Association between the potential distribution of Lutzomyia longipalpis and Nyssomyia whitmani and leishmaniasis incidence in Piauí State, Brazil.

BACKGROUND: Leishmaniases are vector borne diseases caused by Leishmania spp. parasites transmitted by female sandflies (Diptera: Psychodidae) whose geographic distribution is influenced by environmental factors. Among the main tools for studying the distribution of vector species, modeling techniques are used to analyze the influence of climatic and environmental factors on the distribution of these insects and their association with human cases of the disease. METHODOLOGY/PRINCIPAL FINDINGS: Here, we used a multiscale ecological niche modeling approach to assess the environmental suitability of sandfly vectors of the etiological agents of Visceral (VL) and American Cutaneous Leishmaniasis (ACL) in Piauí state, northeastern Brazil, and then evaluated their relationship with human disease incidence. For this, we obtained the geographic coordinates of the vector species Lutzomyia longipalpis and Nyssomyia whitmani through literature review, online databases and unpublished records. These data were used for the development of predictive models of the distribution of both sandflies species based on climatic and environmental variables. Finally, the environmental suitability for the presence of these vectors was compared with the incidence of both the diseases at the municipality level. The final models for each sandfly species showed good predictive powers with performance metric values of 0.889 for Lu. longipalpis and 0.776 for Ny. whitmani. The areas with greater environmental suitability for the presence of these species were concentrated in the central-north region of Piauí and coincide with the location of those municipalities presenting higher incidences of VL and ACL, situated in the central-north and extreme north of the state, respectively. The south and southeast regions of Piauí state have low incidence of these diseases and presented low environmental suitability for the presence of both vectors. CONCLUSIONS/SIGNIFICANCE: We discuss how predictive modeling can guide entomological and epidemiological surveillances and recommend an increased supervision and control activities in Teresina (capital of the state of Piaui), Altos and Pedro II, in addition to other municipalities with similar social and environmental characteristics.

Spatial distribution and effects of land use and cover on cutaneous leishmaniasis vectors in the municipality of Paracambi, Rio de Janeiro, Brazil

ABSTRACT The municipality of Paracambi (Rio de Janeiro, Brazil) reports sporadic cases of American cutaneous leishmaniasis (ACL). Previous studies detected Nyssomyia intermedia (Diptera: Psychodidae) as the main vector in the region, but its spatial distribution and the presence of other vector species have not been evaluated. This study aims at filling this knowledge gap, by studying the ecology of sand flies, their spatiotemporal distribution, and correlation with land use/cover. Two campaigns of monthly sand fly collections using light traps and manual captures were conducted in 1992-1994 and 2001-2003. Females were dissected to detect natural Leishmania infections. The spatial distribution of sand flies was assessed using kernel density maps. Correlations with land use/cover were evaluated by extracting satellite imagery data around the capture points. A total of 17,232 sand flies from 13 species were captured. Medically important species included Ny. intermedia, Migonemyia migonei, Pintomyia fischeri and Ny. whitmani. No Leishmania-infected females were detected. Highest densities were detected in the peri-urban areas Cascata and Sabugo, and in rural areas São José and Mutirão. Ny. intermedia had statistically significant correlations with pasture and agricultural areas. Present results strengthened that Ny. intermedia and Mg. migonei are the main local ACL vectors. Correlations with land use evidence the association between ACL and anthropic environmental change.

Ecological niche modelling and predicted geographic distribution of Lutzomyia cruzi, vector of Leishmania infantum in South America.

In some transmission foci of Leishmania infantum in Brazil, Lutzomyia cruzi could be considered the main vector of this pathogen. In addition, L. cruzi is a permissive vector of L. amazonensis. Its geographical distribution seems to be restricted and limited to Cerrado and Pantanal biomes, which includes some areas in Brazil and Bolivia. Considering that predicting the distribution of the species involved in transmission cycles is an effective approach for assessing human disease risk, this study aims to predict the spatial distribution of L. cruzi using a multiscale ecological niche model based in both climate and habitat variables. Ecological niche modelling was used to identify areas in South America that are environmentally suitable for this particular vector species, but its presence is not recorded. Vector occurrence records were compiled from the literature, museum collections and Brazilian Health Departments. Bioclimatic variables, altitude, and land use and cover were used as predictors in five ecological niche model algorithms: BIOCLIM, generalised linear model (logistic regression), maximum entropy, random forests, and support vector machines. The vector occurs in areas where annual mean temperature values range from 21.76°C to 26.58°C, and annual total precipitation varies from 1005 mm and 2048 mm. Urban areas were most present around capture locations. The potential distribution area of L. cruzi according to the final ecological niche model spans Brazil and Bolivia in patches of suitable habitats inside a larger climatically favourable area. The bigger portion of this suitable area is located at Brazilian States of Mato Grosso do Sul and Mato Grosso. Our findings identified environmentally suitable areas for L. cruzi in regions without its known occurrence, so further field sampling of sand flies is recommended, especially in southern Goiás State, Mato Grosso do Sul (borders with Mato Grosso, São Paulo and Minas Gerais); and in Bolivian departments Santa Cruz and El Beni.

