A modified coproantigen test used for surveillance of Echinococcus spp. in Tibetan dogs

Recently an immunological test for Echinococcus spp. antigens in dog faeces has been developed. The antigens appear to be carbohydrates, which survive proteolytic digestion and environmental degradation. For ELISA a capture antibody is used to capture the antigens, followed by a detection antibody. This paper describes a modification of the test whereby capture and detection antibodies are generated exclusively to the carbohydrate portion of the parasite tegument. Faecal extracts were heated to 70 degrees C overnight and the addition of foetal calf serum to the extracts was not necessary. The use of this modification as a surveillance tool in an extensive field trial of hydatid control in Western Sichuan is described. From 2003 onwards all dogs received a treatment with praziquantel pills in the spring and the autumn of each year. On each of six occasions 580 faecal samples were collected from 29 villages and analysed. Prevalence of Echinococcus spp. coproantigen-positive samples was 50% in year 2000, and decreased from 35% to 17% through 2003-2005. This coproantigen technique is now being used as part of the Chinese National Hydatid Disease Control Program, initially in 10 counties in Sichuan Province.