Behaviour change and competitive exclusion can explain the diverging HIV-1 and HIV-2 prevalence trends in Guinea-Bissau.
The aim of this study was to determine whether a temporary rise in sexual risk behaviour during war in Guinea-Bissau could explain the observed trends in HIV-1 and HIV-2 prevalence, and to explore the possible contribution of competitive elimination of HIV-2 by HIV-1. A simulation model of the heterosexual transmission of sexually transmitted infections was parameterized using demographic, behavioural and epidemiological data from rural Guinea-Bissau, and fitted to the observed HIV-1 and HIV-2 trends with and without a historic rise in risk behaviour. The observed trends could only be simulated by assuming a temporary rise in risk behaviour. Around 30% of the projected decline in HIV-2 prevalence from a peak of 8.7% to 4.3% in 2010 was due to competitive elimination by HIV-1. Importantly for public health, HIV-1 prevalence was predicted to continue increasing and to become the dominant HIV type by 2010. Data collection is required to validate this prediction.
Schmidt
W P
WP
Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK. Wolf-Peter.Schmidt@lshtm.ac.uk
Van Der Loeff
M Schim
MS
Aaby
P
P
Whittle
H
H
Bakker
R
R
Buckner
M
M
Dias
F
F
White
R G
RG
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D015498:HIV-2 / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015995:Prevalence; D012309:Risk-Taking; D012424:Rural Population; D017678:Sex Distribution; D012749:Sexually Transmitted Diseases / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control