Questions About The Polyoma Vaccine
by Joel Blumberg, DVM, Santa Rosa Veterinary Hospital

This article is reprinted from Issue #37 of The Pet Bird Report and may not be reprinted without the written permission of the author, Sally Blanchard or the PBIC, Inc. Illustration by Jeff Riebe.

 

A Hornet’s Nest

This one question can stir up a hornet's nest of opinions among any group having an interest in parrots - breeders, retailers, veterinarians, pet owners, even the birds themselves. Within the space limitations of this column I'll try to give a fair digest of the arguments for and against the use of the polyoma vaccine from the perspective of each of the affected groups. I do feel qualified to enter the fray since I breed parrots. I have worked with several reputable retailers, as well as doing our own retailing at Bird Calls Parrot Farm. I am an avian veterinarian and a devoted (demented?) pet bird owner. Last, but far from least, our own birds are always willing to provide plenty of input.

First, let's go over the stuff that almost everyone can agree on. (I gotta say "almost" because you can always find someone who will disagree about something.)

1. The polyoma virus is out there big time. Polyoma virus infection has been discovered in over 70 species of pet psittacines. The virus has also been detected in finches, canaries, soft bills, doves, chickens, pigeons, turkeys, and pheasants. It is seen all over the world. Published reports have put the level of infection in the average large parrot collection in the United States at 30%. The level of infection among American budgerigars is estimated to be 70%. Recent studies point to cockatiels as having a very high infection rate also.
2. Different species of birds can vary in their susceptibility to polyoma virus infection. For example, English budgerigars seem to be much more resistant than their American cousins.
3. There appear to be differences between species in regard to mortality rate. For example, Polyoma disease has been reported to be more deadly in American budgerigars, caiques, and eclectus. Species which seem more likely to escape the worst effects of polyoma disease are African greys, amazons, and lories.
4. There are species differences in duration of subclinical disease (disease that is not outwardly apparent, but is damaging to the bird internally).
5. Species differ in the likelihood of becoming a "carrier," which sheds the virus into the environment. It looks like the very worst offenders for shedding the virus after becoming infected are American budgies and cockatiels.
6. Although there are species differences in response to polyoma virus exposure, IT IS IMPOSSIBLE TO PREDICT HOW ANY INDIVIDUAL BIRD WILL REACT TO THE VIRUS. Here is a list of possibilities:

    

   • Death with No warning. No preceding illness. No nothing. The virus is so virulent to this particular victim that the bird dies before there is any outward indication that something is wrong. Sudden death most often occurs in recently hatched babies. However, peracute deaths can occur at any age, including adults.
   • Illness first, death later. Some poor souls suffer the effects of polyoma disease before succumbing. They may have kidney damage and pass blood in the urine. Eclectus appear to be particularly prone to this form of the disease. Others may have gastrointestinal signs, such as regurgitation, slow crop emptying, and stunted growth. Hemorrhaging throughout the body is especially common in babies. Neurological disease will appear as seizures, loss of coordination, weakness, or mental lethargy. Finally, the virus overwhelms its victim and the bird dies. This pattern of polyoma disease usually occurs in youngsters, but some adults are also affected this way. During most of the time that these birds are sick, they will shed large amounts of virulent virus into the environment.
   • Illness, then recovery. Most adult birds, and even some youngsters, will become infected and be sick only for awhile and then recover completely. The signs of disease may be more subtle in these birds, i.e. poor appetite, regurgitation, listlessness. Breeders may not produce eggs for a season, eggs may be infertile, or their chicks may die in shell or be very weak. Most birds transiently ill from polyoma virus are never recognized as having the disease. These birds also shed virus into the environment before they recover.
   • Persistent infection. Some birds remain infected with polyoma virus for a very long time - months, years, some possibly forever. These individuals may or may not show signs of illness. They may suffer from other ailments because the polyoma virus has damaged their immune system. Unless the test for polyoma virus is performed, these birds go undetected. These "carrier" birds intermittently release virus into the environment for as long as they remain infected.

   It is important to emphasize again - If your bird, or any bird, is exposed to polyoma virus, there is no way to predict how severely or in which manner it will react.

7. The polyoma vaccine is safe. The only reactions that I have encountered over the past two years giving polyoma vaccinations have been an occasional discoloration or thickening of the skin at the injection site. Using the correct procedure, the vaccine must be cleanly administered under the skin.
8. The polyoma vaccine is effective. Extensive testing under controlled laboratory conditions, as well as in numerous field trials, have shown that approximately 95% of all birds vaccinated will produce an immune response to the vaccine.

To Vaccinate ... Or Not?

