Looking back, it is interesting to note how veterinary pigeon matters have changed over the last 40 years but particularly during the last 10 years. The level of diagnostic ability and veterinary knowledge has dramatically increased and along with this fanciers’ expectations from avian veterinarians have also increased. There is, however, still a surprising amount of misinformation about. Some fanciers are real “gossips”, others are “wannabe” vets and sometimes it seems as if everyone is a veterinary expert. Unfortunately, not all misinformation originates from fanciers, sometimes it is from a vet. Like all professions, the veterinary profession has one or two rogues. Most vets are informed and dedicated to their profession but sadly some are less dedicated and some could even be described as crooks or charlatans. In the past, there were only a small number of qualified avian vets and some fanciers, when they think of avian vets, still think that there are only one or two who can help them with a health problem with their pigeons. There are now, however, about 50 qualified avian vets in Australia. Not all are familiar with pigeon racing but all are familiar with pigeon health problems, the appropriate diagnostic process to investigate these and the correct use of medication. They are able to diagnose medical problems ranging from the minor ones that make race birds a bit less competitive through to the more serious ones where birds are dying. Once a diagnosis has been made, they can then advise a fancier on how the problem developed, how to control it and how to stop it happening again.
At the Melbourne Bird Veterinary Clinic (MBVC), there are four veterinarians and three of these are qualified avian vets. When dealing with a health issue, it is always a matter of correlating the degree of diagnostic effort and expense with the severity of the problem. If the birds are racing well and we are simply monitoring health, then just a general examination and a microscopic examination of a crop flush and faecal smear may be all that is required. Other tests can be done if indicated after examination. With more serious problems, the following is the diagnostic protocol that is followed at the MBVC. This is typical of a thorough diagnostic investigation in most avian practices and can be used as a guide for your veterinarian.
The 12 step process to investigate a serious pigeon health problem
1/ Take a history and develop an understanding of the nature of the problem.
2/Conduct a thorough clinical exam, make assessment of general clinical condition, undertake a microscopic exam of fresh faecal smear, conduct a faecal flotation, undertake a microscopic exam of fresh crop aspirate, check pharyngeal tonsils and laryngeal mound (redness, swelling, abscessation, sialoliths, etc.) in particular.
3/Collect throat, conjunctival (eye) and choanal (‘slot’) swabs for Chlamydia and Mycoplasmal PCRs.
4/Collect blood for full haematology and biochemistry – this gives valuable information about nutrition, the level of training and overall fitness, hydration, organ function, the immune system and infection. This information cannot be gathered from autopsy.
5/ Euthanise bird by giving lethal injection; usually pigeons just “fall asleep”.
6/ Wait 2 hours to do the autopsy; earlier leads to passive bleeding, identified as “congestion” by pathologists, which can make interpretation of tissues microscopically difficult or impossible.
7/ Autopsy within 4 hours of death, later can lead to early autolytic (decomposition) changes and altered bacterial populations, decreasing diagnostic value.
8/ Collect full set of tissues including -- whole head (after removal make a longitudinal incision along the top and back of the skull and crack the skull open to allow formalin to run into the brain case), the anterior oesophagus (sometimes this is the only place you will find Herpes), sections of crop wall, proventriculus, gizzard, several sections of gut, caeca (vestigial) and bursa of Fabricius if visible (i.e. bird <5 months old), trachea, syrinx, lungs, air sac, spleen (often best to collect on first opening the abdomen, if there is bleeding spleen can later be hard to find), liver (left and right lobes), kidney, middle-third of femur (for bone marrow), sciatic nerve, section of spine, skin, heart and pectoral muscle.
9/ Collect PCR for Rota in case you get hepatocellular necrosis of unknown cause; does not matter if the bird is vaccinated against Rota as the PCR does not check for the tiny part of the genome that codes for the capsid VP8 protein that forms the basis of the subunit vaccine. Birds can be negative for Rota on faecal PCR and positive on hepatic PCR. Collect kidney and bowel PCRs for PMV PCR testing.
10/ Collect a second set of the main tissues and freeze these. These are used if further viral identification and testing are required
11/ If anything looks abnormal, target that and make sure a section/sample is collected.
12/ If anything looks infected, collect a swab for MC and S (microscopic examination, culture and antibiotic sensitivity) testing. Collect a similar swab of the gut content.
Everything costs money. It is important that the client’s money is spent wisely and so the samples collected in points 3, 9, 10 and 12 above are held and available if the other tests, in particular the blood profiling and histopathology, are not diagnostic. These samples cost nothing to collect, store well and some can only be collected from a dead pigeon. Overlooking the collection of these may not only compromise the diagnostic process but may necessitate killing another bird unnecessarily to subsequently collect these samples.
