Time trends and changes in the distribution of malaria cases in the Brazilian Amazon Region, 2004-2013

Recent efforts to reduce malaria incidence have had some successes. Nevertheless, malaria persists as a significant public health problem in the Brazilian Amazon. The objective of this study was to describe changes in malaria case characteristics and to identify trends in malaria incidence in the Brazilian Amazon. This study used data from the Malaria Epidemiological Surveillance and Case Notification Information System from 2004 to 2013. The annual parasite incidence (API) was calculated and joinpoint regression was used to assess the trends in API over time. There was a sharp increase in API in the state of Acre, followed by two periods of decrease. Pará also presented inconsistent decreases over the study period. Amapá, Amazonas, Rondônia, and Roraima showed statistically significant decreases over the period. The sharpest decrease occurred in Rondônia, with a reduction of 21.7% in the average annual percent change (AAPC) (AAPC: -21.7%; 95% confidence interval: -25.4%, -17.8%; p < 0.05). This panorama of malaria incidence highlights the importance of integrating evidence-based malaria surveillance and control. Malaria is highly preventable, and eliminating its transmission should be a goal in coming decades.

Revisión histórica de la distribución de Anopheles (Nyssorhynchus) darlingi (Diptera: Culicidae) en la amazonía peruana / Historical review of the distribution of Anopheles (Nyssorhynchus) darlingi (Diptera: Culicidae) in the Peruvian Amazon

Anopheles (Nyssorhynchus) darlingi ha sido reportado desde 1931 en áreas fronterizas del departamento de Loreto, principalmente a lo largo de las fronteras con Brasil y Colombia. En 1994, durante un brote de malaria, An. darlingi fue encontrado en localidades vecinas a Iquitos. En la actualidad, su distribución se ha expandido considerablemente en Loreto. Para los objetivos de este trabajo se realizó una revisión de las referencias bibliográficas disponibles para obtener toda la información posible sobre la distribución de los mosquitos, en particular de los anofelinos en la región Amazónica del país, con énfasis especial en An. darlingi. También se realizaron colectas entomológicas en los departamentos de Madre de Dios y Ucayali con la finalidad de conocer y verificar la distribución de An. darlingi. En la actualidad, la distribución de la especie está circunscrita a localidades al sureste del Perú en localidades fronterizas con Bolivia, en una localidad del río Abujao del departamento de Ucayali, y ampliamente en la región noreste de la cuenca amazónica del departamento de Loreto.

Anopheles (Nyssorhynchus) darlingi has been reported since 1931 in border areas of the department of Loreto, mainly along the borders with Brazil and Colombia. In 1994, during an outbreak of malaria, An. darlingi was found in neighboring towns to Iquitos. At present, its distribution has expanded considerably in Loreto. This paper reviews literature available for all possible information on the distribution of mosquitoes, particularly anopheline in the Amazon region of the country, with special emphasis on An darlingi. Entomological collections were also conducted in the departments of Madre de Dios and Ucayali in order to know and verify the distribution of An. darlingi. At present, the distribution of the species is confined to localities in southeastern Peru with Bolivia border towns, in a town near the Abujao River in the department of Ucayali, and widely in the northeastern region of the Amazon basin of Loreto in Peru.

Insecticidal activity of Leptodactylus knudseni andPhyllomedusa vaillantii crude skin secretions against the mosquitoes Anopheles darlingi andAedes aegypti

Background Mosquitoes are important vectors of several diseases, including malaria and dengue, and control measures are mostly performed using chemical insecticides. Unfortunately, mosquito resistance to commonly applied insecticides is widespread. Therefore, a prospection for new molecules with insecticidal activity based on Amazon biodiversity using the anuransLeptodactylus knudseni andPhyllomedusa vaillantii was performed against the mosquito speciesAnopheles darlingi and Aedes aegypti.Methods The granular secretion from anuran skin was obtained by manual stimulation, and lethal concentrations (LCs) for larvicidal and adulticidal tests were calculated using concentrations from 1-100 ppm. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species.Results The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The calculated LC50 of L. knudseni skin secretions against An. darlingiwas 0.15 and 0.2 ppm for adults and larvae, respectively, but much higher for Ae. aegypti, i.e., 19 and 38 ppm, respectively. Interestingly, the calculated LCs50 of P. vaillantii against both mosquito species in adults were similar, 1.8 and 2.1 ppm, respectively, but the LC50 forAn. darlingi larvae was much lower (0.4 ppm) than forAe aegypti (2.1 ppm).Conclusions The present experiments indicate that skin secretions from L. knudseni and P. vaillantii contain bioactive molecules with potent insecticide activity. The isolation and characterization of skin secretions components will provide new insights for potential insecticidal molecules.(AU)

Aspectos epidemiológicos de malária autóctone na mata atlântica, litoral norte, Estado de São Paulo, 1985 - 2006 / Epidemiological aspects of autochthonous malaria in the Atlantic forest area of the northern coast of the State of São Paulo, 1985 - 2006

Com o objetivo analisar a distribuição espacial e temporal de casos de malária autóctone, segundo: densidade parasitária, sintomas e atividade por ocasião da infecção. Foi feito estudo descritivo retrospectivo de 1985 a 2006, nos municípios de Ubatuba, Caraguatatuba, São Sebastião e Ilhabela. Os dados foram obtidos na ficha de investigação epidemiológica da Superintendência de Controle de Endemias e Sistema de Informação de Notificação de Agravos à Saúde. Dos 83 casos, 77 por cento eram do sexo masculino. São Sebastião e Caraguatatuba apresentaram maior número de casos. Os indivíduos mais acometidos encontraram-se em idade produtiva com Plasmodium vivax, e densidade parasitária de um parasita a cada dois ou mais campos microscópicos. Lazer foi a atividade mais exercida pelos pacientes por ocasião da infecção. Os principais sintomas foram febre, cefaléia, sudorese e mialgia. Foram registrados 4 indivíduos assintomáticos. Esses dados devem contribuir para a melhoria das ações de descentralização do controle da malária na região considerando-a na suspeita clínica e/ou epidemiológica, laboratório de referência e recursos humanos treinados para o diagnóstico e tratamentos adequados.

