Anopheles goeldii Rozeboom & Gabaldón (Diptera, Culicidae): a species of the Nuneztovari Complex of Anopheles Meigen

Anopheles (Nyssorhynchus) goeldiiRozeboom & Gabaldón, 1941, a species of the Nuneztovari Complex, was described based on morphological characteristics of the male, female, larva, pupa, and eggs. The type locality is Boa Vista (= Fordlândia), a district in the vicinity of Rio Tapajós, in the municipality of Aveiro, in the state of Pará, Brazil. Anopheles goeldii is redescribed based on morphological traits of the fourth instar larva, pupa, egg, and male and female. DNA sequences from the cytochrome oxidase subunit I (COI barcode region) of the mitochondrial genome were utilized for species characterization. Specimens of An. goeldii from the Pará, Amapá, and Amazonas states were employed to redescribe the species and to compare with morphologically similar taxa.

Effect of Bacillus sphaericus Neide on Anopheles (Diptera: Culicidae) and associated insect fauna in fish ponds in the Amazon

ABSTRACTWe analyzed the effects of Bacillus sphaericus on Anopheles larvae and on the associated insect fauna in fish farming ponds. Five breeding sites in the peri-urban area of the city of Manaus, AM, Brazil, were studied. Seven samples were collected from each breeding site and B. sphaericus was applied and reapplied after 15 days. The samples were made at 24 h before application, 24 h post-application and 5 and 15 days post-application. We determined abundance, larval reduction and larval density for Anopheles, and abundance, richness, Shannon diversity index and classified according to the functional trophic groups for associated insect fauna. A total of 904 Anopheles larvae were collected and distributed into five species. Density data and larval reduction demonstrated the rapid effect of the biolarvicide 24 h after application. A total of 4874 associated aquatic insects belonging to six orders and 23 families were collected. Regression analysis of diversity and richness indicated that the application of the biolarvicide had no influence on these indices and thus no effect on the associated insect fauna for a period of 30 days. B. sphaericus was found to be highly effective against the larvae of Anopheles, eliminating the larvae in the first days after application, with no effect on the associated insect fauna present in the fish ponds analyzed.

The polytene chromosomes of the mosquito Anopheles bellator compared with those of Anopheles cruzii

A photographic map was made of polytene chromosomes of ovarian nurse cells of Anopheles bellator females. The chromosomes of this species have complete or partial homology with those of A. cruzii, mainly in the telomeric and centromeric regions. Variability at the single band level was observed as asymmetric bands at seven different positions. One inversion (3Ra) was detected in the 3R arm.

Aparelho de sucção tipo aspirador para captura de mosquitos

É feita a descrição de aparelho portátil de sucção tipo aspirador, para captura de mosquitos Culicidae. São sugeridas adaptações para coletas em diferentes situações. São feitos comentários sobre sua aplicação em pesquisa de mosquitos.

Comportamento exófilo de Anopheles darlingi Root, em região meridional do Brasil

Observou-se o comportamento da população "Araraquara" de Anopheles darlingi, em seu ambiente original e em relação à sua atividade exófila com isca humana. As coletas foram realizadas às margens do rio Jacaré-Pepira, no Município de Dourado, Estado de São Paulo, Brasil. O ciclo nictemeral caracteriza-se pelo aspecto bimodal, com os dois picos correspondentes a cada crepúsculo, ou seja, vespertino e matutino. O seu detalhamento permitiu detectar bimodalidade secundária, subdividindo cada pico em um eocrepuscular precedendo ao intracrepuscular propriamente dito. A variação sazonal revelou aumento do número de mosquitos na estação chuvosa e quente e nítido declínio na seca e fria. Embora com dados insuficientes, houve indícios de que o An. albitarsis local, apresente também ritmo bimodal em seu ciclo diário de atividade.

