About 97% of the human cases of the American visceral leishmaniasis (VL) occur in Brazil. In the last few years, the disease expanded to medium- and large-sized cities, in which surveillance and control actions have been intensified, in an effort to control VL spreading. Our two-year study was conducted in Belo Horizonte, the sixth most populous city in Brazil, which is endemic for VL. We focused in two particular districts of recent transmission of the disease, with no reported human cases and submitted to minor surveillance and control actions. Our aim was to draw an epidemiological profile of the local situation concerning Lutzomyia vector, Leishmania parasites, and the main domestic reservoirs (dogs). Lutzomyia longipalpis comprised 96.5% of the total phlebotomine sand flies captured and displayed an expressive minimal infection rate by Leishmania infantum (16.7%). Positive correlations were found between the population densities of L. longipalpis, rainfall and temperature. L. infantum was also detected in the cortelezzii complex and, for the first time, in Lutzomyia lloydi. Leishmania braziliensis, an etiological agent of the American cutaneous leishmaniasis, was also identified in L. longipalpis. Among the 1408 dogs serologically tested by standard enzyme-linked and fluorescence immune assays (ELISA/IFA) 3.6% were positive for VL. L. infantum DNA and Leishmania parasites were identified in 100% and 72.5% of the seropositive dogs, respectively. The co-positivity of other diagnostic tests for VL-Leishmania-nested PCR, imprint and myeloculture-was compared to the standard serology. Both symptomatic or asymptomatic dogs displayed an equal average number of positive diagnostic tests for VL. The districts studied display favorable conditions for the rapid spreading of human infection, in terms of L. longipalpis population density, and presence of L. infantum in both vector and main reservoir.
In the New World, the leishmaniases are primarily transmitted to humans through the bites of Leishmania-infected Lutzomyia (Diptera: Psychodidae) phlebotomine sand flies. Any or both of two basic clinical forms of these diseases are endemic to several cities in Brazil—the American cutaneous leishmaniasis (ACL) and the American visceral leishmaniasis (AVL). The present study was conducted in the urban area of a small-sized Brazilian municipality (Jaboticatubas), in which three cases of AVL and nine of ACL have been reported in the last five years. Jaboticatubas is an important tourism hub, as it includes a major part of the Serra do Cipó National Park. Currently, no local data is available on the entomological fauna or circulating Leishmania. During the one-year period of this study, we captured 3,104 phlebotomine sand flies belonging to sixteen Lutzomyia species. In addition to identifying incriminated or suspected vectors of ACL with DNA of the etiological agent of AVL and vice versa, we also detected Leishmania DNA in unexpected Lutzomyia species. The expressive presence of vectors and natural Leishmania infection indicates favorable conditions for the spreading of leishmaniases in the vicinity of the Serra do Cipó National Park.
RESUMONeste trabalho, avaliou-se, utilizando a técnica de Graham (1941), a presença de ovos de helmintos intestinais em amostras coletadas em objetos de cinco Unidades Básicas de Saúde (UBS) da cidade de Nova Serrana-MG. No total de oito coletas, foram amostrados, nas recepções, 40 mesas de atendimento e 40 assentos de cadeiras e, nos banheiros, 64 maçanetas internas e 64 maçanetas externas de portas. Todas as lâminas foram analisadas por microscopia óptica nos aumentos de 10X e 40X no Laboratório de Microscopia da FUNEDI/UEMG e reexaminadas no Laboratório de Helmintologia e Malacologia Médica do Centro de Pesquisas René Rachou (FIOCRUZ-Minas). Os resultados indicaram a presença de ovos de Enterobius vermicularis, em sua maioria, viáveis, sendo os percentuais de ocorrência calculados por meio de proporção simples. Na recepção, a porcentagem de contaminação foi de 25,0% nas mesas de atendimento e de 17,9% no assento das cadeiras; nos banheiros, 35,7% das maçanetas internas e 21,4% das maçanetas externas apresentaram ovos. Não foram encontrados ovos e larvas de outros helmintos, apenas grãos de pólen, fibras vegetais e esporos de fungos. Foram realizadas palestras direcionadas aos funcionários destas UBS para apresentar-lhes os resultados e discutir medidas para evitar a contaminação de pessoas que frequentam e trabalham nestes locais. Os dados evidenciaram que as salas de espera das UBS podem ser importantes veículos de dispersão e contaminação de enteroparasitos. Medidas de educação em saúde são importantes e devem ser realizadas entre os usuários e funcionários dos postos, pois levam as pessoas a conhecer o problema, mudar seus hábitos e discutir soluções para prevenção e controle desta e de outras endemias.
In the present study we surveyed the fauna of phlebotomine sand flies and small mammals in peridomestic areas from a Brazilian municipality where the American cutaneous leishmaniasis (ACL) is endemic. A total of 608 female phlebotomine sand flies were captured during nine months in 2009 and 2010. Seven different species were represented with 60% of them being Lutzomyia intermedia and Lu. whitmani, both incriminated vectors of ACL. Lu. longipalpis, a proven vector of visceral leishmaniasis (VL) was also captured at high proportion (12.8%). Genomic DNA analysis of 136 species-specific pools of female sand flies followed by molecular genotyping showed the presence of Leishmania infantum DNA in two pools of Lu. longipalpis. The same Leishmania species was found in one blood sample from Rattus norvegicus among 119 blood and tissue samples analysed. This is the first report of Le. infantum in R. norvegicus in the Americas and suggests a possible role for this rodent species in the zoonotic cycle of VL. Our study coincided with the reemergence of VL in Governador Valadares.
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