Larval control of Anopheles (Nyssorhinchus) darlingi using granular formulation of Bacillus sphaericus in abandoned gold-miners excavation pools in the Brazilian Amazon Rainforest

INTRODUCTION: Use of a Bacillus sphaericus based mosquito larvicide was evaluated as an intervention for malaria vector control at a mining site in Amapá, Brazil. Impacts on larval and adult densities of the primary vector Anopheles darlingi were measured over the course of a 52 week study period. METHODS: In Calçoene, State of Amapá, gold mining activity occurs in 19 mining sites in gold-miners of Lourenço. Large pools are formed in mining sites and naturally colonized by Anopheles darlingi. During one year, the impact of applications of VectoLex(r) CG to these larval sources was evaluated. Applications of 20kg/ha were made as needed, based on 10 immature (3rd, 4th instars and pupae) surveillance of health and established thresholds. RESULTS: One hundred percent initial control was observed 48h after each treatment. The pools received from 2-10 (5.3±1.6) treatments during the year. The average re-treatment interval in productive pools was 9.4±4.3 weeks. During weeks 3-52 of the study, mean density of late stage larvae was 78% and pupae were 93% lower in the treated pools than in untreated pools (p< 0.0001, n=51) while reduction of adult mosquitoes was 53% in comparison to the untreated area during the last five months of the study, which were the rainy season (p<0.001). CONCLUSIONS: VectoLex(r) CG reduced immature Anopheles darlingi infestation levels during the entire study period, and reduced adult mosquito populations during the rainy season. .

Prevalence and level of antibodies to the circumsporozoite protein of human malaria parasites in five states of the Amazon region of Brazil

The aim of this study was to determine the prevalence of malaria infection and antibodies against the repetitive epitopes of the circumsporozoite (CS) proteins of Plasmodium falciparum, P. malariae, P. vivax VK210, P. vivax VK247, and P. vivax-like in individuals living in the states of Rondônia, Pará, Mato Grosso, Amazonas, and Acre. Active malaria transmission was occurring in all studied sites, except in Acre. P. falciparum was the predominant species in Pará and Rondônia and P. vivax in Mato Grosso. Infection by P. malariae was low but this Plasmodium species was detected in Rondônia (3.5 percent), Mato Grosso (2.5 percent), and Pará (0.8 percent). High prevalence and levels of serological reactivity against the CS repeat peptides of P. falciparum were detected in Rondônia (93 percent) and Pará (85 percent). Sera containing antibodies against the CS repeat of P. malariae occurred more frequently in Rondônia (79 percent), Pará (76 percent), and Amazonas (68 percent). Antibodies against the repeat epitope of the standard CS protein of P. vivax VK210, P. vivax VK247, and P. vivax-like were more frequent in Rondônia, Pará, and Mato Grosso. The high frequency of reactions to P. malariae in most of the areas suggests that the infection by this Plasmodium species has been underestimated in Brazil.

Wetlands and infections diseases

Existe associaçäo histórica entre terras alagadiças - pântanos, várzeas etc. - e doenças infecciosas, o que levou à modificaçäo deste tipo de terreno no intuito de prevenir as doenças. Houve, ao mesmo tempo, o desenvolvimento de projetos de recursos hídricos que aumentam o risco de doenças. A demanda por mais projetos hidrológicos e a exarcebaçäo da pressäo no sentido de tornar produtivas as áreas alagadiças criam a necessidade de uma abordagem ecológica - com numerosas interfaces ambientais e sanitárias - para a gestäo das terras alagadiças e a avaliaçäo da saúde. Os projetos hidrológicos precisam levar em conta a paisagem, as fronteiras espaciais e as interaçöes transfronteiriças, assim como métodos alternativos de abastecimento d'água para uso humano. Discute os desafios de pesquisa que devem ser enfrentados nesta área.

