Coccidiosis is an infection of the intestinal epithelium caused by microscopic protozoan parasites. It is characterised by an invasion of the intestinal wall by the Coccidia parasite (Coccidia isospora and C. elmeria) which then goes through various stages of growth and multiplication, during which damage occurs to the mucosal and submucosal tissues of the intestine.
Depending on the Coccidia strain involved, the disease can range from subclinical infections to infections that include serious intestinal problems with severe lesions in the gastrointestinal tract, to diarrhoea, resulting in high mortality and/or a negative impact on production in commercial poultry flocks.
All domestic animal species can be infected, as can wild populations, but Coccidiosis is especially prevalent when birds or mammals are grouped together. Coccidia can be seen in any species of bird but in poultry is more commonly seen in chickens, turkeys and geese. It’s also found in budgerigars, pigeons and doves in cage birds. They are less frequently seen in canaries, finches and lorikeets.
Coccidia oocysts (eggs) are passed in the bird’s droppings and are often ingested through food or soil contaminated with infected droppings. The hard-shelled oocysts are highly resistant to environmental conditions and disinfectants, making coccidiosis control difficult.
Symptoms of coccidiosis infection may include any or all of the following signs…
- Diarrhoea, with or without blood
- Weight loss and depression
- Lack of appetite or cessation of eating
- Poor growth and/or death in young or unwell birds
Some birds can carry the organisms and may not show signs of illness.
How is coccidiosis diagnosed?
Examination of fresh, warm faecal smears of the droppings will usually display the eggs (oocysts). Eggs do not show up in every faecal smear and flotation of a dropping sample in the laboratory may be necessary to find the coccidia.
There are a number of different options for the control of coccidiosis. One of the more efficient treatments is Baycox (Toltrazuril) added to drinking water for two days. A repeat treatment may be necessary. Hen housing and the flock’s environment should be cleaned thoroughly daily and then disinfected. Treatment of secondary infections caused by bacteria may also be required.
The possibility of coccidiosis can be minimised or prevented by good hygiene, including frequent cleaning of the hen house. New birds should also be quarantined until they have been examined for coccidia and introduced to flocks only after they have been given a clean bill of health. Cage bird owners should also have their birds regularly checked for coccidia.