title: Demographic but not geographic insularity in HIV transmission among young black MSM.
abstract: OBJECTIVE
  To understand patterns of HIV transmission among young black MSM and others in Mississippi.
  
  
  METHODS
  Phylogenetic analysis of HIV-1 polymerase (pol) sequences from 799 antiretroviral-naive persons newly diagnosed with HIV infection in Mississippi during 2005-2008, 130 (16%) of whom were black MSM aged 16-25 years.
  
  
  METHODS
  We identified phylogenetic clusters and used surveillance data to evaluate demographic attributes and risk factors of all persons in clusters that included black MSM aged 16-25 years.
  
  
  RESULTS
  We identified 82 phylogenetic clusters, 21 (26%) of which included HIV strains from at least one young black MSM. Of the 69 persons in these clusters, 59 were black MSM and seven were black men with unknown transmission category; the remaining three were MSM of white or Hispanic race/ethnicity. Of these 21 clusters, 10 included residents of one geographic region of Mississippi, whereas 11 included residents of multiple regions or outside of the state.
  
  
  CONCLUSIONS
  Phylogenetic clusters involving HIV-infected young black MSM were homogeneous with respect to demographic and risk characteristics, suggesting insularity of this population with respect to HIV transmission, but were geographically heterogeneous. Reducing HIV transmission among young black MSM in Mississippi may require prevention strategies that are tailored to young black MSM and those in their sexual networks, and prevention interventions should be delivered in a manner to reach young black MSM throughout the state. Phylogenetic analysis can be a tool for local jurisdictions to understand the transmission dynamics in their areas.
authors.affiliation: Epidemic Intelligence Service, Scientific Education and Professional Development Program Office, Centers for Disease Control and Prevention, Atlanta, GA, USA. AOster@cdc.gov
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Oster
authors.forename: Danuta
authors.initials: D
authors.lastname: Pieniazek
authors.forename: Xinjian
authors.initials: X
authors.lastname: Zhang
authors.forename: William M
authors.initials: WM
authors.lastname: Switzer
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Ziebell
authors.forename: Leandro A
authors.initials: LA
authors.lastname: Mena
authors.forename: Xierong
authors.initials: X
authors.lastname: Wei
authors.forename: Kendra L
authors.initials: KL
authors.lastname: Johnson
authors.forename: Sonita K
authors.initials: SK
authors.lastname: Singh
authors.forename: Peter E
authors.initials: PE
authors.lastname: Thomas
authors.forename: Kimberlee A
authors.initials: KA
authors.lastname: Elmore
authors.forename: James D
authors.initials: JD
authors.lastname: Heffelfinger
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data*; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission*; D015497:HIV-1 / Q000235:genetics*; D018451:Homosexuality, Male / Q000208:ethnology / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008922:Mississippi / Q000453:epidemiology; D010802:Phylogeny; D012307:Risk Factors; D012725:Sexual Behavior / Q000208:ethnology / Q000706:statistics & numerical data*; D055815:Young Adult