Abstract:
A single troop of free-ranging chacma baboons ( Papio ursinus) was found
to be infected with tuberculosis caused by Mycobacterium bovis. It is
assumed that some members of the troop originally became infected when
feeding on a tuberculous carcass in the veld or on tuberculous material
scavenged at a nearby post mortem facility. Subsequently, apparent
aerosol transmission took place while sleeping in an unused room. Oral
transmission probably also occurred due to continuous contamination of
the floor of this room and the common, narrow access (a train bridge
crossing the Sabi River) to it with faeces and urine. A macroscopic
prevalence of 50% was found and the disease was noted to progress
rapidly in infected baboons. A variety of organs had typical tuberculous
lesions, of which the spleen, lungs and mesenteric lymph nodes were
consistently, grossly affected. Using Restriction Fragment Length
Polymorphism analysis, all but one of the baboon isolates were found to
be identical to the most common African buffalo ( Syncerus caffer)
isolate (genotype 1) in this Park. The opportunistic sleeping facility
was made inaccessible to the troop, which was forced to revert to
sleeping in trees. A follow-up survey six months after closure,
demonstrated that the disease had disappeared from the troop, and that
no spillover infection had occurred into neighbouring troops.
