunk food in their water, making a potent swill-soup that harbor and grow bacteria, possibly worm eggs, protozoa and algae, especially when birds pass droppings that end up in the water bowl, as well. When birds ingest the microbe-laden water, they can build up disease quite easily. Most often, birds with sub-clinical bacterial infections are not obviously ill, and you certainly won't be able to tell just by observing them in their flight cages. But, when the birds are caught up for examination, there may be obvious signs of illness. The choana may be swollen or red, the choanal papillae may be blunted, there may be discharge present in the choana or nares, there may be plaques or white, ropy mucus in the oropharynx, the bird may be wheezy, there may be signs of sinusitis, the cloacal mucosa may be reddened, the bird may be thin, or there may be other subtle signs. Of course, these signs are not specific for bacterial infection, so it is important that the avicultural veterinarian perform diagnostic tests to ascertain exactly what is going on.

I routinely recommend running a complete blood count (CBC) and a culture (both bacterial and fungal) from the abnormal area of an aviary bird, to diagnose exactly what organisms are involved, and which are the most effective antibiotics to treat the infections. Gram's stains are useful as a screening test, but they should never be used as a sole diagnostic tool. Random fecal culturing (without catching up the bird and performing a complete physical exam) is also not an effective method of diagnosing problems, as potentially pathogenic bacteria may be "just passing through" the gastro-intestinal tract of a bird and may not be causing problems at all. Without performing a physical exam, and a CBC, it is possible to diagnose a problem where one does not really exist, which may result in a bird (or group of them) being medicated with antibiotics unnecessarily. If the physical exam is normal, the white blood cell count (WBC) of the bird is also normal, but a potentially dangerous bacteria is cultured, then it may be worth waiting, treating with lactobacillus and acidophilus (good bacteria), and then reculturing the bird a short time later, rather than treating a bird with antibiotics unnecessarily.

1. Bacterial infections are much easier to prevent than treat. Using a watering system may be the best way to prevent low-grade bacterial infections in flocks. Water bottles are often a good option, and there are several other water delivery systems available commercially. Just make sure the lines are easy to periodically disinfect.

2. Even just a few years ago, the top disease that I would have voted for the number one position is malnutrition. However, commercial breeders have paid close attention to the nutritional requirements of their birds, and I would venture to say that if my clients are representative of breeders around the country, then they are, for the most part, doing an excellent job providing a balanced, nutritional diet for their breeders (based on the current knowledge that we have on psittacine nutrition at this time). Many smaller breeders also are doing an excellent job, because, by having fewer birds to feed, they may have more time to offer fresh fare on a regular basis. I don't think that there is a bird owner out there today who hasn't researched, to some extent, what diet to feed their birds. However, just because a breeder offers a balanced, nutritional diet, there is no guarantee that the birds will consume it. Birds fed a major commercially prepared extruded pelleted diet as the primary basis should not be suffering from any major deficiencies, imbalances or overdosages. However, it must be remembered that nutritional research is on-going, and not every commercial diet is appropriate for every species. And I have written it before, and I will continue to repeat this sage advice until every literate bird owner has heard the news. The diet of a bird should never be changed until the bird has had a physical exam and check-up, and been given a clean bill of health. If a bird is harboring subclinical disease, the stress of changing the diet (especially from seeds to pellets) may precipitate a health crisis. Some birds will not eat a new diet, and may actually begin to starve to death, and if a breeder is not closely monitoring birds during the change, some losses may actually occur. I strongly recommend that you discuss the diet you are feeding your breeder and pet birds with an experienced avian veterinarian.

3. Polyomavirus is still prevalent on the avicultural scene, although it rears it's ugly head most often in the nursery, and not in the established, closed aviary. Currently, there is quite a bit of controversy surrounding this virus. Since accurate DNA PCR technology is now commercially available, testing is an excellent way to control the introduction of this virus into the aviary. There are currently questions concerning which species of birds are considered latent carriers of this virus (latent means that the bird is infected for life and periodically sheds the virus, potentially infecting other birds), and which birds, if infected, will only have the virus for a specific period of time, then no longer shed the virus, nor be infective for other birds. Some researchers feel that the budgerigar is the only natural latent carrier. However, other researchers feel that non-budgerigar species of psittacines concurrently infected with another immunosuppressive disease, such as Psittacine Beak and Feather Disease or chlamydiosis, can also be long-term carriers, and even non-budgerigar psittacines that do not harbor other diseases may also be long-term carriers. There is obviously much that we need to learn about this disease.

