Pigeon Herpes Virus

By Clint Robertson

          I had been breeding and showing pigeons since the late 1970s when in 1995 I acquired a group of birds from the southern U.S. to add to my program. It was early spring and the birds settled in and started to breed. About 2 months into the season, in late May, I had raised a number of young birds and was getting ready to start moving them into the young bird pen when I noticed some of them suffering from what appeared to be a respiratory illness. The affected birds first appeared listless and soon after developed a yellow, soft, cheese like crust at the base of the tongue and on the roof of the mouth which, if not removed, would eventually close off the wind pipe causing the bird to gasp for air. This same wet substance would appear in the sinuses and would be accompanied by a nasal discharge. Infected birds could often be heard sneezing and would sometimes shake their heads as if they were uncomfortable. Others showed no outward signs of illness until you opened their beak to see inside. At first I thought it was canker however unlike canker the yellow substance could easily be removed with a Q-tip and no bleeding occurred but it would return no matter what I did. I tried swabbing with an iodine solution however that did not work either. It began to show up in about 25% of the young birds between the ages of 3 and 5 weeks. They would lose weight and eventually have to be destroyed. It seemed like there was nothing I could do to save them. No old birds appeared affected.

I sent some birds to a University for testing and was told after a quick glance, with no testing by the lab, that it was canker however I already knew it was not. When I phoned the lab the person who received the specimen had simply looked in the bird’s beak when it arrived and assumed it was canker and threw it in the garbage and wrote on a report that it was trichomaniasis. After all the trouble I had went through to get that bird to the lab I was really upset. I then made some phone calls to a respected pigeon vet in the U.S. and was told it sounded like Chlamydia which was very difficult to treat. (This is because there is very poor circulation to the respiratory passages where the harmful organisms breed as the organisms are not actually in the bloodstream so it takes higher doses of medication over longer periods of time to get results.) There was no way I could send a sick bird across the border for him to test so I decided to take his best guess and follow his suggested treatment. I was told I needed to put the birds on water soluble Doxycycline for 45 days along with Tylan in the water at the same time. By this time it was really hot humid weather and many more of my young birds were getting sick with the same signs. I started the birds on the medication and it seemed to slow it down to the point where I thought I had it under control. The treatment was very expensive and must have been hard on the birds but they continued to breed successfully.

During this time I finished up breeding and all the young birds that had made it to the weaning pen were fine. Late that fall, after I had finished treatment, I had a couple late hatches and one day I discovered one of them with the same signs and I was really shocked that I had not eliminated the problem. I decided to just ride out the winter and hoped our harsh winter and time would take care of it. My birds wintered great and I had no problems. I mated up the next spring in late March and had another good start to the breeding season. By May it was getting warmer and humid and I had already weaned the first round of young birds with the second round starting to hit the floor when it hit again. No matter what I did I lost every single baby with the signs. I was not able to save even one of them. Again about 25% were infected.

I had several breeds most of which were Jacobins and I used Racing Homers as feeders. To a large degree only fancy birds appeared affected. The majority of young racing homers showed no sign of the illness. I began killing every young bird at the first sign of the disease to try to stop it from spreading. By this time several other breeders I knew were having the same problems. But again it was only with the young birds. It was attacking the young birds at the time when they were most stressed, leaving the nest and trying to learn to eat on their own. Once they were past this stage they never got sick. No old birds appeared affected. It is also interesting to note that certain families of birds within specific breeds that were more closely inbred seemed more susceptible to the illness.

Once again I sent birds for testing at a different recognized Veterinary teaching facility. Again the results told me nothing about the actual problem. They tested organs and identified bacteria present and told me all about what the birds did not have but again no answers. I was again very disappointed and so was my vet who had expected more. When I told the pigeon vet in the U.S. that the Doxy did not work and the problem was back he told me to treat again and this time increase the dosage above what the label said and treat for a longer period. I did this and again it came back. By this time I was starting to learn how to manage the illness. It was obvious that stress and hot humid weather were major factors in bringing the illness on. The first rounds of birds were often not affected. It always hit in May and got worse from then on. More crowded conditions when numbers of young increased saw more dramatic outbreaks. The last rounds in August saw the worst infection rate. Years went by and I spread my birds out with better ventilated lofts and learned to manage the illness better, thinking I was dealing with Chlamydia. With improved management over a few years the infection rate dropped dramatically to the point where I only lost the odd stressed baby (maybe 2 or 3 a year). Then came a breakthrough. My Dad started using a product called Oxine to fog his call ducks when they had respiratory problems. I tried it on an infected 3 week old Jacobin. I fogged the bird three times a day for 3 days so it had to breathe in the vapors and the bird recovered. (We mix inactivated Oxine, which is a chlorine product, at a rate of 6 ounces to 1 gallon of water and apply with a fogger to the birds face and open beak so it breaths it in). This was the first bird I had that recovered and I saved several more in the years that followed. 