Sometimes fanciers have an unrealistic expectation as to what can be diagnosed by fairly basic tests. Sometimes vets are overly keen to give fanciers a diagnosis and make impossible diagnostic claims after inadequate sampling and testing. From a mailed in dropping sample it is only possible to definitively diagnose (and even then, not always) some worms and coccidia. It is not possible to diagnose (or rule out) bacterial or fungal infections. In particular, Streptococcus and Salmonella infections ( just because the organism may be present in the droppings does not mean it is causing disease ) cannot be diagnosed this way. To consider diagnosing any form of canker or respiratory infection in this way is just ridiculous. Any vet who claims to make this diagnosis in this way is deluding not only the fancier but also himself. Similarly it is not possible to diagnose bacterial or fungal infections from a mailed-in throat swab.
I am often asked to review cases and offer a second opinion. Most vets do really great work but the standard of work of some is well below the average of what the profession would expect. A recent case illustrates the point. A fancier was experiencing both poor results and poor returns in his race team. He went to the trouble and expense of sending a live pigeon to an avian vet interstate for diagnostic investigation. On arrival, the bird was handled and droppings were looked at under the microscope. The bird was then euthanized, autopsied and some tissue samples collected for histology (microscopic examination). The pathologist reported that many of the samples were “congested”. From this diagnostic work, the vet was happy to make a diagnosis! He diagnosed that the bird had come in contact with a toxin and asked the fancier to send some grain for testing. The grain was placed onto a medium that stimulates bacteria and fungus on the surface of the grain to germinate. This test is not regarded as an accurate way of assessing grain quality or an accurate measure of fungal or bacterial contamination. But from this test, the vet advised the fancier that the corn was a problem. The fancier stopped using the corn. Nothing changed and the fancier then re-contacted the vet who advised that it was a “very complex” problem and another bird would need to be sent for testing. The fancier then contacted the MBVC.
The vet had not necessarily done anything wrong but most vets would regard his diagnostic investigation as pretty poor. Comparing his work with the above recommended 12-point protocol, many problems are apparent. The main ones are listed below.
Problems with this investigation
a/ Inadequate collection of samples required for an accurate diagnosis. When asked why various samples were not collected, his reply was that “he would rely on the histopathology” for a diagnosis. A seriously flawed approach with many potentially relevant and important things being overlooked.
b/ Poor autopsy technique – when asked if the “congestion” noted by the pathologist was apparent at autopsy or if he had caused it, his simple reply was “I don’t know”. Many important tissue samples were not collected during the autopsy. Yet, despite inadequate tissue collection and poor tissue handling, this was his main diagnostic test.
c/ His preparedness to make a diagnosis that was impossible based on the test results.
What concerned me is that when I contacted the vet in question, he thought he had done a good job. Unfortunately, he had become professionally isolated and his knowledge and diagnostic approach were no longer in step with the profession’s expectations. The frustrating thing for me was that he did not seem to realise this. He seemed simply out of touch with the diagnostic process and also with the standard way that most avian vets would approach this problem. On top of this, some of his testing and advice was flawed and often just wrong and certainly not consistent with what would be regarded as acceptable practice in the profession generally. Veterinarians as professionals may differ in the exact way that they diagnose and manage cases but in this instance the tests being done and treatment recommended did not have a scientific basis. He was substituting his opinion for scientific fact. I found it particularly interesting that he was quick to label this a “complex case”. These days, nothing should really be complex given the correct testing. These days, diagnostic testing is so sophisticated that it is simply a matter of following the usual diagnostic pathway and getting the results.
And so what was wrong with this fancier’s birds? The haematology component of the blood profiling revealed a very high PCV. This stands for Packed Cell Volume and is an indicator of the concentration of red blood cells in the circulation. When PCVs get high, the blood becomes more viscous and the heart has to work harder to pump it around the body. This puts a dramatic increase on the work load of the heart and leads to cardiac insufficiency during exertion and an obvious compromise of race performance. This condition is seen quite commonly. The exact cause of these high PCVs is not known but one suggestion is that it is the response of a pigeon being forced to exercise beyond its fitness or health capability. The condition usually responds to treating any identified health problems ( that are blocking the development of fitness) and simply to just open lofting. Affected birds are kept in their loft routine, i.e. let out and called in at their normal times but are not forced to fly. Leaving birds at liberty for several hours a day I find is a good stress reliever and helps the birds to gradually fly themselves to fitness – those that want to fly do and those that want to rest can, as they start to feel well they fly more and develop their own fitness. During this time, there is no rationing of food. Birds are fed by hand as much as they want to eat twice daily with a moderate protein ration of about 16%, e.g. 40% dun peas, equal parts (about 15% of each) safflower, sorghum, wheat and corn. Usually the condition corrects itself over 2 weeks and the team can gradually be brought back into work. The biochemistry component of the blood profile showed minor damage to the liver and reduced kidney function but histopathology showed no significant damage at a cellular level and subsequent Rota and PMV PCRs (viral DNA checks) ruled out these viruses as being involved. All other tests did not reveal any other complicating factors. There was no evidence of a “toxic” exposure.
