Genetic characterization of residual Triatoma infestans populations from Brazil by microsatellite.

In spite of long-term efforts to eliminate Triatoma infestans (Klug 1834) from Brazil, residual foci still persist in the states of Bahia and Rio Grande do Sul. Data on the genetic variability and structuring of these populations are however lacking. Using nine microsatellite loci, we characterized one residual T. infestans population from Bahia and four from Rio Grande do Sul, and compared them with bugs originally from an older focus in São Paulo; 224 bugs were genotyped. The number of alleles per locus ranged from 5 to 11. Observed and expected heterozygosities per locus ranged, respectively, from 0 to 0.786 and from 0 to 0.764. Significant departures from Hardy-Weinberg equilibrium, mainly due to heterozygote deficits, were detected in all loci and in most populations. Global indices estimated by AMOVA were: Fis was 0.37; Fst was 0.28; and Fit was 0.55; overall indices with p = 0.00 indicated substantial differentiation. Inter-population Fst ranged from 0.118 to 0.562, suggesting strong genetic structuring and little to no gene flow among populations. Intra-population Fis ranged from 0.301 to 0.307. Inbreeding was apparent in all populations except that from Bahia-which might be either linked by gene flow to nearby unsampled populations or part of a relatively large local population. The overall pattern of strong genetic structuring among pyrethroid-susceptible residual T. infestans populations suggests that their persistence is probably due to operational control failures. Detection and elimination of such residual foci is technically feasible and must become a public health priority in Brazil.

[Triatoma tibiamaculata (Pinto, 1926): life table for nymphs, duration of adult forms and oviposition of females]. / Triatoma tibiamaculata (Pinto, 1926): Tábua de vida das ninfas, duração das formas adultas e postura das fêmeas (Hemiptera - Reduviidae).

Under laboratory conditions, the authors analyzed the survival rate of nymphs, the minimum and maximum duration of each stage, the length of life of the winged forms and oviposition of the females. Two groups of 100 eggs each were monitored. In batch A, the specimens were reared in a single glass receptacle. In batch B, the specimens were kept apart, one by one, and when they reached the winged stage, they formed twenty couples, which made it possible to watch over the oviposition of the females and the length of life of each specimen. The egg eclosion rate was 96%; the proportion still alive at the end of the nymph phase was 69.5% in batch A and 78.4% in batch B. The most frequent length of time observed between oviposition and eclosion of first-stage nymphs was 28 days. The nymph phase lasted four to eight months and the adult phase five months. The mean total oviposition in batch B was 181.6 eggs per female.

[Infestation by triatomines in rural settlement and resettlement areas the Region of Pontal do Paranapanema, State of São Paulo]. / Infestação por triatomíneos em assentamentos e reassentamentos rurais na Região do Pontal do Paranapanema, Estado de São Paulo.

This study had the aim of assessing the characteristics of triatomine infestation in human dwellings in rural settlement and resettlement areas with regard to the time when infestation began. We analyzed data relating to 48 triatomine surveys carried out in 105 settlement areas and six resettlement areas in the region of Pontal do Paranapanema between January 1984 and June 2005. Among the 16 surveys in settlement areas, seven (43.8%) had positive findings, all of them in communities established eight or more years previously. Among the 32 surveys in resettlement areas, 23 (71.9%) had positive findings, all of them in communities established for periods shorter than eight years. Since the inhabitants of such communities frequently move, the need for constant vigilance to detect any cases of infestation by vector triatomines in new settlements cannot be overemphasized.

[Chagas' disease: triatomines notification of the São Paulo State during the 1990s]. / Doença de Chagas: notificação de triatomíneos no Estado de São Paulo na década de 1990.