OK, now that I've outlined the areas that everyone (almost) can agree on, let me delve into the controversial side of the discussion - to vaccinate or not to vaccinate.

First let me put on my BREEDER'S hat. (It's camouflage colored and highly textured.) Let's get right down to the nitty gritty with us breeders - we need to make money! I won't go into a long lament, but ask any bird breeder - it ain’t exactly lucrative. In fact, for a lot of us, covering costs would be rather nice. Hardly anyone is giving up their day job. From a breeder's point of view, the polyoma vaccine is expensive. The wholesale price is five times the cost for the common dog and cat vaccines, and these cover several diseases, not just one! Except for a few huge commercial aviaries, the manufacturer will not sell to individual aviculturists. Therefore, the only source of vaccine for most breeders is their avian veterinarian. Because proper vaccination technique is so important to the safety and effectiveness of the vaccine, all but a very few breeders have their veterinarian administer the vaccinations. This gets expensive when there are dozens or hundreds of birds involved. Now, it's true that when a flock is vaccinated, polyoma related problems (poor productivity, secondary infections, "normal" losses, etc.) will decrease and productivity and profitability will increase. However, the expense occurs in big chunks at vaccination time, while the rewards occur over the long haul — months and years. So, when an aviculturist has to decide how to allocate his or her limited funds, it is understandable that repairs, updated equipment, improved husbandry, and better diets get the financial attention. The only way around this dilemma is for buyers of parrots, at all levels, to demand and be willing to pay for vaccinated birds. It certainly isn't fair to expect breeders to cut into a nonexistent profit margin in order for buyers to obtain a superior product.

Another reason a breeder may object to vaccinating his or her birds is the amount of disturbance it causes within the aviary. There are some breeding birds that have never been handled since being placed in their cages years ago. The concern is that birds can be so upset by having their routine interrupted that they will injure themselves, injure their mates, or stop their normal parenting activities. These concerns are valid, but they can be greatly minimized by vaccinating during the non-breeding season and by utilizing quiet competent personnel. An important plus to aviculturists who are vaccinating is the opportunity to examine their birds closely, in many cases for the first time in years. Problems can then be discovered and corrected.

Some breeders decline to vaccinate for polyoma because they claim that there is not a problem in their aviary, so why go to the expense and bother? They may be absolutely correct. If every bird in the aviary was tested negative with the new DNA-based blood test, the facility is operated by the strict "closed aviary concept," and periodic monitoring for polyoma is performed, I would agree that it would be very unlikely for polyoma virus to ever be a problem in such an aviary. However, the vast majority of aviaries are not operated this stringently. As mentioned earlier, in the average aviary, approximately one-third of the population will have evidence of exposure to polyoma virus. Remember, the effects of this virus can be subtle or erratic, so, unless a breeder is looking for it, polyoma may go unrecognized — or accepted and ignored.

The Retail Perspective

The RETAIL PERSPECTIVE on this issue is probably the most complex. By their very nature, strict disease control in even the best pet shops is impossible. Birds, along with their germs, are coming and going constantly. Most retailers obtain their birds from many sources which can vary from hobbyists and modest aviculturists to wholesalers and huge commercial "birdy mills." Some birds may be sold on consignment from individuals who no longer want their birds for a whole variety of reasons. These sources are usually changing constantly. In most cases the retailer has no knowledge nor control (and sometimes no interest) over the production and husbandry practices of his or her suppliers. Birds from these different backgrounds are then kept in close proximity, sharing the same air space, sometimes even the same enclosures. During their passage through the retail outlet there can be a constantly changing population and mixing of birds. All of these birds are unavoidably being stressed by several factors: shipping, changing environment, changing diet, perhaps weaning, growth, new people, etc. As we discussed in previous columns, stress greatly impairs an individual's immune system.

Next, the poor retailer has to contend with people. Now, don't get me wrong, it's not that people are bad. In fact, people are pretty darn crucial to a retailer. After all, it's people who plunk down the moolah for all the stuff that's for sale and enables the retailer to make the car payments and send the kids to camp. It's people who deliver all those animals and products. It's people who make up the staff. However, people can also be a major source of germs to the pet shop animals - especially the birds. A customer may have handled a sick bird at another place (or his or her own home!) just before coming in. A supplier can bring germs in from previous stops. The products themselves may be contaminated if they were grown, processed, collected, manufactured, packaged, housed, shipped, or handled by personnel where there is exposure to birds. And staff? They are animal-lovers. They own animals. They have friends with animals. They do stuff and go places where there are lots of animals - and animal germs. People, who are the lifeblood of any retail business, can be as significant a source of germs in a pet shop as the animals.

