Pigeon owners and breeders are well aware that individual pigeons can die under stress, for example when exposed to stress during nesting or group migration. Juveniles are more vulnerable. The cause of such deaths can be salmonella infection.
Pathogenicity and epidemiology
Over 2,400 different serotypes are known. The most common type of serum in pigeons was Salmonella Typhimurium. Copenhagen (STVC). This serotype has adapted specifically to pigeons and can cause diseases and deaths in them but generally not in other animals.
Symptoms
Symptoms of pigeons can be mild or severe, sometimes symptoms can be chronic but also pigeons can die suddenly. Juveniles are more likely to become seriously infected, while older birds show milder symptoms. If chicks are infected with hatching, it is common for deaths to peak when the chicks are one week old.
Symptoms can be of a general nature and it can be difficult to distinguish the symptoms of salmonella infections from other bacterial infections. Sick birds can show symptoms such as diarrhea, loss of appetite, weakness and poor hygiene. Arthritis is also common as the birds can have difficulty walking and flying, as well as infected birds can get eye infections.
Changes in autopsies seen during autopsy are not limited to salmonella infections. Inflammation and abscesses are seen in the organs that are infected but common are infections of the liver, spleen and intestines.
Diagnosis and treatment
It is necessary to diagnose salmonella , in particular STVC in case of illness and / or death in order to be able to take appropriate action. Diagnosis is made by bacterial culture of samples taken from sick birds, eg faecal samples and / or samples taken by a veterinarian from the swollen joint. However, it is best to grow the bacterium from samples taken from infected organs at autopsy when birds have died.
Diagnosis of salmonella in birds without symptoms is difficult because the bacteria are often not found in samples from them. Samples can be taken from the birds themselves, smear samples from sewage or faecal samples, but environmental samples can also be taken. There may be samples from bedding, dust samples and smear samples from inside the huts where faecal contamination is present. It also matters if you are being treated with antibiotics when taking samples. Salmonella is found irregularly in the faeces of asymptomatic carriers and therefore needs to have a faecal sample taken more than once if a bird infection is suspected.
Salmonella infections can be difficult to detect by antibody testing in blood samples because the tests are usually only for common serotypes in poultry but do not detect antibodies against all salmonella serotypes.
If infection is detected, sick birds can be treated with appropriate antibiotics. Studies abroad have shown that antibiotic resistance can be considerable in pigeon populations due to the extensive use of antibiotics. The status of antibiotic susceptibility in STVC strains in Iceland is not known, but it is always advisable to measure antibiotic susceptibility before starting treatment so that appropriate antibiotics are used. It should be borne in mind that infection in pigeonholes can not be eradicated by treating the whole group with antibiotics. Despite treatment, salmonella can survive in recovering birds. Those birds become asymptomatic carriers that, especially under stress, infect the environment and new birds that are brought into the huts. In addition, the use of antibiotics does not affect environmental infections. The use of antibiotics is therefore only justified for the treatment of sick birds and thus reduces losses.
Infection control, preventive measures
Vaccination of pigeons against salmonella infections can reduce the severity of the disease. It is unlikely, however, that infection in pigeon cabins can be eradicated simply by vaccinating the birds. Vaccination increases resistance to STVC, but in spite of this, the birds can be infected by the bacterium. Because the bacteria are found in the gut, these birds can infect the environment with feces, but to varying degrees depending on the vaccine used. To date, no vaccine has been used in pigeons in Iceland.
Infection control can be reduced by ensuring good hygiene in the huts and preventing congestion. Good ventilation should be considered. Good and regular cleaning together with disinfection with suitable materials in the hut and on the equipment reduces the contagion. Feed and water systems should be set up so that they are not contaminated by dirt. These measures, together with the targeted vaccination of uninfected birds, further reduce the impact of infections in huts where salmonella has developed.
It is difficult to reduce the contagion in huts where asymptomatic carriers are kept. As mentioned before, it is difficult to identify those birds, but if they are found, it is advisable to remove them from the huts.
When buying new pigeons, it is advisable to check the disease status at the place of origin. Pigeons should not be taken from huts unless they have been ill for the past 12 months. Furthermore, repeated samples were taken from pigeons and / or environments that had been detected negatively with respect to salmonella. It can be a good idea to keep new pigeons in isolation for a few weeks to check for illness before placing them in the pigeon loft.
The Food Administration’s response
Salmonella infections in animals are subject to notification to the Food Administration. The Agency assesses the response to a diagnosis to protect animal and human health. If the disease is rare, it may be appropriate to isolate the cases and temporarily limit the spread of infected animals during operations to reduce the risk of infection. If the disease is endemic, isolating infected animals is not justified. In such cases, it is the responsibility of the owner of the animals to minimize the risk of infection and to treat the animals in consultation with their veterinarian.
There is a lack of information on the frequency of STVC in pigeons in Iceland. Matvælastofnun only has information on four diagnoses of salmonella in pigeons in Iceland. Despite this, the disease can be much more widespread in pigeons in Iceland than it lacks diagnosis.
Matvælastofnun believes that there is no need for official restrictions if STVC infection occurs in pigeons due to the specific nature of the bacterium in its animal species. Instead, the agency encourages infection control as described above, but reiterates that it is the responsibility of pigeon owners to inform buyers about diseases in their pigeons. In the same way, the agency encourages pigeon buyers to check with sellers if there have been diseases in the huts and if samples have been taken to monitor salmonella.
The institute encourages pigeon owners as well as everyone who keeps animals to take care of good hygiene as the animals are kept to reduce the risk of infection due to the various diseases. It is desirable that all huts have at least facilities for hand washing and cleaning shoes. Organizers of pigeon competitions and exhibitions are also encouraged to assess the risk of infection at events where pigeons gather from many huts and take appropriate measures.
FoodWorld 