The objective of this study was to analyze the surveillance of Chagas' disease in São Paulo State through notifications registered from 1990 to 1999. The information originated when notification of triatomines was announced by inhabitants and the established control program was followed. 20,563 triatomine notifications were received, showing a decrease over the years, with more accentuated decreases in the area of greatest frequency of Panstrongylus megistus. Each notification corresponded to an average of 1.3 examples of captured triatomines (median = 1), predominantly in the intradomicile area, while during attendance, the mean number of collected insects was 3.6 (median = 2), mostly present in the peridomicile area. The notification distribution permitted the demarcation of three different areas in the state: area 1, comprising the areas of São José do Rio Preto, Araçatuba and part of Presidente Prudente; area 2, São Vicente and Sorocaba; area 3, municipalities located to the northeast of the Campinas region. Analysis showed that entomological surveillance through triatomine notification, despite the fall in the same, has not detected intradomiciliary colonies associated with Trypanosoma cruzi which could give rise to vectorial transmission of Chagas' disease.

[Triatoma rubrovaria (Blanchard 1843): life table of nymphs, duration of the forms and posture of the females]. / Triatoma rubrovaria (Blanchard 1843): tábua de vida das ninfas, duração das formas e oviposição das fêmeas.

The authors followed the development of 150 eggs of Triatoma rubrovaria to enable the construction of a life table for the nymphs. The winged form was reached by 94.64% of the individuals, of which 79 were males and 65 females. The mean lifetime of the males was 115 days and 99 days for the females. Part of this group was divided into 30 couples and kept separated to facilitate the count of egg laying by each female. Another lot was also formed of 30 males and 30 females but these were housed together in a glass crystallizer that allowed the observation of a larger number of eggs laid (7,832 eggs) in relationship to that of the females with only one male (total 5,167 eggs). The good development of the individuals and reproduction of the species in the experimental conditions demonstrated the capacity to maintain colonies of Triatoma rubrovaria in laboratory conditions.

[Broadening the scope of triatomine research in the attendance of notifications of Triatoma sordida (Stål, 1859) in the State of São Paulo]. / Ampliação de raio de pesquisa de triatomíneos na atividade de atendimento às notificações em área de Triatoma sordida (Stål, 1859) no Estado de São Paulo.

The objective of this study was to broaden the inspection of home units to a radius of 200 meters from the residence of each notified case. The notifications received by the regional Services of SUCEN of São José do Rio Preto, Araçatuba and Presidente Prudente were evaluated in August, September and October of 2002. There was a total of 263 notifications of triatomines, of which 79 were positive. Broadening the scope meant another 610 domestic units were included in the investigation and in 14.5% of these triatomines were found. It was observed that 24.7% of the domestic units neighboring the house of the notified case presented positive results in the triatomines investigation. When a notified domestic unit presented a positive result, broadening the scope showed positivity in 42.5% of neighboring domestic units (Odds ratio 2.252 (1.25

[Triatomine: ovicidal action of some pyretroids]. / Triatomíneos: ação ovicida de alguns piretróides.

The insecticidal action on eggs of triatomine have been little considered in the control activitys of Chagas' disease. With objective [corrected] of to compare the potential of three synthetic pyrethroids (deltamethrin,alphacypermethrin and lambdacyhalothrin) on eggs, the authors realized laboratory tests. The pyretroid lambdacialotrin is more efficient. The following species were used in this experiment: Panstrongylus megistus and Triatoma sordida. The specie Triatoma sordida is more susceptible with the pyrethroids utilized.

[Chagas Disease Control Program in the State of São Paulo: persistence of high triatomine infestation rates in some localities during the 1990s]. / Programa de Controle da Doença de Chagas no Estado de São Paulo: persistência de alta infestação por triatomíneos em localidades na década de 1990.

The purpose of our investigation was to analyze the persistence, in the State of São Paulo, of domiciliary units highly infested with Chagas disease triatomine vectors. Comprehensive epidemiologic information collected from 1990 to 1999 in the State of S o Paulo was retrieved from database files. Consistently high infestation rates were found in 43 localities distributed among 21 municipalities in the Ara atuba region. Captures produced predominantly peridomiciliary Triatoma sordida specimens, mostly adult females and fifth-instar nymphs, 94.6% of which containing ingesta negative for human blood. The houses, mostly inhabited (87.4%), were located near the residual woodland savanna in 64.3% of the localities. Poultry coops were found in association with 97.6% of all domiciliary units. Interestingly, in all the houses with persistent infestation, the inhabitants paid no evident attention to hygiene Lack of timely infestation control associated with the biological characteristics of the reduviid species involved, along with the conditions prevailing around the dwellings, favor the repeated invasion and consequent maintenance of colonization by triatomines.

