Impact of Environment and Social Gradient on Leptospira Infection in Urban Slums

Abstract

BackgroundLeptospirosis has become an urban health problem as slum settlements have expanded worldwide. Efforts to identify interventions for urban leptospirosis have been hampered by the lack of population-based information on Leptospira transmission determinants. The aim of the study was to estimate the prevalence of Leptospira infection and identify risk factors for infection in the urban slum setting.Methods and FindingsWe performed a community-based survey of 3,171 slum residents from Salvador, Brazil. Leptospira agglutinating antibodies were measured as a marker for prior infection. Poisson regression models evaluated the association between the presence of Leptospira antibodies and environmental attributes obtained from Geographical Information System surveys and indicators of socioeconomic status and exposures for individuals. Overall prevalence of Leptospira antibodies was 15.4% (95% confidence interval [CI], 14.0–16.8). Households of subjects with Leptospira antibodies clustered in squatter areas at the bottom of valleys. The risk of acquiring Leptospira antibodies was associated with household environmental factors such as residence in flood-risk regions with open sewers (prevalence ratio [PR] 1.42, 95% CI 1.14–1.75) and proximity to accumulated refuse (1.43, 1.04–1.88), sighting rats (1.32, 1.10–1.58), and the presence of chickens (1.26, 1.05–1.51). Furthermore, low income and black race (1.25, 1.03–1.50) were independent risk factors. An increase of US$1 per day in per capita household income was associated with an 11% (95% CI 5%–18%) decrease in infection risk.ConclusionsDeficiencies in the sanitation infrastructure where slum inhabitants reside were found to be environmental sources of Leptospira transmission. Even after controlling for environmental factors, differences in socioeconomic status contributed to the risk of Leptospira infection, indicating that effective prevention of leptospirosis may need to address the social factors that produce unequal health outcomes among slum residents, in addition to improving sanitation.

Semantic publishing: the coming revolution in scientific journal publishing

“…maps). Our simple demonstrations of the potential of such data fusion services for infectious disease epidemiology, in the context of semantic enhancements to Reis et al, 10 described in Shotton et al, 5 and the more sophisticated work of the Royal Society of Chemistry cited above, illustrate how investment of effort at the time of publication can pay back in terms of significantly increased efficiency when data from many different reports need to be integrated to enable meta-analysis and mathematical modelling, since currently research efficiency is severely limited by the cost in terms of time and effort of acquiring such data manually from the published literature.…”

“…In Shotton et al 5 we describe the semantic enhancements that we have made to a recent article by Reis et al 10 We created a document summary containing document statistics; a study summary, a tag Semantic publishing: the coming revolution in scientific journal publishing 89…”

“…We experimented with the use of two automated systems to identify semantically meaningful terms in one article, Reis et al 10 Our trial of the uBio Taxon Finder Web service for finding taxonomic names (http://www.ubio.org/ index.php?pagename=xml_services) was highly successful. It found every instance of taxonomic names in the PLoS NTD text ('Leptospira', 'Leptospira borgspetersenii', 'Leptospira interrogans', 'Leptospira kirschneri', 'Rattus norvegicus'), but also returned one false positive, 'Strina', the name of one of the authors of Reference [52] in that article, showing that some human supervision is required.…”

Estimating Burdens of Neglected Tropical Zoonotic Diseases on Islands with Introduced Mammals

“…28 In particular, efficiency in public services such as solid waste management and access to waste disposal centers lead to decreased rodent population sizes, and decreased contact with commensal rodents and rodentborne pathogens. [29][30][31] This in turn may have a cascading effect on cat abundance through bottom-up processes, 32 and in consequence affect the environmental load of parasites like Toxoplasma gondii. 33,34 However, this pattern has only been studied in large metropolitan areas, and whether it persists at smaller population sizes is currently unknown.…”

<b>Avaliação do potencial imunogênico e vacinal das flagelinas de <i>Leptospira interrogans</i> sorovar Copenhageni</b>

“…É bastante disseminada principalmente em épocas de chuvas, pois muitas áreas estão sujeitas a alagamentos e possuem saneamento básico deficiente. São relatados mais de 10.000 casos de 21 leptospirose grave todo ano (REIS et al, 2008;SUS, 2013). Na pecuária, a leptospirose tem causado grandes perdas econômicas por influenciar o potencial reprodutivo do rebanho.…”