Written by Peter Boskamp
During the tour of the viruses, which we started at the beginning of the year, I want to direct your attention to the Paramyxo virus in the next couple of newsletters.
The Variola- and Herpes viruses were discussed in previous newsletters. Just as these viruses, I want to start by giving some scientific information and give more information in the next newsletter about the practical consequences.
Paramyxo virus (part 1)
This disease among pigeons is caused by the paramyxo virus serotype 1. It consists of a variation of the NCD virus which causes Newcastle among poultry. This disease occurred massively for the first time in Holland and Belgium around 1983. Typical were in the first years, the watery droppings and serious nerves problems. Nowadays, we see various aggressive and less aggressive strains, which could cause nerves problems. The prevention of these virulent strains, made sure that the symptoms are not that recognizable and the diagnosis can be missed. Even the required vaccination before the racing season makes it hard to control this virus. We could say that this virus has gained a foothold in Europe, also called endemic.
The paramyxo virus infection frequently appears in the fall, from August/September through November. The incubation period (the time between infection and the first symptoms) depends on the strength of the virus and can vary from three days to five weeks. In the first years of this virus, the first symptom showed within one week till ten days. The pigeons can carry the virus for a long period without the pigeon fancier’s knowledge.
The pigeons can become infected through contact with already sick pigeons or by inhaling the virus. But even eating infected grains or drinking from an infected drinker could be the cause of the infection.
On not-vaccinated lofts, all pigeons will be infected, but the death ratio can vary, nowadays, it’s usually five percent. Death caused by a paramyxo virus outbreak, is common among youngsters still in the nest bowl.
In case of classical symptoms during a paramyxo virus outbreak, death can occur through the inability to drink or eat caused by problems with the nerves.
Traditionally, the paramyxo virus causes lesions in the brains and kidneys. In the kidneys, there is interstitial nephritis which means that the kidneys are unable to reabsorb enough fluid and the droppings become watery. This has nothing to do with intestinal problems. Thanks to the fluid loss, the pigeons will drink quite a lot and results in the so-called poly-urie poly-dipsie (Pu/Pd). The water intake could increase up to two to three times the normal quantities.
The watery droppings can remain up to two months. The droppings will slowly become more firm. But for a part of the infected pigeons, the watery droppings will remain.
Clearly, there’s a distinction in the fecal matter between diarrhea and Pu/Pd. In the latter, the dropping matter is almost normal, but there’s a small puddle of moister surrounding the feces.
The pigeons could remain in a good condition, but only if they keep eating.
From the moment one can speak about brain damages, the pigeons are unable to eat properly (twisting heads, vibrations of the head, leaning heads) and this will lead to a decline of the condition. In case of paralysis of the feet and wings, due to brain damages, recovery is out of the question.
The light cerebral symptoms will fade away eventually. Still, in case of stress, some symptoms, like a light leaning head or vibration, could appear. A typical symptom of paramyxo infection is pecking next to the food.
The real classical signs of paramyxo are less present nowadays. This leads to pigeon fanciers who contribute watery droppings to diarrhea and threat this with antibiotic, in vain.
In case of the classical symptoms of a paramyxo infection, the diagnosis is made on basis of the symptoms and the disease progression. To confirm this diagnosis, there has to be a serologic test. Obviously, this is only wise when the pigeons are not vaccinated. If this has already happened, the antibodies could originate through the vaccination instead of the infection. If you want to do this properly, after a while, you have to repeat the test to see if the titer has increased due to the virus infection.
During an outbreak, for several years, we perform in our clinic a Quick test which shows if the virus is present in the cloaca or during necropsy of the brain. Through these Quick tests, it is possible to prove if the virus is present in pigeons who you wouldn’t think to check on the paramyxo virus.
Through necropsy, it is possible to prove a paramyxo virus infection. Often the kidneys are swollen. And supporting histology can confirm the diagnosis.
In case of turning heads, you can think of a Salmonella infection as an alternative diagnosis. Also, the brain symptoms could be signs of an overdose of an imidazole compound, which is used to treat Trichomoniasis.
Watery droppings in the nest could come from the change from crop milk to grains during breeding.
In principle, you have to isolate the infected pigeons with moderate symptoms from the flock. Also, you have to avoid stress and direct the treatment on supporting the pigeons. This means that you can’t feed them too much, you can’t limit the water intake and supply them with vitamins and trace element preparations. A treatment focused on raising the resistance is useful. Even an emergency vaccination during an outbreak could be useful, because the protection from the vaccination becomes effective after one week. In Belgium, you have to report a paramyxo infection to the authorities. After mentioning this, there are appropriate measures to be taken.