[The Chagas Disease Control Program of the São Paulo State: the contribution of serology to the epidemiological investigation of triatomine-infested domiciliary units during the 1990s]. / Programa de Controle da Doença de Chagas no Estado de São Paulo: sorologia de moradores como parte de investigação de unidades domiciliares com presença de triatomíneos vetores na década de 1990.

The Chagas Disease Control Program in São Paulo State, Brazil, now in the entomological surveillance phase, includes a serological examination of individuals residing in domiciliary units infested with vector triatomines infected with Trypanosoma cruzi. From 1990 to 1999, this action included area in which triatomine searches were conducted either as a routine procedure, according to their levels of intra- or peridomiciliary infestation, or at the request of local residents. Among residents of the 1,415 UDs inspected, we collected 5,587 blood samples for serological examination, 87 of which (1.56%) tested positive, seven of which from individuals under 29 years of age. The species most frequently captured were Panstrongylus megistus, Triatoma sordida, and Triatoma tibiamaculata in the adult stage. No association was found between presence of seropositive residents and triatomines infected with Tr. cruzi (OR = 1.498; 0.875 < OR < 2.564, 95% C.I.). Our purpose was to use serological testing to investigate the situation of areas identifiable as being at risk of Chagas disease transmission and to compare the results with extant data about Tr. cruzi infection both in humans and vector triatomines.

[Investigation into the effect of household triatomine infestation on awareness among inhabitants of settlements and re-settlements in areas infested with Triatoma sordida in São Paulo State, Brazil]. / Pesquisa sistemática positiva e relação com conhecimento da população de assentamento e reassentamento de ocupação recente em área de Triatoma sordida (Hemiptera, Reduviidae) no Estado de São Paulo, Brasil.

This study aims to analyze the effect of domiciliary infestation by triatomine bugs on the degree to which inhabitants are aware of potential vector transmission of Chagas disease. Such recently constructed dwellings comprise housing groups classified as settlements and re-settlements, selected respectively in the municipalities of Euclides da Cunha Paulista and Paulicéia, São Paulo State, Brazil. Both municipalities are under the jurisdiction of the Presidente Prudente Health Administrative Region. Of the 319 residents, some 100 (76.0% of whom were re-settlement residents) knew about triatomine bugs. Housing units infested with triatomines were inhabited by 93 people. In 79.2% of the infested houses, 26.8% of the residents knew about Chagas disease and its vectors, but in 50.0% of the households, some people did not know what to do in case of triatomine infestation. Population samples from settlements and re-settlements, regardless of sex, age, and the State of origin, showed no difference in attitudes towards the prevention of Chagas disease or knowledge of the disease vector.

Colonization of palm trees by Rhodnius neglectus and household and invasion in an urban area, Araçatuba, São Paulo State, Brazil.

The objective of this study is to report on the colonization of palm trees by Rhodnius neglectus, its invasion in an urban area, in Araçatuba - São Paulo, and the control and surveillance measures that have been put in place. Domiciliary triatomine searches occurred in apartments upon the inhabitants' notification. The collected insects were identified and examined for natural infection and food sources with a precipitin test. To search the palm trees, tarps were used to cover the floor, and a "Munck" truck equipped with a tree-pruning device was utilized. Chemical control was performed with the utilization of a manual compression. In 2009, 81 specimens of Rhodnius neglectus were collected from the domiciles by the population. The precipitin test revealed a presence of human blood in 2.7% of the samples. Entomological studies were carried out in these domiciles and in those located within a radius of 200 meters. The search performed in the palm trees resulted in the capture of 882 specimens of triatomines, negative for tripanosomatids. Mechanical and chemical controls were carried out. New searches conducted in the palm trees in the same year resulted in the capture of six specimens. The mechanical and chemical controls of the palm trees, together with the population's work, proved to be effective, therefore preventing these insects' colonization of the city's domiciles.

