Paratyphoid is caused by a Salmonella bacteria. This Salmonella var. Copenhagen is specific for pigeons. Although this disease is widely acknowledged by pigeon fanciers it is still an underestimated illness.
A lot of fanciers have carriers of paratyphoid in their lofts without knowing or suspecting it. This is exactly the main problem with paratyphoid. As soon as there are clear symptoms and the fancier can do some treatment and vaccination, there is a better health in the loft in general and better racing results. But as long as the symptoms are not clear, the birds just don’t seem to get in good condition without finding an indication why.
The disease can be acute or chronic. The acute disease only occurs when the birds were never infected with Salmonella or vaccinated in their lives and so don’t have any immunity for the disease. In the acute form there is diarrhoea, sometimes even with blood, and anorexia. The pigeons also drink more water. And when there is no treatment there can be deaths because of the dehydration. When the disease gets chronic (in most cases) the Salmonella bacteria gets in internal organs and causes inflammation there, f.e. in kidneys, lungs, liver, spleen and reproductive organs. It can also in some cases (but not that often) cause arthritis or nervous symptoms. Because of the infection in reproductive organs the bacteria can get into the eggs and so cause infection of the hatchlings.
In the chronic form the symptoms are much less clear. In a lot of cases it is just not getting the birds in condition although there is no clear diagnosis of any disease. In a lot of cases the breeding is not always that good with sometimes “black” eggs (dead youngster in the egg) or bad reproductive results in general. Sometimes only one breeding hen just doesn’t seem to get in right condition and has trouble laying eggs. The birds also seem to have less appetite and lose some weight.
The diagnosis of the disease is often difficult. There are a lot of false negatives. This means there is no Salmonella found although the disease is present in the loft. One way of diagnosing is collecting droppings from all pigeons for five consecutive days and let it be investigated. Another good way is through autopsy of ill birds or birds that are strongly suspected of having the disease. A last way is by determining antibodies in blood samples, but also in these cases you only find antibodies in pigeons that have been recently infected.
Next to the difficulties in diagnosing the disease, the main problem is treatment. Actually there is no really good treatment for the illness. Antibiotics and vaccination are both not 100% effective. Most antibiotics can’t clear the carriers of the disease. There is even a lot of scientific data that most antibiotics induce more carriers than without treatment. Only enrofloxacine seems to have best effects also on carriers, but in practice there are still a lot of carriers of the disease after long treatment and high dosage. New scientific data show that with a very high dosage of enrofloxacine there couldn’t be any Salmonella found any more in internal organs after autopsy. Still in practice it is better to do a good vaccination schedule after antibiotic treatment.
The kind of vaccine seems to be less important than the vaccination schedule itself. There are dead and live vaccines. In Belgium there is only a commercial dead vaccine but if the bacteria has been isolated, the fancier can also have an autovaccine made. The advantage of live vaccines would be that there is a better cellular immunity. As this Salmonella is capable of surviving in macrophages, a sort of white blood cells, cellular immunity (killing of infected cells by the immune system) is more important than humoral immunity (immunity by antibodies in the blood). In practice it seems that also dead vaccines are effective, but as said they are not 100%. This means that in some cases the birds can still get ill, but certainly do not die any more.
More important is the vaccination schedule. In all cases it seems very good to vaccinate the birds twice the first time. This means that you should give them a prime vaccination and give a second vaccination one month later. Then, depending on the vaccine, the vaccination has to be repeated once or twice a year.
I always advise to vaccinate even if there is no real indication of problems in the loft. When the fancier doesn’t vaccinate there should be at least a regular examination of the droppings. But in a lot of cases when fanciers follow a good vaccination schedule the racing results are also better.
12/11/2010 - Dr. Ruben Lanckriet
SALMONELLA a FAMILIAR AND IMPORTANT DISEASE FOR PIGEON FANCIERS .
