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.

Ecology of phlebotomine sand flies in an area of leishmaniasis occurrence in the Xakriabá Indigenous reserve, Minas Gerais, Brazil

Abstract INTRODUCTION: Leishmaniasis is a complex vector-borne infectious diseases caused by protozoan parasites in the genus Leishmania and spread by hematophagous phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae). The aim of this study was to investigate the phlebotomine fauna, endophily and exophily of the species found, and possible influence of climatic factors on their populations. METHODS: The study was conducted in the Xakriabá Indigenous Reserve (XIR) in the municipality of São João das Missões in northern Minas Gerais state, Brazil. Insects were collected over three consecutive nights in the last week of each month for 12 months from July 2015 to May 2016 from four houses in four different villages. Two traps were set up in each house: one in the intra-domicile and another in the peri-domicile. RESULTS: A total of 2,012 phlebotomine sand fly specimens representing 23 species and belonging to 10 different genera were captured and identified. Among the studied villages, Riacho do Brejo showed the highest density and diversity of phlebotomine sand flies. The species Lutzomyia longipalpis (80.3%) and Nyssomyia intermedia (7.3%), which are major vectors of visceral and cutaneous leishmaniasis, respectively, had the highest population densities, both in the intra- and peri-domicile. No correlation was observed between climatic factors and the density of phlebotomine sand flies. CONCLUSIONS: The results of the present study may contribute to a better understanding and targeting of the measures for preventing and controlling leishmaniasis by the authorities responsible for indigenous health.

Frequency and diversity of phlebotomine sand flies (diptera: psychodidae) in sinop, state of Mato Grosso, Brazil

Abstract INTRODUCTION: Understanding the diversity of sand flies is important for the epidemiology and control of leishmaniasis. This study aimed to understand the frequency, diversity, and seasonality of medically important sand flies in the municipality of Sinop, State of Mato Grosso, Brazil. METHODS: The study was conducted in an urban area, including four ecotypes with different levels of urbanization. The sand flies were collected using light traps for three nights per month, from May 2014 to April 2015. RESULTS: A total of 62,745 sand flies was collected, 52.34% of which were female. The frequency and diversity of sand flies was the highest in areas of permanent preservation (APPs) (96.85%), and was lower in more urbanized areas. Lutzomyia dasypodogeton was the most frequent species in the APPs. Lutzomyia antunesi was the most frequent in neighborhoods with forest fragments and neighborhoods around APPs, and L. aragaoi was the most frequent in completely urbanized neighborhoods. A higher frequency and diversity of sand flies was observed in the rainy season (87.92%) than in the dry season (12.08%). Eight medically important species were captured, and Lutzomyia antunesi, which is associated with American cutaneous leishmaniasis and visceral leishmaniasis, was observed in all ecotypes throughout the year. CONCLUSIONS: We observed a high frequency and diversity of sand flies in all urban areas, and some species collected were major vectors of leishmaniasis. These results support the need for further studies of the natural rates of infection of these insects and the circulation of the disease in hosts and vectors.

Abundance of Lutzomyia longipalpis in urban households as risk factor of transmission of visceral leishmaniasis

Urban occurrence of human and canine visceral leishmaniasis (VL) is linked to households with characteristics conducive to the presence of sand flies. This study proposes an ad hoc classification of households according to the environmental characteristics of receptivity to phlebotominae and an entomological study to validate the proposal. Here we describe the phlebotominae population found in intra- and peridomiciliary environments and analyse the spatiotemporal distribution of the VL vector Lutzomyia longipalpis of households receptive to VL. In the region, 153 households were classified into levels of receptivity to VL followed by entomological surveys in 40 of those properties. Kruskal-Wallis verified the relationship between the households’ classification and sand fly abundance and Kernel analysis evaluated L. longipalpis spatial distribution: of the 740 sand flies were captured, 91% were L. longipalpis; 82% were found peridomiciliary whilst the remaining 18% were found intradomiciliary. No statistically significant association was found between sandflies and households levels. L. longipalpis counts were concentrated in areas of high vulnerability and some specific households were responsible for the persistence of the infestation. L. longipalpis prevails over other sand fly species for urban VL transmission. The entomological study may help target the surveillance and vector control strategies to domiciles initiating and/or maintaining VL outbreaks.