Moving on from this I have even reviewed cases where vets have invented conditions and then advertised that they are the only ones to be able to diagnose that condition and in turn, market elaborate treatment programs to manage the condition.
A list of qualified avian vets in Australia and New Zealand is listed on the Australian Pigeon Company website. I would encourage all fanciers to use their services but at the same time, if the advice you are getting just does not sound right, get a second opinion.
The importance of correct PMV vaccination
This mini-disease outbreak raises several important issues regarding PMV vaccination. The initial reaction of some fanciers after hearing that the problem was PMV was to conclude that the vaccine was either not effective or that alternatively, we were dealing with a new strain of PMV. Both conclusions are incorrect. There is sufficient genetic overlap between various PMV strains that the vaccine would be effective against any strain. To blame the vaccine is a bit like putting 4 stroke petrol into an engine designed for 2 stroke fuel and then when the engine does not work concluding that there is a problem with the fuel . Like petrol, for a vaccine to work it has to be used correctly. Fanciers are reminded that the killed La Sota PMV vaccine if used correctly is 100% effective. The correct vaccination method is to give 2 shots about 4 weeks apart with both shots being given after 6 weeks of age. This doesn’t sound that hard but some fanciers seem to have trouble following that advice.
Issues regarding PMV vaccination
1/ Do not vaccinate too young
If youngsters are bred from vaccinated parents some of the parent’s immunity passes to the babies. This “passive” immunity interferes with the youngsters developing their own active immunity from vaccination. Thorough testing in 2012, done in Australia, showed that this passive immunity lasts until the babies are about 6 weeks old. A fancier, therefore, giving a young pigeon its first shot under 6 weeks of age cannot be guaranteed that this first shot will work. It is reasonable to give the first shot at 4 weeks at weaning, particularly in a high risk situation but if this is done 2 further shots will need to be given to ensure the development of protective immunity. Remember the birds need 2 shots after 6 weeks of age to be immune.
2/ Importing European vaccines.
In Europe PMV vaccines are available that are made from pigeon origin PMV strains. The advantage of these vaccines is that if birds are vaccinated with these and are exposed to PMV they are less likely to develop into “silent” carriers ie they are less likely to be transient carriers of the virus. The vaccines that are available in Australia stop the birds getting sick with PMV but if exposed they do become infected with the virus for a short period ( several weeks ).This temporary carrier state does the birds no harm but it does mean that they can spread the virus. This is less likely to occur with the European pigeon origin vaccines.
I am aware that some fanciers have imported this vaccine for use in their own birds. Importation of vaccine into Australia is illegal. I don’t want to be critical of these fanciers. I can perhaps understand why fliers have been tempted to do this and feel that probably those involved did not understand the potential ramifications of their actions. I will explain below why this practice should not continue and hope that once they understand the situation that they no longer choose to do this.
Importation of vaccine into Australia is illegal, and for good reason. Vaccines are developed and held in media that are ideal for the growth and maintenance of the virus in the vaccine. This preparation is also attractive to other viruses. This means that there can be no guarantee that there are no other viruses present in the preparation as well. Bear in mind that there can be up to 17,000 different viruses in a single glass of water. It is impossible to check for all of these. Australia does not want to introduce any new viruses. Fanciers who smuggle in a European vaccine illegally will in due course inject their own pigeons and these, with time, will mix with birds from other lofts particularly during racing. This is a great way to introduce and spread a new virus across the country.
Another thing to consider is that vaccines are very fragile. PMV vaccines need to be kept at specific temperatures. It takes 5 days to post a vaccine from Europe to Australia. I feel that the chance of the posted vaccine being within the temperature range required to keep the vaccine fully potent for the whole time is low. Even if ice is still present in the parcel this does not guarantee that the vaccine is OK. If ice sits against the vaccine container it can locally freeze it, which, depending on the vaccine, can reduce the vaccines effectiveness.
Fanciers who smuggle vaccine into Australia therefore risk not giving their birds an effective vaccine and subsequently losing their birds either through the birds catching the disease or alternatively having reduced immunity, inadequate protection , sub clinical disease if exposed to PMV and impaired race performance. This of course is not to mention the risk that they impose on the rest of the Australian pigeon community through introducing another exotic virus.
