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Anopheles darlingi Root and Anopheles aquasalis Curry are the main vectors of malaria that occur in the State of Maranhão. Entomological surveys based on the behavior and infectivity of these vectors are important for the elaboration of disease control strategies. The objectives of this work were to study the behavioral patterns of mosquitoes, determining population and hematophagic peaks, dietary preferences, infectivity rate and characterization of breeding sites in two municipalities in the State of Maranhão: Buriticupu and São José of Ribamar. Larvae and pupae were collected in breeding sites and adult females in home environments. Mosquito behavior, their dietary preferences and Plasmodium spp infection rates were analyzed. The vegetation and physicochemical patterns in the breeding sites found are in agreement with those described for species from the Amazon region and the Brazilian Atlantic coast. Anopheles darlingi was the most prevalent mosquito in Buriticupu breeding and home environments. This species was found mainly fed on human blood and naturally infected with Plasmodium vivax Grassi & Feletti and Plasmodium falciparum Welch. Anopheles aquasalis was more frequent in breeding sites in São José de Ribamar, as well as in home environments, whose specimens were mainly fed with human and bird blood. The main peaks of mosquito occurrence in Buriticupu were between 6 pm to 9 pm and in São José de Ribamar we did not record a definite peak. In the first municipality A. darlingi showed dominance over Anopheles albitarsis Lynch Arribálzaga s.l., Anopheles oswaldoi Peryassú, Anopheles nuneztovari Gabaldón and Anopheles evansae Brèthes,, besides presenting a correlation with rainfall. In the second municipality, A. aquasalis was dominant over A. albitarsis s.l. and there was a correlation between these two species and the rainy season. We conclude that the collected data contribute to elucidate the dynamics of malaria transmission in the region and guide the control actions directed to the elimination of the disease in the country.

BACKGROUND:Chagas disease is caused by the parasite Trypanosoma cruzi and is transmitted through triatomines (Hemiptera: Reduviidae). In the last year, many studies of triatomine gut microbiota have outlined its potential role in modulating vector competence. However, little is known about the microbiota present in the salivary glands of triatomines. Bacterial composition of salivary glands in selected triatomine species was investigated, as well as environmental influences on the acquisition of bacterial communities. METHODOLOGY/PRINCIPAL FINDINGS:The diversity of the bacterial communities of 30 pairs of salivary glands of triatomines was studied by sequencing of the V1- V3 variable region of the 16S rRNA using the MiSeq platform (Illumina), and bacteria isolated from skin of three vertebrate hosts were identified based on 16S rRNA gene sequence analysis (targeting the V3-V5 region). In a comparative analysis of microbiota in the salivary glands of triatomine species, operational taxonomic units belonging to Arsenophonous appeared as dominant in Triatoma spp (74% of the total 16S coverage), while these units belonging to unclassified Enterobacteriaceae were dominant in the Rhodnius spp (57% of the total 16S coverage). Some intraspecific changes in the composition of the triatomine microbiota were observed, suggesting that some bacteria may have been acquired from the environment. CONCLUSIONS AND SIGNIFICANCE:Our study revealed the presence of a low-diversity microbiota associated to the salivary glands of the evaluated triatomines. The predominant bacteria genera are associated with triatomine genera and the bacteria can be acquired in the environment in which the insects reside. Further studies are necessary to determine the influence of bacterial communities on vector competence.

The stomach contents of females from the genus Culicoides were studied to determine their blood food sources and the degree of relations established between these insects and their hosts. The specimens were captured by using CDC light traps within the period from March 2009 to February 2010, in two rural towns in the island of São Luís, Maranhão, Brazil. A total of 930 engorged females were captured, belonging to 12 Culicoides species. Precipitin reaction examination was used, which revealed the blood from 7 different vertebrate types that had been sucked, and the most frequent were: bird (41.9%), rodent (21.2%), dog (15.4%), and human being (7.3%). In double reactions there was a predominance of bird/dog (20%) and dog/cat, dog/opossum, bird/rodent, opossum/rodent, and cat/human being (13.3% each). Among the Culicoides species found, C. paucienfuscatus Barbosa, 1947 stood out, because it only sucked blood from birds. The 11 remaining species have sucked blood both from domestic and synanthropic animals, and 4 out of them also sucked human blood. The results allowed us to conclude that C. paucienfuscatus showed specific relations, it was considered as ornithophilous and the other species were generalist. The presence of these animals in a peridomestic environment is a factor that favors the maintenance of Culicoides in rural villages and the presence of human being among the most sucked vertebrates indicates that besides being included in the diet of female Culicoides, it may participate in occasional epidemiological cycles of parasites, due to the eclectic habit of these insects.