In the next newsletter, I will discuss the practical approach of this serious matter.
Regards in sport,
Peter Boskamp. D.V.M.
Written by Peter Boskamp
Newsletter May 2012
Herpes virus (part 2)
The herpes virus in practice.
In the last newsletter, i described the scientific facts of the Herpes virus. But what is the impact of this virus in everyday practice?
As I explained before, a lot of pigeons are latently infected without any signs of symptoms. We have seen that most of the young pigeons between the age of two and ten weeks old, are infected by this virus. Some are extremely sick so that death follows. In these cases, the symptoms concentrate mostly in the upper-respiratory system and, frequently, the pigeons have the symptoms of Coryza .
But before the birds can reach this level of illness the resistance of the pigeons has to be at a low level. This happens during weaning but even caused by overcrowding in the lofts and during transport in less fortunate circumstances, such as are high temperatures and humidity.
In case of an outbreak, there is not so much you can do to defeat the virus. For virus infections in general, antibiotics are not available and non-effective. Still, there are a lot of fanciers who request for antibiotics to “fight” a virus infection. As long as the expectations are to treat secondary infections, this is no problem. During an infection outbreak, with the diminished resistance of the pigeon caused due to the infection, bacteria that usually are useless are responsible for the secondary infections. It could be wise to treat these secondary infections. The pigeons are busy fighting off the primary infection.
These kind of infections will emerged easier if the pigeon is infected with another infection, like canker, coccidiosis or worms. Fighting off these infections is just as important as increasing the general resistance.
For a long time, the reactions on Herpes infections were laconic. The number of lofts dealing with extreme outbreaks were low. But the last few years, we have seen in our practice an increase of clinical infections, where the severity of the symptoms are growing. Reason for every fancier to become more cautious. A possible reason in this increase is a larger number of Circo infections, because this last virus makes sure that the resistance of the pigeon is low. The Circovirus affects mostly immune cells. The response of the resistance will decline because of this. The degree in which the resistance is affected depends on the moment of infection of the (young) pigeon. The sooner this happens, the more damage the virus does. When the pigeons are vaccinated against paramyxo, but in the meantime are infected with the Circovirus, the response to the vaccination will be none or non-optimal. Protection through the vaccination for the field virus will be limited, the pigeons could show clinical signs of a paramyxo virus infection. The degree in which this will happen, depends on the degree of damage caused by the Circo infection.
Back to the Herpes virus. It is not hard to imagine that pigeons who are latently infected with the Herpes virus (one of the many), in case of Circovirus infection, are first to be affected with the dormant Herpes virus.
The Circovirus affects the immune organs of young pigeons, which still have to develop fully, in a way that the pigeon becomes ill of this Herpes virus. An active Herpes virus can, as we have seen with a diminished resistance, destroy it all. (Often with symptoms which suspect an Adeno-infection)
Under the best circumstances there will be possibly a few symptoms. But during stressful times, the virus will emerge. The orientation of the pigeon will be extremely affected.
It is too short-sighted to contribute the great losses which occur increasingly among youngsters from 2005 until now, to this virus. Personally, i strongly feel that this is happening, possibly accompanied by the paramyxo virus.
The problems were in the picture since the rise of the Circovirus during the millennium. However, in the last couple of years, as we all could have seen, the infection rate increased in a lot of places. Due to the limited capacity of the immune organs, the pigeon is unable to respond adequate. This means that the pigeons can massively multiply the virus. If you put the pigeons in the baskets (in general the pigeons look healthy) during transport, they will become a source of contamination for the entire convoy. After just a week, the infected youngsters can suffer from this virus during the next flight and will be unable to get back home.
There is no medication to cure the virus. Just for the accompanying infections. Therefore, the strategy has to be focused on prevention. On one hand, to support the own resistance of the pigeons if this is possible (for example with Bony SGR or Bony Sambuccaplus).
For viruses in general, we have to protect our patients through vaccination.
25 years ago, there was a vaccination for the Herpes virus. But it was ineffective. Nowadays, the research and development has moved on. Just 25 years ago, I drove a car. But now, 25 years later, my car has a lot more features. The fact is that a vaccine made 25 years ago that was ineffective does not mean that a vaccine developed nowadays still is ineffective. A critical view of these new developments is welcome. And this is a wise thing to do. But we have to stop claiming that the earth is flat, when we all know it isn’t!
