Epidemiologia da leishmaniose visceral no município de Sabará, Região Metropolitana de Belo Horizonte, Minas Gerais, Brasil

Submitted by Nuzia Santos ([email protected]) on 2015-04-14T13:27:59Z No. of bitstreams: 1 Segemar PDF Dissertacao_DIP_JosianeValadaoLopes.pdf: 2965756 bytes, checksum: 73c95fa710aaa33622a85777e6d3f780 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-04-14T13:28:10Z (GMT) No. of bitstreams: 1 Segemar PDF Dissertacao_DIP_JosianeValadaoLopes.pdf: 2965756 bytes, checksum: 73c95fa710aaa33622a85777e6d3f780 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2015-04-14T13:28:19Z (GMT) No. of bitstreams: 1 Segemar PDF Dissertacao_DIP_JosianeValadaoLopes.pdf: 2965756 bytes, checksum: 73c95fa710aaa33622a85777e6d3f780 (MD5)Made available in DSpace on 2015-04-14T13:28:19Z (GMT). No. of bitstreams: 1 Segemar PDF Dissertacao_DIP_JosianeValadaoLopes.pdf: 2965756 bytes, checksum: 73c95fa710aaa33622a85777e6d3f780 (MD5) Previous issue date: 2014Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brasil.A proposta deste trabalho foi estudar algumas das variáveis envolvidas na transmissão da leishmaniose visceral (LV) em oito bairros do município de Sabará (MG). Para o levantamento da fauna de flebotomíneos, influência dos fatores climáticos, identificação de repasto sanguíneo e infecção natural por Leishmania, para isso foram realizadas capturas utilizando armadilhas luminosas do tipo HP, tanto no peri como no intradomicílio, nos seguintes bairros: Alvorada, Novo Alvorada, Alvorada Velho, Bom Retiro, Nova Vista, Casa Branca, Rio Negro e Ana Lúcia, no período de janeiro de 2011 a dezembro 2012. Além desses estudos, foram realizados dois inquéritos caninos censitários nos mesmos bairros, nos anos de 2011 e 2012, para o cálculo da taxa de positividade. Para análises parasitológicas e moleculares, foram selecionados aleatoriamente 50 cães soropositivos para os testes de RIFI e ELISA, que foram eutanasiados e necropsiados para obtenção de amostras de pele, linfonodo mesentérico e baço, além de aspirado de medula óssea. Com essas amostras, foram realizados os testes: exame direto (parasitológico), PCR e mielocultura visando confirmar a infecção e identificar a espécie de Leishmania circulante. A fauna flebotomínica foi constituída de quatro espécies, sendo Lutzomyia longipalpis a mais abundante, totalizando 95,0% dos exemplares capturados. Destes, 23,0% foi capturado no intradomicílio. Verificou-se uma tendência no aumento do número de espécimens após o período chuvoso. Das 28 fêmeas ingurgitadas, 67,9% se alimentaram no homem (Homo sapiens) e 25,0% tiveram como fonte alimentar a ave (Gallus gallus). Nove pools foram utilizados para verificar a infecção natural, destes três se apresentaram positivos e, após sequenciamento de DNA, foi observado que a espécie circulante nos vetores foi Leishmania infantum. A taxa média de infecção canina foi de 4,25% em 2011 e 3,34% em 2012. A positividade das amostras (pele, baço, medula e linfonodo) obtidas dos cães soropositivos foi de 100,0% pela PCR, 76,0% pela mielocultura e 66,0% pelo exame parasitológico direto. Entre os quatro tipos de amostras estudadas, o linfonodo foi o tecido que apresentou maior positividade (98,0%). O sequenciamento de DNA das amostras positivas de linfonodo indicou Le. Infantum como sendo a espécie circulante nos cães do município. Após se correlacionarem os casos humanos, caninos e a presença da espécie Lu. longipalpis, encontrada positiva para Le. infantum, pode-se sugerir que os bairros Alvorada e Nova Vista merecem atenção especial como importantes áreas de risco para LV no município.The purpose of the present study was to investigate some epidemiological aspects related the transmission of visceral leishmaniasis (VL) in eight districts of the town of Sabará, in the Brazilian state of Minas Gerais. We surveyed the local phlebotomine sand fly fauna and the main feeding sources, analyzed the interference of climate variables on the populational fluctuation and verified the rates of natural infection of vector species of VL. The entomological captures were performed with HP light traps, from January 2011 to December 2012, in both intra and peridomiciles of houses located in the following districts of Sabará: Alvorada, Novo Alvorada, Alvorada Velho, Bom Retiro, Nova Vista, Casa Branca, Rio Negro and Ana Lúcia. During our study, the plebotomine sand fly population showed a tendency to increase after the rainy period. Four species of phlebotomine sand flies were present, most of them (95.0%) being Lutzomyia longipalpis. Twenty-three percent of them was captured inside the houses. Amongst 28 engorged females, 67.9% had fed on humans (Homo sapiens) and 25% on chicken (Gallus gallus). Leishmania infantum DNA was genotyped in three of nine pooled samples of Lu. longipalpis. Two canine census surveys were performed in the same districts allowing the calculation of the average positivity rate of canine VL, in each year of study, as 4.25% in 2011 and 3.34% in 2012. Fifty among the seropositive dogs for VL faded to euthanasia were randomly selected for parasitological and molecular analyses of tissues (skin, mesenteric lymph nodes and spleen, as well as bone marrow aspirates). All those samples gave 100% of positivity by PCR, 76% positivity by myeloculture and 66% positivity by direct parasitological examination. The highest overall positivity (98%) was obtained with lymph nodes, where the infecting parasite was also genotyped as L. infantum. The combined analysis of the human and canine cases of VL and the vector population data in Sabará, allow us to suggest that Alvorada and Nova Vista districts deserve special attention as main risk areas of VL in the city

Baseline susceptibility to alpha-cypermethrin in Lutzomyia longipalpis (Lutz & Neiva, 1912) from Lapinha Cave (Brazil).