Evaluation of parasitological examination, kDNA polymerase chain reaction and rK39-based immunochromatography for the diagnosis of visceral leishmaniasis in seropositive dogs from the screening-culling program in Brazil

Introduction Dogs play a primary role in the zoonotic cycle of visceral leishmaniasis (VL). Therefore, the accurate diagnosis of infected dogs, primarily asymptomatic dogs, is crucial to the efficiency of VL control programs. Methods We investigated the agreement of four diagnostic tests for canine visceral leishmaniasis (CVL): parasite detection, either after myeloculture or by direct microscopic examination of tissue imprints; kinetoplast-deoxyribonucleic acid-polymerase chain reaction (kDNA-PCR); and an immunochromatographic test (ICT). An enzyme-linked immunosorbent assay (ELISA) and an indirect immunofluorescence test (IFAT), both of which were adopted as part of the screening-culling program in Brazil, were used as reference tests. Our sample set consisted of 44 seropositive dogs, 25 of which were clinically asymptomatic and 19 were symptomatic for CVL according to ELISA-IFAT. Results The highest and lowest test co-positivities were observed for ICT (77.3%) and myeloculture (58.1%), respectively. When analyzed together, the overall percentage of co-positive tests was significantly higher for the symptomatic group compared to the asymptomatic group. However, only ICT was significantly different based on the results of a separate analysis per test for each group of dogs. The majority (93.8%) of animals exhibited at least one positive test result, with an average of 2.66 positive tests per dog. Half of the symptomatic dogs tested positive for all four tests administered. Conclusions The variability between test results reinforces the need for more efficient and reliable methods to accurately diagnose canine VL, particularly in asymptomatic animals. .

Phlebotomine sandfly fauna and natural Leishmania infection rates in a rural area of Cerrado (tropical savannah) in Nova Mutum, State of Mato Grosso in Brazil

Introduction American cutaneous leishmaniasis (ACL) has been reported in every municipality of the State of Mato Grosso, Brazil, but the transmission epidemiology remains poorly understood. Our study was developed in a rural area of the Nova Mutum municipality where four autochthonous cases of ACL were reported in 2009. Our aims were to describe the local phlebotomine sandfly fauna and to investigate the infection rates and infecting Leishmania species in the captured sandflies. Methods Entomological captures were performed bimonthly at 10 fixed sites close to the edge of a forested area between June 2011 and April 2012. Results A total of 3,743 phlebotomine sandflies belonging to 31 distinct species were captured. Approximately 75% of the specimens were females. The most abundant species (45.4%) was Lutzomyia antunesi, which was consistently captured at every site. Species that are epidemiologically important for ACL, such as L. flaviscutellata, L. whitmani and L. umbratilis, were also captured. L. antunesi and L. ubiquitalis were naturally infected by Leishmania braziliensis or Le. guyanensis, with minimum infection rates of 0.88% and 6.67%, respectively. Surprisingly, L. antunesi was infected by Le. infantum (synonym chagasi). Conclusions The natural infection of L. antunesi and L. ubiquitalis by Leishmania sp. suggests that these species might play a role in the zoonotic cycle of ACL in Nova Mutum. The presence of Le. infantum in L. antunesi suggests that there may be a risk of an outbreak of visceral leishmaniasis (VL) in Nova Mutum. .

First description of autochthonous canine visceral leishmaniasis in the metropolitan region of Vitória, State of Espírito Santo, Brazil / Primeira descrição de leishmaniose visceral canina autóctone na Região Metropolitana de Vitória, Estado do Espírito Santo, Brasil

INTRODUCTION: We investigated autochthonous canine visceral leishmaniasis (CVL) in the metropolitan region of Vitória (MRV), an area in which a human case was previously reported. METHODS: Serological, parasitological, and molecular tests were performed in 201 dogs. RESULTS: Twenty-six (13%) and 12 (6%) dogs were identified as positive using in-house enzyme-linked immunosorbent assay (ELISA) and rK39 tests, respectively. Two dogs had a positive culture for Leishmania chagasi, and 4 were polymerase chain reaction (PCR)-positive for Leishmania spp. One positive dog belonged to the aforementioned patient. CONCLUSIONS: Although the responsible vector was not found, our results provide evidence of autochthonous CVL in the MRV, a non-endemic area for VL.