Now that the situation has been explained I would be very disappointed if the illegal importation of vaccines into this country continues. The smuggling of vaccines into this country by any fancier is to be strongly condemned.
3/ Yellow lumps at the vaccine injection site
At the Melbourne Bird Veterinary Clinic we have seen and tested many of these birds now. Without exception they have turned out to be infections. Pigeons don’t have the enzymes in their white blood cells to produce liquid pus like a mammal. Pus in birds is thick, yellow and cheesy. People blame the vaccine for the formation of these yellow lumps but of course this makes no sense. It is common sense that if the yellow lumps were caused by an innate feature of the vaccine then it would affect all lofts to a similar extent. I see on the internet fanciers condemning the vaccine because they get a lot of birds with yellow lumps after vaccination. One fancier actually stated that a third of his birds got them. All they are announcing to the world is that they have a poor vaccination technique. If the needle becomes contaminated between pigeons with dust from the loft, or is touched or is injected too deeply into the crop then it will be contaminated with bacteria and infect subsequent pigeons. The tip of the needle should go just below the skin and when correctly injected a white ‘flare’ should be seen just below the skin. There is no need to attempt to sterilise the skin with disinfectant as pigeon skin is virtually sterile anyway. If concerned, fanciers should just change the needle every 10 or so pigeons or whenever they think it may have become contaminated. Needles literally cost less than 5 cents each. This means that even if the needle is changed for every pigeon it costs less than $5.00 for 100 pigeons. Hardly a big expense.
4/Fake veterinary news
Several years ago some information was spread, I am sorry to say , by a veterinarian that although it was necessary to vaccinate now in Australia against PMV, that the vaccine in some way, by an as yet unknown mechanism, altered the development of natural immunity in young pigeons. The vet went onto explain that as a result these pigeons were more vulnerable to disease and it was now necessary to use new methods and products developed by him to counter the damaging effects of the PMV vaccination on immunity. This information which can be described as fake veterinary news was presented as veterinary fact when this was just not the case. It was purely personal opinion. The veterinary profession as a whole does not believe that this is the case, there are no studies showing that this happens. The proposed mechanism is unknown because it does not exist. It is all just a hoax. Unfortunately the fake news led to many fanciers not vaccinating their pigeons. Some of these subsequently lost significant numbers of birds to the disease. As a veterinary colleague of mine at the University stated, the vet who spread this false information has the blood of hundreds, if not thousands of pigeons on his hands. It is worth remembering that some Victorian doctors, several years ago, that spread misinformation that led to some parents not vaccinating their children were struck off. The irony of it all is that the multimillion dollar vaccine companies that make the vaccines put a lot of time, effort and money into ensuring that the base that the vaccine is in, be it oil or otherwise actually enhances the immunity formed by the vaccine itself. These vaccines then have to pass the extremely rigorous testing protocol demanded by the Australian authorities before market release with safety of use being a top concern. In a conversation with the Pfizer manager in charge of distribution of the company’s products throughout the Australia-Pacific region, he explained that the company was concerned about the unfounded criticism of one of their vaccines and that legal action against the veterinarian concerned was an option.
5/ Live (NDV4) vaccines vs killed La Sota vaccines
When we did the 18 month long PMV vaccine trial in 2012 we found that when pigeons received a single dose of La Sota vaccine, 70% were fully immune in 4 weeks. When they were given a second shot 4 weeks 100% became immune. Conversely when the pigeons were given NDV4 none were immune after 4 weeks. When given a second shot most but not all became immune and the level of immunity that developed was not as high as that produced by the La Sota vaccine. Recently some people have been advocating the use of NDV4. My simple answer is why – particularly when there is a safe, more effective vaccine available. Some Queensland fanciers have suggested that because NDV4 is alive it can give the pigeons the disease. This is nonsense. The live virus in the vaccine has been modified so that it cannot cause disease. The only way that use of the NDV4 vaccine can cause disease is that if it is used, because it fails to cause the development of immunity in all pigeons this means that if they are exposed to PMV then some of them will get sick.
The simple answer to all of this, is that unlike other diseases, notably Rota virus, where a completely effective vaccine is still a work in progress, we are a bit spoilt with PMV. We have a safe, effective vaccine that has been extensively trialled. These trials were completed 7 years ago and the result of these trials was made widely available being published in the national pigeon magazines and also the peer reviewed Australian Veterinary Journal.
If fanciers have any comments, queries or questions about PMV vaccine use they are more than welcome to contact me. I am happy to reply and comment. In the meantime prevent PMV killing or damaging your birds by using the killed La Sota vaccine . The Australian brand names are “Poulvac and “Newcavac” and remember it is 2 shots about 4 weeks apart with both shots being given after 6 weeks of age and then annual boosters.