Anopheles (Kerteszia) cruzii (DIPTERA: CULICIDAE) IN PERIDOMICILIARY AREA DURING ASYMPTOMATIC MALARIA TRANSMISSION IN THE ATLANTIC FOREST: MOLECULAR IDENTIFICATION OF BLOOD-MEAL SOURCES INDICATES HUMANS AS PRIMARY INTERMEDIATE HOSTS

Anopheles (Kerteszia) cruzii has been implicated as the primary vector of human and simian malarias out of the Brazilian Amazon and specifically in the Atlantic Forest regions. The presence of asymptomatic human cases, parasite-positive wild monkeys and the similarity between the parasites infecting them support the discussion whether these infections can be considered as a zoonosis. Although many aspects of the biology of An. cruzii have already been addressed, studies conducted during outbreaks of malaria transmission, aiming at the analysis of blood feeding and infectivity, are missing in the Atlantic Forest. This study was conducted in the location of Palestina, Juquitiba, where annually the majority of autochthonous human cases are notified in the Atlantic Forest of the state of São Paulo. Peridomiciliary sites were selected for collection of mosquitoes in a perimeter of up to 100 m around the residences of human malaria cases. The mosquitoes were analyzed with the purpose of molecular identification of blood-meal sources and to examine the prevalence of Plasmodium. A total of 13,441 females of An. (Ker.) cruzii were collected. The minimum infection rate was calculated at 0.03% and 0.01%, respectively, for P. vivax and P. malariae and only human blood was detected in the blood-fed mosquitoes analyzed. This data reinforce the hypothesis that asymptomatic human carriers are the main source of anopheline infection in the peridomiciliary area, making the probability of zoonotic transmission less likely to happen.

Larvas de Anopheles (subgênero Kerteszia) Theobald 1905 encontradas em criadouros artificiais, no Estado do Paraná, Brasil

Discute-se encontro de larvas de duas espécies de anofelinos do subgênero Kerteszia - An. (Ker.) cruzii e An. (Ker.) bambusicolus - em criadouros artificiais, no Estado do Paraná, Brasil.

Isoenzimatic analysis of four Anopheles (Kerteszia) cruzii (Diptera: Culicidae) populations of Brazil

Anopheles cruzii is a small sylvatic mosquito and primary human Plasmodium vector in Southern Brazil. The distribution of this bromeliad-breeding mosquito follows the Atlantic forest coastal distribution, where bromeliads are abundant. Morphological, genetic, and molecular polymorphisms among different populations have been reported and it has recently been suggested that An. cruzii is a complex of cryptic species. The aim of this work is to analyze the gene flow between different populations of An. cruzii collected in four localities within the geographic distribution range of the species, and to examine if An. cruzii is a complex of cryptic species. The genetic distances show that populations of the states of Santa Catarina, São Paulo, and Rio de Janeiro are genetically closer (0.032 to 0.083) than populations of Bahia (0.364 to 0.853) based on profiles from 10 distinct isoenzyme loci. The Fst was lower (0.077) when the Bahia population was excluded than when it was included (0.300) in the analyses. The inferred number of migrants per generation was 2.99 individuals among populations from the states of Santa Catarina, São Paulo, and Rio de Janeiro and 0.58 migrants per generation among all populations. Results suggest that An. cruzii is a complex of species and that the specimes of state of Bahia can be considered as belonging to a species that is distinct from other three closely-related populations studied.