O conteúdo estomacal de fêmeas do gênero Culicoides foi estudado para determinar suas fontes alimentares sanguíneas e o grau de relações estabelecidas entre esses insetos e seus hospedeiros. Os espécimes foram capturados em armadilhas luminosas tipo CDC no período entre março de 2009 e fevereiro de 2010, em duas localidades rurais da ilha de São Luís-MA. Foram capturadas 930 fêmeas ingurgitadas, pertencentes a 12 espécies de Culicoides. Foi utilizado o exame da reação da precipitina, que revelou o sangue de sete tipos diferentes de vertebrados que haviam sido sugados, sendo os mais frequentes: ave (41,9%), roedor (21,2%), cão (15,4%) e ser humano (7,3%). Nas reações duplas predominaram ave/cão (20%) e cão/gato, cão/gambá, ave/roedor, gambá/roedor e gato/humano (13,3% cada). Dentre as espécies de Culicoides encontradas, C. paucienfuscatus Barbosa, 1947 destacou-se, por ter sugado apenas sangue de aves. As 11 espécies restantes sugaram sangue tanto de animais domésticos como de sinantrópicos, sendo que, destas, quatro também sugaram o sangue humano. Os resultados permitiram concluir que C. paucienfuscatus apresentou relações específicas, foi considerada ornitófila e as outras espécies foram generalistas. A presença desses animais em ambiente peridoméstico é um fator que favorece a manutenção dos Culicoides nos povoados rurais e a presença do ser humano como um dos vertebrados mais sugados indica que além de fazer parte da dieta das fêmeas de Culicoides, pode participar de eventuais ciclos epidemiológicos de parasitas, devido ao hábito eclético desses insetos.

Introduction The blood meal source of sandflies provides valuable information about the vector/host interaction and allows for an understanding of American cutaneous leishmaniasis (ACL) transmission mechanisms. The aim of this study was to identify the blood meal sources of Lutzomyia (Nyssomyia) intermedia in an endemic area of leishmaniasis in Brazil's State of Paraná using a precipitin test. Methods Sandflies were collected in the rural locality of Epitácio Pessoa within the City of Adrianópolis, State of Paraná, in southern Brazil. A total of 864 female sandflies were captured, and 862 (99.8%) were identified as L. intermedia species. However, two unidentified specimens were considered to be part of the genus Lutzomyia. Results Among the females examined, 396 specimens presented reactions to a certain type of tested antiserum, and most (67.9%) reacted to the simple type. These sandflies fed mainly on the blood of birds, opossums, and rodents, but specimens that fed on the blood of humans, dogs, horses, cattle, and cats were also found. Among the cross-reactions found (32.1%), bird/rodent, bird/opossum, bird/dog, bird/human, and horse/dog cross-reactions were the most common. Conclusions These results demonstrate a tendency in the eclectic feeding behavior of L. intermedia and support its potential role as a vector for ACL in the study area.

Introduction Panstrongylus megistus is commonly found in wild environments of the State of Rio Grande do Sul, Brazil. The aim of this study was to characterize the network of refuges used by triatomine in a forest fragment of Porto Alegre and to identify Trypanosoma cruzi infection, associated hosts and the epidemiological importance of both hosts and triatomines. Methods Techniques including the spool-and-line method and active searching (transects) were used to identify natural foci. Results The food source for each triatomine was determined using the precipitin test, and the infection of marsupials was determined by xenodiagnosis. A total of 33 adults (domestic environment) and 27 nymphs (wild environment) of P. megistus were found in addition to 43 Didelphis albiventris specimens. The infection rates of triatomine adults, triatomine nymphs and opossums with T. cruzi I were 64%, 73% and 69%, respectively. Birds, rodents and opossums were the main resources used by triatomine. Conclusions This work presents the first characterization of a natural focus of P. megistus in Rio Grande do Sul. The natural characteristics of this focus and its implication in the transmission of T. cruzi are discussed.