In 2005, a Hungarian colleague reported good results with a new Herpes vaccine. I was skeptical. After all, it is generally assumed that it is hard to develop good and effective vaccines against the Herpes virus. But it was possible for other species. For cats, there is a effective vaccine, as well as for cattle. The vaccine strongly reduced the Herpes virus problems amongst cattle.
In the last couple of years, I contacted a company to get the vaccine available in Holland. During 2011, when the vaccine became available, we have vaccinated 5,000-6,000 pigeons with the combination vaccine (Herpes-paramyxo). We vaccinated twice, with three to five weeks between the injections. With every vaccination, I told the fanciers: ‘don’t shoot the piano player!’ Surely, we had to experience if there were less mortals among these vaccinated youngsters. And we had to exclude the factor ‘luck’.
The first season expired, and I can report a group of happy and satisfied pigeon fanciers. There were reports saying that there were less stray youngsters and there were reports stating that the pigeons did not suffer as often as they used to do from respiratory problems.
Cautiously I dare to claim, still with some hesitation, that this vaccine can contribute in a positive way in keeping the virus within the limits of the growing problem of dying youngsters. After this season, we can with the available and more detailed data, exclude the factor ‘luck’ completely. It is possible that by frequently vaccinating, we can reduce the problems with the Herpes virus, like it works for cattle.
If you don’t see any benefit in vaccinating, you can consider to support and optimize the resistance of the pigeons.
If you meet at your loft a Herpes virus outbreak this season, be wise enough to, with optimal support for the youngsters, give the pigeons enough time to eliminate the infection. After all, even we can’t enter and play in a game if we are suffering the flu. If you still make the choice to enter the pigeons for a race it is almost for sure that most of the pigeons get lost.
Written by Peter Boskamp
Newsletter April 2012
Herpes Virus Part I
In the last newsletter, I started to describe the viruses which affect the pigeon sport most at this time. Because of several observations and practical experiences which require more research, I talked first about the scientific data as far as the research goes, to continue with the more practical aspects and consequences of an infection with the variola virus.
I will describe the Herpes virus in the same way. About two years ago, I dedicated some of my time to the herpes virus. But the questions about this virus remain. That is why I’m revisiting this subject. In this newsletter I will talk about the scientific data so far. The next newsletter is about the more practical aspects and the consequences.
The herpes virus.
The herpes virus among pigeons (DHV1) is starting to get more and more attention. It deserves the attention it gets from the pigeon fancier. The virus occurs (without any symptoms) in a lot of pigeons. This can be reduced through the specific antibodies in quite a lot of pigeons. It is estimated that at least fifty percent of the pigeons have these antibodies. Thus over half of the pigeons are latently infected. Herpes viruses tend to ‘retire’ after infection of the host. In periods of stress the virus can regain its effectiveness. This would explain why most of the symptoms show when the resistance of youngster is down, for example after weaning and during training flights.
Sometimes older pigeons secrete this virus without showing any symptoms. These pigeons are known as a virus carrier.
For a long time, people ignored herpes infections in pigeons. The clinical cases of a pigeon herpes infection are rare. Usually the youngsters are infected at an early age, especially during feeding, by the old pigeons. They have enough resistance due to the antibodies received from the mother (maternal antibodies). That is why these pigeons won’t show any clinical signs. But they are infected for the rest of their lives.
Clinical signs can be expected in pigeons who came into contact with the virus and who haven’t got enough or any antibodies. This could happen with recently bought youngsters placed at the same loft of the youngsters of the pigeon fancier. The signs can appear after 5-7 days. When rapid cell multiplication occurs, the infection pressure can become so high that youngsters with few antibodies show symptoms and become sick. This way, the virus can remain active in the loft for a long time. With all of the consequences for the youngsters racing season. The recovery of the herpes virus can take from one week up to three weeks.
During stress situations such as in the transporters, the carriers of the herpes virus can secrete the virus. This will occur sooner if the resistance of the pigeon is low.
Research in Germany showed that in the month July there is a spike in the virus secretion during transport and the research showed that 60% of all manure samples are positive for the herpes virus.
Especially young pigeons, two to ten weeks old, are most likely to show clinical symptoms. These symptoms vary quite a lot. From acute mortality with losses among the youngsters through to the more usual conjunctivitis, which we address as ‘ the membrane’. Traditionally, the herpes virus is connected with the Coryza contagiosa complex (infectious snot).