[Control Program of Chagas disease in São Paulo, Brazil: the control and surveillance of vector transmission]. / Programa de Controle da Doença de Chagas no estado de São Paulo, Brasil: o controle e a vigilância da transmissão vetorial.

The control of the vectors of Chagas' disease in the State of Sao Paulo are discussed, mainly those activities that led to the elimination of Triatoma infestans. Secondary factors that helped the control such as rural exodus are also analyzed. The article shows that since 1965 the control became a campaign with different phases due to the epidemiological situation, the acquired knowledge and the entomological surveillance. After 25 years of work, the elimination of all the focus of Triatoma infestans was finally reached and the campaign was ended. However, due to the possibility of reintroduction of the vector in rural areas by passive transportation besides the presence of secondary vectors (Triatoma sordida and Panstrongylus megistus) in several localities, the vector control activities were not interrupted and the surveillance is continuous.

[Analysis on the food source of Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) and its present importance as a vector for Trypanosoma cruzi, in the State of Minas Gerais]. / Análise da fonte alimentar de Panstrongylus megistus (Hemiptera, Reduviidae, Triatominae) e sua atual importância como vetor do Trypanosoma cruzi, no Estado de Minas Gerais.

INTRODUCTION: Investigation of the food source of triatomines helps in understanding the biology of these insects, and also helps to infer their importance in transmitting Trypanosoma cruzi to humans. METHODS: The present study aimed to use the precipitin reaction to record the food source of triatomines from 54 municipalities in the central-western region of the State of Minas Gerais, as well as their natural infection by flagellates similar to Trypanosoma cruzi. RESULTS: From July 2003 to March 2007, 416 insects were evaluated, all from the species Panstrongylus megistus. Among all these occurrences, birds (70%) and humans (22.5%) were the major blood sources. Sixteen (3.8%) of the insects were found to be positive for flagellates similar to Trypanosoma cruzi, and eight performed hematophagia on humans. CONCLUSIONS: The results show the need to increase the entomological surveillance in this region, given that the possibility of new cases of Chagas disease occurring through vector transmission was detected.

Vigilância epidemiológica da doença de Chagas no estado de São Paulo no período de 2010 a 2012 / Epidemiological Surveillance of Chagas disease in the State of São Paulo, Brazil, 2010-2012

Objetivo: descrever os indicadores da vigilância epidemiológica da doença de Chagas no estado de São Paulo, Brasil. Métodos: foi realizado estudo descritivo dos indicadores entomológicos e epidemiológicos obtidos a partir das atividades desenvolvidas pela Superintendência de Controle de Endemias (Sucen) no período de 2010 a 2012. Resultados: foram realizadas 3.867 notificações de insetos, dos quais 72,0 por cento eram triatomíneos; das 2.785 notificações de triatomíneos recebidas, as pesquisas realizadas nos atendimentos resultaram no encontro do vetor em 746 domicílios; onde foram coletados 15.634 exemplares de triatomíneos, 3,4 por cento deles positivos para Trypanosoma cruzi; a espécie mais coletada foi a Triatoma sordida, predominantemente no peridomicílio; não foi constatada reação positiva para T. cruzi em qualquer das amostras de morador examinadas. Conclusão: apesar do elevado número de notificações de triatomíneos e da constatação de positividade para T. cruzi nesses vetores, não foram encontradas evidências de transmissão da doença de Chagas.

Objective: to describe epidemiological surveillance indicators of Chagas disease in the State of São Paulo, Brazil. Methods: this was a descriptive study of entomological and epidemiological indicators obtained based on activities undertaken by the Endemic Disease Control Department (SUCEN) between 2010-2012. Results: there were 3,867 notifications of insects, of which 72.0 per cent were triatomines. Of the 2,785 triatomine notifications received, the vector was subsequently found in 746 households visited, 15,634 specimens of triatomines were collected, 3.4 per cent were positive for Trypanosoma cruzi. Triatoma sordida was the most collected species and was predominantly found in housebold surroundings. Sample household residents had no positive reaction for T. cruzi. Conclusion: despite the high number of triatomine notifications and T. cruzi positive results in these vectors, no evidence was found of Chagas’ disease transmission.