INTRODUÇÃO: Descrevemos um foco de leishmaniose visceral canina (LVC) autóctone na Região Metropolitana de Vitória (RMV) onde um caso humano foi registrado anteriormente. MÉTODOS: Testes sorológicos, parasitológicos e moleculares foram realizados em 201 cães. RESULTADOS: Vinte e seis (13%) e 12 (6%) foram positivos para um teste ELISA in house e rK39, respectivamente. Dois cães apresentaram cultura positiva para Leishmania (Leishmania) chagasi e quatro PCR positivo para Leishmania spp. Um dos cães positivo pertencia ao paciente supracitado. CONCLUSÕES: Embora o vetor não tenha sido encontrado, nossos resultados fornecem evidências da LVC autóctone na RMV, área não-endêmica para leishmaniose visceral.

Assessment of sand fly (Diptera, Psychodidae) control using cypermethrin in an endemic area for visceral leishmaniasis, Montes Claros, Minas Gerais State, Brazil / Avaliação do controle de flebotomíneos (Diptera, Psychodidae) usando cipermetrina em área endêmica para leishmaniose visceral, Montes Claros, Minas Gerais, Brasil

Montes Claros in Minas Gerais State, Brazil, was considered an intense transmission area for visceral leishmaniasis. This study evaluated sand fly fauna after insecticide application. Captures were performed in 10 districts from September 2005 to August 2006 with CDC light traps inside and outside each residence. Cypermethrin was sprayed in two cycles during November/2005 and May/2006. The 636 specimens collected, belonging to 10 species, were predominantly Lutzomyia longipalpis (79 percent), and most frequently males (70 percent). The highest percentage of specimens were captured in areas surrounding domiciles (85.8 percent). The main species were observed to be sensitive to treatment with the insecticide. The results showed a reduction in the number of sand flies collected after use of cypermethrin in homes and annexes, and with residual effect lasting from two to four months.

Montes Claros foi considerada área de transmissão intensa para leishmaniose visceral no Estado de Minas Gerais, Brasil. Este trabalho avaliou a fauna de flebotomíneos após a aplicação do inseticida. Entre setembro de 2005 e agosto de 2006, foram realizadas capturas com 20 armadilhas luminosas CDC em 10 bairros do município, no intra e no peridomicílio de cada residência. Dois ciclos de borrifação com cipermetrina foram realizados nos meses de novembro/2005 e maio/2006. Coletou-se 636 exemplares pertencentes a 10 espécies, com predominância de Lutzomyia longipalpis (79 por cento). Machos foram coletados com maior frequência (70 por cento). O peridomicílio apresentou a maior porcentagem dos espécimens capturados (85,8 por cento). Observou-se que as principais espécies foram sensíveis ao tratamento com o inseticida. Os resultados mostraram uma redução do número de flebotomíneos coletados devido ao uso de cipermetrina nos domicílios e seus anexos, mas com efeito residual atuante entre dois e quatro meses.

Epidemiological aspects of human and canine visceral leishmaniasis in Montes Claros, State of Minas Gerais, Brazil, between 2007 and 2009 / Aspectos epidemiológicos da leishmaniose visceral humana e canina em Montes Claros, Estado de Minas Gerais, Brasil, entre 2007 e 2009