If we recite the complete characteristics of the herpes virus, you have to consider that these occur in only a limited number of cases. Often you can observe only a small range of these symptoms. Reaching the diagnosis ‘herpes virus infection’ is hard with only a few observable, clinical symptoms. The most typical symptoms are a yellowish coating in the beak and pharynx. These coated are, in contrast to diphtheria caused by serious canker infections (which occur sporadically nowadays) as a loose membrane on the mucous membrane of the beak, tongue and pharynx. The virus affects primarily the upper-respiratory tract and the mouth- and throat cavity and the larynx, the crop and the esophagus. Because of the degradation of the crop, pigeons are having a hard time digesting their food, and it is causing the complete loss of their appetite. Although the syndrome occurs mostly among youngsters, from two to ten weeks old, old pigeons can shows signs as well. During a serious outbreak, the mortality rate can be as high as fifty per cent, due to this virus infection. But the seriousness of the occurring symptoms depends on the resistance of the pigeons and the virulence of the virus itself. This virulence varies quite a lot, so the seriousness of the symptoms vary as well. Often we encounter mild symptoms, which only shows through a membrane in the eyes.
Other diseases which show symptoms like coated in the beak, are canker, the smallpox-diphtheria antitoxin and candidiasis. Sometimes you can detect dried mucous after a long flight. The smallpox-diphtheria antitoxin and canker have a rather cheese like moisture and so they have a different diagnosis.
Because the majority of the herpes virus infection have a mild infection course, the role of this virus is more in the spectrum of the ornithosis-complex. Against the virus itself, you can do little. If there is a serious infection, you can treat the pigeon with preventive medication to support the pigeon in fighting of other additional infections. If the infected pigeons are prize winning pigeons, you can treat these pigeons with Acyclovir for ten days consecutive to temper the infection and reduce the influence of the virus. You can’t expect a panacea. To complete the support of the very sick and infected pigeons, you can use Marbocap and Synulox. In case of a herpes virus infection, you have to disinfect the loft with Koudijs-dry fumigant or Virkon S (let it soak).
In the next newsletter, I will describe the more practical consequences of this herpes virus.
Peter Boskamp D.V.M.
Written by Peter Boskamp
In my previous newsletters, I indicated that there are a number of pathogens threatening our pigeons. Viruses are in a sense problematic, because of the, usually few curatives (healing) which can be undertaken. In case of a virus infection we can only treat the secondary infection to minimize the discomfort for the pigeon. The only way to prevent these attackers is vaccination. But this is only possible if there’s a vaccine available. In a few cases there are still no vaccines, not yet anyway. An example is the Circovirus. Today there is no vaccine available for this virus, which cause serious consequences. I will explain in the following newsletters the most common viruses.
In this newsletter I will address the smallpox virus. In the first part of this newsletter I will explain the scientific side of this virus.
1. Scientific information
2. Personal comments – practice
Small pox among pigeons is caused by Avipox columbae. The virus is host specific, but related to chicken- and turkey pox. This is known as the so called typical pox. There are also atypical variola infections. One of these atypical variola infections is the blood wart virus. This virus is not likely to be related to the typical variola. It causes the well-known blood warts, which often occur under the wings.
The fact that variola is host specific means that pigeons cannot contract the smallpox virus from, for example, chicken, canaries or even sparrows.
Way of infection
As said, pigeons can only be infected with the pigeon variola. An exception are chicken, they can have an immunological reaction to the pigeon variola.
Smallpox occurs frequently among pigeons. Even with wild or city pigeons.
Traditionally, this disease bursts out in the late summer or the fall. The cause of this can be found within the fact that in that period of the year the insects and bugs who spread the virus, are more common, like mosquito’s. But even the red feather mite can spread the same virus.
Besides the insects which spread the virus, an important factor in the spreading of variola are the “fights” between pigeons. Basket infections can provide the outburst of the virus in program players. The outburst occurs after one week of the flight on which the pigeons were infected. The performances of the pigeons during that flight were not affected. The incubation, the time between the infection and the actual outburst of the virus, is usually seven to ten days, with an extension to 20 days.
Fights and bites of insects make sure that the virus can penetrate the body of the pigeon. Pigeons that are infected with variola excrete the virus through saliva, tears and sometimes through the manure. The virus is released after the destruction of the epithelial cells and spreads further.
We distinguish two clinical pictures of smallpox:
- 1. The skin manifestation.
Usually the little smallpox occurs on the skin, most of the times the skin surrounding the eyes or the corners of the mouth of the beak. But even, although less frequent, around the ears, the cloacae and the paws. In short, on the small feathered skin areas.
