title: Molecular epidemiology of HIV: tracking AIDS pandemic.
abstract: BACKGROUND
  Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) epidemic is a global threat to maternal and child health, especially in developing countries. It is estimated that 800 000 children are infected and 580 000 children die of AIDS-related illnesses every year. Molecular epidemiology has been a useful tool in analyzing the origin of HIV and tracking the course of global HIV spread. This article provides an overview of recent advances in the field of molecular epidemiology of HIV across the world, and discuss the biological implications.
  
  
  METHODS
  Based on the near full-length or partial nucleotide sequence information, the phylogeny and recombinant structure of HIV strains are analyzed. Using genotype classification of HIV as a molecular marker, the origin and the genesis of HIV epidemic are investigated.
  
  
  RESULTS
  The HIV-1 group M, a major HIV group responsible for current AIDS pandemic, began its expansion in human population approximately 70 years ago and diversified rapidly over time, now comprising a number of different subtypes and circulating recombinant forms (CRF). Of note, recent studies revealed that new recombinant strains are arising continually, becoming a powerful force in the spread of HIV-1 across the globe.
  
  
  CONCLUSIONS
  Global dissemination of HIV is a dramatic and deadly example of recent genome emergence and expansion. Molecular epidemiological investigation is expected to provide information critical for prevention and future vaccine strategies.
authors.affiliation: Laboratory of Molecular Virology and Epidemiology, AIDS Research Center, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, Japan. takebe@nih.go.jp
authors.forename: Yutaka
authors.initials: Y
authors.lastname: TakebE
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kusagawa
authors.forename: Kazushi
authors.initials: K
authors.lastname: Motomura
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000453:epidemiology* / Q000635:transmission*; D014943:Global Health; D006678:HIV / Q000235:genetics*; D006801:Humans; D017720:Molecular Epidemiology