Submitted by Nuzia Santos ([email protected]) on 2016-03-09T17:20:31Z No. of bitstreams: 1 Baseline susceptibility to alpha-cypermethrin in Lutzomyia longipalpis.pdf: 4698596 bytes, checksum: 43af4b1ddc46d98530c8bb6e3131a826 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2016-03-10T12:07:19Z (GMT) No. of bitstreams: 1 Baseline susceptibility to alpha-cypermethrin in Lutzomyia longipalpis.pdf: 4698596 bytes, checksum: 43af4b1ddc46d98530c8bb6e3131a826 (MD5)Made available in DSpace on 2016-03-10T12:07:19Z (GMT). No. of bitstreams: 1 Baseline susceptibility to alpha-cypermethrin in Lutzomyia longipalpis.pdf: 4698596 bytes, checksum: 43af4b1ddc46d98530c8bb6e3131a826 (MD5) Previous issue date: 2015Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Leishmanioses. Belo Horizonte, MG, BrasilPrefeitura de Montes Claros. Centro de Controle de Zoonoses. Montes Claros, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Leishmanioses. Belo Horizonte, MG, BrasilFundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Laboratório de Leishmanioses. Belo Horizonte, MG, BrasilBackground: Given the increase in cases of visceral leishmaniasis in recent years, associated with the socio-economic impact of this disease, as well as the wide distribution of Lutzomyia longipalpis in Brazil and the likelihood that this vector may develop resistance to insecticides used for control, the Ministry of Health considers as crucial the creation of a network in order to study and monitor the resistance of this vector to insecticides used for control. In this sense, this study aimed: 1) to characterize the susceptibility of L. longipalpis from Lapinha Cave (Lagoa Santa, MG - Brazil) to Alfateck SC200 in field bioassays, and 2) to define the susceptibility baseline to alpha-cypermethrin in laboratory bioassays, checking the possibility of using it as susceptibility reference lineage (SRL). Findings: The field bioassays revealed that the tested population was highly susceptible to alpha-cypermethrin in all time periods with high mortality (~100 %) in all treated surfaces before six months after spraying. In the laboratory bioassays, the studied population presented LD 50 ,LD 95 and LD 99 to 0.78013, 10.5580 and 31.067 mg/m2, respectively. The slope was 1.454121. Conclusions: The studied population of L. longipalpis was considered as adequate for SRL according criterion recommended by Pan-American Health Organization and has proven susceptibility to tested insecticide in the field. One cannot rule out the possibility of finding populations of L. longipalpis more susceptible to alpha-cypermethrin; therefore, further research is necessary on other populations with potential use as a SR

Dogs with divergent serology for visceral leishmaniasis as sources of Leishmania infection for Lutzomyia longipalpis phlebotomine sand flies - an observational study in an endemic area in Brazil.

Visceral leishmaniasis (VL) is a neglected tropical disease, caused by Leishmania (Kinetoplastida, Trypanosomatidae) species. In Brazil, the transmission of this parasite essentially occurs through the bite of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae) previously infected with Leishmania infantum. Aiming at preventing VL expansion over the country, integrated control actions have been implemented through a Visceral Leishmaniasis Surveillance and Control Program (VLSCP). Among the actions currently adopted by the program, the screening-culling of seropositive dogs for canine VL (CVL) is particularly polemic. Dogs with negative or divergent serology for CVL remain in their owner's domicile and are monitored by public health agents. In the present study, we determined the prevalence of CVL and analyzed the implementation of the VLSCP screening-culling action, in an area in Brazil where there has been a recent expansion of VL. Canine census surveys were conducted semiannually for two years (Aug/2015 to Feb/2017). Serological diagnosis of CVL was performed in accordance with current VLSCP protocol: immunochromatography (TR-DPP) followed by enzyme-linked immunosorbent assay (ELISA EIE). 6,667 dogs were serologically screened for CVL, of which 567 (8.5%) were positive in both tests and 641 (9.6%) had divergent results. A variable percentage (6.3% to 65.4%) of the dogs in the latter group became positive within nine months from the first result. Xenodiagnosis was conducted in canine samples belonging to any of the three possible serological statuses for CVL-positive, divergent or negative. Leishmania spp. DNA was detected in Lu. longipalpis that fed on 50.0% (5/10) of dogs with positive serology and on 29.4% (5/17) of dogs with divergent serological status for CVL. Therefore, dogs with divergent serology for CVL may be as Leishmania-infective to Lu. longipalpis as seropositive ones. Even with the adoption of euthanasia for seropositive dogs, part of the canine population will continue to serve as a source of Leishmania infection for phlebotomine sand flies