THE PATHOGENESIS OF AFRICAN SWINE FEVER IN THE RESISTANT BUSHPIG

Bushpigs and warthogs are natural reservoir hosts of African swine fev er virus (ASFV) in the wild, showing no clinical signs of disease when infected with the same highly virulent isolates of ASFV that induce r apid, haemorrhagic death in domestic pigs. In contrast to domestic pig s, infection of bushpigs with Malawi isolate results in low levels of virus replication and lymphocyte apoptosis within the spleen, and a re latively low spread of virus to other lymphoid tissues. However, at 10 days post-infection, a high degree of apoptosis was seen in B lymphoc ytes of the B cell follicles in bushpig lymph nodes. Virus infected ce lls were present amongst the apoptotic B cells of these follicles, sug gesting that indirect factors released from ASFV infected macrophages signal surrounding lymphocytes to enter apoptosis, The susceptibility/ resistance of domestic pigs/bushpigs to ASFV may serve as a unique vet erinary model for the recently emerging haemorrhagic disease of man.