SEROEPIDEMIOLOGICAL STUDY OF AFRICAN HORSE SICKNESS VIRUS IN THE-GAMBIA

An indirect enzyme-linked immunosorbent assay was used for the screeni ng of horse sera from The Gambia for antibodies against African horse sickness virus (AHSV). The AHSV antigen used for coating was semipurif ied according to the method of Manning and Chen (Curr. Microbiol. 4:38 1, 1980); control mock-infected Vero cell antigen was treated in the s ame manner. A total of 459 horse serum samples were assayed at a singl e dilution (1:10), and their reactivities were compared with those of reference positive anti-AHSV and reference negative horse sera. A tota l of 81% of the horse serum samples clearly contained antibodies again st AHSV; this consisted of 18% (of the total number of serum samples) strongly positive, 46.5% moderately positive, and 16.5% weakly but sti ll clearly positive. Such results suggest a high prevalence of AHSV in the regions from whence the samples originated. Reports from investig ations in other countries in this area of West Africa have also shown a high prevalence for anti-AHSV antibodies in equids. The question is raised as to how the animals became seropositive and whether the obser vations represent an increased resistance of horses living in a region in which AHS is enzootic.