Susceptibility of Aedes aegypti larvae to temephos and Bacillus thuringiensis var israelensis in integrated control

The susceptibility of field collected Aedes aegypti larvae was evaluated in terms of median lethal time (LT50) and final mortality, when treated with temephos, Bacillus thuringiensis var israelensis as well as mixtures of these two agents. Third instar larvae were shown to be more susceptible than early and late fourth instar ones to the entomopathogen. Survival of some individuals when exposed to temephos suggest possible resistance. Temporal synergism in early fourth instar larvae was detected when they were exposed to mixtures of Bti-temephos. The possibility of this integrated treatment is commented on.

Dengue in the South-eastern region of Brazil: historical analysis and epidemiology

The aim of the study is an historical analysis of the work undertaken by the Public Health organizations dedicated to the combat of the Aedes aegypti, as well as an epidemiolocal study of persons with unexplained fever, with a view to evaluating the ocurrence of dengue within the population. The Mac-Elisa, Gac-Elisa, hemaglutination inhibition, isolation and typage tests were used. Organophosphate intoxication in agricultural workers was also assessed by measuring concentrations of serie cholinesterase. A sera samples of 2,094 were collected in 23 towns, and the type 1 dengue virus was detected in 17 towns and autochthony was confirmed in 12 of them. The cholinesterase was measured in 2,391 sera samples of which 53 cases had abnormal levels. Poisoning was confirmed in 3 cases. Results reveal an epidemic the gravity of which was not officially know. The relationshipe between levels of IgM and IgG antibodies indicates the outbreak tendency. The widespread distribution of the vector is troubling because of the possibility of the urbanization of wild yellow fever, whereas the absence of A. aegypti in 2 towns with autochthony suggests the existence of another vector. Since there is no vaccine against dengue, the combat of the vector is the most efficient measure for preventing outbreaks. The eradication of the vector depends on government decisions which depend, for their execution, on the organization of the Health System and the propagation of information concerning the prevention of the disease using all possible means because short and long term results depend on the education and the active participation of the entire population.

Aedes (Stegomyia) aegypti L. e a culicideofauna associada em área urbana da região sul, Brasil

Foram mostrados alguns aspectos sobre a ecologia de 11 espécies de Culicidae que procriam em recipientes, em uma área urbana do Sul do Brasil. Os mais variados tipos de recipientes foram listados como eficientes criadouros para larvas de culicídeos. Aedes aegypti apareceu como espécie recém-introduzida e limitada somente a duas áreas da cidade. As espécies predominantes foram: Culex quinquefasciatus, Culex coronator, Aedes aegypti, Aedes fluviatilis e Limatus durhamii.

Evaluation of organophosphorus and synthetic pyrethroid insecticides against six vector mosquitoe species

Three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquitoe species: Culex quinquefasciatus (Filariasis) and Aedes albopictus (Dengue) (both laboratory and field strains); laboratory strains of Aedes aegypti (Dengue), Anopheles slephensi and Anopheles culicifacies (Malaria), and Culex tritaeniorhynchus (Japanese encephalitis) in India. From the LC50 values obtained for these insecticides, it was found that all mosquito species including the field strains of Cx. quinquefasciatus and Ae. albopictus were highly susceptible Except for Cx. quinquefasciatus (field strain) against malathion, 100% mortality was observed at the discriminating dosages recommended by World Health Organization. The residual effect of alphamethrin, deltamethrin, malathion and folithion at 25 mg (ai)/m² on different surfaces against six species of vector mosquitoes showed that alphamethrin was the most effective on all four treated surfaces (mud, plywood, cement and thatch). Nevertheless, residual efficacy lasted longer on thatch than on the other surfaces. Therefore, synthetic pyrethroids such as alphamethrin can be effectively employed in integrated vector control operations.

