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BACKGROUND HIV-1 prevalence typically rises more rapidly at young ages in women than in men in sub-Saharan Africa. Greater susceptibility to infection on exposure in women is believed to be a contributory factor as is greater exposure to previously infected sexual partners of the opposite sex. We investigated the latter hypothesis using data from a field(More)
BACKGROUND Sexually transmitted infections spread through a network of contacts created by the formation of sexual partnerships. In physics, networks have been characterized as "scale-free" if they follow a power law with an exponent between 2 and 3. OBJECTIVE The objective of this study was to test statistically whether distributions of numbers of sexual(More)
BACKGROUND WHO advocates the use of directly observed treatment with a short-course drug regimen as part of the DOTS strategy, but the potential effect of this strategy worldwide has not been investigated. METHODS We developed an age-structured mathematical model to explore the characteristics of tuberculosis control under DOTS, and to forecast the effect(More)
BACKGROUND AND OBJECTIVES The concept of a core group of individuals who change sexual partners frequently has played an important role in the study of the epidemiology of sexually transmitted diseases (STDs). It is widely believed that the core group is important in the persistence of infection and that it provides a sensible target for control(More)
OBJECTIVE The authors conducted an assessment of the role of beer halls in the HIV epidemic of rural Zimbabwe as part of the ongoing identification of risky places for the targeting of prevention activities. STUDY A population-based survey of 9480 adults collected data on number of visits to beer halls in the last month, together with sociodemographics,(More)
From an analysis of the distributions of measures of transmission rates among hosts, we identify an empirical relationship suggesting that, typically, 20% of the host population contributes at least 80% of the net transmission potential, as measured by the basic reproduction number, R0. This is an example of a statistical pattern known as the 20/80 rule.(More)
Substantial changes are needed to achieve a more targeted and strategic approach to investment in the response to the HIV/AIDS epidemic that will yield long-term dividends. Until now, advocacy for resources has been done on the basis of a commodity approach that encouraged scaling up of numerous strategies in parallel, irrespective of their relative(More)
OBJECTIVES To measure HIV-1 discordance among migrant and non-migrant men and their rural partners, and to estimate the relative risk of infection from inside versus outside primary relationships. DESIGN A cross-sectional behavioural and HIV-1 seroprevalence survey among 168 couples in which the male partner either a migrant, or not. METHODS A detailed(More)
OBJECTIVE To monitor the HIV-1 epidemic in Western Uganda and the possible impact of interventions. DESIGN Results from sentinel surveillance of HIV-1 seroprevalence were compared with cross-sectional serosurvey data and model simulations. METHODS Age-specific trends in HIV-1 prevalence between 1991 and 1997 amongst antenatal clinic (ANC) attenders in(More)
The major role of mathematical models of transmission dynamics and population biology of sexually transmitted diseases is helping understand the influence of the many biologic, social, and behavioral factors that influence the incidence or prevalence of infection. Various models can examine heterogeneity in sexual behavior and determine how individual(More)