Development of an indirect ELISA for the diagnosis of equine piroplasmosis.

An indirect ELISA (iELISA) for the detection of specific anti-Theileria equi antibodies in horse serum was developed. Its performance showed good concordance (K= 0.79) when compared with a competitive ELISA recommended by the World Organisation for Animal Health. Horse serum samples from two provinces located in the north and east of Argentina (Formosa and Entre Rios, respectively) were analyzed by this iELISA. A high percentage of positive horses were found in Formosa, consistent with the climatic conditions of the region that are apt for the development of tick vectors. Surprisingly, seropositive animals were also detected, although in a lower proportion, in Entre Rios, which has a temperate weather and is presumably tick free. Breeding of thoroughbred racing horses is an important economic asset of Argentina. Since equine piroplasmosis is a constraint for horse export, the epidemiological situation in different regions of the country needs to be assessed for the implementation of control measures. The iELISA developed in this work provides a convenient tool for this type of study.