Composição e atividade de mosquitos Culicidae. Emprego de armadilha CDC no Vale do Ribeira, Estado de São Paulo, Brasil

Com o emprego da armadilha CDC determinou-se a composição específica da fauna de mosquitos Culicidae em locais com vegetação primária, situados em terras baixas e próximas a mangues, no litoral sul do Estado de São Paulo (Brasil). Como resultado geral foram obtidos cerca de 64 espécies ou grupos. Entre as que foram mais freqüentes destacaram-se Culex (Mel.) sacchettae (71,6%), Anopheles (Ker.) cruzii (10,5%), Phoniomiya spp. (8,2%) e Culex (Mel.) taeniopus (2,9%). Também com este método de coleta, nos horários crepuscular vespertino, noturno, ao lado do uso de isca ave e roedor, a dominância nítida foi de Cx. sacchettae, ao contrário do que ocorreu no mesmo local com isca humana, quando An. cruzii foi a espécie predominante. A diversidade calculada para o interior, margem da mata, campo aberto e domicílio, tendo sido de 1,7 a 6,2 revelou fauna relativamente rica para Culicidae. Não obstante a marcante presença de Culex (Cux.) quinquefasciatus no domicílio, foi inesperada a elevada freqüência de Cx. sacchettae. Além disso, a presença proporcional de An. cruzii no solo e copa sugere mobilidade desse anofelino no interior da floresta, enquanto que a sua atividade em ambiente extraflorestal revelou ser restrita. Nesse particular, Cx. sacchettae demonstrou ser espécie ubiqüista e ocorrente durante todos os meses do ano, porém com picos mais elevados nas estações verão e outono.

Encontro de imaturos de Anopheles cruzii em bromélias de área urbana, litoral de São Paulo

Primeiro relato da ocorrência de larvas de Anopheles (Kerteszia) cruzii, mosquito essencialmente silvestre, em bromélias de solo em área urbana do município de Ilhabela, litoral norte do estado de São Paulo. De março de 1998 a julho de 1999 foram capturadas 312 formas imaturas de An. cruzii, sendo 8,6% em bromélias do ambiente urbano, 40,1% em bromélias do periurbano e 51,3% na mata. O número médio de bromélias com An. cruzii foi de 4,0% dentre o total de pesquisadas, com valores próximos de positividade para ambiente periurbano e mata. A presença de An. cruzii no ambiente urbano provavelmente é resultante da sua ocorrência prévia na mata, aliada à elevada presença desse criadouro na área urbana, de fonte alimentar e abrigos disponíveis. Alerta-se para a possibilidade de transferência de infecções entre esses ambientes

Studies on mosquitoes (Diptera: Culicidae) and anthropic environment: 11 - Biting activity and blood-seeking parity of Anopheles (Kerteszia) in South-Eastern Brazil

An. (Ker.) cruzii and An. (Ker.) bellator were monitored by the use of human bait and Shannon trap collections during a one-year period in 1994. Indoor and outdoor collections were made on human bait and inside the forest environment a Shannon trap was used. Both were undertaken in the evening crepuscular period. Results showed a greater abundance of An. cruzii in the forest, where as An. bellator was more abundant in the domiciliary environment. Through the application of the Polovodova method an age grading was established. Computing the parous and nulliparous females with Christopher's Stage III and above, more than 30.0% of blood-seeking specimens of both anophelines had had a previous blood meal. The higher abundance of An. bellator as compared with that of An. cruzii in the domiciliary environment may be explained by the influence of the neighboring low-lying coastal islands of the estuary system.

Encontro de imaturos de Anopheles cruzii em bromélias de área urbana, litoral de São Paulo

Primeiro relato da ocorrência de larvas de Anopheles (Kerteszia) cruzii, mosquito essencialmente silvestre, em bromélias de solo em área urbana do município de Ilhabela, litoral norte do estado de São Paulo. De março de 1998 a julho de 1999 foram capturadas 312 formas imaturas de An. cruzii, sendo 8,6% em bromélias do ambiente urbano, 40,1% em bromélias do periurbano e 51,3% na mata. O número médio de bromélias com An. cruzii foi de 4,0% dentre o total de pesquisadas, com valores próximos de positividade para ambiente periurbano e mata. A presença de An. cruzii no ambiente urbano provavelmente é resultante da sua ocorrência prévia na mata, aliada à elevada presença desse criadouro na área urbana, de fonte alimentar e abrigos disponíveis. Alerta-se para a possibilidade de transferência de infecções entre esses ambientes.