BY DR COLIN WALKER
Paratyphoid- one of the most familiar and important diseases for pigeon fanciers. Paratyphoid is caused by a bacteria called Salmonella. This is the disease that has been with pigeon fanciers since pigeons were first kept and yet even in recent years, this problem is still revealing some of its secrets to us. Much of our understanding and knowledge, diagnostic methods and treatments have changed in the last 10 years. This chapter is a summary of our current knowledge about this disease and includes the current diagnostic techniques and recommended treatments.
Nature of the Disease
Paratyphoid affects pigeons world -wide. All types of domestic pigeons can be affected. Salmonella, however, at least in Australia, appears to cause clinical disease in fancy pigeons more commonly than racing pigeons. Some breeds of fancy pigeons seem particular susceptible, in particular modenas, show homers and the performing flying breeds such as tumblers, tipplers and rollers but particularly doneks.
The outcome of exposure to Salmonella is very much affected by factors relating directly to the individual pigeon including its age, general health, level of nutrition, paratyphoid vaccination status, genetic make-up and whether it has had any earlier exposure to the disease that might have enabled it to establish some nature immunity. As a general rule younger pigeons are more susceptible to clinical disease. Management and environmental factors that compromise the general health of the birds, such as overcrowding, poor diet and concurrent parasitic infections, all compromise the birds’ ability to resist infection and increase vulnerability to clinical disease. Infected birds shed Salmonella in their droppings and the bacteria, once in the loft environment, can survive and multiply. Poor hygiene in the form of accumulated droppings in the loft and also feeding and watering practices that allow for dropping contamination of food and water, not only compromise health generally but provide high exposure to the organism. Salmonella bacteria survive particularly well in the loft environment if it is warm and damp. Severe outbreaks of clinical disease can occur if there is high exposure to the organism in a group of pigeons, which have a reduced ability to fight the infection due to poor management practices or a poor loft environment.
In pigeons, the disease can take several forms:
In young pigeons the usual form seen is called the bowel form of the disease. In young pigeons, after ingestion, the bacteria multiplies in the bowel, causing an enteritis that can be fatal. This is the classic ‘going light’ with the birds developing weight loss, lethargy, green diarrhoea and loss of appetite, sometimes leading to rapid death. This is the usual form seen in very young pigeons but can occur in older pigeons with an impaired ability to fight infection.
Older birds (i.e. greater than 3 months of age) are more likely to survive bacterial replication in the bowel but the bacteria can then penetrate the bowel wall, enter the blood stream and then be carried throughout the body. Signs displayed by infected birds depend on where the bacteria localise.
Common sites that the bacteria infect are:
The meninges – leading to the meningeal form of the disease. The meninges are the membranes surrounding the brain, when inflamed this interferes with the brain’s function so that the bird may be poorly co-ordinated, hold its head in an unusual position or be paralysed.
The joints – leading to a Salmonella bacterial arthritis. Affected joints in the wings and the legs become red, hot, painful and swollen. The infection can erode cartilage from the joint surface and cause extensive damage to the joint generally. A delay in the onset of treatment may mean the joint is left permanently damaged.
The gonads – affected birds often look remarkably well, with the infection only becoming obvious at the next breeding season. Hens with infected ovaries often have late or irregular ovulations or no ovulations at all. Salmonella can be incorporated in the egg at the time of its formation in infected hens. The bacteria then infect the developing embryo. Embryonic death can occur (usually in the mid-third of incubation). If the chick survives through to hatching, it may hatch in a weakened state, dying in the first two weeks of life. In young cocks with infected testes, Salmonella is a cause of premature infertility.
Multiple organs – Here the bacteria become widely distributed throughout the body, localizing in many organs, which may include the liver, kidney, spleen and respiratory system. Pigeons with this form of the disease present as very sick pigeons. They are often hunched, fluffed, not eating, have green mucoid droppings, rapidly lose weight and may die, often quite quickly.