INTRODUCTION: Visceral leishmaniasis (VL) is an expanding zoonosis in Brazil and is becoming urbanized in several Brazilian regions. This study aims to describe the epidemiological features of human and canine VL in the municipality of Montes Claros, State of Minas Gerais, by focusing on their spatial distribution. METHODS: Data concerning human cases and reactive dogs for VL from 2007 to 2009 were obtained from the Information System for Disease Notification (SINAN) and from reports of the local Centro de Controle de Zoonoses (CCZ), respectively. The addresses of human and canine cases have been georeferenced and localized in thematic maps, allowing their spatial visualization as well as the identification of areas at risk of VL transmission. RESULTS: Ninety-five cases of human VL were reported in the period. The 0-9-year-old age group (48.4 percent) was the most affected, within which the majority consisted of male patients (64 percent). Of the samples collected for the canine serological survey, 2,919 (6.3 percent) were reactive to VL. The spatial localization of these cases shows that the disease was scattered in the urban area of the municipality. Areas showing a higher dissemination risk were concentrated in the central, northwestern, and southern regions of the city. CONCLUSIONS: Identifying the areas most at risk in urban Montes Claros may help guide actions toward local epidemiological vigilance and control.

INTRODUÇÃO: A leishmaniose visceral (LV) é uma zoonose em expansão no Brasil e está se tornando urbana em várias regiões brasileiras. Este estudo descreve aspectos epidemiológicos da LV humana e canina no município de Montes Claros, Minas Gerais, com enfoque na distribuição espacial de sua incidência. MÉTODOS: É um estudo epidemiológico descritivo, que utiliza dados relativos à casos humanos e soro-positividade canina para LV, obtidos do Sistema de Informação de Agravos de Notificação (SINAN) e de relatórios do Centro de Controle de Zoonoses (CCZ) local. Os endereços dos casos estudados foram georreferenciados e localizados em mapas temáticos que permitem sua visualização espacial, bem como a identificação de áreas de risco de transmissão da doença. RESULTADOS: A leishmaniose visceral humana e canina mostrou ampla distribuição espacial em Montes Claros. No período entre 2007 a 2009, foram notificados 95 casos humanos da doença. O grupo etário entre 0 e 9 anos foi o mais afetado (48.4 por cento) com maior prevalência no sexo masculino (64 por cento). Dentre as amostras caninas coletadas para investigação sorológica, 2.919 (6,3 por cento) foram reativas para LV. A localização espacial desses casos mostra que a doença está disseminada na área urbana do município. As áreas com maior risco de disseminação concentraram-se nas regiões central, noroeste e sul da cidade. CONCLUSÕES: A identificação das áreas de maior risco na zona urbana de Montes Claros poderá guiar as ações de vigilância epidemiológica e de controle locais.

Controle da leishmaniose visceral no município de Porteirinha, estado de Minas Gerais, no período de 1998 a 2003 / Control of visceral leishmaniasis in the town of Porteirinha, state of Minas Gerais, Brazil, from 1998 to 2003

INTRODUÇÃO: No município de Porteirinha, Estado de Minas Gerais, foram registrados 23 casos humanos de leishmaniose visceral (LV) nos anos de 1998 e 1999. MÉTODOS: Foi realizado um estudo envolvendo a tríade de ações preconizadas no controle da LV. Pacientes com leishmaniose humana foram tratados e cães sorologicamente positivos foram eutanasiados, trimestralmente. O inseticida piretróide α-cipermetrina foi aplicado nos bairros onde casos humanos foram registrados. RESULTADOS: Houve uma redução da soroprevalência canina e de flebotomíneos capturados, após a implementação das medidas de controle, refletindo na diminuição de casos humanos de leishmaniose visceral. CONCLUSÕES: Os resultados mostraram a eficiência destas medidas quando empregadas em conjunto.

INTRODUCTION: In the town of Porteirinha, State of Minas Gerais, 23 human cases of visceral leishmaniasis (VL) in 1998 and 1999 were recorded. METHODS: A study was conducted involving the triad of action recommended for the control of VL. Patients were treated and serologically positive dogs were euthanized quarterly. The pyrethroid insecticide α-cypermethrin was applied in the neighborhoods where human cases were recorded. RESULTS: A reduction in canine seroprevalence and sand flies occurred following the implementation of control measures, reflecting in a reduction in human cases of VL. CONCLUSIONS: The results show the efficiency of such control measures when used in association.

