Researchers Test Anticoccidial Vaccine

Coccidiosis affects mostly kids around weaning time. Worldwide, it is the most important disease in the goat industry. Control of coccidiosis is hampered by resistance against coccidiostatic drugs. As such, a vaccine would be desirable.

Spanish and German researchers conducted an oral immunization trial with live attenuated sporulated Eimeria ninakohlyakimovae oocysts. An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable (or "live"). The experimental design included a total of 18 goat kids divided into the four treatment groups.

Goat kids immunized with live attenuated E. ninakohlyakimovae oocysts excreted significantly less oocysts in the feces (95.3% reduction) than kids infected with non-attenuated ones. Furthermore, immunization with live but attenuated oocysts resulted in ameliorated clinical coccidiosis compared to goat kids infected with untreated oocysts and resulted in equally reduced signs of coccidiosis after challenge infection compared to acquired immunity driven by non-attenuated oocysts.

Overall, the study demonstrated for the first time that live attenuated E. ninakohlyakimovae oocysts orally administered showed almost no pathogenicity but enough immunogenicity in terms of immunoprotection. Importantly, vaccinated animals still shed low amounts of oocysts, guaranteeing environmental contamination and consecutive booster infections to sustain ongoing immunity.

Source:  J. Veterinary Parasitology, October 2013