AIDS RESEARCH AND HUMAN RETROVIRUSES Volume 17, Number 8, 2001, pp. 759–763 Mary Ann Liebert, Inc. Sequence Note Emergence of New HIV-1 Subtypes Other Than Subtype C among Antenatal Women in Lusaka, Zambia RAY HANDEMA, 1,2 HIROSHI TERUNUMA, 1 FRANCIS KASOLO, 2 HIROTAKE KASAI, 1 MOSES SICHONE, 3 GEORGINA MULUNDU, 2 XUEWEN DENG, 1 KOZI ICHIYAMA, 2 SATOSHI MITARAI, 1,2 MITSUO HONDA, 4 NAOKI YAMAMOTO, 5 and MASAHIKO ITO 1 ABSTRACT Molecular epidemiology of HIV-1 in Zambia was investigated by direct sequencing of PCR products from samples collected from antenatal attendees in Lusaka, Zambia. One hundred and forty samples were initially screened for HIV, using antibody assays. Thirty-three (23.6%) samples were HIV-1 positive. Sequences of the HIV-1 env gp120 region were obtained from 28 of 33 (85%) HIV-1-positive samples. Twenty-six of the 28 se- quences were HIV-1 env subtype C-like as previously reported. However, one HIV-1 env subtype D-like virus and one HIV-1 env subtype G-like virus were identified. This is the first time that these two HIV-1 env sub- type viruses have been identified in Zambia, suggesting that more subtypes could be in existence. 759 T HE ACQUIRED IMMUNE DEFICIENCY SYNDROME (AIDS) is caused by the human immunodeficiency virus (HIV). Two major types of HIV, HIV-1 and HIV-2, are known. HIV- 1 has a worldwide distribution, whereas HIV-2 is more lo- calized in West Africa. Three groups of HIV-1 designated M (major), N (new, or non-M, non-O), and O (outlier) have been revealed by phylogenetic analyses of numerous strains of HIV-1 isolates from different geographic regions. 1 Group M viruses have been further divided into subtypes A, B, C, D, F, G, H, J, and K. 2 Almost all HIV-1 subtypes have been identified in sub-Sa- haran Africa, with a remarkable heterogeneous distribution. The most prevalent subtypes are A and its recombinants in West Africa, A and D in eastern Africa, and C in the Horn and southern Africa. 1–3 Geographically, Zambia is landlocked and bordered by eight countries. HIV-1 subtypes other than C have been re- ported in some of the neighboringcountries. 1–3 With the con- stant human traffic into Zambia, it is possible that subtypes predominant in neighboring countries may already exist in Zambia. Nevertheless, most of the HIV-1 strains in Zambia have been reported to be subtype C, 4–6 although two studies identified an A/C recombinant 7 and subtype O. 8 In these stud- ies, sequences were generated mostly from samples collected from commercial sexual workers, who may not accurately rep- resent the general population because of their mobility and fre- quent sexual partners from abroad. This study therefore focused on HIV-1 subtype distribution among antenatal women who represent a stable general population as a part of a nationwide molecular epidemiology study that seeks to determine the dis- tribution of HIV-1 subtypes in Zambia. Seven urban health centers (described in Results) were se- lected, which represent an even distribution of the population in Lusaka (estimated to be 1 million). Pregnant women attend- ing an antenatal clinic for the first time were recruited in this study. Inclusion criteria were (1) no history of an HIV test, (2) no illness on physical examination, (3) living in Lusaka, (4) no history of traveling abroad in the last year, and (5) ability to give informed consent. All HIV-positive cases were thus as- sumed to be new infections acquired within Zambia. Venous 1 Department of Microbiology, Yamanashi Medical University, Yamanashi, Japan. 2 Virology Laboratory, University Teaching Hospital, Lusaka, Zambia. 3 Central Board of Health, Lusaka, Zambia. 4 AIDS Research Center, NIID, Japan. 5 Department of Microbiology, Tokyo Medical Dental University, Tokyo, Japan.