Phlebotomine sandflies (Diptera: Psychodidae) in Governador Valadares, a transmission area for American tegumentary leishmaniasis in State of Minas Gerais, Brazil / Flebotomíneos (Diptera: Psychodidae) em Governador Valadares, área de transmissão de leishmaniose tegumentar americana no Estado de Minas Gerais, Brasil

INTRODUCTION: A study on the phlebotomine sandfly fauna was carried out in an endemic area for American tegumentary leishmaniasis in the municipality of Governador Valadares, in the State of Minas Gerais, Brazil. METHODS: Captures were undertaken using HP light traps in four districts, on three nights per month, for one year (from January to December 2008). Correlations between climatic factors (temperature, relative air humidity and rainfall) and the numbers of sandflies collected was observed. RESULTS: 5,413 phlebotomine specimens were caught and were identified as belonging to 12 species. Of these specimens, 2,851 (52 percent) were females and 2,562 (48 percent) were males. CONCLUSIONS: Lutzomyia intermedia predominated (29.9 percent of the species caught), thus suggesting that they were responsible for transmission of American tegumentary leishmaniasis, together with L. whitmani, which was also found in the area (4.3 percent). The presence of L. longipalpis (11.9 percent), the main vector for visceral leishmaniasis in Brazil, is an important finding, which makes rigorous entomological surveillance of the area necessary.

INTRODUÇÃO: Um estudo da fauna de flebotomíneos foi realizado em uma área endêmica para leishmaniose tegumentar americana no município de Governador Valadares, no Estado de Minas Gerais, Brasil. MÉTODOS: Capturas foram feitas com armadilhas luminosas HP em quatro bairros, três noites por mês, durante o período de janeiro a dezembro de 2008. A correlação entre fatores climáticos (temperatura, umidade relativa do ar e pluviosidade) e o número de flebotomíneos coletados foi avaliada. RESULTADOS: Foram capturados 5.413 espécimes de flebotomíneos, distribuídos em 12 espécies, sendo 2.851 (52 por cento) fêmeas e 2.562 (48 por cento) machos. CONCLUSÕES: Lutzomyia intermedia foi predominante com 29,9 por cento das espécies capturadas, sugerindo ser a responsável pela transmissão de LTA, juntamente com L. whitmani, que também foi encontrada na região (4,3 por cento). A presença de L. longipalpis (11,9 por cento), principal vetor de LV no Brasil, é um dado relevante tornando-se necessário uma rigorosa vigilância entomológica na região.

Infecção natural de Lutzomyia (Lutzomyia) longipalpis (Diptera: Psychodidae) por Leishmania infantum chagasi em flebotomíneos capturados no município de Janaúba, Estado de Minas Gerais, Brasil / Natural infection with Leishmania infantum chagasi in Lutzomyia (Lutzomyia) longipalpis (Diptera: Psychodidae) sandflies captured in the municipality of Janaúba, State of Minas Gerais, Brazil

INTRODUÇÃO: A leishmaniose visceral tem sido notificada em quase todos os estados do Brasil, e principalmente no norte de Minas Gerais, onde a doença é endêmica. Este estudo visou detectar a infecção natural de Lutzomyia longipalpis e identificar através da técnica de PCR/RFLP a espécie de Leishmania encontrada nos flebotomíneos do município de Janaúba. MÉTODOS: Utilizando-se armadilhas luminosas, foram capturadas 1.550 fêmeas de L. longipalpis, que agrupadas em pool de 10 exemplares foram submetidas à extração e amplificação de DNA, através das técnicas de PCR genérico e cacofonia. RESULTADOS: Dos 155 pools, seis apresentaram-se positivos para Leishmania sp., sendo a taxa de infecção do município de 3,9 por cento. Através da PCR/RFLP determinou-se que o padrão de digestão das amostras positivas foi semelhante ao da cepa referência Leishmania chagasi (MHOM/BR/74/PP75). CONCLUSÕES: A detecção de infecção natural associada a estudos sobre a epidemiologia da LV sugere que L. longipalpis esteja envolvida na transmissão de L. infantum chagasi em Janaúba, principalmente nas áreas de intensa transmissão de LV.

