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Below is a listing of the most common
diseases of pigeons.
1) Canker – Trichomoniasis
Causes
and Clinical Signs
Canker
is due to a parasitic organism called Trichomonas colombi and three forms are
recognised affecting the pharynx, navel and internal organs respectively. The majority of adult pigeons are symptomless carriers of the organism
but clinical cases may occur if the bird is under stress and in young pigeons
the disease may be severe and even fatal. The
disease is spread from adults to squabs in the crop milk and between pigeons by
the oral route.
A. Pharyngeal Form
Cheesy yellow deposits are seen on the membranes of the
pharynx at the back of the mouth. The
deposits can affect food intake and also breathing. Severely affected birds are depressed, food intake is reduced
and they become emaciated. Affected
birds may have diarrhoea. Water
intake may increase.
B. Navel Form
This
form occurs in young birds that are affected in the nest box from affected crop
milk dripping onto the nest box floor. A
typical cheesy yellow deposit is present under the skin at the navel and it may
spread from here to the internal organs.
C. Internal Form
The internally affected organs include liver, crop and
lung in which the cheesy yellow deposits may be found. The clinical signs of the internal form vary depending upon the organ
involved but usually diarrhoea and emaciation are a feature of this condition.
Diagnosis
Diagnosis has to be based on the clinical signs in the
living birds. Samples of crop
smears are positive in the majority of adult birds and diagnosis is dependent on
the number of organisms present. Post
mortem examination of cadavers will give a positive diagnosis of the internal
form. The disease needs to be
distinguished from Pox, Tuberculosis, Aspergillosis and Salmonellosis.
Treatment
Dimetridazole is very effective against Trichomonas.
All susceptible and in contact birds would be treated for a period of
seven days. In some a
broad-spectrum antibiotic or multi vitamin may be recommended.
Prevention
No flock can be permanently kept free of this organism.
Due to its severity in young birds we recommend a treatment of all birds at the
end of the flying season and the treatment of adults for a period of five to
seven days after egg laying and before the squabs are hatched.
2) Coccidiosis
Causes and Clinical Signs
Coccidiosis is due to a parasitic organism that affects
the birds intestines. Two types of
coccidia affect pigeons, Eimeria columbanum and Eimeria labbeanna. The clinical disease due to these organisms is identical.
Most adult birds are affected to some degree but only
when large numbers of parasites are present is treatment necessary.
In young birds and adults under stress an acute form of
the disease may be seen. The
organism affects the lining of the gut causing diarrhoea and blood may be
present. Affected birds are
depressed, rapidly become emaciated and may die.
The Coccidia in the gut produce ‘Oocysts’, which are
passed out in the faeces. These
mature in the environment and will then affect other birds if ingested.
Diagnosis
Microscopic examination of faeces is necessary to
diagnose the disease in live birds. As
many birds have a low level of disease it is the number of Oocysts present which
is important when arriving at a diagnosis.
The disease needs to be distinguished from
Salmonellosis, Trichomoniasis, bacterial gut infections and worm infestation.
Treatment
Treatment for Coccidiosis will be dispensed by the
veterinary surgeon as necessary. Follow
up medication with antibiotics or multi vitamins may also be beneficial.
Prevention
Good hygiene in the loft is essential, as is the
provision of clean uncontaminated food and water. If birds show signs of diarrhoea an Oocyst count would be advised.
Routine faeces analysis before pairing is also recommended.
3) External Parasites
Causes and Clinical signs
Ticks, mites and lice can all live on the body of pigeons
and will cause damage of varying degrees depending on the type and severity of
infestation.
Anaemia, feather damage, respiratory problems (air sac
mites) and poor growth in young birds may all result from external parasite
infestation.
Some external parasites spend their whole life cycle on
the bird and spread is by direct bird to bird contact e.g. mange mites, plumage
lice, feather mites, quill mites and scaly leg mites. Other parasites spend most of their time in the environment
only visiting the pigeon to feed e.g. red mites and ticks.
Diagnosis
Ticks are common during the warm summer months and are
visible to the naked eye. Mites are
very small and can rarely be seen by the naked eye. If infestation is suspected samples need to be submitted to
the laboratory for microscopical examination.
Lice are just visible to the naked eye – if in doubt
their presence can be confirmed by microscopic examination.
The red mite spends it days in cracks and crevices of the
pigeon loft only visiting the pigeon at night to feed.
Where cases of anaemia or reduced performance and
agitation are obvious in birds external parasites should be suspected and
regular visual inspection of the birds should be undertaken to identify the
presence of ticks and lice.
