Epidemiology and pathogenicity of African bat lyssaviruses

Lyssaviruses belonging to all four known African Lyssavirus genotypes (gts) have been reported and isolated from South Africa over the past few decades. These are: (1) Duvenhage virus (gt4), isolated again in 2006 from a human fatality; (2) Mokola virus (gt3), isolated irregularly, mostly from cats; (3) Lagos bat virus (gt2) continually isolated over the past four years from Epomophorus fruit bats and from incidental terrestrial animals and (4) Rabies virus (gt1) - with two virus biotypes endemic in mongoose and in canid species (mostly domestic dogs, jackals and bat-eared foxes), respectively. Only two of these are associated with bats in Southern Africa, viz. Duvenhage virus and Lagos bat virus (gts 4 and 2). For both these genotypes the authors have embarked on a programme of comparative study of molecular epidemiology. Duvenhage virus nucleoprotein nucleotide sequence analysis indicated a very low nucleotide diversity even though isolates were isolated decades apart. In contrast, individual isolates of Lagos bat virus were found to differ significantly with respect to nucleoprotein gene nucleotide sequence diversity as well as in pathogenicity profiles.