Canine visceral leishmaniasis in area with recent Leishmania transmission: prevalence, diagnosis, and molecular identification of the infecting species.

INTRODUCTION: Canine visceral leishmaniasis (CVL) is an endemic disease in Brazil, and integrated control actions have been adopted by the Brazilian Ministry of Health to control its spread. However, the transmission profile is unknown in areas with recent CVL cases, including Itaúna, located in the Brazilian state of Minas Gerais, where the present study was carried out. METHODS: A total of 2,302 dogs from 12 neighborhoods were serologically tested for canine VL using the current diagnostic protocol adopted by the Brazilian Ministry of Health. Test positivity rate (TPR) and CVL prevalence were determined for each neighborhood. The presence of Leishmania was assessed in 60 seropositive dogs which had been recommended for euthanasia. Twenty-two of them (37%) were asymptomatic, and 38 (63%) were symptomatic for CVL. Parasitological (myeloculture and smear/imprint) and molecular (PCR) methods were employed for Leishmania detection in bone marrow, spleen, mesenteric lymph nodes, and ear skin. The infecting Leishmania species was identified by DNA sequencing. RESULTS: CVL prevalence (per 1,000 dogs) varied from 0.0-166.67, depending on the neighborhood, with a mean of 68.96 (SD 51.38). Leishmania DNA was detected in at least one tissue from all seropositive dogs, with comparable TPR among tissues. Leishmania parasites were identified in most (54/60) seropositive dogs, and the infecting parasite was identified as Leishmania infantum in all of these. CONCLUSIONS: Prevalence of CVL is a contributor to the spread of visceral leishmaniasis in Itaúna.

Ecology of phlebotomine sand flies in a Brazilian area with recent leishmaniasis transmission (Itaúna, in Minas Gerais state).

INTRODUCTION: Leishmaniasis constitutes a serious but neglected tropical disease. Recently, socio-environmental, biological and physical changes have altered the range of leishmaniasis, causing it to spread into urban areas. In Minas Gerais, the disease is endemic, exhibiting regional differences and reaching urban centers. The purpose of this study was to evaluate entomological aspects related to the ecoepidemiology of leishmaniasis in Itaúna. METHODS: Monthly catches with HP traps were carried out from June 2017 to May 2018, in three ecological areas (urban, rural, and forest). The adaptability of the species to anthropic environments was assessed using the synanthropy index (SI). RESULTS: We collected 1306 specimens of phlebotomine sand flies. Of the species of medical importance, Lutzomyia longipalpis, the vector of Leishmania infantum, represented 90.4% of the specimens identified at species level (n=1260). Nyssomyia whitmani, the vector of Leishmania braziliensis, represented 1.6% of the total. Lu. longipalpis displayed an SI of +95.8, a value that denotes a marked preference for human environments. For Ny. whitmani, the SI was -25, expressing the tendency of this species to occupy uninhabited areas. The population of the three most numerous species captured increased with rain, high temperatures, and high relative humidity. Although captured at low numbers, Ny. whitmani showed a different profile concerning the climate variables analyzed. CONCLUSIONS: Understanding the epidemiology of the disease may assist the health services in formulating effective control measures for improving community health and contributing to the establishment of a dynamic relationship and a global awareness of the health/disease process.

Canine visceral leishmaniasis in area with recent Leishmania transmission: prevalence, diagnosis, and molecular identification of the infecting species

Abstract INTRODUCTION: Canine visceral leishmaniasis (CVL) is an endemic disease in Brazil, and integrated control actions have been adopted by the Brazilian Ministry of Health to control its spread. However, the transmission profile is unknown in areas with recent CVL cases, including Itaúna, located in the Brazilian state of Minas Gerais, where the present study was carried out. METHODS: A total of 2,302 dogs from 12 neighborhoods were serologically tested for canine VL using the current diagnostic protocol adopted by the Brazilian Ministry of Health. Test positivity rate (TPR) and CVL prevalence were determined for each neighborhood. The presence of Leishmania was assessed in 60 seropositive dogs which had been recommended for euthanasia. Twenty-two of them (37%) were asymptomatic, and 38 (63%) were symptomatic for CVL. Parasitological (myeloculture and smear/imprint) and molecular (PCR) methods were employed for Leishmania detection in bone marrow, spleen, mesenteric lymph nodes, and ear skin. The infecting Leishmania species was identified by DNA sequencing. RESULTS: CVL prevalence (per 1,000 dogs) varied from 0.0-166.67, depending on the neighborhood, with a mean of 68.96 (SD 51.38). Leishmania DNA was detected in at least one tissue from all seropositive dogs, with comparable TPR among tissues. Leishmania parasites were identified in most (54/60) seropositive dogs, and the infecting parasite was identified as Leishmania infantum in all of these. CONCLUSIONS: Prevalence of CVL is a contributor to the spread of visceral leishmaniasis in Itaúna.

Ecology of phlebotomine sand flies in a Brazilian area with recent leishmaniasis transmission (Itaúna, in Minas Gerais state)

Abstract INTRODUCTION: Leishmaniasis constitutes a serious but neglected tropical disease. Recently, socio-environmental, biological and physical changes have altered the range of leishmaniasis, causing it to spread into urban areas. In Minas Gerais, the disease is endemic, exhibiting regional differences and reaching urban centers. The purpose of this study was to evaluate entomological aspects related to the ecoepidemiology of leishmaniasis in Itaúna. METHODS: Monthly catches with HP traps were carried out from June 2017 to May 2018, in three ecological areas (urban, rural, and forest). The adaptability of the species to anthropic environments was assessed using the synanthropy index (SI). RESULTS: We collected 1306 specimens of phlebotomine sand flies. Of the species of medical importance, Lutzomyia longipalpis, the vector of Leishmania infantum, represented 90.4% of the specimens identified at species level (n=1260). Nyssomyia whitmani, the vector of Leishmania braziliensis, represented 1.6% of the total. Lu. longipalpis displayed an SI of +95.8, a value that denotes a marked preference for human environments. For Ny. whitmani, the SI was -25, expressing the tendency of this species to occupy uninhabited areas. The population of the three most numerous species captured increased with rain, high temperatures, and high relative humidity. Although captured at low numbers, Ny. whitmani showed a different profile concerning the climate variables analyzed. CONCLUSIONS: Understanding the epidemiology of the disease may assist the health services in formulating effective control measures for improving community health and contributing to the establishment of a dynamic relationship and a global awareness of the health/disease process.

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

BACKGROUND: 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 LD50, LD95 and LD99 to 0.78013, 10.5580 and 31.067 mg/m(2), 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 SRL.

Epidemiologia da leishmaniose visceral no município de Sabará, Região Metropolitana de Belo Horizonte, Minas Gerais, 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), PCRe 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.

Epidemiologia da leishmaniose visceral no município de Sabará, Região Metropolitana de Belo Horizonte, Minas Gerais, Brasil / Epidemiology of visceral leishmaniasis in the municipality of Sabara metropolitan region of Belo Horizonte, Minas Gerais, Brazil

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), PCRe 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...