Despite the severity of symptoms sometimes displayed by infected birds, all birds are worth treating. The main factor determining whether or not a successful outcome is achieved is the time between diagnosis and starting the correct treatment. A delay often gives the disease too much of a head start. Birds with the meningeal form of the disease may be so poorly co-ordinated that they need to be hand fed. However, brain infection in birds always carries a much better prognosis than in mammals. In mammals, function returns after brain injury because adjacent areas of brain tissue learn to take over the function of the damaged area. Birds, however, have stem cells in their central nervous system, which gives them the ability to actually regrow damaged areas of brain. When in the joint, the infection can quickly damage the cartilage surface. Even with successful treatment, this rarely heals perfectly leading to joint pain on exertion. The prognosis for subsequent racing is guarded but these birds can be retained for breeding. Both the testes and ovary are fragile organs and a delay in treatment can lead to permanent damage and a reduction in fertility.
When pigeons are exposed to Salmonella, a variety of outcomes can occur. Some birds may clear the organism from their system without becoming unwell. Some will become sick. Even with effective treatment and apparent recovery, not all birds will clear the organism from their system. Birds that appear normal but are carrying the infection in their bodies are called asymptomatic carriers. We now know that these are the main source of infection. These carrier birds intermittently shed the organism in their droppings. Further birds become infected, typically, through ingesting food or water contaminated with these birds droppings. Asymptomatic carriers although carrying the organism in their system may appear completely normal or, at most, only show mild systems such as intermittent diarrhoea or perhaps even more subtly reduced race performance or reduced reproductive ability.
A common thought amongst fanciers is that if some birds are unwell and there is evidence of mice in the loft, then perhaps their birds could have paratyphoid. Up until recent years, standard knowledge throughout the veterinary and pigeon community was that paratyphoid in pigeons was caused by the bacterium Salmonella typhimurium. This species of Salmonella was regarded as a wide-spread organism in nature. It was thought that the variety that infected pigeons also infected many other animals, particularly rodents. After all, the organism’s name “typhimurium” literally means typhoid of mice. It is now thought that this is unlikely. We still have a lot to learn, but our understanding of Salmonella infection in pigeons has changed over the past few years. Today’s technology enables us to type various strains of Salmonella very specifically. The Salmonella strains that can cause clinical disease in pigeons can be identified right down to the phage type. It is thought that these phage types are likely to only cause disease in pigeons. This means that Salmonella strains found in other animals such as wild birds, chickens and other mammals including rodents don’t cause disease in pigeons. It seems likely that Salmonella in pigeons is a pigeon to pigeon disease with the source of infection being asymptomatic carrier birds or their droppings. Non- infected birds can be exposed to asymptomatic carriers in the race basket or in the home loft if carriers are introduced by the fancier.
The Infectious Organism
The actual type of Salmonella that infects pigeons has been identified as Salmonella enterica, subsp. enterica, serovar typhimurium, variant copenhagen, Anderson phage types DT2 and DT99. The available evidence suggests that disease in pigeons is caused by these serotypes. Evidence also shows that these types are isolated extremely infrequently from species other than pigeons. Further research is expected to show that these types are in fact what is called ‘host adapted’, having evolved with the pigeon and only capable of infecting it. Other Salmonellas can occasionally be isolated from the droppings of pigeons, but it is thought that these are simply transients, having been accidently ingested by the bird and passing through the system but not capable of causing disease. Many pigeon fanciers who currently believe that pigeons catch Salmonella from rodents will need to alter their way of thinking as we now know that this is no longer the case. Several other species of Salmonella are also known to infect only one species. Examples include Salmonella gallinarum that only infects chickens (causing Fowl Typhoid), Salmonella dublin (that only infects cattle) and Salmonella choleraesius (that only infects pigs).
The knowledge that the variety of Salmonella that causes clinical disease in pigeons is species-specific for pigeons and can only cause disease in them has two immediate ramifications:
Zoonoses – historically pigeons and their droppings have been regarded as a potential source of Salmonella infection in humans. Obviously this needs to be reviewed.