This study had the aim of analyzing the spatial and temporal distribution of autochthonous malaria cases according to parasite density, symptoms and activity at the time of infection. A retrospective descriptive study was undertaken in the municipalities of Ubatuba, Caraguatatuba, São Sebastião and Ilhabela, covering 1985 to 2006. The data were obtained from the epidemiological investigation files of the Superintendency of Endemic Disease Control and the Information System for Health Threat Notification. Out of the 83 cases notified, 77 percent were male. São Sebastião and Caraguatatuba presented the largest numbers of cases. The individuals most affected with Plasmodium vivax were at productive ages, with a parasite density of one parasite for every two or more microscope fields. At the time of becoming infected, these patients were mostly doing leisure activities. The main symptoms were fever, headache, sweating and myalgia. Four asymptomatic cases were detected. These data are expected to contribute towards improving the decentralized malaria control actions in the region, through considering malaria among the clinical and/or epidemiological suspicions, with a reference laboratory and trained personnel for adequate diagnosis and treatment.

GIS-based prediction of malaria risk in Egypt

Environmental variables in a malaria geographic information system [GIS] database were analysed to discriminate between governorates at high and low risk of malaria. Only Fayoum governorate was categorized as a high risk area for malaria during the last 2 decades. Discriminant models correctly classified 96.3% of the risk categories and indicated that the most important predictor of risk is hydrogeology. Further GIS spatial analysis indicated that the high malaria risk in Fayoum is associated with a unique environmental envelope of biotic [presence of both efficient malaria vectors] and abiotic [hydrogeology and soil] variables. Recommendations for surveillance and control are discussed

Estimation of malaria transmission in high-risk provinces of Morocco

The malaria transmission level of Plasmodium vivax was monitored in four high-risk provinces in Morocco. Intensive mosquito collection by light traps and manual catches resulted in the capture of four species: Anopheles labranchiae, An. sergenti, An. cinereus, and An. claviger. All An. sergenti and An. labranchiae females collected were tested for the presence of two phenotypes of P. vivax [PVK210 and PVK247] antigen by enzyme-linked immunosorbent assay [ELISA]. No P. vivax antigen was detected in 1347 mosquitoes analysed. A parallel parasitological investigation was conducted. Of 2665 slides examined from a population of 4343 people for detection of P. vivax, no slide was positive. The results confirm the break in malaria transmission in residual foci. The use of ELISA is recommended in future epidemiological studies of human malaria

The distribution of two major malaria vectors, Anopheles gambiae and Anopheles arabiensis, in Nigeria

The distribution of Anopheles gambiae and An. arabiensis across the ecological zones of Nigeria (arid savanna in the north gradually turns into humid forest in the south) was investigated. Results of the present study were compared to the distributions determined from samples of indoor-resting females reported by an earlier study over 20 years ago. Larvae were sampled in the rainy seasons of 1997 and 1999 from 24 localities, 10 of which were sampled in both years. Specimens were identified by the polymerase chain reaction method. Results showed that species composition changed significantly among the 10 localities in both years (chi2=13.62, P = 0.0002), but this change was significant in only four of the 10 localities. The identity of the prevalent (more abundant) species changed between 1997 and 1999 in only three of 10 localities. An. arabiensis was prevalent in several localities in the southern Guinea savanna, an area where it was virtually absent over 20 years ago. The data suggest that An. arabiensis has extend its range, although differences in sampling technique (larval sampling versus adult collection) can not be ruled out as a possible explanation

Assessing the effects of global warming and local social and economic conditions on the malaria transmission

Objetivo: Apresenta-se um modelo matemático mostrando como esse instrumento pode ser importante para descrever a transmissäo da malária. Métodos: Baseado no modelo proposto previamente, foram quantificados os efeitos de dois fatores que podem afetar a transmissäo da malária: a temperatura ambiente e as condiçöes socioeconômicas locais. Resultados/Conclusöes: A quantificaçäo foi feita estudando o modelo proposto no estado estacionário e na sua dinâmica. Dependendo do nível de risco de malária, os principais efeitos na transmissäo de malária säo devidos à temperatura ambiente ou às condiçöes socioeconômicas

Malária no Estado de Santa Catarina, no período de janeiro/70 a junho/87: aspectos epidemiológicos / Malaria in the Santa Catarina state in the period comprehended between January/1970 and June/1987: epidemiological aspects

Dados da transmissäo na área de Bromélia-malária do Estado de Santa Catarina foram levantados durante o período de 1970-1987. Os fatores epidemiológicos mais significativos no desencadeamento desse processo foram discutidos. Foram ressaltados os resultados obtidos e os problemas enfrentados com a aplicaçao do Programa de Erradicaçao da Malária na área. Foi estudada a distribuiçäo dos casos importados durante o período 1983-1987 e analisado o risco da possível reintroduçäo da endemia em áreas erradicadas, considerando-se a alta vulnerabilidade e expressiva receptividade da área de Bromélia-malária desse Estado.