Introduction We attempted to supplement traditional insecticide spraying by treating peridomiciliar food sources with a powder formulation. Methods Two groups of houses were treated with deltamethrin suspension concentrate (SC), one of which had its primary peridomestic food sources treated with deltamethrin 2P. Results Triatoma brasiliensis was the most commonly captured triatomine. Birds, dogs and rodents were the major food sources identified by the precipitin reaction; 554 domestic animals received powder treatment. A sharp reduction in infestation rates was observed in the two groups up to 360 days after spraying. Conclusion The combination SC + 2P did not improve the control of triatomines.

The objective of this study was to evaluate the feeding behavior of Triatoma vitticeps through the identification of its food sources and the characterization of the blood ingestion process. In addition, we aimed to verify if the saliva of this vector interferes with the perception of the host during the feedings by creating a nervous impulse. Here, we demonstrated that the T. vitticeps saliva reduces, gradually and irreversibly, the amplitude of the compound action potential of the nervous fibre, which helps decrease the perception of the insect by the host. The precipitin reaction demonstrated the feeding eclecticism of this vector, with the identification of eight food sources - most of them found simultaneously in the same insect. The analysis of the electrical signals produced by the cibarial pump during meals demonstrated that the best feeding performance of T. vitticeps nymphs that fed on pigeons is mainly due to the higher contraction frequency of the pump. The longer contact period with the host to obtain a complete meal compared with other triatominae species of the same instar could favor the occurrence of multiple blood sources in T. vitticeps under natural conditions, as it was evidenced by the precipitin test.

A cohort initiated with 121 eggs, yielding 105 first instar nymphs (eclosion rate: 86.78%), allowed us to observe the entire life cycle of Triatoma ryckmani under laboratory conditions (24ºC and 62% relative humidity), by feeding them on anesthetized hamsters. It was possible to obtain 62 adults and the cycle from egg to adult took a mean of 359.69 days with a range of 176-529 days (mortality rate of nymphs: 40.95%). Mean life span of adults was of 81 days for females and 148 days for males. The developmental periods of 4th and 5th nymphs were longer than those of the other instars. This suggests that young siblings have a better chance of taking a hemolymph meal from older ones, in order to survive during fasting periods during prolonged absences of vertebrate hosts from natural ecotopes. The stomach contents of 37 insects showed blood from rodents (15 cases), lizards (7 cases), birds (6 cases) and insect hemolymph (7 cases). Out of 10 insects fed by xenodiagnosis on a Trypanosoma cruzi infected mouse, all but one became infected with the parasite.

O objetivo deste estudo foi determinar as fontes de alimento sanguíneo de fêmeas de Lutzomyia whitmani, espécie de flebotomíneo incriminada no Maranhão como principal vetor da leishmaniose cutânea americana. Para isso, 70 fêmeas desta espécie coletadas no município de Axixá, área com um dos maiores números de casos de leishmaniose cutânea americana em humanos no Maranhão, foram analisadas utilizando a técnica da precipitina. Dos indivíduos analisados, 90% apresentaram reação a algum tipo de antissoro e dentre estes, 73% apresentaram reações do tipo simples com predominância para sangue de galinha (22,2%), roedor (14,3) e humano (12,7%). Nas reações duplas predominaram as combinações galinha/humano (6,3%), galinha/gambá (4,8%), boi/humano e gambá/humano (3,2%). Assim, concluímos que seres humanos, animais domésticos e sinantrópicos constituem fonte alimentar sanguínea para Lutzomyia whitmani podendo desempenhar um papel importante no ciclo de transmissão da leishmaniose cutânea americana explicando os casos da doença em Axixá.The aim of this study was to determine the sources of blood meals for females of Lutzomyia whitmani, a phlebotomine species incriminated as the main vector for American cutaneous leishmaniasis in Maranhão. For this, 70 Lutzomyia whitmani females were collected in the municipality of Axixá, an area with one of the greatest numbers of cases of American cutaneous leishmaniasis in humans in Maranhão. They were analyzed using the precipitin technique. Ninety percent of the specimens showed a reaction to some type of antiserum positive immune reaction, among which 73% presented single reactions, with predominance for chicken blood (22%), rodent blood (14.3%) and human blood (12.7%). Among the double reactions, the predominant combinations were chicken/human (6.3%), chicken/opossum (4.8%), ox/human (3.2%) and opossum/human (3.2%). Thus, we conclude that humans and domestic and synanthropic animals are blood meal sources for Lutzomyia whitmani and may play an important role in the transmission cycle for American cutaneous leishmaniasis, thus explaining the cases of this disease in Axixá.