Import requirements – currently in Australia there are periodic outbreaks of paratyphoid in legally imported pigeons whilst in quarantine. The Government tests this Salmonella and when identified as Salmonella typhimurium, a strain regarded as endemic in Australia, the birds are still allowed entry into the country. The aim of quarantine is to prevent the introduction of exotic disease. Thus, so detecting the presence of a disease already known to be in Australia is not a reason to halt release of the birds. Given the current technology, this protocol perhaps needs to be revisited to ensure that these strains are in fact not exotic to Australia. Salmonella in pigeons in Europe (the source of most import birds) behaves quite differently than in Australia. Given the current protocol there is the potential to introduce now Salmonella strains with different drug resistances and clinical characteristics etc. The Government has suggested that it is up to the pigeon community to present evidence to them as to why the protocol should be changed but, of course, most pigeon fanciers do not want the protocol changed, they just want to get the birds, even though they run the risk of getting a new exotic Salmonella variety. At the moment, it appears the current situation will continue until there is some disease disaster at which time there will be a lot of finger pointing.
As our knowledge continues to evolve over time, Salmonella will become more fully understood but as it stands at the moment, it seems that pigeons carry very distinct varieties of Salmonella. It is only certain phage types that cause clinical disease in them. These phage types do not cause disease in other animals. These Salmonella phage types can be carried totally asymptomatically by carrier birds. The standard knowledge that particularly in pigeon lofts, exposure to rodents and to a lesser extent other animals and birds as the usual source Salmonella is no longer accurate. The likely source of infection is chronic asymptomatic carrier pigeons.
MANAGING SALMONELLA IN THE LOFT
The aim of any pigeon racer is to keep the stock birds healthy and in breeding condition and to field successful race teams. As paratyphoid can adversely affect both these things, it is obviously important that the disease is correctly managed. The initial aim ideally should be to keep the organism out of the loft. Although ideal, this is difficult to prevent given the nature of pigeon racing and showing where many birds from many lofts intermittently mix . Some fanciers accept introduction of the organism as an inevitability, so for them the aim then shifts to doing what can be done to protect the birds and minimising the impact of the disease should it gain entry.
TREATING THE DISEASE
Treating paratyphoid involves several steps.
Accurate diagnosis. Make sure the problem is Salmonella. Don’t jump to conclusions. The symptoms of Salmonella infection resemble those of other diseases. Don’t make an intelligent guess by yourself based on symptoms. In particular, not all ‘dead in shell’ youngsters are due to Salmonella, in fact most aren’t. There is the potential to waste both money and time on the wrong medications and approach while the real cause of the health issue just becomes more established. Consult an avian vet and get an accurate diagnosis.
Effective antibiotic treatment. Once Salmonella has been diagnosed by your vet it is always best to have the actual strain identified in your birds tested by your vet’s lab against a number of antibiotics to see which antibiotic is most effective at treating it. This test is called a micro, culture and sensitivity (abbreviated to mc and s) and is surprisingly economical. With today’s multi-resistant strains of Salmonella, it is possible to spend a lot of money and put a lot of effort into using an antibiotic that just will not work. Don’t be cheap. Have the testing done. That way you will be confident that the antibiotic you are using will be effective in your loft. Most common Salmonella strains are sensitive to either the fluoroquinolone antibiotics, e.g. enrofloxacin, “Baytril” or sulphur-based antibiotics, eg trimethoprim/sulphadiazine, “Sulpha AVS”. Some are sensitive to tetracyclines, e.g. doxycycline. Few are sensitive to the penicillins, e.g. amoxicillin. Once the antibiotic to be used has been selected, this needs to be given as a long course. Treatment times of 10 – 14 days are usual.
Thorough cleaning. While the antibiotic course is proceeding, the loft needs to be thoroughly cleaned. A diagnosis of Salmonella is one of the few indications for actually wetting the loft with a disinfectant. Pick the morning of a warm day. Thoroughly clean the loft. Move the birds out. Spray the diluted disinfectant (e.g. “F10” or “Virkon”) onto the scraped surface and into the nooks and crannies.
Another disinfectant agent recommended by vets is chlorine dioxide. A common brand name is “Oxine A.H.”. This is useful to help control not only bacterial but also viral problems. When using this, citric acid is added to make ‘activated oxine’. The resultant solution will turn yellow and give off a faint odour of chlorine. This is diluted into water 5 ppm for the drinking water and 200 ppm for loft fogging (e.g. with a “Fog master”). After adding water the solution can be used for 7 – 10 days and does not lose potency. The birds can be left in the loft during fogging.