INTRODUCTION: Visceral leishmaniasis has been notified in nearly all states of Brazil, and particularly in the north of Minas Gerais, where the disease is endemic. The aim of this study was to detect natural infection of Lutzomyia longipalpis and, through the PCR/RFLP technique, identify Leishmania species found in sandflies in the municipality of Janaúba. METHODS: Using light traps, 1,550 females of L. longipalpis were caught and grouped into pools of 10 specimens to be subjected to DNA extraction and amplification, by means of generic PCR and cacophony. RESULTS: Out of the 155 pools, six were positive for Leishmania sp., and thus the infection rate in the municipality was 3.9 percent. Through PCR/RFLP, the digestion pattern among the positive samples was found to be similar to that of the reference strain of Leishmania chagasi (MHOM/BR/74/PP75). CONCLUSIONS: The detection of natural infection associated with studies on the epidemiology of visceral leishmaniasis suggests that L. longipalpis is involved in transmission of L. infantum chagasi in Janaúba, particularly in areas of intense transmission of visceral leishmaniasis.

Evidência de transmissão de leishmaniose visceral por Lutzomyia cruzi no município de Jaciara, Estado de Mato Grosso, Brasil / Evidence of transmission of visceral leishmaniasis by Lutzomyia cruzi in the municipality of Jaciara, State of Mato Grosso, Brazil

INTRODUÇÃO: O município de Jaciara foi classificado em 2003, como área de transmissão de leishmaniose visceral em situação de surto. O trabalho objetivou determinar evidência de transmissão de Leishmania (Leishmania) infantum chagasi por Lutzomyia cruzi no município de Jaciara, Estado de Mato Grosso, Brasil. MÉTODOS: O município situa-se a 127km da capital Cuiabá e é um importante ponto de atração para os praticantes de eco-turismo. Fêmeas de Lutzomyia cruzi, capturadas com armadilha de CDC, foram dissecadas para confirmação da espécie e armazenadas a -20ºC em pools de 10 indivíduos para extração de DNA, PCR genérico, RFLP específico e eletroforese em gel de poliacrilamida. RESULTADOS: O levantamento entomológico demonstrou a ocorrência abundante de Lutzomyia cruzi e ausência de Lutzomyia longipalpis, principal vetora da Leishmania (Leishmania) infantum chagasi. Uma das três amostras analisadas apresentou banda característica de DNA de Leishmania (120pb) em PCR genérico. Para confirmação da espécie de Leishmania, na RFLP utilizaram-se controles positivos de Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis e Leishmania (Leishmania) infantum chagasi digeridas com enzima de restrição HaeIII. Constatou-se um padrão de bandas semelhante à Leishmania (Leishmania) infantum chagasi em uma amostra, confirmando a detecção de infecção natural de Leishmania (Leishmania) infantum chagasi em Lutzomyia cruzi. CONCLUSÕES: A ocorrência de casos humanos e cães positivos, a presença da Lutzomyia cruzi e a ausência de Lutzomyia longipalpis, bem como a detecção de infecção natural por Leishmania (Leishmania) infantum chagasi, evidenciam a participação de Lutzomyia cruzi na transmissão da leishmaniose visceral em Jaciara, Estado de Mato Grosso, Brasil.

INTRODUCTION: The municipality of Jaciara was classified in 2003 as a transmission area for visceral leishmaniasis in outbreak situations. This study aimed to establish evidence of transmission of Leishmania (Leishmania) infantum chagasi by Lutzomyia cruzi in the municipality of Jaciara, State of Mato Grosso, Brazil. METHODS: This municipality is located 127 km from the state capital (Cuiabá) and is an important center for ecotourism practitioners. Females of Lutzomyia cruzi, captured using CDC traps, were dissected to confirm the species and stored at -20ºC in pools of 10 individuals for DNA extraction, generic PCR, specific RFLP and electrophoresis on polyacrylamide gel. RESULTS: The entomological survey showed abundant occurrence of Lutzomyia cruzi and absence of Lutzomyia longipalpis (the main vector for Leishmania (Leishmania) infantum chagasi). One of the three samples showed a characteristic DNA band from Leishmania (120 bp) in generic PCR. To confirm the Leishmania species via RFLP, positive controls for Leishmania (Leishmania) amazonensis, Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum chagasi digested with restriction enzyme HaeIII were used. A pattern of bands similar to Leishmania (Leishmania) infantum chagasi was found in one sample, thus confirming the detection of natural infection with Leishmania (Leishmania) infantum chagasi in Lutzomyia cruzi. CONCLUSIONS: The occurrences of positive cases in humans and dogs, the presence of Lutzomyia cruzi and the absence of Lutzomyia longipalpis together with the detection of natural infection with Leishmania (Leishmania) infantum chagasi, indicate that Lutzomyia cruzi participates in visceral leishmaniasis transmission in Jaciara, State of Mato Grosso, Brazil.