O objetivo deste estudo foi determinar as fontes alimentares sanguíneas de flebotomíneos por meio da reação da precipitina, em Buriticupu, na Amazônia maranhense, Brasil, de julho de 2002 a junho de 2004. Foram detectadas reações simples (87,6%), duplas (8%) e não reagentes (4,4%). A presença de flebotomíneos alimentados com sangue humano (6,7%) e de possíveis reservatórios de Leishmania no peridomicílio ajuda a explicar a ocorrência de casos autóctones de leishmaniose tegumentar no Município de Buriticupu.The objective of this study was to determine the blood feeding sources for sand flies based on the precipitin test in Buriticupu, Amazon Region, Maranhão State, Brazil, from July 2002 to June 2004. Single (87.6%) and double (8%) reactions and non-reactive samples (4.4%) were found. The presence of sand flies fed on human blood (6.7%) and blood of animals that are possible peridomiciliary Leishmania reservoirs helps explain the reporting of autochthonous tegumentary leishmaniasis cases in Buriticupu.

O estudo dos hábitos alimentares e do conteúdo intestinal dos flebotomíneos permite a identificação dos hospedeiros, indicando os potenciais reservatórios das leishmanias. Este trabalho objetivou determinar a preferência alimentar de Lutzomyia longipalpis e sua relação com a transmissão da leishmaniose visceral. As capturas mensais foram realizadas em área de transmissão de leishmaniose visceral, município de Várzea Grande, Estado de Mato Grosso, no período de janeiro de 2004 a junho de 2006, utilizando-se armadilhas de luz CDC. Foram capturadas 2.376 fêmeas de Lutzomyia longipalpis, das quais 104 (4,4%) estavam ingurgitadas, sendo 32 (30,8%) capturadas no intradomicílio e 72 (69,2%) no peridomicílio. Após reação de precipitina, observou-se que as fêmeas de Lutzomyia longipalpis alimentaram-se preferencialmente em aves (30,8%) e roedores (21,2%), mas também foram encontradas fêmeas alimentadas de sangue de humanos, gambás, bois, cavalos e cães, demonstrando o caráter oportunista da espécie.Studies on the feeding habits and intestinal content of sandflies make it possible to identify hosts, thereby indicating potential reservoirs for Leishmania. The present study had the aim of determining the feeding preferences of Lutzomyia longipalpis and its relationship with the transmission of visceral leishmaniasis. Specimens were caught every month in a transmission area of visceral leishmaniasis, in the municipality of Várzea Grande, State of Mato Grosso, from January 2004 to June 2006, using CDC light traps. 2,376 females of Lutzomyia longipalpis were caught, of which 104 (4.4%) were engorged. Among these, 32 (30.8%) were caught inside homes and 72 (69.2%) in areas surrounding homes. From the precipitin reaction, it was observed that Lutzomyia longipalpis females fed preferentially on birds (30.8%) and rodents (21.2%), but they were also found to have fed on blood from humans, opossums, oxen, horses and dogs, thus demonstrating the opportunist nature of this species.

Os autores utilizaram a técnica de precipitina para identificar as fontes alimentares de Panstrongylus lutzi (Neiva & Pinto, 1923) em 20 municípios do Estado do Ceará, Brasil. Os resultados detectaram a presença de sangue de oito diferentes fontes sanguíneas e alimentações mistas, demonstrando que Panstrongylus lutzi é uma espécie eclética. Altas taxas de infecção por tripanosomatídeos foram detectadas.The authors used precipitin technique to detect the feeding sources of Panstrongylus lutzi (Neiva & Pinto, 1923) in 20 municipalities of Ceará State, Brazil. The results detected the presence of blood from eight different blood sources and mixed feedings, demonstrating that Panstrongylus lutzi is an eclectic species. High infection rates for Trypanosoma like-cruzi were detected.

