An 11-Year Surveillance of HIV Type 1 Subtypes in Nagoya, Japan

Abstract

To monitor active HIV-1 transmission in Nagoya, Japan, we have been determining the subtypes of HIV-1 infecting therapy-naive individuals who have newly visited the Nagoya Medical Center since 1997. The subtypes were determined by phylogenetic analyses using the base sequences in three regions of the HIV-1 genes including gag p17, pol protease (PR) and reverse transcriptase (RT), and env C2V3. Almost all HIV-1 subtypes from 1997 to 2007 and 93% of all HIV-1 isolates in 2007 were subtype B. HIV-1 subtypes A, C, D, and F have been detected sporadically since 1997, almost all in Africans and South Americans. The first detected circulating recombinant form (CRF ) was CRF01_AE (11-year average annual detection rate, 7.7%). Only two cases of CRF02_AG were detected in 2006. A unique recombinant form (URF ) was first detected in 1998 and the total number of URFs reached 25 by year 2007 (average annual detection rate, 4.7%). Eleven of these 25 were detected from 2000 to 2005 and had subtypes AE/B/AE as determined by base sequencing of the gag p17, pol PR and RT, and env C2V3 genes (average annual detection rate, 3.7%). Unique subtype B has been detected in six cases since 2006. All 17 of these patients were Japanese. Other recombinant HIV-1s have been detected intermittently in eight cases since 1998. During the 11-year surveillance, most HIV-1s in Nagoya, Japan were of subtype B. We expect that subtype B HIV-1 will continue to predominate for the next several years. Active recombination between subtype B and CRF01_AE HIV-1 and its transmission were also shown.

Genetic Analysis of HIV-1 in Japan: a Comprehensive Analysis of Donated Blood

“…More than 90z of the early and more recent HIV-1-positive blood samples were donated by men. These findings were similar to previous reports (25,27,38). In Japan, epidemiological trends for HIV-1 categorized by HIV-1 subtype have not changed over the last decade.…”

“…HIV-1 env C2V3 sequences were used for subtype analysis of blood donations from areas throughout Japan, with almost 90z of these HIV-1 isolates being subtype B and consistent with results of previous studies (25,27,30). Furthermore, analysis of pol sequences, which encode the entire protease and most of the reverse transcriptase enzyme, was performed to identify trends in subtype B circulation and drug-resistance mutations for the 2 largest HIV-1 endemic areas, the Tokyo and Osaka metropolitan areas, which are home to about 70z of all infections in Japan.…”

“…The env C2V3 (HXB2; nucleotides (nt) 7011-7350) sequences were amplified by PCR as described by Imai et al (31,32). The pol sequences encoding the entire protease and most of the reverse transcriptase (HXB2; nt 2059-3599) were amplified by PCR as described by Fujisaki et al (25) with slight modifications. Briefly, PCR with primers K1 (5 ?…”

“…Data on HIV-1 infection are submitted to the National AIDS Surveillance database, and these data include information regarding HIV-1-positive blood donations. To understand the distribution of HIV subtypes in Japan, epidemiological studies of samples collected by hospitals or health centers in specific geographic regions are conducted continuously (25)(26)(27)(28)(29). According to the National AIDS Surveillance database, about 10z of new HIV-1 infections are identified among blood donors in Japan.…”

HIV-1 CRF01_AE and Subtype B Transmission Networks Crossover: A New AE/B Recombinant Identified in Japan

“…20,21 Obtained sequence data were subjected to phylogenetic analyses with reference sequences (Supplementary Table S2A) of HIV-1 subtypes A through K and CRF01_AE from the HIV sequence database at the Los Alamos National Laboratory (www.hiv.lanl.gov/). Multiple sequence alignment was performed using the MUSCLE program, and genetic distances were calculated based on the maximum composite likelihood model using MEGA software v.5.2.1.…”