Treatment
Treatment of birds with a parasiticide together with a
thorough cleaning and disinfection of premised is necessary where external
parasites cause problems.
External parasites are a particular problem to young
birds. Thorough cleaning of the loft before the breeding season together with
any treatment of the birds if examination shows them to be infected would be
recommended.
Prevention
Regular cleaning and disinfection of the loft will help
control the population of external parasites.
4) Ornithosis
Causes and Clinical Signs
Ornithosis is due to a micro-organism called Clamydia.
It is susceptible to antibiotics like bacteria but lives within and
destroys body cells like a virus.
Clinical signs vary from poor performance to an acute
disease causing a marked conjunctivitis, decreased appetite, respiratory
disease, diarrhoea and death.
The acute form is particularly prevalent in young birds
and older birds under stress. In
some cases the conjunctivitis can lead to secondary bacteria infection of the
eye resulting in blindness. Recovered
birds are likely to carry the disease and subsequently spread it to other
pigeons.
Diagnosis
Diagnosis of this disease in the live bird is difficult
and must rely heavily on the clinical symptoms present. Blood tests will identify birds that have been exposed to the organism
but are not a good indication of the present disease status.
Where dead birds are available, samples from the liver or
spleen can give a positive diagnosis in the laboratory. The disease needs to be distinguished from Mycoplasma infection,
Haemophylus infection and “One Eyed Cold”.
NOTE
There is a very real danger of this infection being
transmitted to man. Pigeon fanciers
who suffer from a prolonged flu-like disease are recommended to consult their
doctor who should be aware of their contact with pigeons. Where cases are diagnosed in pigeons the
Department of the Environment, Food and Rural Affairs (DEFRA) must be
informed.
Treatment
Due to the danger of human infection, the risk to young
birds and the fact that chronically infected birds are more prone to other
diseases, the treatment of affected birds with Chlortetracycline for an adequate
period is essential. Treatment
lengths of 30 to 60 days would be recommended. The use of multi vitamin may also be advised.
Prevention
No specific measures are available to prevent the
condition. Try to maintain birds in
good bodily condition and make sure the loft is regularly cleaned and
disinfected. If the disease is
suspected veterinary advice should be sought.
5) Paramyxovirus
Causes and Clinical Signs
Paramyxovirus infection is due to a virus known as PMV3.
Affected birds will at first have an increased thirst and will pass
liquid faces - this may be followed by nervous signs. The nervous signs seen include paralysis, torsion of the neck and
uncoordinated body movements – not all these signs will necessarily occur in
each affected bird.
Diagnosis
Diagnosis is based largely on the clinical signs and it
can be confirmed by blood tests. The disease needs to be differentiated from
Salmonellosis, other causes of wet droppings and other causes of nervous signs
including poisoning.
Treatment
As this condition is due to a virus no specific treatment
is available. Antibiotics and multi
vitamins may be used if the birds are under stress.
Prevention
As treatment of Paramyxovirus is unrewarding due to the
absence of useful antiviral agents, prevention of this disease is very
important. There are vaccines
licensed for use in pigeons in the U.K.
Timing of Vaccination
The best time to vaccinate young birds is during the last
two weeks of March and the first week of April. The young birds should be at least 3 weeks old and
vaccination should be complete 10 to 14 days before the onset of the old-bird
racing season. This will prevent
infection of susceptible young birds by virus mechanically brought back to the
loft by the older birds. If
vaccination cannot be completed before the old bird racing season then young
birds must be kept separate from the older birds and vaccination must be
completed 10 to 14 days before the start of the young-bird racing season. The best time to vaccinate older birds is during November and
December before the start of the laying season.
Vaccines are given subcutaneously in the midline of the
neck with the needle towards the tail of the bird. Great care must be taken to keep the needles, bottles etc as
clean as possible. Needles should
be changed after every ten birds or more often if they become contaminated.
Take care in disposing of used needles; they should be returned to the
practice in a solid container so that they can be disposed of correctly. Any post vaccine reaction in the bird should be reported immediately to
the veterinary surgeon.
6) Poisoning
Causes and Clinical Signs
Poisoning in pigeons can be due to a wide variety of
products hence the clinical signs can vary greatly but they are likely to
include nervous signs, diarrhoea, depression and sudden death. Poisoning may be
from substances encountered away from the loft e.g. Organo Phosphorous compounds
or substances found around the loft e.g. Phenolic compounds, vermin baits and
veterinary medicines used incorrectly. Where poisoning is suspected then any
dead birds together with a full clinical history should be submitted to the
practice.
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