Providing ongoing good care. Birds that are rundown cannot mount a good immune response. Part of the job of clearing any infection comes down to the pigeon’s immune system. This needs to be in good shape. Ensuring the birds are well fed, kept clean, not over crowded, have good parasite control and are in a loft that is warm, well ventilated and dry sets the stage for the immune system to work well and help clear the infection. Problems here will interfere with the bird’s ability to recover. Thorough veterinary testing will reveal any other concurrent health issues that need to be addressed. General management and the loft environment should be reviewed.
DIAGNOSING THE DISEASE
It may seem overly apparent, but basically paratyphoid is diagnosed by identifying the presence of Salmonella bacteria associated with disease. It is important to remember that strains of Salmonella can be transiently present within the digestive tract and found in the droppings of healthy pigeons. Simply detecting the presence of Salmonella here is not a diagnosis of paratyphoid. One needs to identify the particular type of Salmonella capable of infecting pigeons and associate this with an actual infection. Paratyphoid can be diagnosed in a number of ways. The two common ways are:
Bacterial Culture. Your vet can collect a swab from a suspect site internally from a dead bird during autopsy or in a live bird from the cloaca, throat, droppings or surgery site. Once collected the bacteria on this swab, be it Salmonella or not, can be cultured (i.e. grown), identified and ideally also tested against a number of antibiotics to see which is the most effective. In pigeons growing Salmonella from any site out of the bowel is always a diagnosis of paratyphoid. When Salmonella is identified within the bowel or droppings, in order to ensure it is not a transient, it needs to be associated either with clinical symptoms associated with infection of the bowel, e.g. persistent diarrhoea, or alternatively inflammation of the bowel identified through histopathology (microscopic examination by a pathologist). Histopathology, although very accurate has the disadvantage of taking up to a week to do and can be moderately expensive.
Antigen Detection Test or QUICK test. In a simple test with a long name (sandwich lateral flow immunochromatographic assay) protein on the surface of the bacteria can be detected. Again, a sample is collected either during autopsy or from a live bird. This sample is mixed with an extraction fluid, the resultant supernatant is dripped onto a test paper and a colour change occurs if the Salmonella protein (or antigen) is present. Quick and easy, this test is comparatively cheap and takes under 10 minutes to do. The ability of this test to give a quick answer is a big advantage, particularly during the racing season where starting accurate medication promptly allows a quick return to competitive racing for the team.
Common ways that a diagnosis is reached are:
In a group of utility, exhibition or racing pigeons. In a group of pigeons displaying symptoms consistent with paratyphoid, a cull bird that is representative of the group is selected and euthanized. This bird must be a typical member of the group so that its results can be realistically extrapolated to be representative of the group as a whole. Within four hours of death the bird is autopsied. This time limit is important as tissue breakdown and invasion of decomposition bacteria occur if done after this time. Tissue samples are collected for histopathology (staining and microscopic examination) and swabs are collected from potential sites of infection for bacterial culture. These tests, although very thorough and accurate, have the disadvantage of taking up to a week to get results and can be relatively expensive.
In a race team during the season. A bird may not be available for euthanasia. In race teams during the race season symptoms can be very subtle. Performance may be below expectations. Individuals may intermittently have diarrhoea. Other tests for disease may be negative. Detecting Salmonella consistently in the droppings (by culture or QUICK test) may warrant a treatment trial on an appropriate antibiotic. A good response to treatment is suggestive of paratyphoid.
In the breeding loft. Breeding birds with poor reproductive performance can be anaesthetised and an endoscope inserted through a keyhole incision in their left flank to examine the gonads. During examination a swab can be collected directly from the gonad for bacterial culture or QUICK test. Identifying Salmonella enables a diagnosis of paratyphoid and identifies the cause of the reduced fertility. Fertile eggs that fail to hatch can be autopsied and samples collected for culture, a QUICK test or histopathology.