COLONIZATION OF PALM TREES BY Rhodnius neglectus AND HOUSEHOLD AND INVASION IN AN URBAN AREA, ARAÇATUBA, SÃO PAULO STATE, BRAZIL / Colonização de palmeiras por Rhodnius neglectus e invasão domiciliar em área urbana, Araçatuba, São Paulo, Brasil

The objective of this study is to report on the colonization of palm trees by Rhodnius neglectus, its invasion in an urban area, in Araçatuba - São Paulo, and the control and surveillance measures that have been put in place. Domiciliary triatomine searches occurred in apartments upon the inhabitants' notification. The collected insects were identified and examined for natural infection and food sources with a precipitin test. To search the palm trees, tarps were used to cover the floor, and a “Munck” truck equipped with a tree-pruning device was utilized. Chemical control was performed with the utilization of a manual compression. In 2009, 81 specimens of Rhodnius neglectus were collected from the domiciles by the population. The precipitin test revealed a presence of human blood in 2.7% of the samples. Entomological studies were carried out in these domiciles and in those located within a radius of 200 meters. The search performed in the palm trees resulted in the capture of 882 specimens of triatomines, negative for tripanosomatids. Mechanical and chemical controls were carried out. New searches conducted in the palm trees in the same year resulted in the capture of six specimens. The mechanical and chemical controls of the palm trees, together with the population's work, proved to be effective, therefore preventing these insects' colonization of the city's domiciles.

O objetivo deste trabalho é relatar a colonização de palmeiras por Rhodnius neglectus, sua invasão em área urbana, na cidade de Araçatuba - São Paulo, o controle e as medidas de vigilância instituídas. As pesquisas de triatomíneos nos domicílios ocorreram nos apartamentos quando da notificação pelo morador. Os insetos coletados foram identificados, examinados quanto à infecção natural e teste de precipitina. Na pesquisa das palmeiras foram utilizados lonas para forração do chão e caminhão Munck equipado com moto poda. O controle químico foi realizado com a utilização de compressor manual. No ano de 2009, foram coletados pela população 81 exemplares de Rhodnius neglectus em domicílios. O teste de precipitina acusou presença de sangue humano em 2,7% das amostras. Pesquisas entomológicas foram realizadas nestas edificações e naquelas situadas em um raio de 200 metros onde ocorreram as invasões. A pesquisa realizada nas palmeiras resultou na captura de 882 exemplares de triatomíneos, negativos para tripanosomatídeos. Foi realizado controle mecânico e químico. Novas pesquisas realizadas nas palmeiras avaliadas no mesmo ano resultaram na coleta de seis exemplares. Os controles mecânicos e químicos das palmeiras aliado ao trabalho de participação popular mostraram-se factíveis impedindo a colonização destes insetos nos domicílios da cidade.

Busca ativa de triatomíneos em área com ausência de notificações como subsídio à estratégia de vigilância entomológica no Estado de São Paulo / Active search of triatomines in area without report of bugs for the population as a subsidy of entomolgical survellance in the state of São Paulo

