August 14, 2014

UK researchers find breakthrough in fight against coccidiosis

Researchers at the Royal Veterinary College (RVC) are a step closer to finding a new cost-effective vaccine for the intestinal disease, coccidiosis, which can have devastating effects on poultry production.

Coccidiosis is caused by protozoan parasites of the genus Eimeria, closely related to the parasites that cause malaria in humans. The infection affects chickens' intestines and if not controlled has extremely high morbidity and mortality rates.

Domestic chickens can be infected by seven species of Eimeria, each colonising a preferred region of the intestine causing symptoms of differing severity. In a decade-long collaborative research project, biologists at the RVC have helped produce full genome sequences of all seven of these species.

This is a major breakthrough for the poultry production industry in its fight against coccidiosis, which puts the worldwide economic cost of the disease at about US$3 billion. This is mainly due to production losses combined with costs of prevention and treatment.

Coccidiosis affects all livestock but is particularly harmful to poultry because of the high housing density of chickens during the production process. Eimeria species that cause coccidiosis have a direct faecal-oral life cycle that is ideal for spreading rapidly through susceptible hosts when housed in close quarters.

These parasites are also particularly devastating because they survive for long periods in environments such as faeces and litter. This means most chicken flocks in the world are vulnerable, with many inevitably becoming infected. Drugs are commonly used to control the parasites, but resistance evolves rapidly and there is a continuing need to develop new, effective controls of the disease.