Malaria in Sucre State, Venezuela

Faz uma revisäo do program de pesquisa sobre malária no Estado de Sucre, Venezuela, à luz de uma abordagem ecossistêmica. O objetivo era determinar quais métodos poderiam ter sido introduzidos no início do estudo para torná-lo mais ecológico e interdisciplinar. A fase inicial do estudo näo incluía uma abordagem ecossistêmica ou controle integrado da doença, que só foram incorporados quando dois ecossistemas contrastantes no Estado de Sucre foram selecionados para pesquisa, junto com um método de controle de vetores com base nos resultados. Uma política de saúde bem-definida com uma abordagem ecossistêmica é crucial para o sucesso de uma estratégia de pesquisa e controle. Esta revisäo sugere que a sustentabilidade é baixa se todos os atores näo estiverem envolvidos no desenho e implementaçäo das estratégias de pesquisa e controle. A falta de participaçäo comunitária coloca em cheque a sustentabilidade das intervençöes. Conclui-se que havia dois desafios interdependentes para o controle da malária no Estado de Sucre: o desenvolvimento de uma abordagem ecossistêmica para pesquisa e controle da malária e a implementaçäo de uma estratégia integrada de controle de doenças, em que a malária seria uma das principais questöes sanitárias.

A survey of the Anopheles Mosquitoes (Diptera: Culicidae) along the Acre And Purus Rivers, Amazon Basin, Brazil

From January 19 to February 25, 1997 an entomological survey of the seringais and larger towns along the Acre and Purus rivers was made as part of the project Revisitando a Amazônia de Carlos Chagas; da Borracha a Biodiversidad. Eleven anopheline species and 1285 specimens were collected landing on human baits. The four most abundant species were Anopheles albitarsis s.l. (n=778), A. darlingi (n=359), A. rangeli (n=69) and A. oswaldoi (n=60). A total of 252 larvae were collected of which 10 anopheline species were identified. The most abundant species collected were A. albitarsis s.l. (n=88), A. deaneorum (n=45) and A. triannulatus (n=40). The low numbers of Anopheles collected and the absence of the principal malaria vector A. darlingi at the seringais sites suggests that they arc not high risk malarious areas. Other Diptera collected were Culex sp., Mansonia titillans, Mansonia pseudotitillans, Psorophora ciliata, Psorophora sp., Coquillettidia (Rhynchotaenia) sp., Simulium amazonicum and S. sanguineum.

Entre os meses de Janeiro/Fevereiro de 1997, foi realizado um levantamento entomológico nos seringais c comunidades localizadas no vale do rios Acre e Purus, como parte do projeto Revisitando a Amazônia de Carlos Chagas; da Borracha a Biodiversidade. Foram capturados no processo de pouso, um total de 1.285 anofelinos pertencentes a 11 espécies. As quatro espécies encontradas em maior número foram: Anopheles albitarsis s.l. (n=778). A. darlingi (n=359) A. rangeli (n=69) e A. oswaldoi (n=60). Também foram coletadas um total de 252 larvas pertencentes a 10 espécies de anofelinos. As espécies mais abundantes foram: A. albitarsis (n=88), A. deaneorum (n=45) e A. triannulalus (n=40). O número reduzido de anofelinos coletados e a ausência do A. darlingi nos seringais sugere que essa região não é de alta endemicidade para malária. Outros mosquitos do gênero Diptera coletados foram: Culex sp., Mansonia titillans, Mansonia pseudotitillans, Psorophora ciliata, Psorophora sp., Coquillettidia (Rhynchotaenia) sp., Simulium amazonicum e S. sanguineum.

Métodos para el control integrado de los vectores de la malaria en Venezuela / Control by method formrd by vectors of the Venezuelan malaria

En la presente revisión se discuten las ventajas, desventajas y la utilidad de todos los métodos de lucha antivectorial que han sido utilizados para el control y erradiación de la malaria en Venezuela entre 1936 y 1993. Entre estos destacan principalmente el rociamiento intradomiciliario con insecticidas de acción residual prolongada, las aplicaciones espacialeso nebulizaciones de insecticidas, la lucha antilarvaria tradicional y más recientemente el control biológico (principalmente bacterias) y el manejo vectorial integrado (combinación de bacterias con aplicación espacial de insecticidas). A su vez se destaca la utilidad de algunas estrategias de control integrado, usadas con éxito en otros países, pero que por diversas razones han sido ignoradas en el país durante décadas

Estudo do mecanismo de açäo do campo elétrico na incorporaçäo de cálcio iônico em células ósseas / Mechanism of action study of electric field in incorporation of ionic calcium in bone cells