Now, I'm not aware of any studies into the psyche of microbes, but I just betcha that at some level they have emotions. And, if they do, they would be totally ecstatic to encounter a population of high stress potential victims. Having the opportunity to infect so many individuals whose immune defenses are down is entering germ paradise, fulfilling a microorganism's greatest fantasy. It is a known fact that happy germs are very democratic. They are more than willing to share the wealth. An infection caused by one disease agent can make it easier for the next one to gain access to the victim. The polyoma virus can be an eager and major participant in the germ-happy scenario. Horror stories abound about polyoma virus outbreaks in retail establishments.

So, am I saying that any disease control is impossible in a pet shop? Absolutely not! What I am saying is that, despite the fact that there are inherent difficulties which make perfect control impossible, there are a great many ways for pet shops to minimize the risk of disease in their animals. There are some excellent courses and programs available to pet shop personnel aimed specifically to train them on how to provide for the health and well-being of pet shop "livestock." There are excellent retail establishments which make a tremendous effort to provide healthy birds and are always looking for ways to improve their situation.

Polyoma vaccination is an important component of a pet shop health program. Ideally, birds should be fully protected prior to entering the retail facility. However, there is still some benefit to vaccinating birds already in the store. I won't go into the technical details of how to establish a health plan which incorporates protection against polyoma virus. Such programs do now exist and have been adopted by progressive retailers. Quality health programs and polyoma vaccination add to the overhead costs of these conscientious establishments, which is reflected in higher prices for their birds. It is up to all of us bird people to demand quality from retailers and to enthusiastically support those which provide it!

The Veterinary Viewpoint

When it comes to the VETERINARY VIEWPOINT on polyoma vaccination, I can really get going - and often do, to the dismay of my staff, who try valiantly (and with limited success) to keep me on schedule. I'll try very hard to confine my remarks here to under book length. (I'm sure Sally's red pen will be a big help!)

For many years the veterinary profession was strongly criticized by the owners and breeders of pet birds for not providing the same level of medical care as was available to other domestic species. The criticism was truly justified. Pet bird medicine and surgery was virtually an unknown entity in the veterinary school curricula. Finding a pet hospital that would even see a bird was a very iffy proposition. What little we did with pet birds was an attempt to combine what we learned in our poultry medicine classes in vet school with our cat and dog knowledge and techniques. By today's standards, the results were pretty mediocre. Understandably there were a lot of disgruntled pet bird owners.

In the 1980's the popularity of pet birds began its meteoric rise, which continues today. Importation increased dramatically and so did avian diseases. We all know the horror stories associated with indiscriminate gathering, brokering, shipping, and confining of birds in quarantine stations. In an attempt to control some of the worst of the diseases that came out of those places, some vaccines were developed. In the vast majority of cases the vaccines worked and thousands of birds were protected. Unfortunately, there were also some vaccine reactions. Some birds got very lethargic, lost their appetites, and dropped weight. Other birds got severe reactions at the vaccine site and had to have surgery to remove damaged tissue. A very small fraction of vaccinated birds died.

I've got to emphasize that the problems associated with these early vaccines were very few and that the vast majority of vaccinated birds achieved disease protection smoothly. However, this fact was no comfort to the bird owner whose pets or breeders were among those which reacted adversely. As is natural with all of us human animals, bad news makes for a good story. The recounting of unfortunate experiences with the vaccines was passed from person to person with great enthusiasm. Of course, with each repetition the number and severity of the problems would grow and grow. This phenomenon occurred throughout the avicultural community as well as among veterinarians. The legacy of our early halting attempts to practice pet bird medicine, and the stories that came out of our past efforts to vaccinate pet birds, was the creation of a real phobia, bordering on hostility, toward the very concept of pet bird vaccination. These negative attitudes have carried over to the present time, especially among "old time" breeders and even among some of my colleagues.

However, all that I've described above is history. Today the situation is significantly different in so many ways. Veterinary schools now offer advanced degrees in avian medicine and surgery. Extremely important advanced research is being conducted in dozens of institutions. The keeping and breeding of the pet bird species is so prevalent now that even the commercial sector is investing in and developing avian products, therapeutics, and specialized equipment. The Association of Avian Veterinarians is more active than ever in promoting, coordinating, and disseminating this burgeoning knowledge to avian veterinarians throughout the world. In other words we're finally doing it right! Avian medicine is getting the kind of attention and support that triggered so many breakthroughs in other areas of veterinary medicine.