Morphometrical diagnosis of the malaria vectors Anopheles cruzii, An. homunculus and An. bellator

Background: Anopheles (Kerteszia) cruzii is a primary vector of Plasmodium parasites in Brazil's Atlantic Forest. Adult females of An. cruzii and An. homunculus, which is a secondary malaria vector, are morphologically similar and difficult to distinguish when using external morphological characteristics only. These two species may occur syntopically with An. bellator, which is also a potential vector of Plasmodium species and is morphologically similar to An. cruzii and An. homunculus. Identification of these species based on female specimens is often jeopardised by polymorphisms, overlapping morphological characteristics and damage caused to specimens during collection. Wing geometric morphometrics has been used to distinguish several insect species; however, this economical and powerful tool has not been applied to Kerteszia species. Our objective was to assess wing geometry to distinguish An. cruzii, An. homunculus and An. bellator. Methods: Specimens were collected in an area in the Serra do Mar hotspot biodiversity corridor of the Atlantic Forest biome (Cananeia municipality, State of Sao Paulo, Brazil). The right wings of females of An. cruzii (n= 40), An. homunculus (n= 50) and An. bellator (n= 27) were photographed. For each individual, 18 wing landmarks were subjected to standard geometric morphometrics. Discriminant analysis of Procrustean coordinates was performed to quantify wing shape variation. Results: Individuals clustered into three distinct groups according to species with a slight overlap between representatives of An. cruzii and An. homunculus. The Mahalanobis distance between An. cruzii and An. homunculus was consistently lower (3.50) than that between An. cruzii and An. bellator (4.58) or An. homunculus and An. bellator (4.32). Pairwise cross-validated reclassification showed that geometric morphometrics is an effective analytical method to distinguish between An. bellator, An. cruzii and An. homunculus with a reliability rate varying between 78-88%. Shape analysis revealed that the wings of An. homunculus are narrower than those of An. cruzii and that An. bellator is different from both of the congeneric species. Conclusion: It is possible to distinguish among the vectors An. cruzii, An. homunculus and An. bellator based on female wing characteristics.

Kerteszia subgenus of Anopheles associated with the Brazilian Atlantic rainforest: current knowledge and future challenges

Background: The Atlantic rainforest ecosystem, where bromeliads are abundant, provides an excellent environment for Kerteszia species, because these anophelines use the axils of those plants as larval habitat. Anopheles (K.) cruzii and Anopheles (K.) bellator are considered the primary vectors of malaria in the Atlantic forest. Although the incidence of malaria has declined in some areas of the Atlantic forest, autochthonous cases are still registered every year, with Anopheles cruzii being considered to be a primary vector of both human and simian Plasmodium. Methods: Recent publications that addressed ecological aspects that are important for understanding the involvement of Kerteszia species in the epidemiology of malaria in the Atlantic rainforest in the Neotropical Region were analysed. Conclusion: The current state of knowledge about Kerteszia species in relation to the Atlantic rainforest ecosystem was discussed. Emphasis was placed on ecological characteristics related to epidemiological aspects of this group of mosquitoes. The main objective was to investigate biological aspects of the species that should be given priority in future studies

Mosquitoes in degraded and preserved areas of the Atlantic Forest and potential for vector-borne disease risk in the municipality of Sao Paulo, Brazil

In order to assess the epidemiological potential of the Culicidae species in remaining areas of the Brazilian Atlantic Forest, specimens of this family were collected in wild and anthropic environments. A total of 9,403 adult mosquitoes was collected from May, 2009 to June, 2010. The most prevalent among species collected in the wild environment were Anopheles (Kerteszia) cruzii, the Melanoconion section of Culex (Melanoconion), and Aedes serratus, while the most common in the anthropic site were Coquillettidia chrysonotum/albifera, Culex (Culex) Coronator group, and An. (Ker.) cruzii. Mosquito richness was similar between environments, although the abundance of individuals from different species varied. When comparing diversity patterns between environments, anthropic sites exhibited higher richness and evenness, suggesting that environmental stress increased the number of favorable niches for culicids, promoting diversity. Increased abundance of opportunistic species in the anthropic environment enhances contact with culicids that transmit vector-borne diseases.

