Infestação por roedores associada a fatores ambientais numa comunidade carente com altorisco de transmissão da leptospirose

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-04T12:40:14Z No. of bitstreams: 1 Santos NJ Rat infestation associated with environmental....pdf: 8205931 bytes, checksum: 34c35277157c365ab5edec3527aac553 (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2018-04-04T12:51:53Z (GMT) No. of bitstreams: 1 Santos NJ Rat infestation associated with environmental....pdf: 8205931 bytes, checksum: 34c35277157c365ab5edec3527aac553 (MD5)Made available in DSpace on 2018-04-04T12:51:53Z (GMT). No. of bitstreams: 1 Santos NJ Rat infestation associated with environmental....pdf: 8205931 bytes, checksum: 34c35277157c365ab5edec3527aac553 (MD5) Previous issue date: 2015Brazilian National Research Council (grants 300861/1996, 554788/2006), the US National Institutes of Health (grants AI052473 and TW00919) and Capes (Coordination for the Improvement of Higher Education Personnel, Brazilian Ministry of Education).Universidade Federal da Bahia. Escola de Medicina Veterinária e Zootecnia. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, BrasilFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Yale University. School of Public Health. New Haven, USAFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Saúde Coletiva. Salvador, BA, BrasilO estudo analisou fatores ambientais que facilitam a presença de alimento, água e abrigo para roedores e risco de infestação por roedores numa comunidade com alto risco de transmissão da leptospirose. Foram realizados inquéritos ambientais detalhados em 221 domicílios. Modelos de regressão multivariada avaliaram a associação entre infestação por roedores e nível socioeconômico e atributos ambientais obtidos através de inquéritos com Sistemas de Informação Geográfica. O estudo mostrou uma taxa global de 45,9% de infestação domiciliar. Sinais de Rattus norvegicus eram os mais prevalentes, presentes em 74% dos domicílios infestados. O risco de infestação por roedores esteve associado a fatores ambientais que forneciam abrigo aos ratos, tais como cercas e muros dilapidados (OR: 8,95; IC95%: 2,42-33,12) e domicílios construídos diretamente sobre encostas (OR: 4,68; IC95%: 2,23-9,81). Cada incremento de um metro de distância a partir do esgoto mais próximo esteve associado a uma diminuição de 3% (IC95%: 1%-5%) no risco de infestação por roedores. A falta de saneamento básico nos locais de moradia das famílias pobres facilita a infestação por ratos e é alvo prioritário para intervenções educativas.We analyzed environmental factors that provide food, water and harborage to rodents and the risk of household rodent infestation in a slum community with a high risk of leptospirosis transmission. Detailed environmental surveys were performed in 221 households. Multivariate regression models evaluated the association between rodent infestation and socioeconomic status and environmental attributes obtained from Geographical Information System surveys. The general household infestation rate was 45.9%. Rattus norvegicus signs were the most prevalent, present in 74% of the infested households. The risk for rodent infestation was associated with environmental factors supporting harborage for rats, such as dilapidated fences/walls (OR: 8.95; 95%CI: 2.42-33.12) and households built on an earthen slope (OR: 4.68; 95%CI: 2.23- 9.81). An increase of 1 meter from the nearest sewer was associated with a 3% (95%CI: 1%-5%) decrease in the risk of rodent infestation. A lack of sanitation where poor people live provides factors for rat infestation and could the target of educational interventionsEl estudio analizó factores ambientales que facilitan la presencia de alimento, agua y abrigo para roedores y el riesgo de infestación por roedores en una comunidad sin recursos con alto riesgo de transmisión de la leptospirosis. Se realizaron encuestas ambientales detalladas en 221 domicilios. Los modelos de regresión multivariada evaluaron la asociación entre infestación por roedores, nivel socioeconómico y características ambientales, obtenidos a través de encuestas con Sistemas de Información Geográfica. El estudio mostró una tasa global de un 45,9% de infestación domiciliaria. Los indicios de Rattus norvegicus eran los más prevalentes, presentes en un 74% de los domicilios infestados. El riesgo de infestación por roedores estuvo asociado a factores ambientales que proporcionaban abrigo a las ratas, tales como cercas y muros derruidos (OR: 8,95; IC95%: 2,42-33,12) y domicilios construidos directamente sobre pendientes (OR: 4,68; IC95%: 2,23-9,81). Cada incremento de un metro de distancia, a partir del alcantarillado más próximo, estuvo asociado a una disminución de un 3% (IC95%: 1%-5%) en el riesgo de infestación por roedores. La falta de saneamiento básico en las viviendas de las familias pobres facilita la infestación por ratas y es el objetivo prioritario para intervenciones educativas

Rat infestation associated with environmental deficiencies in an urban slum community with high risk of leptospirosis transmission

Abstract: We analyzed environmental factors that provide food, water and harborage to rodents and the risk of household rodent infestation in a slum community with a high risk of leptospirosis transmission. Detailed environmental surveys were performed in 221 households. Multivariate regression models evaluated the association between rodent infestation and socioeconomic status and environmental attributes obtained from Geographical Information System surveys. The general household infestation rate was 45.9%. Rattus norvegicus signs were the most prevalent, present in 74% of the infested households. The risk for rodent infestation was associated with environmental factors supporting harborage for rats, such as dilapidated fences/walls (OR: 8.95; 95%CI: 2.42-33.12) and households built on an earthen slope (OR: 4.68; 95%CI: 2.23-9.81). An increase of 1 meter from the nearest sewer was associated with a 3% (95%CI: 1%-5%) decrease in the risk of rodent infestation. A lack of sanitation where poor people live provides factors for rat infestation and could the target of educational interventions

Household rat infestation in urban slum populations: Development and validation of a predictive score for leptospirosis.