It starts with little nodules of the size of a matchstick button, or vesicles which can grow to the typical lesions, consisting of overgrowth of skin cells that can be dropped.
- 2. The manifestation of diphtheria.
In which overgrowth of the mucous membrane in the beak happens, including the tongue and the pharynx. These so-called pseudo membranous, (yellow) lesions can be misunderstood by a fancier for a canker contamination. It is to be said that when there’s a variola infection, it is easy to diagnose a canker contamination. But the lesions in the beak are primarily caused by smallpox. Pigeons won’t die from a smallpox infection itself, but if the overgrowth surrounding the beak and eyes grows too serious, the pigeons are not able to feed themselves and due to this fact, will die from starvation.
Whether the pigeons get a serious overgrowth, or just a single pox, it all depends on the resistance of the pigeon and the virulence (infection power) of the virus. Sometimes the infection stays limited to a single pox. This happens amongst the pigeons which were once vaccinated, but at the time of contamination had little resistance. Other (not vaccinated) pigeons in the loft can develop serious overgrowth of the eyes, nasal caps, beak and in the mouth and pharynx in the meantime.
The diagnosis is easy to establish through the clinical manifestations. One has to consider a “Multiple” diagnostic for Trichominiasis, Candidiasis or a Herpes infection. Sometimes the inflammation lesions of a fight can mimic a starting pox. But usually the symptoms are obvious.
The disease is, as said, a viral infection and antibiotic as a treatment does not help. Still, in a lot of cases, serious cases, antibiotics can be used to treat and includes the effects of secondary bacterial infections. For the virus itself, it’s no remedy.
In case of severe overgrowth, you can try to remove the overgrowth by using a sharp spoon. It should be noted that the best thing to do is to remove just the upper layer to prevent unnecessary bleeding. After this, you can moisten a swab with 2% iodine solution or a solution of iodine in glycerin, and rub it on the lesions. This has to be repeated for several days consecutively. In case of just minor overgrowth, the best solution is to rub the iodine solution without removing the upper layer of the skin. The pox will dry out after while and drop off after four to six weeks. The pigeon will recuperate fair to good. Exceptions are the pigeons who suffer from overgrowth under the nasal capes.
You cannot treat the pox near the eyes with the iodine solution if there is a chance that the iodine comes in contact with the eye.
The only way to prevent the pigeons from an outbreak of the smallpox is vaccination.
Once infected by the variola virus the pigeon will be protected for lifetime against this virus. This is not the same for vaccinated pigeons. It is recommended that one repeat the vaccination for smallpox every year. If the pigeons remain on a regular base in a contaminated environment , the vaccination will be stretched out in a ‘natural’ way through exposure to the wild virus. If exposure to the wild virus is omitted, which is usually the case, the protection through the vaccination will weaken, which means that the pigeons are more or less susceptible for the variola virus.
The pigeons must be at least six weeks old to get a sufficient immune response from the vaccination.
It is possible to vaccinate through the feather follicle method or the combination Colombovac PMV-Pox vaccination.
Don’t use this vaccine in combination with a, for example, paratyphoid vaccine due to the then to be expected serious vaccination reactions.
When you use the feather follicle method, you have to be careful not to damage the skin and cause any bleeding when you’re pulling out a dozen feathers. If this unfortunately happens, you have to make use of the other leg for the pigeon’s safety. If you don’t, there is a reasonable chance that the vaccination is incomplete, because the bleeding will not allow the vaccine to enter the pigeon’s body.
With a little brush, moisten with the vaccine, you have to rub the vaccine on the skin in the opposite direction of the feather growth. After the vaccination the pigeon can show after eight to ten days a vaccination reaction, which means that the pigeon can stay together. During this reaction, it is not recommended to let the pigeons fly because of the threat in of serious losses.
It is recommended to vaccinate well before the racing season.
Vaccinated pigeons can still be carriers of the virus, so the best way is to vaccinate all the birds.
If you decided to make the choice to vaccinate by the feather follicle method, the pigeons can’t given the opportunity to take a bath during a week direct after the vaccination. Further, it is important to check for an actual vaccination reaction. This is really important to see if the vaccine is working. In this case the follicles in the skin will be swollen and the skin changed from color.
The smallpox virus is less sensitive for moisture, air, drought and low temperatures. . So the virus can remain in the loftt for a longer time.
In the next part of the newsletter I will talk elaborate about the practical aspects of a smallpox infection.
Till next time !