Kerteszia subgenus of Anopheles associated with the Brazilian Atlantic rainforest:current knowledge and future challenges

Abstract Background The Atlantic rainforest ecosystem, where bromeliads are abundant, provides an excellent environment for Kerteszia species, because these anophelines use the axils of those plants as larval habitat. Anopheles (K.) cruzii and Anopheles (K.) bellator are considered the primary vectors of malaria in the Atlantic forest. Although the incidence of malaria has declined in some areas of the Atlantic forest, autochthonous cases are still registered every year, with Anopheles cruzii being considered to be a primary vector of both human and simian Plasmodium. Methods Recent publications that addressed ecological aspects that are important for understanding the involvement of Kerteszia species in the epidemiology of malaria in the Atlantic rainforest in the Neotropical Region were analysed. Conclusion The current state of knowledge about Kerteszia species in relation to the Atlantic rainforest ecosystem was discussed. Emphasis was placed on ecological characteristics related to epidemiological aspects of this group of mosquitoes. The main objective was to investigate biological aspects of the species that should be given priority in future studies.

Natural infection in anopheline species and its implications for autochthonous malaria in the Atlantic forest in Brazil

Abstract Background A descriptive study was carried out in an area of the Atlantic Forest with autochthonous malaria in the Parelheiros subdistrict on the periphery of the municipality of São Paulo to identify anopheline fauna and anophelines naturally infected with Plasmodium as well as to discuss their role in this peculiar epidemiological context. Methods Entomological captures were made from May 2009 to April 2011 using Shannon traps and automatic CDC traps in four areas chosen for their different patterns of human presence and incidences of malaria (anthropic zone 1, anthropic zone 2, transition zone and sylvatic zone). Natural Plasmodium infection was detected by nested PCR based on amplification of the 18S rRNA gene. Results In total, 6,073 anophelines were collected from May 2009 to April 2011, and six species were identified in the four zones. Anopheles cruzii was the predominant species in the three environments but was more abundant in the sylvatic zone. Anopheles (Kerteszia) cruzii specimens from the anthropic and sylvatic zones were positive for P. vivax and P. malariae. An. (Ker.) bellator, An. (Nys.) triannulatus, An. (Nys.) strodei, An. (Nys.) lutzi and An. (Ano) maculipes were found in small numbers. Of these, An. (Nys.) triannulatus and An. (Nys.) lutzi, which were collected in the anthropic zone, were naturally infected with P. vivax while An. (Nys.) triannulatus from the anthropic zones and An. (Nys.) strodei from the transition zone were positive for P. malariae. Conclusion These results confirm that Anopheles (Kerteszia) cruzii plays an important role as a major Plasmodium vector. However, the finding of other naturally infected species may indicate that secondary vectors are also involved in the transmission of malaria in the study areas. These findings can be expected to help in the implementation of new measures to control autochthonous malaria in areas of the Atlantic Forest.

Entomological characterization and natural infection of anophelines in an area of the Atlantic Forest with autochthonous malaria cases in mountainous region of Espírito Santo State, Brazil

