title: Patterns and trends in Pakistan's heterogeneous HIV epidemic.
abstract: BACKGROUND
  Considerable HIV transmission occurs among injection drug users (IDUs) in Pakistan and recently the HIV prevalence has been increasing among male (MSW), hijra (transgender; HSW) and female (FSW) sex workers. We describe past and estimate future patterns of HIV emergence among these populations in several cities in Pakistan.
  
  
  METHODS
  The density of these key populations per 1000 adult men was calculated using 2011 mapping data from Karachi, Lahore, Faisalabad, Larkana, Peshawar and Quetta, and surveillance data were used to assess bridging between these key populations. We used the UNAIDS Estimation and Projection Package model to estimate and project HIV epidemics among these key populations in Karachi, Lahore, Faisalabad and Larkana.
  
  
  RESULTS
  The density and bridging of key populations varied across cities. Lahore had the largest FSW population (11.5/1000 adult men) and the smallest IDU population (1.7/1000 adult men). Quetta had the most sexual and drug injection bridging between sex workers and IDUs (6.7%, 7.0% and 3.8% of FSW, MSW and HSW, respectively, reported injecting drugs). Model evidence suggests that by 2015 HIV prevalence is likely to reach 17-22% among MSWs/HSWs in Karachi, 44-49% among IDUs in Lahore and 46-66% among IDUs in Karachi. Projection suggests the prevalence may reach as high as 65-75% among IDUs in Faisalabad by 2025. HIV prevalence is also estimated to increase among FSWs, particularly in Karachi and Larkana.
  
  
  CONCLUSIONS
  There is a need to closely monitor regional and subpopulation epidemic patterns and implement prevention programmes customised to local epidemics.
authors: Canada-Pakistan HIV/AIDS Surveillance Project, , Islamabad, Pakistan.
authors: Tahira
authors: T
authors: Reza
authors: Dessalegn Y
authors: DY
authors: Melesse
authors: Leigh Anne
authors: LA
authors: Shafer
authors: Momina
authors: M
authors: Salim
authors: Arshad
authors: A
authors: Altaf
authors: Altaf
authors: A
authors: Sonia
authors: Gayatri C
authors: GC
authors: Jayaraman
authors: Faran
authors: F
authors: Emmanuel
authors: Laura H
authors: LH
authors: Thompson
authors: James F
authors: JF
authors: Blanchard
mesh_terms: D000293:Adolescent; D000328:Adult; D058872:Epidemics / Q000706:statistics & numerical data*; D004812:Epidemiologic Methods; D005260:Female; D005544:Forecasting / Q000379:methods*; D062305:Geographic Mapping; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D010154:Pakistan / Q000453:epidemiology; D015995:Prevalence; D018571:Sentinel Surveillance; D060386:Sex Workers / Q000706:statistics & numerical data*; D015819:Substance Abuse, Intravenous / Q000453:epidemiology*
keywords: COMMERCIAL SEX; HIV; INJECTING DRUG USE; MODELING; SEXUAL NETWORKS
references: Lancet. 2005 Jul 2-8;366(9479):57-60
references: 15993234
references: Sex Transm Infect. 2008 Aug;84 Suppl 1:i1-4
references: 18647859
references: Bull Narc. 1993;45(1):91-105
references: 8305909
references: Sex Transm Infect. 2004 Aug;80 Suppl 1:i5-9
references: 15249692
references: AIDS. 2002 Jun 14;16(9):W1-14
references: 12045507
references: AIDS. 1991 Dec;5(12):1509-13
references: 1814333
references: JAMA. 1989 Feb 17;261(7):1008-12
references: 2915408
references: Sex Transm Infect. 2011 Feb;87(1):73-80
references: 21084440
references: Lancet. 2010 Mar 20;375(9719):1014-28
references: 20189638
references: Drug Alcohol Depend. 2003 Jul 20;71(1):17-24
references: 12821202
references: Sex Transm Infect. 2013 Sep;89 Suppl 2:ii18-28
references: 23314301
references: Soc Sci Med. 2005 Sep;61(5):1026-44
references: 15955404
references: Sex Transm Infect. 2004 Aug;80 Suppl 1:i31-38
references: 15249697
references: AIDS. 2010 Jul;24 Suppl 2:S77-84
references: 20610953
references: Addiction. 1999 Sep;94(9):1323-36
references: 10615718
references: Int J STD AIDS. 2003 Jun;14(6):361-71
references: 12816662
references: Sex Transm Infect. 2008 Oct;84 Suppl 2:ii24-7
references: 18799488
references: J Urban Health. 2009 Jul;86 Suppl 1:131-43
references: 19507037
references: J Pak Med Assoc. 2006 Mar;56(3):119-24
references: 16696511
references: Int J Infect Dis. 2006 Sep;10(5):364-71
references: 16793307