ABSTRACT
Integrated vector management is a pillar of the South Asian visceral leishmaniasis (VL) elimination program, but the best approach remains a matter of debate. Sand fly seasonality was determined in 40 houses sampled monthly. The impact of interventions on Phlebotomus argentipes density was tested from 2006-2007 in a cluster-randomized trial with four arms: indoor residual spraying (IRS), insecticide-treated nets (ITNs), environmental management (EVM), and no intervention. Phlebotomus argentipes density peaked in March with the highest proportion of gravid females in May. The EVM (mud plastering of wall and floor cracks) showed no impact. The IRS and ITNs were associated with a 70-80% decrease in male and female P. argentipes density up to 5 months post intervention. Vector density rebounded by 11 months post-IRS, whereas ITN-treated households continued to show significantly lower density compared with households without intervention. Our data suggest that both IRS and ITNs may help to improve VL control in Bangladesh.
Subject(s)
Insect Vectors , Insecticides , Leishmaniasis, Visceral/prevention & control , Mosquito Nets , Animals , Bangladesh , Humans , Leishmaniasis, Visceral/transmission , SeasonsABSTRACT
Since 1990, South Asia has experienced a resurgence of kala-azar (visceral leishmaniasis). To determine risk factors for kala-azar, we performed cross-sectional surveys over a 3-year period in a Bangladeshi community. By history, active case detection, and serologic screening, 155 of 2,356 residents had kala-azar with onset from 2000 to 2003. Risk was highest for persons 3-45 years of age, and no significant difference by sex was seen. In age-adjusted multivariable models, 3 factors were identified: proximity to a previous kala-azar patient (odds ratio [OR] 25.4, 95% confidence interval [CI] 15-44 within household; OR 3.2 95% CI 1.7-6.1 within 50 m), bed net use in summer (OR 0.7, 95% CI 0.53-0.93), and cattle per 1,000 m2 (OR 0.8, 95% CI 0.70-0.94]). No difference was seen by income, education, or occupation; land ownership or other assets; housing materials and condition; or keeping goats or chickens inside bedrooms. Our data confirm strong clustering and suggest that insecticide-treated nets could be effective in preventing kala-azar.
Subject(s)
Leishmaniasis, Visceral/epidemiology , Adolescent , Adult , Age Factors , Aged , Bangladesh/epidemiology , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Odds Ratio , Risk Factors , Seasons , Socioeconomic FactorsABSTRACT
Visceral leishmaniasis, or kala azar (KA), affects the rural poor, causing significant morbidity and mortality. We examined the epidemiologic, social, and economic impact of KA in a village in Bangladesh. A population-based survey among 2,348 people demonstrated a KA incidence of 2% per year from 2000 to 2002, with a case-fatality rate of 19% among adult women, compared with 6-8% among other demographic groups. Kala azar cases were geographically clustered in certain sections of the village. Anti-leishmanial drug shortages and the high cost of diagnosis and treatment caused substantial emotional and economic hardship for affected families. Communities wanted to learn more about KA, and were willing to take collective action to confront the problems it causes. To decrease the KA burden in endemic areas, community efforts should be supplemented with effective treatment programs to ensure access to appropriate and affordable diagnosis and case management.