Acredita-se que sinais elétricos endógenos afetem o netabolismo ósseo, sendo as respostas fisiológicas ao estímulo eletrico devidas a mecanismos celulares que envolvem variaçöes na concentraçäo citosólica de cálcio. No presente estudo esse efeito celular foi investigado através da estimulaçäo direta, por campo elétrico de intensidade fisiolgicamente significativa de 10 mV/cm e freqüência 1,t MHz, de células ósseas em cultura primária. Observou-se que o efeito e intermediado por canais de transporte de cálcio do tipo L

Spatial and temporal distribution of anopheline larvae in two malarious areas in Sucre State, Venezuela

The spatial and temporal distribution of anopheline larvae was studied in two coastal malarious areas of Sucre, State, Venezuela. Seven habitat types were sampled in the village of Guayana and eight species of Anopheles were collected. Anopheles aquasalis was the predominant species collected and was most abundant in the brackish marsh habitat (71 larvae per 100 samples). It was most abundant during the rainy season. At the second location, Santa F e, six habitat types were sampled and four anopheline species were collected. Habitats where An. aquasalis was most abundant were temporary freshwater ponds (34 larvae per 100 samples) and mangroves (10.5 larvae per 100 samples). At this location it was also most abundant in the rainy season. During the dry season it was collected in small numbers in river pools (1.3 larvae per 100 samples) along with large numbers of An. pseudopunctipennis (479 larvae per 100 samples). Larval control could be an important component of the malaria control program because major habitats could be defined and presence and abundance of larvae was limited to specific times of year

Adult abundance, biting behavior and parity of Anopheles aquasalis, Curry 1932 in two malarious areas of Sucre State, Venezuela

The principal vector of malaria in eastern Venezuela, Anopheles aquasalis, is exophagic and exophilic. Control using indoor insecticide house sprays has failed to lower the number of malaria cases. Therefore, studies were initiated in two villages of the eastern coastal state of Sucre to better understand this vector's biology and develop a more integrated control program. An. aquasalis was found to have a crepuscular biting behavior with a major peak at dusk and a minor peak at dawn. Mosquitos were collected more outdoors than indoors. Forty-seven percent of the biting took place before people went to bed (22:30 hr) and 69 per cent of the mosquitos biting during this time period bite outdoors. Outdoor biting could be the reason why indoor spraying alone did not lower malaria cases. Seasonal abundance was greater in the rainy season compared to the dry season. Seasonal parous rates were high (78.3 per cent -100 per cent ) and similar indoors and outdoors and between dry and wet season in Santa F e. In Guayana, the seasonal parity was lower (34.6 per cent -42.2 per cent ) than Santa F e with indoor parity slightly higher than outdoors. Malaria cases were higher in Santa F e, but adult mosquito density was much lower than in Guayana. This difference could have been due to higher parity in Santa F e compared to Guayana. The greater distance to the nearest breeding site and presence of alternative hosts in Guayana can not be discounted as factors which contributed to the difference in malaria transmission between locations. We concluded that knowledge on seasonal occurrence, biting activity, resting behavior and breeding site location can be used to design a new control strategy for this vector

Ecology of malaria vectors in the Americas and future direction

The resurgence of malaria in the Americas has renewed interest in Anopheles biology. Anopheles darlingi, An. albimanus, An. nuneztovai and An aquasalis are reconfirmed as major malaria vectors and other species are playing important roles in regional malaria transmission. Adultbiting activity and larval ecology are discussed in detail. Seasonal abundance and daily biting activity of Anopheles vary considerably among species and geographically for the same species. Anopheles albimanus has the least amount of variation in biting activity over its range and An. darlingi has the greatest. All species studied are more exophilic and exophagic than endophilic and endophagic. Anopheles darling is more antropophilic, endophilic and endophagic than other Anophelines. Larval studies remain more descriptive than comprehensive. Research on Anophelines is becoming more integrated and biologists are using new biochemical techniques and ecological principles to answer critical questions. This "pluralization" will help us understand species complexes, population dynamics and malaria transmission. integrated control programs will require more regional, in-depth ecological studies