Phlebotominae distribution in Janaúba, an area of transmission for visceral leishmaniasis in Brazil

In Brazil, visceral leishmaniasis (VL) is caused by Leishmania chagasi parasites that are transmitted to man through the bites of infected females of Lutzomyia longipalpis sand flies. In order to evaluate transmission risk and to clarify the epidemiology of this tropical disease, studies focused on the vector and favorable environmental conditions are of fundamental importance. In this work, we surveyed the phlebotomine sand fly fauna in Janaúba, a Brazilian municipality that is endemic for VL. During a two-year period, entomological captures were performed monthly in 15 districts with high, moderate and low profiles of VL transmission. A total of 14,591 phlebotomine sand flies were captured (92 percent L. longipalpis), with a predominance of males. Most specimens were captured in the peri-domicile setting, although the number of specimens captured in the intra-domicile setting emphasises the anthropophilic behaviour of this insect. The population density of L. longipalpis was modulated by climate variations, particularly with clear increases immediately after the rainy season. However, the pattern of distribution did not coincide with the occurrence of human or canine cases of VL. This suggests that the eco-epidemiology of VL is particular to each area of transmission and must be taken into account during the design of public health control actions.

Preferência alimentar de Lutzomyia longipalpis (Lutz & Neiva, 1912) em área de transmissão de leishmaniose visceral em Mato Grosso / Feeding preference of Lutzomyia longipalpis (Lutz & Neiva, 1912) in transmission area of visceral leishmaniasis in Mato Grosso

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 por cento) estavam ingurgitadas, sendo 32 (30,8 por cento) capturadas no intradomicílio e 72 (69,2 por cento) no peridomicílio. Após reação de precipitina, observou-se que as fêmeas de Lutzomyia longipalpis alimentaram-se preferencialmente em aves (30,8 por cento) e roedores (21,2 por cento), 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 percent) were engorged. Among these, 32 (30.8 percent) were caught inside homes and 72 (69.2 percent) in areas surrounding homes. From the precipitin reaction, it was observed that Lutzomyia longipalpis females fed preferentially on birds (30.8 percent) and rodents (21.2 percent), 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.

Phlebotomine sand flies (Diptera: Psychodidae) in the municipality of Várzea Grande: an area of transmission of visceral leishmaniasis in the state of Mato Grosso, Brazil

Visceral leishmaniasis (VL) has been naturally transmitted in periurban areas due to the emergence and reemergence of its vectors in such areas. Aimed to further knowledge on ecological aspects affecting the occurrence of phlebotomine sand flies in VL transmission areas in the municipality of Várzea Grande, state of Mato Grosso (MT), Brazil, sand fly captures were carried out. Monthly collections of sand flies were undertaken with CDC light-traps, which were left in both intradomiciliary and peridomiciliary areas of ten residences during four consecutive days between January 2004 and June 2006. Twenty-two species of genus Lutzomyia and one of Brumptomyia were captured. The most abundant species was Lutzomyia longipalpis (65.23 percent), followed by L. evandroi (16.26 percent), L. lenti (7.69 percent), L. whitmani (4.92 percent), L. sallesi (2.34 percent) and L. termitophila (1.32 percent). The highest density of the main VL vector, L. longipalpis, was found in peridomiciliary areas, mostly males. No significant correlation was found between environment (temperature, air relative humidity and rain fall) and phlebotomine density; although a slight increase in sand fly density has been observed in the period following rainfalls, particularly L. longipalpis. No correlation was observed between distribution and density of L. longipalpis, prevalence of human VL cases and the presence of serologically positive dogs. The presence of infected dogs, increased vector density, susceptibility rate and interruption of epidemiological surveillance may raise the risk of VL transmission to man in Várzea Grande.

