title: An anthropologically based model of the impact of asymptomatic cases on the spread of Neisseria gonorrhoeae.
abstract: Neisseria gonorrhoeae (GC) remains a serious burden in many high-sexual-activity, undertreated populations. Using empirical data from a 2009 study of GC burden among pastoralists in Kaokoveld, Namibia, we expand the standard gonorrhoea transmission model by using locally derived sexual contact data to explore transmission dynamics in a population with high rates of partner exchange and low treatment-seeking behaviour. We use the model to generate ball-park estimates for transmission probabilities and other parameter values for low-level (i.e. less than approx. 1200 copies/20 µl PCR reaction) asymptomatic infections, which account for 74% of all GC infections found in Kaokoveld in 2009, and to describe the impact of asymptomatic, low-level infections on overall prevalence patterns. Our results suggest that GC transmission probabilities are higher than previously estimated, that untreated infections take longer to clear than previously estimated and that a high prevalence of low-level infections is partially due to larger numbers of untreated, asymptomatic infections. These results provide new insights into the natural history of GC and the challenge of syndromic management programmes for the eradication of endemic gonorrhoea.
authors: School of Natural Resources and Environment, University of Michigan, Dana Building, 440 Church Street, Ann Arbor, MI 48109, USA Department of Anthropology, Stanford University, 450 Serra Mall, Building 50, Stanford, CA 94305, USA mahazel@stanford.edu.
authors: Ashley
authors: A
authors: Hazel
authors: School of Medicine, Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI 48109-0620, USA.
authors: Simeone
authors: S
authors: Marino
authors: Department of Mathematics, Ford School of Public Policy, Center for the Study of Complex Systems, University of Michigan, Weill Hall, 735 South State Street no. 4203, Ann Arbor, MI 48109, USA.
authors: Carl
authors: C
authors: Simon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D060432:Anthropology, Medical / Q000379:methods; D058345:Asymptomatic Infections / Q000453:epidemiology*; D002353:Carrier State / Q000453:epidemiology* / Q000635:transmission; D003198:Computer Simulation; D016358:Contact Tracing / Q000379:methods; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005260:Female; D006069:Gonorrhea / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009276:Namibia / Q000453:epidemiology; D015995:Prevalence; D018570:Risk Assessment / Q000379:methods; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Africa; asymptomatic gonorrhoea; epidemiological anthropology; infectious disease model; rural health