I recommend that all neonate non-budgerigar psittacines receive a series of at least two vaccinations against polyomavirus while still in the breeder's nursery, given at the manufacturer's recommended intervals. It is safest to not sell un-weaned baby birds, however, this is not always practical, so by vaccinating babies prior to their sale and exposure to other birds that may be shedding the virus, the risk of babies contracting the virus will be minimized. The adult flock should be vaccinated, as well. The vaccination program should be discussed and decided between the aviculturist and avicultural veterinarian.

4. Although not considered one disease, per se, reproductive problems would need to be on my list of the top five diseases in the aviary. It continues to amaze me that breeders will feed a non-productive pair of birds year after year and do nothing about it. A breeder may purchase a "proven" pair of birds, and when I examine them, it may be that the pair are both tattooed underneath the same wing (meaning that the surgical sexing showed that they are both the same sex), or one bird may have had no tattoo, and the other tattooed under BOTH wings (try and figure out the sexes of THOSE birds!) Other birds may have severe internal papillomatous disease that is preventing them from successfully breeding. Chronic sub-clinical or low-grade infections may prevent birds from breeding.

Inadequate nestboxes (the wrong size, shape, openings, substrate) may prevent successful reproduction. Incompatibility may also prove to be a problem, especially in the Old World Species, such as the Poicephalus group, African Grey parrots, and Eclectus. Birds that don't feel safe often won't breed, and simply changing their environment may do the trick.

Birds with decreased fertility, increased dead-in-shell eggs, or weak-hatch neonates should receive a full work-up, as recommended by the avicultural veterinarian.

5. Rounding out the top five aviary diseases (Gee, I feel like Casey Casem!) is chlamydiosis (aka psittacosis, parrot fever, ornithosis). This disease is caused by a very primitive bacteria that must live and reproduce within the cells of its host. Studies performed in Florida, where I practice, indicate that a high percentage of pigeons and doves here carry this organism. I do tend to see this disease most frequently in outdoor aviaries where cages and nestboxes are not protected from the droppings of these ubiquitous birds.

We need to educate breeders and pet owners about chlamydiosis. This disease is not the result of breeders running dirty aviaries. Chlamydiosis still, on occasion, connotes a leprosy-like disease in the minds of some bird owners. Even if you live up North or out West, the pet retailer that you purchased your bird from may have a relationship with a Florida broker who buys baby birds from a bunch of backyard breeders who do not periodically test their flocks or babies for chlamydiosis. However, even the best of flocks may be exposed to the chlamydial organism from wild birds, or from a carrier that sheds the organism, exposing breeder or pet birds.

This disease is considered a zoonosis, meaning that it is potentially contagious to humans, and in some states, it is a reportable disease. The newer generations of tetracyclines are most often used for the treatment, most commonly doxycycline. This treatment should be undertaken only when prescribed by a qualified avian veterinarian. Over-the-counter antibiotics or taking tetracycline capsules and trying to mix them in food or water are NOT considered acceptable treatments. Using antibiotics as a blanket treatment for chlamydiosis periodically is no substitute for sound prevention. The correct treatment must be used at the proper dose for the proper length of time for a bird to be adequately treated, and there is no guarantee of a cure, although most birds can be successfully treated. There is no quick fix for chlamydiosis.

Several tests are available, and your vet will decide which type is most appropriate in your situation. There is no way to state with 100% accuracy that a live bird is free of chlamydiosis. Diagnosis may require blood titers, DNA PCR technology, and plasma electrophoresis, in conjunction with a CBC and blood chemistry panel.

So, there you have it. Those are the five most common diseases that are usually seen in aviary birds. I would like to mention that Proventricular Dilatation Disease (PDD) is definitely on the increase, both in aviaries and in baby birds. Several researchers are working on providing new ways to diagnose this dreaded, progressively fatal disease in live birds. Also, Pacheco's disease (a herpes virus), is also making a comeback. I continue to see internal papillomatous disease, most often in macaws, Amazons and Hawk-headed parrots. Researchers are working on new diagnostics for that, too. So, you can see, that although avian veterinarians are able to diagnose and treat many common diseases, there is still a lot of research to be done. Please consider having your bird club donate to a group performing valuable, often life-saving research on avian diseases, such as the Association of Avian Veterinarian's Sponsorship Program that donates 100% of its donations directly to avian research.

To adequately manage an aviary, it is imperative that the aviculturist develop a good working relationship with an avian veterinarian willing to come out and evaluate the aviary periodically. By practicing good preventative medicine, it is possible to minimize the risk of many of those avian diseases lurking out there!

Copyright © 1999 Margaret A. Wissman, D.V.M. All Rights Reserved http:// www.exoticpetvet.net