Domestic rats are the principal reservoir for urban leptospirosis. However, few studies have identified infestation markers in slums and evaluated their predictivity for leptospirosis risk. We compared households with leptospirosis cases in Salvador, Brazil between 2007 and 2009 and their neighbors using a case control design, surveying for rodent infestation signs and environmental characteristics. With the 2007-2008 data, a conditional logistic regression modeling identified the peridomiciliar presence of rodent burrows (OR, 3.30; 95% CI, 1.50-7.26), rat feces (2.86; 1.24-6.59), runs (2.57; 1.06-6.22), households bordering abandoned houses (2.48; 1.04-6.02), and unplastered walls (2.22; 1.02-6.02) as risk factors and developed a predictive score for leptospirosis. With an independent data set from 2009, a receiver operating characteristic (ROC) curve analysis evaluated the prediction score performance, with the area under the curve being 0.70 (95% CI, 0.64-0.76) for score development and 0.71 (0.65-0.79) for validation. Results indicate that high proportions of urban slum households are infested with R. norvegicus. The score performed well when identifying high-risk households within slums. These findings need confirmation in other urban centers, but suggest that community-based screening for rodent infestation can allow to target rodent and environmental control measures in populations at highest risk for leptospirosis

Influence of Household Rat Infestation on <i>Leptospira</i> Transmission in the Urban Slum Environment

<div><p>Background</p><p>The Norway rat (<i>Rattus norvegicus</i>) is the principal reservoir for leptospirosis in many urban settings. Few studies have identified markers for rat infestation in slum environments while none have evaluated the association between household rat infestation and <i>Leptospira</i> infection in humans or the use of infestation markers as a predictive model to stratify risk for leptospirosis.</p><p>Methodology/Principal Findings</p><p>We enrolled a cohort of 2,003 urban slum residents from Salvador, Brazil in 2004, and followed the cohort during four annual serosurveys to identify serologic evidence for <i>Leptospira</i> infection. In 2007, we performed rodent infestation and environmental surveys of 80 case households, in which resided at least one individual with <i>Leptospira</i> infection, and 109 control households. In the case-control study, signs of rodent infestation were identified in 78% and 42% of the households, respectively. Regression modeling identified the presence of <i>R. norvegicus</i> feces (OR, 4.95; 95% CI, 2.13–11.47), rodent burrows (2.80; 1.06–7.36), access to water (2.79; 1.28–6.09), and un-plastered walls (2.71; 1.21–6.04) as independent risk factors associated with <i>Leptospira</i> infection in a household. We developed a predictive model for infection, based on assigning scores to each of the rodent infestation risk factors. Receiver operating characteristic curve analysis found that the prediction score produced a good/excellent fit based on an area under the curve of 0.78 (0.71–0.84).</p><p>Conclusions/Significance</p><p>Our study found that a high proportion of slum households were infested with <i>R. norvegicus</i> and that rat infestation was significantly associated with the risk of <i>Leptospira</i> infection, indicating that high level transmission occurs among slum households. We developed an easily applicable prediction score based on rat infestation markers, which identified households with highest infection risk. The use of the prediction score in community-based screening may therefore be an effective risk stratification strategy for targeting control measures in slum settings of high leptospirosis transmission.</p></div

Rodent-related and environmental characteristics associated with <i>Leptospira</i> transmission among case and control households at the community study site, Salvador, Brazil.

a<p>Case and control households comprised of households in which cohort subject(s) with evidence of <i>Leptospira</i> infection resided and neighborhood households which were located >30 m of a case household and did not have a member with evidence of <i>Leptospira</i> infection during the study period, respectively.</p>b<p>Median and inter-quartile range (IQR) values are shown for continuous variables.</p>c<p>Values are not shown for non-significant associations.</p>d<p>Categories and variable defined in the CDC form <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0003338#pntd.0003338-CDC1" target="_blank">[22]</a>.</p>e<p>Presence of exposed earth slope (>45°) within 10 m of the household.</p>f<p>Walls composed of exposed bricks without external application of stucco or plastering.</p><p>Rodent-related and environmental characteristics associated with <i>Leptospira</i> transmission among case and control households at the community study site, Salvador, Brazil.</p

Environmental variables related to source of food, water, harborage and access for rodents and rodent active signs in the study area.

<p>(A and B) Photographs of the typical environment at the community study site, which shows a valley in which households are situated and the proximity of households to open sewers, exposed garbage and bushes or shrubbery. (C and D) Rodent burrows. (D and E) Rodent runs. (F) <i>Rattus norvegicus</i> fecal droppings.</p