No Espírito Santo, os casos de malária autóctone estão distribuídos na região serrana próximo aos fragmentos de Mata Atlântica. Uma vez que alguns aspectos da doença são obscuros, a detecção das possíveis espécies de vetores pode auxiliar na elucidação de incertezas epidemiológicas. Estudos entomológicos e de infecção natural foram realizados com anofelinos (Diptera: Culicidae) capturados no município de Santa Tereza, ES. Capturas mensais foram realizadas de março de 2004 a fevereiro de 2006. Armadilhas CDC-CO2 foram utilizadas do crepúsculo (18:00h) ao amanhecer (6:00h), para capturar anofelinos nos seguintes habitats: próximo ao domicílio e área aberta (solo), margem e interior da mata (solo e copa). Armadilhas Shannon também foram utilizadas nos mesmos locais que as de CDC-CO2. Capturou-se o total de 2.290 anofelinos distribuídos em 10 espécies. A maior frequência relativa foi de Anopheles (Kerteszia) cruzii Dyar & Knab / A.(K.) homunculus Komp, sendo a maioria capturada em CDC-CO2 instalada na copa da mata. A principal espécie capturada em armadilha Shannon foi A.(Nyssorhynchus) strodei Root. O maior número de anofelinos foi capturado entre julho e setembro das 18:00h às 22:00h. Provavelmente A.(K.) cruzii é responsável pela transmissão da malária dentro ou próximo aos fragmentos de Mata Atlântica. Entretanto, a participação de outras espécies não pode ser ignorada, visto que 53 por cento da amostragem foi constituída pelo subgênero Nyssorhynchus. A detecção de Plasmodium vivax no tórax de A. cruzii, A. parvus (Chagas) e A. galvaoi Causey, Deane & Deane por meio de PCR reforça esse argumento

Investigações sôbre o comportamento de formas adultas de mosquitos Silvestres no Estado de Sao Paulo, Brasil

Apresentaram-se os resultados das observações sobre o comportamento de formas adultas de Culicidae silvestres na área de Casa Grande, de zona de florestas primitivas situada na parte nordeste do Estado de São Paulo, Brasil. As investigações focalizaram os mosquitos de hábitos diurnos e crepusculares-noturnos, durante o período de 1963 a 1966. Foram obtidos dados concernentes à composição especifica, distribuição, ciclo anual da densidade, estratificação vertical na floresta e possíveis relações com o ambiente doméstico. A região estudada é considerada como bioma ou ecossistema do Anopheles (Kerteszia) cruzii e, dessa maneira, êsse mosquito compareceu de maneira predominante nas observações, merecendo por isso especial atenção. As outras espécies distribuiram-se predominantemente entre os Sabethini, além de alguns Culicini. No que concerne à domesticidade, o Anopheles cruzii apresentou-se como apreciável freqüentador das casas, seguido pelo Aedes serratus. Além disso, aquele anofelino mostrou-se acentuadamente acrodendrófilo, parecendo ser dotado de alguma ornitofilia.

Bromeliad-associated mosquitoes from Atlantic forest in Santa Catarina Island, southern Brazil (Diptera, Culicidae), with new records for the State of Santa Catarina

Bromeliad-associated mosquitoes (Diptera: Culicidae) in Atlantic Forest in Florianópolis, Santa Catarina, southern Brazil, were studied, examining plants of Vriesea philippocoburgi Wawra and Aechmea lindenii (E. Morren) Baker var. lindenii at secondary Atlantic rain forest, and A. lindenii and Vriesea friburgensis Mez var. paludosa (L. B. Smith) at "restinga" per month, during 12 months. No immature forms of mosquitoes were collected from A. lindenii in the secondary forest. Collections obtained 368 immature mosquitoes, none of them from A. lindenii from rain forest. Culex (Microculex) spp. constituted 79.8% of the total, Wyeomyia (Phoniomyia) spp. 17.93%, and Anopheles (Kerteszia) cruzii (Dyar & Knab, 1908) only 1.36%. The study shows the great predominance of species of medical importance not yet proved, and the small number of immature stages of anopheline mosquitoes. The rainfall, but not the mean temperatures, significantly influenced the quantity of mosquitoes from V. philippocoburgi. Significant differences between the quantities of immature forms of all the bromeliad species were found, and the shape of the plants could be important to the abundance of mosquitoes. All six species of Cx. (Microculex) found are recorded for the first time in the State of Santa Catarina, and all six species of Wyeomyia (Phoniomyia) are recorded for the first time in bromeliads in this state.