O comportamento e hábitos alimentares de algumas espécies da flebotomíneos têm sido útil na compreensão da epidemiologia das leishmanioses. No município de Porteirinha (MG), foram realizadas capturas mensais sistematizadas utilizando-se 28 armadilhas luminosas tipo CDC, durante o período de janeiro a dezembro de 2002. Foram capturadas 14 espécies de flebotomíneos, totalizando 1.408 exemplares. De acordo com o ambiente, os resultados obtidos mostraram que o peridomicílio apresentou a maior (53,3%) porcentagem dos espécimens encontrados na região, embora parte (46,7%) da fauna também tenha sido encontrada no intradomicílio. O repasto sanguíneo de 38 fêmeas de Lutzomyia longipalpis, provenientes do campo, foi identificado através da reação de precipitina. Os resultados indicam que Lutzomyia longipalpis foi a espécie predominante (65,1%), mostrando-se oportunista, podendo sugar uma ampla variedade de vertebrados.Studies on the behavioral and feeding habits of some species of phlebotominae sand flies have contributed to the comprehension of the epidemiology of leishmaniasis. In the present work, systematic captures were performed monthly in the municipality of Porteirinha (MG) using 28 light traps (CDC) from January to December 2002. Fourteen different species of phlebotomine were captured in a total of 1,408 specimens. The highest percentage of individuals (53.3%) was collected in the peridomicile against 46.7% in the intradomicile. Lutzomyia longipalpis was the predominant species in that region. The blood feeding of 38 females of this species from the field was analyzed by precipitin reaction. The results indicated that Lutzomyia longipalpis is an opportunist (65.1%) species that feeds on a wide variety of vertebrates in nature.

Triatoma dimidiata has been found in several cities and towns of those countries where the insect is a domestic or peridomestic pest. In Central America, urban infestations occur in the capitals of at least five countries. During 2001 and 2002 a survey was carried out in the county of San Rafael, Heredia province, located 15 km northwest of San José, capital of Costa Rica, in order to determine the degree of infestation by T. dimidiata in an entire city block. Six peridomestic colonies of the insect were detected in the backyards of eight households. The ecotopes occupied by the insects consisted of store rooms with old objects, wood piles or firewood, and chicken coops. A total of 1917 insects were found in the six foci, during two sampling periods, and a mean infection rate by Trypanosoma cruzi of 28.4% was found in 1718 insects examined. The largest colony found in one of the households yielded 872 insects that were thriving mainly at the expenses of two dogs. Opossums and adult insects were common visitors of the houses and it became evident that this marsupial is closely related to the peridomestic cycle of the Chagas disease agent. Lack of colonization of the insect inside the human dwellings is explained by the type of construction and good sanitary conditions of the houses, in contrast to the situation in most peridomiciliary areas. Stomach blood samples from the insects showed that the main hosts were, in order of decreasing frequency: rodents, dogs, fowl, humans, opossums, and cats. The fact that no indication of infection with Chagas disease could be detected in the human occupants of the infested houses, vis a vis the high infection rate in dogs, is discussed.

OBJETIVO: Triatoma pseudomaculata, espécie peridomiciliar, é encontrada apresentando baixa taxa de infecção por Trypanosoma cruzi. Com o objetivo de identificar os possíveis reservatórios de T. cruzi, investigou-se a ocorrência desse triatomíneo no domicílio, bem como suas fontes alimentares. MÉTODOS: De janeiro de 2001 a julho de 2002 foram capturados 921 espécimes de T. pseudomaculata em 13 municípios do sul do Estado do Ceará. O conteúdo intestinal dos triatomíneos foi retirado, espalhado em disco de papel de filtro e analisado por precipitina para os seguintes anti-soros: ave, roedor, cão, gambá, lagarto, boi/cabra, gato, porco, barata e humano. A investigação da presença de T. cruzi foi feita observando-se parte do conteúdo intestinal dos insetos a fresco, entre lâmina e lamínula, e pela sua semeadura em meio de cultura. RESULTADOS: Do total examinado, 184 (90,6%) foram positivos para os anti-soros testados: ave (62,5%)> roedor (33,7%)> cão (20,1%)> gambá (9,8%)> lagarto (5%)> boi-cabra (5%)> gato (2,7%)> porco (2,2%)> barata (2,2%)> humano (1,6%). As alimentações variaram de zero (não reagiram) a quatro da seguinte forma: não reagiram (9,4%), uma (57,1%), duas (26%), três (7%) ou quatro (0,5%). Das fontes alimentares identificadas apenas três espécimes (1,6%) foram positivos para T. cruzi. CONCLUSÕES: A baixa incidência de sangue humano mostra que T. pseudomaculata está bem adaptado ao peridomicílio. Porém, a vigilância epidemiológica na região sul do Estado do Ceará se faz necessária tendo em vista a proximidade da espécie ao domicílio.

