Case-Control Study of Mosquito Nets Against Malaria in the Amazon Region of Colombia

Nast, Alexander; Rodríguez, Margarita; Pérez, Ligia; Caicedo, Juan Carlos; Cruz, Jesús López de la; Prieto, Guillermo; Arroyo, José Antonio; Cotacio, Maria Cristina; Suárez, Martha Cecilia; Hoz, Fernando de la; Hall, Andrew J.

doi:10.4269/ajtmh.2005.73.140

Cited by 36 publications

(44 citation statements)

References 25 publications

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“…Consistent with the third hypothesis, two studies have provided evidence that insecticide-treated bed-nets are effective for malaria control in Amazonia. The first was a case-control study in Colombia that showed more than 50% reduction in malaria, relative to no net use, although the advantage of impregnated over non-impregnated nets was not statistically significant [56]. The second study, a randomized trial of lambdacyhalothrin- versus placebo-treated nets in the Amazonas State of Venezuela, showed a protective efficacy of 55% [57].…”

Section: Discussionmentioning

confidence: 99%

Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

et al. 2014

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BackgroundNew frontier settlements across the Amazon Basin pose a major challenge for malaria elimination in Brazil. Here we describe the epidemiology of malaria during the early phases of occupation of farming settlements in Remansinho area, Brazilian Amazonia. We examine the relative contribution of low-density and asymptomatic parasitemias to the overall Plasmodium vivax burden over a period of declining transmission and discuss potential hurdles for malaria elimination in Remansinho and similar settings.MethodsEight community-wide cross-sectional surveys, involving 584 subjects, were carried out in Remansinho over 3 years and complemented by active and passive surveillance of febrile illnesses between the surveys. We used quantitative PCR to detect low-density asexual parasitemias and gametocytemias missed by conventional microscopy. Mixed-effects multiple logistic regression models were used to characterize independent risk factors for P. vivax infection and disease.Principal Findings/Conclusions P. vivax prevalence decreased from 23.8% (March–April 2010) to 3.0% (April–May 2013), with no P. falciparum infections diagnosed after March–April 2011. Although migrants from malaria-free areas were at increased risk of malaria, their odds of having P. vivax infection and disease decreased by 2–3% with each year of residence in Amazonia. Several findings indicate that low-density and asymptomatic P. vivax parasitemias may complicate residual malaria elimination in Remansinho: (a) the proportion of subpatent infections (i.e. missed by microscopy) increased from 43.8% to 73.1% as P. vivax transmission declined; (b) most (56.6%) P. vivax infections were asymptomatic and 32.8% of them were both subpatent and asymptomatic; (c) asymptomatic parasite carriers accounted for 54.4% of the total P. vivax biomass in the host population; (d) over 90% subpatent and asymptomatic P. vivax had PCR-detectable gametocytemias; and (e) few (17.0%) asymptomatic and subpatent P. vivax infections that were left untreated progressed to clinical disease over 6 weeks of follow-up and became detectable by routine malaria surveillance.

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Section: Discussionmentioning

confidence: 99%

Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

et al. 2014

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“…Así mismo, en la región amazónica de Colombia se encontró que el uso del toldillo disminuye el riesgo de infección por malaria en un 50% comparado con no emplearlo (24). Considerando la alta disponibilidad del toldillo en la población urbana de Quibdó, podría considerarse la implementación de campañas de impregnación de toldillos.…”

Section: Discussionunclassified

Epidemiología de malaria urbana en Quibdó, Chocó.

