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.

Comparative PCR-based diagnosis for the detection of Leishmania infantum in naturally infected dogs.

The applicability of molecular biology/PCR for canine visceral leishmaniasis diagnosis presents challenges, mainly due to the diversity of targets described. The objectives of this study were to compare the sensitivities and reliability of five targets (kDNA/120, kDNA/145, ITS1, hsp70/234 and hsp70/1300) in four different tissue samples (bone marrow, popliteal lymph node, skin and conjunctival swab). Sixty-five dogs (32 males and 33 females) naturally infected with Leishmania infantum and ten dogs without infection were examined. Dogs were characterized by serological and parasitological methods. The parasitological test was considered the gold standard for analysis. All tests presented high specificity 100% (95% CI 0.72-1), and variable sensitivity. The targets kDNA/145, ITS1, kDNA/120, hsp70/234 and hsp70/1300 detected 100% (65/65), 93.4% (61/65), 92.3% (60/65), 84.61% (55/65) and 72.3% (77/65) of positive animals respectively. The performance of PCR methods was analyzed in two different scenarios. The highest sensitivity value identified in all scenarios studied was kDNA/145. Our results suggest that popliteal lymph node and conjunctival swab samples, besides being less invasive collections, represent a good substratum for PCR-based diagnosis, and the target kDNA/145 is the best choice for detecting L. infantum DNA in naturally infected dogs.

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.

Seasonality of sand flies (Diptera: Psychodidae) and Leishmania DNA detection in vector species in an area with endemic visceral leishmaniasis

BACKGROUND Leishmaniases are a serious health problem in southeast Brazil, including the city of Belo Horizonte (BH), Minas Gerais state (MG), where there are high rates of incidence and mortality due to visceral leishmaniases. BH is divided into nine sanitary districts (SD) of which one, the Venda Nova SD, was selected for this study because it has high rates of positivity for canine leishmaniasis and high incidence of human leishmaniasis. OBJECTIVES This study aimed to survey the sand fly fauna in Venda Nova SD from August 2011 to July 2013 and perform a descriptive analysis of the vector population. METHODS The sampling was carried out using automatic HP light traps at all covered areas of the Venda Nova SD, in a total of eighteen light traps. Sampled specimens were identified following Galati (2003), and females were submitted to molecular techniques for the detection and identification of Leishmania DNA. A simple environmental description was done for it area and Kernel estimation was used to infer vector density for each study site. FINDINGS A total of 2,427 sand fly specimens belonging to eight species and five genera were collected of which 95.3% were Lutzomyia longipalpis. The seasonal variation curve was delineated by this species. Lu. longipalpis was the most abundant at all collection points and in all months of the study, and exhibited a natural infection rate of 1.01% for Leishmania infantum and 1.77% for Leishmania braziliensis. MAIN CONCLUSIONS The results show the presence and adaptation of Lu. longipalpis to the anthropic environment of BH and reinforces its role as the main vector of L. infantum in the region.

Seasonality of sand flies (Diptera: Psychodidae) and Leishmania DNA detection in vector species in an area with endemic visceral leishmaniasis.

BACKGROUND: Leishmaniases are a serious health problem in southeast Brazil, including the city of Belo Horizonte (BH), Minas Gerais state (MG), where there are high rates of incidence and mortality due to visceral leishmaniases. BH is divided into nine sanitary districts (SD) of which one, the Venda Nova SD, was selected for this study because it has high rates of positivity for canine leishmaniasis and high incidence of human leishmaniasis. OBJECTIVES: This study aimed to survey the sand fly fauna in Venda Nova SD from August 2011 to July 2013 and perform a descriptive analysis of the vector population. METHODS: The sampling was carried out using automatic HP light traps at all covered areas of the Venda Nova SD, in a total of eighteen light traps. Sampled specimens were identified following Galati (2003), and females were submitted to molecular techniques for the detection and identification of Leishmania DNA. A simple environmental description was done for it area and Kernel estimation was used to infer vector density for each study site. FINDINGS: A total of 2,427 sand fly specimens belonging to eight species and five genera were collected of which 95.3% were Lutzomyia longipalpis. The seasonal variation curve was delineated by this species. Lu. longipalpis was the most abundant at all collection points and in all months of the study, and exhibited a natural infection rate of 1.01% for Leishmania infantum and 1.77% for Leishmania braziliensis. MAIN CONCLUSIONS: The results show the presence and adaptation of Lu. longipalpis to the anthropic environment of BH and reinforces its role as the main vector of L. infantum in the region.

Epidemiological aspects of vector, parasite, and domestic reservoir in areas of recent transmission and no reported human cases of visceral leishmaniasis in Brazil.

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.

Phlebotomine sand fly fauna and leishmania infection in the vicinity of the Serra do Cipó National Park, a natural Brazilian heritage site.

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.

Estudo da variabilidade genética de Leishmania (Viannia) braziliensis Vianna, 1911 de diferentes regiões do Brasil