Flebotomíneos (Diptera: Psychodidae) de um foco de leishmaniose tegumentar no Estado de Minas Gerais / Sandflies (Diptera: Psychodidae) in an outbreak of cutaneous leishmaniasis in the State of Minas Gerais

Na localidade do Brejo do Mutambal, situado no município de Varzelândia (MG), área endêmica para leishmaniose tegumentar, foram realizadas capturas mensais sistemáticas utilizando-se armadilhas luminosas do tipo CDC durante o período de janeiro a dezembro de 2000. Foram capturadas 19 espécies de flebotomíneos, totalizando 6.756 exemplares. Lutzomyia intermedia (5,1 por cento), L. migonei (0,4 por cento) e L. whitmani (0,1 por cento), relacionadas com a transmissão de leishmaniose tegumentar, foram capturadas em número reduzido. Lutzomyia longipalpis foi a espécie predominante (34,8 por cento), sugerindo também um risco de transmissão da leishmaniose visceral. A proporção de insetos capturados no peridomícilio foi de 91,7 por cento enquanto no intradomicílio foi de 8,3 por cento. A interferência de fatores climáticos (temperatura, umidade relativa do ar e pluviosidade) sobre a dinâmica populacional de flebotomíneos foi avaliada.

Between January and December 2000, systematic monthly capture of phlebotomine sandflies was undertaken by means of light traps of CDC type in Brejo do Mutambal, an endemic area for American cutaneous leishmaniasis located in the municipality of Varzelândia, State of Minas Gerais. Nineteen phlebotomine species were captured, totaling 6,756 specimens. The species correlated with ACL transmission were captured in low numbers, as follows: Lutzomyia intermedia (5.1 percent), L. migonei (0.4 percent) and L. whitmani (0.1 percent). Lutzomyia longipalpis was the predominant species captured (34.8 percent), thus also suggesting a risk of visceral leishmaniasis transmission. The proportion of sandflies captured in areas surrounding homes was 91.7 percent while 8.3 percent were captured inside homes. The interference of climatic factors (temperature, relative air humidity and rainfall) on phlebotomine population dynamics was evaluated.

Epidemiology of visceral leishmaniasis through spatial analysis, in Belo Horizonte municipality, state of Minas Gerais, Brazil

The geographic information system approach has permitted integration between demographic, socio-economic and environmental data, providing correlation between information from several data banks. In the current work, occurrence of human and canine visceral leishmaniases and insect vectors (Lutzomyia longipalpis) as well as biogeographic information related to 9 areas that comprise the city of Belo Horizonte, Brazil, between April 2001 and March 2002 were correlated and georeferenced. By using this technique it was possible to define concentration loci of canine leishmaniasis in the following regions: East; Northeast; Northwest; West; and Venda Nova. However, as for human leishmaniasis, it was not possible to perform the same analysis. Data analysis has also shown that 84.2 percent of the human leishmaniasis cases were related with canine leishmaniasis cases. Concerning biogeographic (altitude, area of vegetation influence, hydrographic, and areas of poverty) analysis, only altitude showed to influence emergence of leishmaniasis cases. A number of 4673 canine leishmaniasis cases and 64 human leishmaniasis cases were georeferenced, of which 67.5 and 71.9 percent, respectively, were living between 780 and 880 m above the sea level. At these same altitudes, a large number of phlebotomine sand flies were collected. Therefore, we suggest control measures for leishmaniasis in the city of Belo Horizonte, giving priority to canine leishmaniasis foci and regions at altitudes between 780 and 880 m.

Aspectos da ecologia e do comportamento de flebotomíneos em área endêmica de leishmaniose visceral, Minas Gerais / Aspects of the ecology and behaviour of phlebotomines in endemic area for visceral leishmaniasis in State of Minas Gerais

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 por cento) porcentagem dos espécimens encontrados na região, embora parte (46,7 por cento) 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 por cento), mostrando-se oportunista, podendo sugar uma ampla variedade de vertebrados.