In birds with the joint form of the disease, a sample of joint fluid can be collected in a technique called a FNA (fine needle aspirate). The sample can be submitted to the lab for culture or have a QUICK test done on it.
Difficulty in Treating the Disease
If paratyphoid is identified in the loft, it is a very difficult disease to eradicate, for several reasons: -
Problems with antibiotics – Salmonella being a bacteria can be treated with antibiotics. Affectively treating Salmonella with antibiotics is however difficult. This is because
Salmonella has a very particular characteristic shared by only a small number of bacteria. One of the ways the body protects itself from bacterial infection is through a process called cell mediated immunity. In this process, white blood cells act a bit like little ‘Pacman’ engulfing bacteria. Most bacteria once engulfed by a white blood cell are digested by that white blood cell. Salmonella after being engulfed by a white blood cell, such as a macrophage, can survive within that white blood cell. Once there, the Salmonella cannot be reached by antibiotics, the white blood cell protecting the bacteria from them. With the death of the white blood cell the Salmonella is re-released into the system.
Salmonella bacteria in an infected bird are widely distributed throughout the body in the blood stream. At some sites, small pockets of infection called abscesses form. These abscesses become surrounded by walls of scar-like tissue as the body tries to protect itself. Salmonella in these abscesses can survive antibiotic courses and ‘seed out’, back into the system from them once antibiotic courses end.
Pigeon fanciers and vets overuse and misuse antibiotics treating Salmonella infections often leading to inadequate doses and too short courses to effectively kill all organisms. The tougher, harder-to-kill strains are left behind. These ‘resistant’ strains make it harder and harder to successfully treat subsequent disease outbreaks.
Salmonella can survive and multiply in the environment. Even if antibiotic courses were able to completely clear the organism from an infected bird, and they still do this when used correctly in most birds, unless the environment in correctly cleaned the birds become reinfected from that contaminated environment. It is worth noting here the old practice of using lime in pigeon lofts. Lime, apart from creating a dust aerosol when the pigeons fly that irritates the birds’ lungs and air-sacs, creates an alkaline environment in the loft. Salmonella actually prefers an alkaline environment to survive. These days, fanciers should use a proper disinfectant that is registered for this purpose. They are cheap and readily available. Examples include “F10” and “Virkon”.
The difficulty of long-term control is the detection of persistent carriers after treatment. A successful treatment is one where the infection is cleared from greater than 90% of birds. Because of the difficulties associated with treatment, some birds will continue to carry Salmonella after treatment. These birds can subsequently, particularly if stressed, shed Salmonella, re-contaminating the environment and reinfecting successfully treated birds. Repeat treatments are sometimes necessary. There is no fool-proof way of identifying carriers, although repeat cultures and QUICK tests on individuals can be done. Birds, particularly valuable birds that continue to show symptoms or relapse after treatment, can be repeatedly treated in isolation. Some fanciers prefer to cull persistent carriers. Actually detecting Salmonella in all carriers is virtually an impossible task and some birds deemed to be successfully treated will in fact still have the organism in them. Unidentified carriers remaining in the loft is the most common reason for treatment failure.
Keeping the disease out of the loft
Because of the difficulties involved in treatment and successfully eradicating the organism once established in the loft, an effort should be made to try and stop the birds becoming infected in the first place. As mentioned earlier this can be hard in the racing loft because of the large proportion of the lofts inhabitants leaving the loft, mixing with birds of other lofts and then returning on a weekly basis.
In the stock loft bird movement is less and although no method is fool-proof, some measures will decrease the chance of Salmonella gaining entry. Ideally, only obtain birds from lofts (including studs) known to not have a problem with Salmonella. New birds should be regarded as potential sources of the disease. Under stress carriers may shed the organism in their droppings where it can be detected. Veterinary examination of the droppings at other times may give a negative result even in a bird carrying the disease. Quarantining birds (for usually about 6 weeks) is a good idea. Any birds that occasionally become quiet and develop greenish diarrhoea during quarantine should be suspect. As stated above there is no fool-proof way preventing Salmonella entering the stock loft but being selective about where new birds come from, applying a quarantine period and monitoring and testing during this time will all minimise the risk. A further and important way of preventing Salmonella becoming established is vaccination.