Phlebotomine sand flies (Diptera, Psychodidae) from Rio de Janeiro State, Brazil: species distribution and potential vectors of leishmaniases

Phlebotomine sand flies (Diptera, Psychodidae) from Rio de Janeiro State, Brazil: Species distribution and potential vectors of leishmaniases. Rio de Janeiro State, in Brazil, has endemic areas of both cutaneous and visceral leishmaniases. In these areas, entomologic surveillance actions are highly recommended by Brazil's Ministry of Health. The present work describes the results of sand fly captures performed by the Health Department of Rio de Janeiro State between 2009 and 2011 in several municipalities. An updated species list and distribution of phlebotomine sand flies in the state are provided based on an extensive literature review. Currently, the sand fly fauna of Rio de Janeiro State has 65 species, belonging to the genera Brumptomyia (8 spp.) and Lutzomyia (57 spp.). Distribution maps of potential leishmaniases vector species Lutzomyia (Nyssomyia) intermedia, L. migonei, L. (N.) whitmani, L. (N.) flaviscutellata and L. (Lutzomyia) longipalpis are provided and their epidemiological importance is discussed.

Leishmaniasis transmission in an ecotourism area: potential vectors in Ilha Grande, Rio de Janeiro State, Brazil.

BACKGROUND: The south coast of Rio de Janeiro State, in Brazil, is endemic for cutaneous and visceral leishmaniases and is frequently visited by tourists from different parts of the world. Since the complex epidemiology of leishmaniases demands local studies, the goal of this study was to investigate the phlebotomine sand fly fauna and leishmaniases transmission in Ilha Grande, an ecotourism area of Angra dos Reis municipality. METHODS: Sand fly fauna was sampled in three monitoring stations using HP light traps in domiciles, peridomiciles and forests. Species abundance was evaluated by the Index of Species Abundance. A Leishmania natural infection survey was done using multiplex PCR and dot blot hybridization. RESULTS: During 15 consecutive months of sand fly monitoring, 1093 specimens from 16 species were captured. The potential leishmaniases vectors found were Lutzomyia (Nyssomyia) intermedia, L. migonei, L. (N.) flaviscutellata, L. (Psychodopygus) ayrozai and L. (Lutzomyia) longipalpis. Five species were new records in Ilha Grande: L. (Sciopemyia) microps, L. termitophila, L. firmatoi, L. rupicola and L. (P.) ayrozai. Higher species richness was found inside forest areas, although potential leishmaniases vectors were present in deforested areas, peridomiciles and inside houses. Lutzomyia (N.) intermedia and L. migonei were the most abundant species. Females of L. migonei showed a high rate (10.3%) of natural infection by Leishmania (Viannia) sp., probably Leishmania (V.) braziliensis. CONCLUSIONS: The detection of leishmaniases transmission and potential vectors in Ilha Grande is of public health concern, especially because tourists are frequently visiting the island. Besides reinforcing the epidemiological importance of L. (N.) intermedia in Rio de Janeiro State, the role of L. migonei in cutaneous leishmaniasis transmission is highlighted with its high rate of Leishmania natural infection. The finding of L. (L.) longipalpis confirmed the human autochthonous case of visceral leishmaniasis from the island. The presence of L. (N.) flaviscutellata in peridomestic areas is also an important finding, since the species is involved in the transmission of diffuse cutaneous leishmaniasis. Health education practices directed to the local community and tourists are important control actions that can be taken in Ilha Grande to reduce the burden of leishmaniases.

Integrated Tools for American Cutaneous Leishmaniasis Surveillance and Control: Intervention in an Endemic Area in Rio de Janeiro, RJ, Brazil.