In my humble opinion, the current polyoma vaccine ranks right up there as a major breakthrough. It is every bit as significant as parvovirus and distemper vaccines in dogs or leukemia and distemper vaccines in cats. My practice saw one case of canine distemper two years ago. I can't remember our last case of feline distemper. In the "old days" we encountered these diseases weekly! The only reason for the dramatic decline in the incidence of these devastating diseases is vaccination, widespread continuous vaccination.

Polyoma today is like distemper of twenty years ago. With the new tests available I am encountering it nearly as often as I used to diagnose distemper. This doesn't have to be the case. The polyoma vaccine gives us the weapon to reduce the incidence of this disease to an insignificant level comparable to distemper. Therefore, when I consider how serious polyoma virus is in our domestic parrot population, philosophically and morally I feel bound to recommend mass vaccination of all captive psittacines.

Now, don't get me wrong. I don't claim that polyoma vaccination is going to solve all health problems in parrots. It is no substitute for sound husbandry practices in aviaries, strict sanitation in pet shops, or balanced diet and loving care in our homes. All the polyoma vaccine will do is protect against polyoma virus infection. That's more than enough reason for me to recommend it. If we truly love birds as we claim (You wouldn't be reading the Pet Bird Report if you didn't. Right?), we all have to be willing to pay for it - which ultimately means the buyer. Anytime any of us in any area of the parrot world purchases a bird, we must insist upon, and be willing to pay for the cost of that bird being protected against polyoma virus.

As An Individual Pet Owner?

For us INDIVIDUAL PET BIRD OWNERS, the decision to vaccinate is based upon the opportunities for the polyoma virus and our bird(s) to get together. If there is absolutely no way for the virus to meet up with a bird, then vaccination is unnecessary. However, consider the possible routes polyoma virus can take to enter a bird's environment:

• One of your other birds is already infected and you don't know it.
• Birds visit the groomer.
• Birds are boarded.
• Birds accompany owner to pet shops, bird marts, feed stores, bird clubs.
• Birds visit their veterinarian. (Gulp! I gotta admit that our super-duper best disinfectants and air purifiers can't get the risk to absolute zero.)
• Owner goes to pet shop, bird mart, feed store, bird club, or veterinarian - and doesn't shower and change clothes immediately upon returning home.
• Cages, toys, food, perches, at some point in their existence, share the same air space with unprotected birds.
• Bird visits homes housing unprotected birds.
• Unprotected bird(s) visit your home.
• Owner visits homes housing unprotected birds.
• Owners of unprotected birds enter your home.
• Cages, perches, or birds brought outdoors with direct or indirect exposure to native species — a big question mark. Polyoma virus definitely infects finches. It has been isolated from a number of soft-bill and waterfowl species.

If you or your bird will encounter any of the above situations any time in the next year, then polyoma vaccination will provide peace of mind that you have protected your feathered pets as much as you can.

If a trip to your avian veterinarian is difficult for you because of logistics or the emotional effect it has on your bird, discuss these concerns with your veterinarian. He or she encounters these problems routinely and can offer useful suggestions. Perhaps a home visit can be arranged.

If financial considerations are involved — I want to be diplomatic here; I don't want to be accused of drumming up business for my fellow avian vets or being insensitive to individual economic situations, but, talking now as an advocate of pet birds, the price of vaccination should be budgeted into the costs required to provide the normal care for any pet. The cost of vaccinating a pet bird against polyoma virus is comparable to the costs of the common dog and cat vaccinations. When you consider how much we spend pampering our feathered darlings with cages, toys, food, treats, playpens, recordings, perches, etc., the amount spent on vaccination is not very much at all. Vaccinating any animal is simply part of responsible pet ownership.

In conclusion, A WORD FROM THE BIRD is in order. Magic, my African gray would like to speak on behalf of all her fellow avians who keep people as pets—and servants. "Polyoma is no joke, and I don't want our owners to jeopardize our health or lives by not getting us vaccinated. Now, I know it's kinda scary to go to the doctor, and being poked isn't something that I would choose to do every day, but, actually the vaccine is no big deal ... but, don't let your owner know this. If you play your cards right you can work on your owner's sympathy after getting your vaccine. It should be good for at least a special snack, maybe even a new toy. Do whatever it takes—be good, be bad, be cute, be entertaining, be noisy, be quiet, be cuddly, but definitely be insistent—have your owner get you protected against polyoma virus!"

IS POLYOMA VACCINATION NECESSARY? IT IS TO THE BIRD WHICH WILL BE EXPOSED NEXT MONTH.

If this article helped you and you appreciated the information, The Companion Parrot Quarterly continues to have in-depth, practical articles such as this one. PLEASE SUBSCRIBE