The strain was isolated in 1969 from a sick boy in Kenya by de Geus (1971) and studied by Dikken et al. (1978). Time name nyanza was sugested for the new serovar, with reference strain Kibos. It conforms to the Saxkoebing subgroup. The serovar nyanza was officially recognized by the TSC in 1986 and is included in the REvised List of 1988 (Kmety, Dikken, 1988).