Culicídeos do lago de Itaipu, no rio Paraná, Sul do Brasil

De janeiro a dezembro de 1991 foram realizadas capturas mensais de culicídeos, no Município de Guaíra, Estado do Paraná (Brasil), na margem esquerda do lago de Itaipu, ao lado da via de acesso que conduzia aos Saltos das Sete Quedas, usando-se armadilha luminosa de Shannon, e isca humana em área urbanizada. Obtiveram-se informações sobre a fauna culicidiana, as espécies prevalentes, a variação sazonal, o horário de maior densidade e a afinidade dos mosquitos em relação ao hospedeiro humano. Foram identificadas 41 espécies de culicídeos dos gêneros Anopheles, Aedes, Aedomyia, Coquillettidia, Culex, Mansonia, Psorophora e Uranotaenia. Capturaram-se 21.280 mosquitos em armadilha de Shannon e 1.010 em isca humana. As espécies mais freqüentes em armadilha de Shannon - Coquillettidia shannoni, Mansonia humeralis, Anopheles triannulatus, Aedes scapularis e Anopheles albitarsis - perfizeram 82,78% dos mosquitos capturados. Em isca humana Aedes scapularís, Mansonia humeralis e Anopheles albitarsis, somaram 91,21% dos insetos capturados. Em armadilha de Shannon o horário de maior atividade das espécies prevalentes foi entre 19 e 22 h. Em isca humana Aedes scapularis teve maior densidade das 20 às 21 h, enquanto Mansonia humeralis e Anopheles albitarsis prevaleceram das 18 às 19 h. Dentre as espécies prevalentes em armadilha de Shannon, Coquillettidia shannoni, Mansonia humeralis e Anopheles albitarsis tiveram pico de atividade no mês de abril, Anopheles triannulatus em janeiro e Aedes scapularis em fevereiro.

Periodic dynamic systems for infected hosts and mosquitoes

A mathematical model for the purpose of analysing the dynamic of the populations of infected hosts anf infected mosquitoes when the populations of mosquitoes are periodic in time is here presented. By the computation of a parameter lambda (the spectral radius of a certain monodromy matrix) one can state that either the infection peters out naturally) (lambda <= 1) or if lambda > 1 the infection becomes endemic. The model generalizes previous models for malaria by considering the case of periodic coefficients; it is also a variation of that for gonorrhea. The main motivation for the consideration of this present model was the recent studies on mosquitoes at an experimental rice irrigation system, in the South-Eastern region of Brazil.

The use of wide-mesh gauze impregnated with lambda-cyhalothrin covering wall openings in huts as a vector control method in Suriname

An alternative vector control method, using lambda-cyhalothrin impregnated wide-mesh gauze covering openings in the walls of the houses was developed in an area in the Eastern part of the interior of Suriname. Experimental hut observations showed that Anopheles darlingi greatly reduced their biting activity (99-100%) during the first 5 months after impregnation. A model assay showed high mortality both of mosquitoes repelled by the gauze as well as of those that succeeded in getting through it. A field application test in 270 huts showed good acceptance by the population and good durability of the applied gauze. After introducing the method in the entire working area, replacing DDT residual housespraying, the malaria prevalence, of 25-37% before application dropped and stabilized at between 5 and 10% within one year. The operational costs were less than those of the previously used DDT housespraying program, due to a 50% reduction in the cost of materials used. The method using widemesh gauze impregnated with lambdacyhalothrin strongly affects the behavior of An. darlingi. It is important to examine the effect of the method on malaria transmission further, since data indirectly obtained suggest substantial positive results.