Leishmania (Viannia) braziliensis é a espécie mais prevalente nos casos humanos da leishmaniose tegumentar nas Américas. Polimorfismo genético têm sido encontrado em populações naturais de diferentes espécies de Leishmania, o que explicaria a adaptação destes parasitos às mudanças observadas nas condições ambientais. Neste estudo utilizou-se um painel significativo de isolados L. braziliensis de focos de LTA de diferentes regiões geográficas e biomas do Brasil. Os polimorfismos do DNA genômico foram analisados utilizando-se diferentes marcadores genéticos, comparou-se a variabilidade genética intra-específica das amostras e determinou-se as relações fenéticas entre elas. Na eletroforese de isoenzimas (MLEE), a maioria das amostras (87,3%) apresentou o perfil de migração idêntico ao da cepa padrão de L. braziliensis (M2903); 8 amostras (10,2%) apresentaram apenas um eletromorfo diferente para a enzima IDHNADP. Duas amostras (2,6%) apresentaram o perfil mais heterogêneo, com padrões diferentes de L. braziliensis para 3 enzimas (G6PDH, IDHNADP e MDH). Estas amostras foram designadas como variantes. Para o RAPD-PCR com o iniciador M1340F pode-se observar que o conjunto dos isolados formaram claramente dois grandes clusters, pela análise com o programa NTSYS, refletindo a diversidade genética entre as amostras de L. braziliensis testadas. A análise dos perfis gerados pela SSR-PCR evidenciou que os iniciadores CARY e K7 foram capazes de mostrar variabilidade intra-específica. Observou-se que com o iniciador CARY, as amostras agruparam-se em um clustrer, incluindo a cepa de referência de L. braziliensis. Por outro lado, com o iniciador K7 observou-se a formação de dois clusters.

Uma árvore consenso foi gerada por parcimônia com os dados concatenados dos três marcadores utilizados (M1340F, CARY e K7) e observou-se a formação de dois clusters onde a maioria das amostras do bioma Amazônia /região Norte (58%) e região Nordeste (62%) estão juntas em um grupo e o bioma Cerrado /região Centro-Oeste (100%), Cerrado e Mata Atlântica (67%) e a região Sul (80%) estão em outro grupo, o que concorda com a análise feita pelo método de distância genética. Foram encontrados dois perfis para ITS1- HAEIII e após a análise dos géis foram identificados três perfis para hsp70-BstUI. Observou-se que o índice de similaridade médio entre as amostras para os testes de isoenzimas, RAPD-PCR com o iniciador M1340, SSR-PCR com o iniciador CARYe K7 foi de aproximadamente 70%, demonstrando a existência de variabilidade de L. braziliensis confirmada através das diferentes técnicas utilizadas. Combinando os resultados da análise por biomas e por região, podemos dizer que a maioria das amostras do bioma Amazonas, região Norte e bioma Caatinga estão sempre agrupadas em um mesmo clustere o bioma Cerrado, região centro-oeste em outro cluster. Este estudo refletiu a diversidade genética existente em L. braziliensis sugerindo a possibilidade de uma associação entre variabilidade e origem geográfica

Estudo da variabilidade genética de Leishmania (Viannia) braziliensis Vianna, 1911 de diferentes regiões do Brasil / Study of genetic variability of Leishmania (Viannia) braziliensis Vianna, 1911 from different regions of Brazil

Leishmania (Viannia) braziliensis é a espécie mais prevalente nos casos humanos da leishmaniose tegumentar nas Américas. Polimorfismo genético têm sido encontrado em populações naturais de diferentes espécies de Leishmania, o que explicaria a adaptação destes parasitos às mudanças observadas nas condições ambientais. Neste estudo utilizou-se um painel significativo de isolados L. braziliensis de focos de LTA de diferentes regiões geográficas e biomas do Brasil. Os polimorfismos do DNA genômico foram analisados utilizando-se diferentes marcadores genéticos, comparou-se a variabilidade genética intra-específica das amostras e determinou-se as relações fenéticas entre elas. Na eletroforese de isoenzimas (MLEE), a maioria das amostras (87,3%) apresentou o perfil de migração idêntico ao da cepa padrão de L. braziliensis (M2903); 8 amostras (10,2%) apresentaram apenas um eletromorfo diferente para a enzima IDHNADP. Duas amostras (2,6%) apresentaram o perfil mais heterogêneo, com padrões diferentes de L. braziliensis para 3 enzimas (G6PDH, IDHNADP e MDH). Estas amostras foram designadas como variantes. Para o RAPD-PCR com o iniciador M1340F pode-se observar que o conjunto dos isolados formaram claramente dois grandes clusters, pela análise com o programa NTSYS, refletindo a diversidade genética entre as amostras de L. braziliensis testadas. A análise dos perfis gerados pela SSR-PCR evidenciou que os iniciadores CARY e K7 foram capazes de mostrar variabilidade intra-específica. Observou-se que com o iniciador CARY, as amostras agruparam-se em um clustrer, incluindo a cepa de referência de L. braziliensis. Por outro lado, com o iniciador K7 observou-se a formação de dois clusters.

Uma árvore consenso foi gerada por parcimônia com os dados concatenados dos três marcadores utilizados (M1340F, CARY e K7) e observou-se a formação de dois clusters onde a maioria das amostras do bioma Amazônia /região Norte (58%) e região Nordeste (62%) estão juntas em um grupo e o bioma Cerrado /região Centro-Oeste (100%), Cerrado e Mata Atlântica (67%) e a região Sul (80%) estão em outro grupo, o que concorda com a análise feita pelo método de distância genética. Foram encontrados dois perfis para ITS1- HAEIII e após a análise dos géis foram identificados três perfis para hsp70-BstUI. Observou-se que o índice de similaridade médio entre as amostras para os testes de isoenzimas, RAPD-PCR com o iniciador M1340, SSR-PCR com o iniciador CARYe K7 foi de aproximadamente 70%, demonstrando a existência de variabilidade de L. braziliensis confirmada através das diferentes técnicas utilizadas. Combinando os resultados da análise por biomas e por região, podemos dizer que a maioria das amostras do bioma Amazonas, região Norte e bioma Caatinga estão sempre agrupadas em um mesmo clustere o bioma Cerrado, região centro-oeste em outro cluster. Este estudo refletiu a diversidade genética existente em L. braziliensis sugerindo a possibilidade de uma associação entre variabilidade e origem geográfica