American cutaneous leishmaniasis (ACL) is a focal disease whose surveillance and control require complex actions. The present study aimed to apply integrated tools related to entomological surveillance, environmental management, and health education practices in an ACL-endemic area in Rio de Janeiro city, RJ, Brazil. The distribution of the disease, the particular characteristics of the localities, and entomological data were used as additional information about ACL determinants. Environmental management actions were evaluated after health education practices. The frequency of ACL vectors Lutzomyia (N.) intermedia and L. migonei inside and outside houses varied according to environment characteristics, probably influenced by the way of life of the popular groups. In this kind of situation environmental management and community mobilization become essential, as they help both specialists and residents create strategies that can interfere in the dynamics of vector's population and the contact between man and vectors.

Aspectos da ecologia de potenciais vetores de leishmanioses (diptera: psychodidae: phlebotominae) na Ilha Grande, Angra dos Reis, Rio de Janeiro / Aspects of the ecology of sand flies from Ilha Grande, Angra dos Reis, Rio de Janeiro

Evidências sugerem que a ecoepidemiologia das leishmanioses vem sendo impactada por alterações ambientais, causadas pelo homem ou por eventos naturais. Neste processo, algumas espécies de flebotomíneos, vetores das leishmanioses, já foram reportadas em ambientes modificados. A Ilha Grande apresenta casos esporádicos de Leishmaniose Tegumentar Americana (LTA) desde a ocorrência do primeiro surto, em 1975, bem como um caso autóctone de Leishmaniose Visceral Americana (LVA). A ilha apresenta características ambientais interessantes para estudos ecológicos que busquem entender como espécies de flebotomíneos, vivendo em condições naturais, podem se adaptar a ambientes que sofreram alterações de origem antrópica, principalmente causados pelo aumento das atividades relacionadas ao turismo. O presente trabalho pretendeu explorar aspectos ecológicos da fauna de flebotomíneos da Ilha Grande, área de Mata Atlântica pertencente ao município de Angra dos Reis, no litoral sul do estado do Rio de Janeiro. Foram realizadas capturas mensais utilizando armadilhas luminosas em três Estações de Monitoramento (EM) com diferentes características ambientais: Vila do Abraão, Enseada das Estrelas e Praia Vermelha. Após 13 meses de monitoramento, 931 flebotomíneos foram capturados, pertencentes a 17 espécies. Cinco espécies foram descritas pela primeira vez na Ilha Grande: Lutzomyia microps, L. termitophila, L. firmatoi, L. rupicola e L. ayrozai. Destacaram-se como vetores de leishmanioses: L. intermedia, L. migonei, L. flaviscutellata e L. longipalpis. A Vila do Abraão, EM com ambiente mais modificado por ações de origem antrópica, apresentou valores de riqueza e diversidade de espécies menores, quando em comparação à Enseada das Estrelas, EM cujo ambiente sofreu menos impacto. Porém, espécies de vetores foram capturadas em todas as EMs. A Praia Vermelha, mais de 30 anos após o surto de LTA, não sofreu grandes mudanças em seu ambiente, e mesmo após a ocorrência de recentes desastres naturais, continua apresentando altos valores de abundância relativa dos vetores L. intermédia e L. migonei. Dentre os vetores, foram capturadas no intradomicílio as espécies L. intermedia, L. migonei e L. longipalpisNão foi observada correlação estatisticamente significativa entre a frequência de vetores e dados climáticos (temperatura e umidade relativa do ar). L. intermédia e L. migonei foram mais frequentes em peridomicílios com criação de animais (galinhas, cães e gatos), árvores frutíferas (principalmente bananeiras) e mata secundária. As evidências sugerem L. intermedia como principal vetor de LTA na Ilha Grande. O achado de fêmeas de L. migonei naturalmente infectadas por Leishmania (Viannia) sp. e sua presença no peridomicílio associada a galinheiros sugere sua participação na transmissão local de LTA. Após o registro do primeiro caso de Leishmaniose Tegumentar Anérgica Difusa no estado do Rio de Janeiro, a ocorrência de L. flaviscutellata na Vila do Abraão merece destaque. O registro de L. longipalpis na localidade de ocorrência do único caso humano de LVA permitiu o fechamento do caso, em aberto no Sistema de Informação de Agravos de Notificação do Ministério da Saúde desde 2005.