Identification by the blood incubation infectivity test of Trypanosoma brucei subspecies isolated from game animals in the Luangwa Valley, Zambia.

A total of 7 stocks of Trypanosoma brucei subspecies, isolated from naturally infected game animals in the Luangwa Valley, Eastern Province, Zambia were examined using a modified version of the Blood Incubation Infectivity Test (BIIT). One stock giving consistent BIIT responses typical of T.b. rhodesiense, was obtained from warthog (Phacochoerus aethiopicus). Four other stocks, 2 from hyaena (Crocuta crocuta), 1 from a waterbuck (Kobus ellipsiprymnus) and 1 from a lion (Panthera leo) responded like T.b. brucei. One stock from a waterbuck and 1 from a giraffe (Giraffa camelopardalis) failed to infect mice after incubation in human serum for 30 min at 37 degrees C when first tested, but after 5 or 6 further serial passages in mice and even with serum incubation time increased to 5 h, they retained infectivity.