Triatomine infestation, prevalence of T. cruzi antibodies in humans and domestic animals, and variables potentially associated with the presence of triatomines in a rural domiciliary unit (DU) were investigated in nine municipalities and one district of Paraná, Brazil, from June 1996 to February 2000. DUs were defined as all houses and annexes on a given piece of property. Blood samples from human volunteers, dogs, and cats were submitted to indirect immunofluorescence. An epidemiological form was completed for each DU. A logistic model was adopted in order to identify associations. Seven out of nine municipalities were positive for triatomines. T. infestans was not captured, but T. sordida, P. megistus, and R. neglectus were. Different variables were considered decisive for the presence of triatomines across the municipalities: proximity to residual wooded areas, i.e. either scrub forest (capoeira) or islands of residual forest (slightly dense vegetation), longer time of residence, existence of inhabited houses, and past DU infestation. In order to ensure proper continuation of the recommended Chagas disease control program, entomo-epidemiological surveillance measures need to be maintained.Avaliou-se a infestação por triatomíneos, a prevalência sorológica para T. cruzi em humanos e em animais domésticos, e a pesquisa de variáveis que poderiam estar associadas à presença de triatomíneos na unidade domiciliar (UD) em área rural de nove municípios e um distrito do Paraná, Brasil, junho/1996 a fevereiro/2000. Uma UD foi definida como todas as casas e anexos existentes na propriedade. Amostras de sangue de voluntários humanos, cachorros e gatos foram submetidos à imunoflorescência indireta. Uma ficha epidemiológica foi preenchida para cada UD pesquisada. Foi adotado um modelo logístico para identificar associações. Sete dos nove municípios foram positivos para triatomíneos. T. infestans não foi capturado. T. sordida, P. megistuse R. neglectusforam as espécies capturadas. Diferentes variáveis foram consideradas decisivas para a presença de triatomíneos nos municípios: proximidade à mata residual-capoeira ou ilhas de mata densa, maior tempo de residência, existência de casas habitadas e UD infestada no passado. A fim de assegurar a continuidade do controle da doença de Chagas, medidas de vigilância entomo-epidemiológicas devem ser mantidas nesses municípios.