          Then in 2009, after much investigation and consultation with my vet and Dr. Gordon Chalmers I found two labs that were highly recommended in Canada to do pathology reports on pigeons. I sent birds to both facilities and we asked for thorough testing. Finally we got what we wanted. The testing was thorough and the reports were detailed. One of the things I asked for was that the birds be tested for Chlamydia. I was cautioned that in some provinces such as Ontario, Chlamydia is a reportable disease and if birds tested positive there could be consequences. I asked that we proceed anyways. It turned out that my birds did not have Chlamydia at all. What they had was Pigeon Herpes Virus. Suddenly it was all so clear to me. No wonder the medications had not worked.

          I immediately contacted Dr. Chalmers and we discussed how to manage the illness. First I was informed that Pigeon Herpes Virus is present in many lofts world wide. My first thought was to get rid of all my racing homers who I now knew carried the virus and get new feeders to transfer my Jacobin eggs to so they would not get the virus. Dr. Chalmers suggested that this was not the thing to do. He told me that my homers were likely the key to controlling the virus. Over the years my homers have developed antibodies to the virus. They pass on these antibodies to the young birds they feed. The antibodies from the parents simply protect the young until they are at an age when their own immune system is well enough developed to allow these birds to produce their own antibodies.  Antibodies from the parents will decrease in level over time in the young birds after which they can produce their own protection from a better developed immune system. However Dr. Chalmers tells me the infection is often persistent in infected birds because of the carrier state.  There seems to be a stand-off between the presence of the virus and the immune system.  The virus is held at bay by an active immune system until some level of stress depresses the immune system and allows the virus to multiply and to be shed in droppings, nasal and oral secretions, etc.. When the young bird is stressed prior to acquiring immunity it is most susceptible to the virus. It seems performing breeds like adult racing homers are much stronger and rarely show signs of the virus even if they have it. However susceptible young racing lines can and do become infected with this virus.  Herpes is a persistent infection in pigeons and appears in susceptible birds if their immunity is low [usually youngsters].  Infected adult pigeons, like herpes-infected humans and other animals, can be persistent carriers. By eliminating as much stress as possible in my loft I was able to virtually eliminate loses and signs from it. Based on experience Dr. Chalmers and I would agree that there is a need to develop lines of birds – regardless of strain or breed – that have greater resistance to disease in general.  Maybe by selecting breeders from among those birds whose youngsters are healthy survivors would be a good approach for all of us in pigeons.  

          Most breeders with good loft management will have little if any problem from the virus. In many lofts canker and salmonella will cause much higher mortality than Pigeon Herpes Virus. There are many strains of Herpes Virus and we know that they are all quite species specific. Pigeon Herpes Virus will not transfer to humans.

          I have heard some breeders refer to the signs of Pigeon Herpes Virus as wet canker. There are other signs of Pigeon Herpes Virus that do occur. One is a typical grey color inside the mouth of the birds. It has been reported to me that this can occur in old birds and although they often continue to breed they lose body condition over time and eventually become too weak and will die or need to be destroyed. Remember you cannot treat this virus.

          This article and my experience helps to stress the importance of sending birds to be examined in a lab. We need to know what we are dealing with before we can deal with it properly. We must not abuse medications. Some day our lives or the lives of our children may depend on our actions today and the way we use medications.

Another good article on Pigeon Herpes Virus can be found online at    http://www.epah.net/birds/Herpesvirus.htm

I would like to thank Dr. Gordon Chalmers for his assistance and advice in helping me to prepare this article. Comments from Dr. Chalmers appear in bold italics.