Survey of cyclopids (Crustacea, Copepoda) in Brazil and preliminary screening of their potential as dengue vector predators

INTRODUCTION: Cyclopid copepods are known to be good mosquito controllers, specially as regards the larvae of the dengue vectors Aedes aegypti and Ae. albopictus. MATERIAL AND METHOD: The objective of the study was to survey the local copepod fauna and search for new strains of M. longisetus var. longisetus, comparing the potential of the samples found with the current strain ML-01 against Ae. albopictus larvae, under laboratory conditions. Eleven bodies of water in Campinas, SP, Brazil, were screened for copepods by collecting 1.5 l of water from each of then. The predatory potential of adults copepods was evaluated over 24 h, in the laboratory, for groups of 5 individuals preying upon 30 first instar Ae. albopictus larvae. RESULTS AND CONCLUSION: The following cyclopid species were found: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. The predatory potential of these copepods ranged from nil to 97.3%. A sample collected in the field containing only M. longisetus var. longisetus showed the best control efficiency with no significant difference from a three-year old laboratory culture (ML-01) of the same species evaluated for comparison. The sample with few M. albidus var. albidus was ranked in second place showing an average 25.9% efficiency. The use of copepods in trap tires as dengue vector controllers is discussed.

Encontro de Aedes (Stegomyia) albopictus (Skuse) em Bromeliaceae na periferia de São Paulo, SP, Brasil

Foram coletadas larvas de Aedes albopictus em uma planta da família Bromeliaceae, na periferia da cidade de São Paulo, SP, Brasil. Esse encontro abre perspectivas de estudo para avaliação do potencial desse vegetal como criadouro desse mosquito no País.

Produtividade de criadouro de Aedes albopictus em ambiente urbano

INTRODUÇÃO: O encontro de Aedes albopictus na cidade de Cananéia, região Sudeste do Estado de São Paulo, Brasil, ensejou a ocasião de realizar observações que visassem avaliar a produtividade de criadouro grande e permanente. Como objetivo, após selecionar o habitat a ser estudado, tentou-se avaliar-lhe a contribuição para a densidade local do mosquito. MATERIAL E MÉTODO: Em área predeterminada procedeu-se a levantamento de criadouros potenciais. Constatada a presença da espécie, foi selecionado um dos recipientes que preenchia os requisitos desejados. O acompanhamento foi feito de maneira ininterrupta, no período de novembro de 1996 a maio de 1997. As observações obdeceram a ritmo quinzenal retirando, cada vez, amostra da água correspondente a 0,14, ou seja, um sétimo do volume total de 70 litros. Procurou-se coletar, identificar e numerar, por sexo, as pupas existentes. Concomitantemente, procedeu-se à captura de formas adultas. Foi utilizada a isca humana das 15:00 às 18:00h, instalada a cerca de 6 metros do mencionado criadouro. Finda essa coleta, foi feita aspiração com 30 min. de duração em locais de abrigo representados pela abundante vegetação circunjacente. RESULTADOS: Nas coletas de formas imaturas do criadouro, o Ae. albopictus compareceu com 44,9%. Ao longo de 15 amostras regularmente realizadas obteve-se a média de 31,13 pupas pertencentes a essa espécie. O índice de emergência(E) foi de 2,1. A multiplicação desse valor por sete forneceu a média diária de 14,7 fêmeas. Nas coletas de adultos desse sexo, a média de Williams para a isca humana foi de 30,7, enquanto a densidade média horária da aspiração dos locais de abrigo foi de 9,2. O cálculo do acúmulo diário concluiu pela presença de 22,8 fêmeas, por dia, capazes de freqüentar a isca humana, nessa situação e condições. DISCUSSÃO: A contagem de pupas possibilitou estimar a produtividade de criadouro de Ae. albopictus, tipo grande (dez litros ou mais) e de caráter permanente. A água acumulada no recipiente estudado apresentou-se rica em matéria orgânica, predominantemente de natureza vegetal. Neste particular, não há como compará-lo a reservatórios destinados ao armazenamento de água para uso doméstico. A falta de manutenção desses reservatórios poderá contribuir para levar a situação, se não idêntica, pelo menos próxima da evidenciada no trabalho. Embora se trate de espécie até agora não incriminada como vetora, é de se admitir que as observações encontradas possam ser utilizadas no programa de erradicação de Ae. aegypti que está em curso no Brasil.