Estudou-se por meio da reação da precipitina, o conteúdo estomacal de Lutzomyia longipalpis nos ambientes intradomiciliar e peridoméstico, no Município de Raposa, Maranhão, área de transmissão de leishmaniose visceral ou "calazar". De 2.240 fêmeas capturadas, 547 (24,4%) estavam alimentadas com sangue de vertebrados nas proporções que seguem: ave (87,9%); roedor (47,2%); humano (42,4%), cão (27,6%); mucura (26,6%) e eqüino (22,5%). A investigação levada a efeito em 120 habitações confirmou a galinha como o animal doméstico mais comum no ambiente peridoméstico (28,3%), seguido pelo cão (21,7%), gato (17,5%), jumento (13,3%), pombo (7,5%), coelho (3,3%) e pato (3,3%); enquanto o cavalo, marreco e porco representaram, cada um, 1,7%. Entre os animais sinantrópicos, a mucura foi a mais citada naquele ambiente (39,3%), seguida pelo rato (37,9%), morcego (14,3%) guaxinim (3,6%), raposa (2,1%), cobra (1,4%) e sapo (1,4%). A presença no peridomicílio de animais domésticos e sinantrópicos e o encontro de flebótomos alimentados, ao mesmo tempo, com sangue humano, de mucura e de canídeos, corroboram a hipótese de que a transmissão do calazar esteja ocorrendo realmente no ambiente antrópico, no Município de Raposa.A precipitin test was employed to study the alimentary tract content of Lutzomyia longipalpis in the intra- and peridomiciliary environments in the municipality of Raposa, Maranhão State, a transmission area for visceral leishmaniasis or kala azar. Out of 2,240 female sandflies captured, 547 (24.4%) had fed on vertebrate blood, with the following proportions: avian (87.9%); rodent (47.2%); human (42.4%); canine (27.6%); opossum (26.6%); and equine (22.5%). Based on a survey of 120 human dwellings, chickens were found to be the most common domestic animals in the peridomicile (28.3%), followed by dogs (21.7%), cats (17.5%), donkeys (13.3%), pigeons (7.5%), rabbits (3.3%), ducks (3.3%), and horses, mallards, and pigs (1.7% each). Synanthropic animals included opossums (39.3%), followed by rats (37.9%), bats (14.3%), raccoons (3.6%), foxes (2.1%), snakes (1.4%), and frogs (1.4%). The peridomiciliary presence of domestic and synanthropic animals as well as sandflies that had fed on human, opossum, and canid blood supports the hypothesis that kala azar transmission has been taking place in the anthropic environment in the municipality of Raposa.

BACKGROUND:The new epidemiological scenario of orally transmitted Chagas disease that has emerged in Brazil, and mainly in the Amazon region, needs to be addressed with a new and systematic focus. Belém, the capital of Pará state, reports the highest number of acute Chagas disease (ACD) cases associated with the consumption of açaí juice. METHODOLOGY/PRINCIPAL FINDINGS:The wild and domestic enzootic transmission cycles of Trypanosoma cruzi were evaluated in the two locations (Jurunas and Val-de Cães) that report the majority of the autochthonous cases of ACD in Belém city. Moreover, we evaluated the enzootic cycle on the three islands that provide most of the açaí fruit that is consumed in these localities. We employed parasitological and serological tests throughout to evaluate infectivity competence and exposure to T. cruzi. In Val-de-Cães, no wild mammal presented positive parasitological tests, and 56% seroprevalence was observed, with low serological titers. Three of 14 triatomines were found to be infected (TcI). This unexpected epidemiological picture does not explain the high number of autochthonous ACD cases. In Jurunas, the cases of ACD could not be autochthonous because of the absence of any enzootic cycle of T. cruzi. In contrast, in the 3 island areas from which the açaí fruit originates, 66.7% of wild mammals and two dogs displayed positive hemocultures, and 15.6% of triatomines were found to be infected by T. cruzi. Genotyping by mini-exon gene and PCR-RFLP (1f8/Akw21I) targeting revealed that the mammals and triatomines from the islands harbored TcI and Trypanosoma rangeli in single and mixed infections. CONCLUSION/SIGNIFICANCE:These findings show that cases of Chagas disease in the urban area of Belém may be derived from infected triatomines coming together with the açaí fruits from distant islands. We term this new epidemiological feature of Chagas disease as "Distantiae transmission".

Epidemiological surveillance activities were implemented in 1980 in Mambaí and Buritinópolis counties, Goiás State. Twenty years later the authors evaluated the impact of these vector control measures on Chagas' disease transmission, based on entomological indicators. Entomological investigation was conducted using the man-hour technique and covering all domiciles. In order to study vector food sources the stomach contents of triatomines were analyzed using the modified precipitins technique. Triatomines were shown to be present in 48 (71.6%) of the 67 locations. Peridomiciliary infestation rates in Mambaí and Buritinópolis were 8.7% and 12.1%, respectively, while intradomiciliary rates were 0.7% and 1.2%. Triatoma sordida was the species identified in 97.3% of all captured specimens. It was also the only species found to be naturally infected with Trypanosoma cruzi. Birds were the most frequent food source (45%) for Triatoma sordida. The most significant result was the complete absence of Triatoma infestans in the two counties.