Avaliações das notificações de triatomíneos pela população em áreas de maior dispersão da espécie Panstrongylus megistus apontaram que as mesmas não têm ocorrido, ou acontecem de forma bastante esporádica. Para monitorar a situaçãofoi proposta realização de busca ativa em localidades destas áreas. O critério para a estimativa da amostra das localidades considerou a positividade observada no intra e peridomicílios em imóveis pesquisados no período de 1990 a 1999. Nos anos de 2008 e 2009 foram pesquisadas as unidades domiciliares de 110 localidades, totalizando 4466 domicílios com 20 positivos, perfazendo uma positividade de 0,04% para intradomicílio e 0,4% para o peridomicílio.Coletaram-se 136 exemplares de triatomíneos, 90,4% referentes à espécie Triatoma sordida e 9,6% a Panstrongylus megistus, concentrados noperidomicílio (92,3%). Todos os exemplares examinados foram negativos para Trypanosoma cruzi. Os resultados permitem afirmar que a estratégia de vigilância está sendo conduzida de maneira eficaz, e que, embora se constate a presença de focos de triatomíneos no peridomicílio, não ocorre à instalação de colônias na intradomicílio. Os trabalhos de educação em saúde devem ser intensificados visando manter a população motivada a identificar a presença desses insetos, encaminhar às áreas competentes para a confirmação e controle de eventuais focos de infestação

Situação atual da vigilância entomológica da doença de Chagas no Estado de São Paulo / Current situation of entomological surveillance ofChagas disease in the State of São Paulo

O propósito deste estudo foi avaliar a vigilância entomológica da doença de Chagas no Estado de São Paulo, no período de 2007 a 2009. Na ocorrência de notificação de triatomíneo, a pesquisa entomológica tem sido desencadeada pela Sucen, na casa onde se deu o seu encontro e naquelas situadas em seu entorno. Em se constatando sua presença, o controle químico é realizado. No período em questão a Sucenrecebeu 4.709 notificações de triatomíneos, procedentes de 328municípios com coleta de 7.604 exemplares. Os atendimentos a essasnotificações resultaram positivos em 1.058 domicílios, com captura de10.248 triatomíneos. Na pesquisa realizada nas moradias situadas aoredor da casa notificante, em 592 domicílios constatou-se presença de4.573 vetores. As espécies atoma sordida (92,1%) e Panstrongylusmegistus (5,8%) foram as que se destacaram. A taxa de colonização dointradomicílio foi de 13,9%. A positividade para Trypanosoma cruzi foide 1,2%. Reagiram para sangue humano 3,1% dos triatomíneos. A sorologia aplicada a 31 moradores foi positiva em uma amostra. A vigilância em vigor no Estado de São Paulo tem se mostrado eficaz, selecionando previamente casas a serem pesquisadas. Tem ocorridode forma contínua, permitindo monitorar a situação, garantir a sustentabilidade das ações e assegurar a detecção precoce de triatomíneos e o seu controle

Programa de Controle da Doença de Chagas no estado de São Paulo, Brasil: o controle e a vigilância da transmissão vetorial / Control Program of Chagas disease in São Paulo, Brazil: the control and surveillance of vector transmission

Discute-se o controle dos transmissores da doença de Chagas, no Estado de São Paulo, e as atividades que levaram à eliminação do Triatoma infestans. São destacados os fatores coadjuvantes as ações de controle, particularmente o êxodo rural. A partir de 1965, o combate tomou a forma de uma verdadeira campanha, com fases distintas em função das alterações epidemiológicas, experiência adquirida e pressão dos custos. Após 25 anos de trabalho a campanha foi considerada encerrada, com a eliminação dos focos da espécie do planalto paulista. Porém, em função da possibilidade da reintrodução de Triatoma iinfestans(transporte passivo) e da presença, em diversas localidades, de exemplares de espécies vetoras semidomiciliares (Triatoma sordida e Panstrogylus megistus) as atividades de controle não foram interrompidas. Em consequência, continuam em andamento as ações de vigilância entomológica.

The control of the vectors of Chagas' disease in the State of Sao Paulo are discussed, mainly those activities that led to the elimination of Triatoma infestans. Secondary factors that helped the control such as rural exodus are also analyzed. The article shows that since 1965 the control became a campaign with different phases due to the epidemiological situation, the acquired knowledge and the entomological surveillance. After 25 years of work, the elimination of all the focus of Triatoma infestans was finally reached and the campaign was ended. However, due to the possibility of reintroduction of the vector in rural areas by passive transportation besides the presence of secondary vectors (Triatoma sordida and Panstrongylus megistus) in several localities, the vector control activities were not interrupted and the surveillance is continuous.