The distribution of HIV-1 subtypes in Fukuoka, Japan.

To determine the incidence of human immunodeficiency virus type-1 (HIV-1) subtypes in Fukuoka, Japan, viruses from 41 HIV-1 infected individuals were subtyped. Subtyping by V3-loop enzyme-linked immunosorbent assay (ELISA) showed 31 of the 41 subjects as subtype B (MN type), one as subtype A, one as subtype C, and eight untypable. The subject infected with subtype C was identified as a foreigner; the subtype A subject was Japanese. A phylogenetic analysis of nucleic acid sequences from the env C2-V3 region was also conducted. Genetic subtyping was successful for 25 samples: 23 samples were determined as subtype B, one subtype A and one subtype E. One of the individuals infected with subtype B, as well as the subtype A and subtype E subjects, were not Japanese. This study indicated that subtype B (USA and European type) is still dominant among HIV-1 infections in Fukuoka. Further, no Japanese were subtype E positive, which is increasing in the Kanto region. It is notable, however, that subtype A and subtype C infections, which are rare in Japan, were found in Fukuoka, located far from the metropolitan area of Tokyo.