Decreasing the incidence of disease if Salmonella enters the loft
In various countries around the world, paratyphoid vaccines are available. Some are better than others. The modern vaccines confer good immunity against the known disease causing strains of Salmonella and fanciers should take advantage of them when they are available. Each brand comes with its own manufacturer’s instructions. These should be followed. The usual recommendation is to vaccinate twice in the first year of life, often at a 3 – 4 week interval and then give annual boosters. Often boosters are timed to be given before times of anticipated high exposure (such as just before racing) or just before a time of anticipated stress (such as just before breeding). It is not unusual to give 10 – 14 day courses of antibiotics before vaccination to clear any latent infections from as many birds as possible and then vaccinate them before they are re-exposed. Vaccinating carrier birds does no harm and may be beneficial but will not clear the bacteria from these birds.
Caring for the birds as well as you can creates a situation where the birds are more likely to resist infection if they become exposed. All the same, the birds should be monitored for symptoms consistent with Salmonella and if a fancier becomes suspicious their cause should be promptly investigated by a veterinarian ( hopefully before the disease becomes established).
In many countries of the world, including Australia Salmonella vaccines are not available. In some lofts the disease has already been diagnosed, eg in a previous racing or breeding season and is proving difficult to eradicate. Sometimes fanciers are concerned that there may be undetected carriers in the loft. Because of the ongoing mixing of birds during racing Salmonella exposure is always a possibility. In situations like these, your veterinarian may recommend prophylactic preventative treatment for Salmonella in an effort to head off a potential flare up of paratyphoid. The two common times that this is done are:
Before breeding – if Salmonella has been diagnosed as a cause of late or irregular laying in the hens, embryonic deaths, reduced nestling viability or death, premature infertility in cocks etc., in a previous breeding season then rather than predictably wait for similar problems to re-occur your vet may recommend treating the birds with an appropriate antibiotic, eg ‘Sulpha AVS’ for 10 – 14 days finishing 2-3 weeks prior to pairing. This is not an attempt to eradicate the disease but rather an effort to reduce the level of Salmonella in the stock loft as a whole so that the disease is less likely to have an impact once breeding has commenced. The 2 to 3 week break between treatment and pairing enables tissue healing to occur at previous sites of infection and allow normal bowel populations of bacteria to re-establish. Probiotics on the food or in the water after the antibiotic course is completed will help with this process. Multi-vitamin mineral and amino acid supplements are also useful during this time to ‘build the birds up’ ready for breeding. This treatment should be combined with a thorough clean of the loft.
Prior to racing – as with the stock birds, a 10 to 14 day course of an appropriate antibiotic as indicated by your vet can be given to the race team finishing 2 – 3 weeks prior to racing. During the racing season the birds are likely to be exposed to Salmonella in the race baskets. Starting the season with healthy birds, controlling other diseases throughout the racing season and maintaining ongoing hygiene and general good care should minimise the impact of exposure. If the disease does gain entry to the loft and cause clinical disease during the season this is serious. Unless detected very early then ideally racing should be stopped and an effective long (10 days plus) antibiotic treatment (antibiotic choice determined by testing) given and racing only resumed when the problem has resolved. The protocol followed by some fanciers of giving short antibiotic courses (ie 2 – 3 days) intermittently through the season to prevent/treat this condition is a waste of time and only encourages the development of resistant Salmonella strains and asymptomatic carriers. It is also thought that these short courses may actually increase the incidence of the disease over time in another way – by continually disrupting the population of normal bowel bacteria which help to protect the bowel from Salmonella invasion. Where paratyphoid vaccines are available fanciers should vaccinate their birds prior to racing.
When Not to Treat
There are times when prophylactic antibiotic courses should not be considered.
