title: Foci of endemic simian immunodeficiency virus infection in wild-living eastern chimpanzees (Pan troglodytes schweinfurthii).
abstract: Simian immunodeficiency virus of chimpanzees (SIVcpz) is the immediate precursor to human immunodeficiency virus type 1 (HIV-1), yet remarkably, the distribution and prevalence of SIVcpz in wild ape populations are unknown. Studies of SIVcpz infection rates in wild chimpanzees are complicated by the species' endangered status and by its geographic location in remote areas of sub-Saharan Africa. We have developed sensitive and specific urine and fecal tests for SIVcpz antibody and virion RNA (vRNA) detection and describe herein the first comprehensive prevalence study of SIVcpz infection in five wild Pan troglodytes schweinfurthii communities in east Africa. In Kibale National Park in Uganda, 31 (of 52) members of the Kanyawara community and 39 (of approximately 145) members of the Ngogo community were studied; none were found to be positive for SIVcpz infection. In Gombe National Park in Tanzania, 15 (of 20) members of the Mitumba community, 51 (of 55) members of the Kasekela community, and at least 10 (of approximately 20) members of the Kalande community were studied. Seven individuals were SIVcpz antibody and/or vRNA positive, and two others had indeterminate antibody results. Based on assay sensitivities and the numbers and types of specimens analyzed, we estimated the prevalence of SIVcpz infection to be 17% in Mitumba (95% confidence interval, 10 to 40%), 5% in Kasekela (95% confidence interval, 4 to 7%), and 30% in Kalande (95% confidence interval, 15 to 60%). For Gombe as a whole, the SIVcpz prevalence was estimated to be 13% (95% confidence interval, 7 to 25%). SIVcpz infection was confirmed in five chimpanzees by PCR amplification of partial pol and gp41/nef sequences which revealed a diverse group of viruses that formed a monophyletic lineage within the SIVcpzPts radiation. Although none of the 70 Kibale chimpanzees tested SIVcpz positive, we estimated the likelihood that a 10% or higher prevalence existed but went undetected because of sampling and assay limitations; this possibility was ruled out with 95% certainty. These results indicate that SIVcpz is unevenly distributed among P. t. schweinfurthii in east Africa, with foci or "hot spots" of SIVcpz endemicity in some communities and rare or absent infection in others. This situation contrasts with that for smaller monkey species, in which infection rates by related SIVs are generally much higher and more uniform among different groups and populations. The basis for the wide variability in SIVcpz infection rates in east African apes and the important question of SIVcpz prevalence in west central African chimpanzees (Pan troglodytes troglodytes) remain to be elucidated.
authors.affiliation: Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: Mario L
authors.initials: ML
authors.lastname: Santiago
authors.forename: Magdalena
authors.initials: M
authors.lastname: Lukasik
authors.forename: Shadrack
authors.initials: S
authors.lastname: Kamenya
authors.forename: Yingying
authors.initials: Y
authors.lastname: Li
authors.forename: Frederic
authors.initials: F
authors.lastname: Bibollet-Ruche
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Bailes
authors.forename: Martin N
authors.initials: MN
authors.lastname: Muller
authors.forename: Melissa
authors.initials: M
authors.lastname: Emery
authors.forename: David A
authors.initials: DA
authors.lastname: Goldenberg
authors.forename: Jeremiah S
authors.initials: JS
authors.lastname: Lwanga
authors.forename: Ahidjo
authors.initials: A
authors.lastname: Ayouba
authors.forename: Eric
authors.initials: E
authors.lastname: Nerrienet
authors.forename: Harold M
authors.initials: HM
authors.lastname: McClure
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Heeney
authors.forename: David P
authors.initials: DP
authors.lastname: Watts
authors.forename: Anne E
authors.initials: AE
authors.lastname: Pusey
authors.forename: D Anthony
authors.initials: DA
authors.lastname: Collins
authors.forename: Richard W
authors.initials: RW
authors.lastname: Wrangham
authors.forename: Jane
authors.initials: J
authors.lastname: Goodall
authors.forename: John F Y
authors.initials: JF
authors.lastname: Brookfield
authors.forename: Paul M
authors.initials: PM
authors.lastname: Sharp
authors.forename: George M
authors.initials: GM
authors.lastname: Shaw
authors.forename: Beatrice H
authors.initials: BH
authors.lastname: Hahn
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004197:Disease Reservoirs; D019353:Endemic Diseases; D005243:Feces / Q000821:virology; D005260:Female; D008297:Male; D002679:Pan troglodytes / Q000821:virology*; D015995:Prevalence; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D016097:Simian Acquired Immunodeficiency Syndrome / Q000453:epidemiology*; D015302:Simian Immunodeficiency Virus / Q000302:isolation & purification*; D013636:Tanzania / Q000453:epidemiology; D014454:Uganda / Q000453:epidemiology; D014556:Urine / Q000821:virology
chemical_list: D017931:DNA Primers