Sexually Transmitted Infections

Moses, S; Ngugi, E N; Costigan, A; Kariuki, C; Maclean, I; Brunham, R C; Plummer, F A

doi: 10.1136/sti.78.suppl_1.i114pmid: 12083429

Although it seems possible in a developing country context such as Kenya, given appropriate inputs and a sound approach, to shift a sexually transmitted disease (STI) epidemic from phase II to III, it is not entirely clear how to go beyond this stage, to low levels of endemicity or even elimination. Perhaps the most important challenge now is to expand STI treatment and community STI/HIV prevention programmes to a much larger scale. Although successful programmes have been implemented in many areas of sub-Saharan Africa on a small scale, a significant impact in reducing the STI/HIV burden will not occur until programme reach is expanded to district, provincial, and national levels.

Elliott, L J; Blanchard, J F; Beaudoin, C M; Green, C G; Nowicki, D L; Matusko, P; Moses, S

doi: 10.1136/sti.78.suppl_1.i139pmid: 12083433

Feasible epidemiological approaches are required to make a better assessment of the stage of an epidemic and to monitor its transition through various phases. Application of the Lorenz curve and Gini coefficient to summarise the inequality in STD incidence rates between jurisdictions in Manitoba, Canada, was found to provide useful insights into the concentration of these epidemics over time and thus their transition through epidemic phases. Further exploration of the statistical properties of these and other indices of inequality and their potential application to STD epidemiology is warranted. New epidemiological tools are also required for better monitoring of the impact of prevention and control activities and to inform the content of these activities.

Garnett, G P

doi: 10.1136/sti.78.suppl_1.i14pmid: 12083434

In developing appropriate interventions to control sexually transmitted infections (STIs) it is important to understand the distribution of infections, and how this distribution is influenced by the dynamic nature of epidemics. The epidemiology of STIs has been described as a series of phases, which loosely positions a population within the history of an epidemic. The relation between a mathematical theory describing STI epidemiology and the taxonomy of “phases” is explored in this review of the transmission dynamics of STIs. The likelihood of spread and persistence of infection depends upon the basic reproductive number, whereas the endemic prevalence of infection depends upon the way in which heterogeneity in risk focuses the density dependent constraints limiting the spread of infection. All interventions aimed at reducing the prevalence and incidence of infection must act through the reproductive number. The key parameters determining the reproductive number and the relevance of risk behaviours depend upon the biology of the particular infection. The division between high transmission probability, short duration infections and low transmission probability, long duration infections is explored.

Wong, T; Sutherland, D

doi: 10.1136/sti.78.suppl_1.i189pmid: 12083442

National goals should be “SMART”—specific, measurable, achievable, resource sensitive, and timed. To be meaningful, these goals must be sustainable and realistic within the time frame and fiscal limitations. Multisector partnerships are essential for the goals to become operational.

Changalucha, J; Gavyole, A; Grosskurth, H; Hayes, R; Mabey, D

doi: 10.1136/sti.78.suppl_1.i91pmid: 12083452

The social determinants and epidemiology of sexually transmitted disease (STD) were studied in rural communities in Mwanza Region, Tanzania, in the context of the phase specific model of STD transmission. The prevalence of HIV and syphilis was higher in communities close to main roads, and lower in communities living on islands in Lake Victoria, probably reflecting the proportion of high risk individuals in the population. The prevalence of Herpes simplex virus type 2 infection, gonorrhoea, chlamydial infection, and trichomoniasis was similar in all types of community, reflecting the fact that these infections remain in the hyperendemic phase. The transmission of STDs is fuelled by high population mobility and by the presence of high risk individuals in rural as well as roadside communities.

Decosas, J; Padian, N

doi: 10.1136/sti.78.suppl_1.i40pmid: 12083446

Zimbabwe has widespread and widely disseminated epidemics of most major sexually transmitted infections (STI) including HIV. This epidemiological situation is examined from a broad historical perspective, exploring the interactions between the population incidence of STI and the social profile of the country. The results suggest opportunities for upstream prevention efforts. Examples of these include: integration of prevention with care and social support; increasing general communication and openness about sexuality; economic support initiatives including income generating and micro-credit programmes, offering living accommodations for families in cities, mines, and military camps; and programmes focusing on adolescents before they become sexually active.

Boerma, J T; Urassa, M; Nnko, S; Ng'weshemi, J; Isingo, R; Zaba, B; Mwaluko, G

doi: 10.1136/sti.78.suppl_1.i97pmid: 12083453

This analysis focuses on how sociocultural and economic characteristics of a poor semi-urban and rural population (Kisesa ward) in north west Tanzania may directly and indirectly affect the epidemiology of HIV and other sexually transmitted infections (STI). Poverty and sociocultural changes may contribute to the observed high levels of marital instability and high levels of short and long term migration in Kisesa, especially among younger adults. Marriage and migration patterns are important underlying factors affecting the spread of HIV. The most cost-effective intervention strategy may be to focus on the trading centre in which mobility is higher, bars were more common, and HIV prevalence and incidence were considerably higher than in the nearby rural villages. If resources suffice, additional work can be undertaken in the rural villages, although it is not clear to what extent the rural epidemic would be self sustaining if the interventions in the trading centre were effective.

Wohlfeiler, D

doi: 10.1136/sti.78.suppl_1.i176pmid: 12083440

Forces at work are described which encourage professionalisation and a reliance on one on one HIV prevention interventions among gay men. Community involvement is intrinsically linked to epidemic phases; when the threat diminishes, so does the community's ability to sustain community level interventions. The area of structural and environmental interventions, which can reinforce safe behaviour when community interest in collective action wanes, provides a potential complementary solution for prevention workers, researchers, and funders alike.

Lowndes, C M; Alary, M; Meda, H; Gnintoungbé, C A B; Mukenge-Tshibaka, L; Adjovi, C; Buvé, A; Morison, L; Laourou, M; Kanhonou, L; Anagonou, S

doi: 10.1136/sti.78.suppl_1.i69pmid: 12083450

Rekart, M L

doi: 10.1136/sti.78.suppl_1.i47pmid: 12083447

HIV infection is increasing among sex workers and injection drug users in southern Vietnam. Vietnamese sex workers returning from Cambodia are an important factor. This phase I growth stage is being accelerated by widespread prostitution and escalating heroin use. Sexually transmitted disease (STD) rates are significant in sex workers but low in the general population. STD epidemics in developing countries may not follow the dynamic topology that is common in developed countries. Vietnam has the potential for significant HIV and STD epidemics but also the capacity to respond to these threats.