Ochoa

Osório

2006

biomedica

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Introducción. La malaria urbana es un problema de salud pública en Colombia y poco se conoce acerca de sus características epidemiológicas, las cuales es necesario conocer para la implementación de medidas de control. Objetivo. Determinar las características epidemiológicas de la malaria en el área urbana del municipio de Quibdó, Chocó. Materiales y métodos. Los casos de malaria diagnosticados en la ciudad de Quibdó entre marzo y julio del 2001 fueron clasificados como autóctonos e importados a partir de historias de viaje a áreas endémicas o lugar de residencia. Los casos autóctonos fueron ubicados en el mapa con el fin de identificar las zonas de riesgo a partir del cálculo de morbilidad estandarizada por edad y sexo. Resultados. Durante el periodo de estudio se incluyeron 839 casos de malaria: 77% por Plasmodium falciparum; 19% por Plasmodium vivax y 4% fueron infecciones por ambas especies. El 24,4% de los casos por P. falciparum y 39,1% de los casos de P. vivax se clasificó como autóctono. La zona de mayor riesgo de malaria se ubicó en los barrios del suroriente de la ciudad. Conclusiones. La transmisión de malaria es focalizada y las áreas de mayor riesgo de infección están ubicadas cerca de zonas con vegetación. La información obtenida en este estudio permite concentrar esfuerzos en las zonas de mayor riesgo y optimizar la utilización de recursos.Palabras clave: malaria/epidemiología, Plasmodium falciparum, Plasmodium vivax, asentamientos urbanos, Colombia. Epidemiology of urban malaria in Quibdo, Choco.Introduction. Although urban malaria is a public health problem in Colombia, little is known about its epidemiological characteristics, needed for the implementation of rational control strategies. Objective. To determine the epidemiological characteristics of malaria in the urban area of the municipality of Quibdó, in northwest Colombia. Materials and methods. Malaria cases diagnosed in the city of Quibdó between March and July, 2001 were classified as autochthonous or imported based on travel histories to endemic areas and place of residency. Autochthonous cases were mapped and risk areas identified using sex and age standardized morbidity ratios. Results. During the study period 839 malaria cases were included: 77% due to Plasmodium falciparum; 19% due to P. vivax and 4% infections due to both species. 24.4% of P. falciparum cases and 39.1% of P. vivax cases were classified as autochthonous. Those neighborhoods located in the southeast of the town showed the highest risk for malaria. Conclusion. As in other urban areas, malaria transmission in the city of Quibdo is focal and the areas with the highest risk are located near vegetation zones. These results are useful to prioritize areas for intervention and the allocation of resources.

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“…Alexander et al 20 em um estudo de casos e controles e aplicando um modelo multivariado, mostraram que o uso de mosquiteiros impregnados esteve associado a uma redução de 56% dos casos de malária quando comparados com a população que não usou estas tecnologias. Esse resultado é similar ao encontrado na revisão de Lengeler 21 , em que foi encontrado um valor de 48% de eficácia.…”

Section: Os Sistemas De Vigilância E Controle Da Malária Na Fronteiraunclassified

Situação da malária na tríplice fronteira entre Brasil, Colômbia e Peru

et al. 2013

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O objetivo deste artigo é analisar a situação da vigilância da malária na tríplice fronteira entre Brasil, Colômbia e Peru. É um estudo qualitativo com aplicação de questionários em cidades da fronteira realizado em 2011. Os resultados foram analisados pela metodologia DOFA e apontaram diferenças significativas entre os sistemas de vigilância da malária na fronteira. Observou-se como debilidades a desarticulação entre atores responsáveis, a insuficiência de pessoal treinado, a alta rotatividade das equipes e a falta de médicos especialistas em malária nos hospitais locais. Verificou-se ainda o desconhecimento sobre a malária e suas formas de prevenção na população entrevistada. As fortalezas são a inserção de novos atores institucionais, a melhora da qualificação profissional, a distribuição de mosquiteiros impregnados e possibilidades de complementaridade entre os sistemas de vigilância a serem aproveitadas pela cooperação entre as equipes de saúde da fronteira, pois o controle da malária só pode ter sucesso tomando-se esta região em seu conjunto.

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Case-Control Study of Mosquito Nets Against Malaria in the Amazon Region of Colombia

Cited by 36 publications

References 25 publications

Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

Epidemiology of Disappearing Plasmodium vivax Malaria: A Case Study in Rural Amazonia

Epidemiología de malaria urbana en Quibdó, Chocó.

Situação da malária na tríplice fronteira entre Brasil, Colômbia e Peru

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