EPIDEMIOLOGY OF AFRICAN HORSESICKNESS - ANTIBODIES IN FREE-LIVING ELEPHANTS (LOXODONTA-AFRICANA) AND THEIR RESPONSE TO EXPERIMENTAL-INFECTION

The presence of low levels of group- and type-specific antibodies agai nst African horsesickness virus in the serum of some free-living eleph ants was reconfirmed. Experimental infection resulted in conflicting r esults. No detectable viraemia nor virus could be demonstrated in the organs of the six elephant calves and none of them mounted significant levels of neutralizing antibodies against the virus. On the other han d, all calves showed a slight rise in ELISA titres. This rise, however , was modest when compared with the rise in experimentally infected ze bra. The presence of low levels of group- and type-specific antibodies in the serum of some free-living elephants is judged to be the result of natural hyperimmunization due to frequent exposure to infected bit ing insects. Elephants should therefore, despite the presence of low l evels of antibodies, be regarded as poorly susceptible and unlikely to be a source of African horsesickness virus.