IMMUNE-RESPONSES OF THE CAMEL (CAMELUS-DROMEDARIUS) TO CONTAGIOUS ECTHYMA (ORF) VIRUS-INFECTION

An enzyme-linked immunosorbent assay (ELISA) was developed together wi th a western blotting technique for the detection of total and specifi c IgG and IgM antibodies to the contagious ecthyma (orf) virus in came l (Camelus dromedarius) sera and for identifying the seroreactive anti gens of the virus. An outbreak of generalised contagious ecthyma in ca mels was diagnosed for the first time in Libya; the seropositivity rat e in a herd with clinically affected camels was 37.9% (and was related to clinical signs) and in apparently normal herds was 0% to 6.8%. Two viral antigenic determinants (22 and 40 kDa) were shared by the weste rn blotting patterns of all the positive camel sera tested, another vi ral antigenic component of 28 kDa was shared by the positive sera with high ELISA titres. Very close similarity was seen with the western bl ot of orf-positive sheep sera. It is considered that the ELISA techniq ue was valid for orf serodiagnosis in the camel and could be usefully applied to other species at risk of orf infection.