Foram capturados quatro exemplares de Triatoma vitticeps e um de Panstrongylus geniculatus, no intradomicílio, no município de São Fidélis, Rio de Janeiro. Ficou comprovado a infecção positiva para Trypanosoma cruzi num dos exemplares de Triatoma vitticeps. Dois moradores da residência, um adulto e uma adolescente apresentaram sorologia positiva.Four specimens of Triatoma vitticeps and one of Panstrongylus geniculatus were caught inside a home in the municipality of São Fidélis, Rio de Janeiro. One of the specimens of Triatoma vitticeps proved positive for infection with Trypanosoma cruzi. Two people living in that home (one adult and one adolescent) presented positive serology.

Estudou-se por meio da reação da precipitina, o conteúdo estomacal de Lutzomyia longipalpis nos ambientes intradomiciliar e peridoméstico, no Município de Raposa, Maranhão, área de transmissão de leishmaniose visceral ou "calazar". De 2.240 fêmeas capturadas, 547 (24,4%) estavam alimentadas com sangue de vertebrados nas proporções que seguem: ave (87,9%); roedor (47,2%); humano (42,4%), cão (27,6%); mucura (26,6%) e eqüino (22,5%). A investigação levada a efeito em 120 habitações confirmou a galinha como o animal doméstico mais comum no ambiente peridoméstico (28,3%), seguido pelo cão (21,7%), gato (17,5%), jumento (13,3%), pombo (7,5%), coelho (3,3%) e pato (3,3%); enquanto o cavalo, marreco e porco representaram, cada um, 1,7%. Entre os animais sinantrópicos, a mucura foi a mais citada naquele ambiente (39,3%), seguida pelo rato (37,9%), morcego (14,3%) guaxinim (3,6%), raposa (2,1%), cobra (1,4%) e sapo (1,4%). A presença no peridomicílio de animais domésticos e sinantrópicos e o encontro de flebótomos alimentados, ao mesmo tempo, com sangue humano, de mucura e de canídeos, corroboram a hipótese de que a transmissão do calazar esteja ocorrendo realmente no ambiente antrópico, no Município de Raposa.

Abstract INTRODUCTION: Studying the feeding preferences of triatomines is an important entomological surveillance tool, since continuous surveillance of the disease is necessary. METHODS: The precipitin reaction was used to describe the feeding preferences of triatomines along with their natural infection by flagellates similar to Tyrpanosoma cruzi. Six hundred eighty-seven insects were examined, including Triatoma brasiliensis, Triatoma pseudomaculata, and Panstrongylus lutzi. RESULTS: Sixty-nine (10%) of 687 triatomines examined tested positive for flagellates similar to T. cruzi, and 8 (1.2%) of these fed on human blood. CONCLUSIONS: This study found potential transmitters of Chagas disease both inside and outside the domiciliar environment.

Estudou-se por meio da reação da precipitina, o conteúdo estomacal de Lutzomyia longipalpis nos ambientes intradomiciliar e peridoméstico, no Município de Raposa, Maranhão, área de transmissão de leishmaniose visceral ou "calazar". De 2.240 fêmeas capturadas, 547 (24,4%) estavam alimentadas com sangue de vertebrados nas proporções que seguem: ave (87,9%); roedor (47,2%); humano (42,4%), cão (27,6%); mucura (26,6%) e eqüino (22,5%). A investigação levada a efeito em 120 habitações confirmou a galinha como o animal doméstico mais comum no ambiente peridoméstico (28,3%), seguido pelo cão (21,7%), gato (17,5%), jumento (13,3%), pombo (7,5%), coelho (3,3%) e pato (3,3%); enquanto o cavalo, marreco e porco representaram, cada um, 1,7%. Entre os animais sinantrópicos, a mucura foi a mais citada naquele ambiente (39,3%), seguida pelo rato (37,9%), morcego (14,3%) guaxinim (3,6%), raposa (2,1%), cobra (1,4%) e sapo (1,4%). A presença no peridomicílio de animais domésticos e sinantrópicos e o encontro de flebótomos alimentados, ao mesmo tempo, com sangue humano, de mucura e de canídeos, corroboram a hipótese de que a transmissão do calazar esteja ocorrendo realmente no ambiente antrópico, no Município de Raposa.