Coccidiosis - the bane of poultry lovers worldwide.
Avian Coccidiosis is a well recognised & economically significant disease of Australian poultry, causing annual worldwide losses of over $3 billion US.
Coccidiosis in chickens is caused by various species of ubiquitous protozoan parasites, of the genus Eimeria. Seven species of Eimeria have been identified in Australia to date, with the most damaging in commercial flocks being Eimeria tenella. The parasite infects & damages the intestinal tract, causing bloody droppings, poor growth, loss of condition, significant mortality, and impaired immunity which allows the establishment of secondary infections. Warm temperatures and high humidity often precede outbreaks, as these conditions favour rapid reproduction of the parasite.
The most pathogenic species of Eimeria include:
E. acervulina, E. brunetti, E. maxima, E. mitis, E. necatrix, E. praecox and E. tenella
It is common for flocks to carry more than one species of Eimeria at any time, and species may differ between backyard and commercial flocks. A recent Australian study identified Eimeria infection in 98% of unvaccinated commercial flocks, and 81% of backyard flocks. It's generally accepted that all chickens raised on litter are exposed to coccidiosis infection, with the peak danger period being between 4- 8 weeks of age. Commercial producers commonly lose 10-20% of unvaccinated young chickens to coccidiosis.
The portion of the chicken's digestive tract infected by Eimeria depends on the species it is infected with. (Source: The Merck Veterinary Manual)
- Often none until 3-4 days after the birds have been infected by ingesting Eimeria oocytes.
- loss of appetite
- depression, lethargy, listlessness
- characteristic "droopy" or "hunched posture
- ruffled feathers
- blood in droppings
- death within 4-5 days from infection