During breeding – antibiotics disrupt the normal population of bowel bacteria. These bacteria are necessary for nutrient absorption and digestion. Their role is particularly important in young growing birds. Antibiotics therefore have the potential to compromise the growth of nestlings. During breeding there are also difficulties in effectively dosing all of the birds in the loft. For antibiotic courses to be effective all birds in the loft need to get their dose. When antibiotics are used in the drinking water during breeding, the parents drink the water and get a dose. By the time they feed their young chicks they have absorbed this and the chicks get none. When medication ceases the chicks then reinfect the parents. Little has been gained.
During moulting – because of their effect on the bowel bacteria and resultant interference with nutrient absorption antibiotics, when used for longer treatments during the time of feather growth ,can adversely affect, both the structural quality and pigment deposition of feathers .
Young growing pigeons – these birds need exposure to potentially harmful bacteria (and other organisms) periodically at non-disease causing levels during growth to develop their natural immunity. Antibiotics interfere with this.
During these times antibiotic treatment would only usually be recommended in the face of a Salmonella outbreak. In this situation we will risk side effects for the definite benefit of treating active disease, otherwise Salmonella antibiotic treatments should be avoided.
Health Programmes to Control Salmonella – Summary
In the Race Loft
When available vaccinate all birds following the manufacturer’s recommendations. Usually two vaccinations 3 -4 weeks apart initially followed by annual boosters. Time annual boosters to be given 6 weeks before racing starts (time of high exposure).
If the loft has a history of Salmonella give ‘Sulpha AVS’ for 10 – 14 days finishing 3 – 4 weeks prior to racing.
Maintain good management practices and a good loft environment. Management flaws such as overcrowding, poor hygiene and poor control of parasitic disease weaken the birds and predispose them to infection.
If an outbreak occurs during racing then, if less than 3% of birds are affected separate these and treat them with an appropriate antibiotic, eg ‘Baytril 2.5%’ 0.5ml per bird per day for 10 days or 10mls to 1 litre or ‘Sulpha AVS’ 3gms to 4 litres are common choices. Disinfect the loft and treat in-contact but still healthy birds with probiotics. If greater than 3% of birds are affected, suspend racing, all birds should be given a 10 day course of an appropriate antibiotic during which time the loft is thoroughly cleaned and disinfected (with ‘Virkon’, ‘F10’ or ‘Oxine AH’). Only resume racing when the problem resolves. Samples can be tested as treatment comes to an end to see if the paratyphoid has cleared or the course needs to be continued.
In the Racing Stock Loft and Exhibition Loft
When available vaccinate all birds following the manufacturer’s recommendations. Usually two vaccinations 3 -4 weeks apart initially followed by annual boosters. Time annual boosters to be given 6 weeks before breeding starts (time of increased stress).
If the loft has an history of Salmonella give ‘Sulpha AVS’ for 10 – 14 days finishing 3 – 4 weeks prior to breeding.
Maintain good management practices and a good loft environment. Management flaws such as overcrowding, poor hygiene and poor control of parasitic disease weaken the birds and predispose them to infection.
If Salmonella appears during the breeding season it is as much an indication of inadequate preparation for the breeding season as it is a problem during the breeding season. Failure to meet the breeding birds’ increased nutritional requirements during breeding and poor hygiene are the usual triggers for a disease outbreak. Treating birds accurately with chicks of different ages through the drinking water because of their variable water intake is an impossible task. Inadequate intake fails to provide a therapeutic dose. Excessive intake risks antibiotic side effects. To be effectively treated birds need to be individually dosed and this includes the nestlings. In some lofts with large numbers of birds this may be an impossible task and the breeding season may need to be shortened. The usual approach is to thoroughly clean and disinfect the loft and then maintain ongoing hygiene. Review the birds’ nutrition. Ask the vet to do health checks to identify any other health problems present that may need treatment. Treat all birds with probiotics in the drinking water and treat birds individually, to the beak, with antibiotics (eg ‘Baytril 2.5%’, 1ml per kilo body weight, adults therefore receive approximately 0.5ml daily, nestlings 0.1ml for every 100gm body weight).