BACKGROUND The transmission routes for American cutaneous leishmaniasis (ACL) are in flux, so studies examining its transmission in humans, mammalian hosts, and sand fly vectors are urgently needed. OBJECTIVES The aim of this work was understand the epidemiological cycles of Leishmania spp., which causes ACL in the Andean Region of Venezuela, by identifying the Leishmania and the sand fly species involved in human and dog infections. METHODS Thirty-one biopsies from patients in Mérida and Táchira states with suspected ACL were studied by both parasitological tests (cultures and hamster inoculation) and a molecular test [Internal transcribed spacer 1 (ITS1) nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)]. We also conducted a survey to detect Leishmania infection in dogs (Immunifluorescence antibody test and ITS1 nested PCR-RFLP) and sand flies (ITS1 nested PCR-RFLP) from El Carrizal, a highly endemic focus of ACL in Venezuela. FINDINGS Three different Leishmania species were identified in the clinical samples from humans (Leishmania braziliensis, L. guyanensis, and L. mexicana) and dogs (L. guyanensis and L. mexicana). The predominant sand fly species found were those from the Verrucarum group (infected with L. mexicana) and Lutzomyia migonei (infected with L. guyanensis and L. mexicana). MAIN CONCLUSIONS We show that Lu. migonei may be the putative vector in two ACL epidemiological cycles, involving L. guyanensis and L. mexicana. We also report for the first time the presence of L. guyanensis in domestic animals.

Se estudiaron algunos aspectos de la bionomía de vectores de leishmaniasis cutánea en la localidad El Carrizal, Municipio Tovar, Venezuela: Lutzomyia youngi, Lutzomyia spinicrassa y Lutzomyia migonei. Las capturas mensuales se realizaron a lo largo del año 2008 usando trampas CDC y Shannon. Se investigó: (i) riqueza de especies, (ii) relaciones riqueza-trampa-hábitat (doméstico, peri-doméstico y selvático), (iii) fluctuaciones mensuales y relación con variables climáticas, (iv) relación factores climáticos-casos de leishmaniasis cutánea en El Carrizal y Tovar (2000-2008). Predominaron las hembras del grupo Verrucarum y los machos de Lu. youngi. Las capturas con CDC revelaron el predominio de Lu. migonei en el habitat peridoméstico donde probablemente mantienen la transmisión, mientras que las hembras del grupo Verrucarum contribuirían a mantenerla dentro de las casas. La mayor abundancia de las tres especies ocurrió en noviembre después del pico más alto de lluvias. La correlación especie-clima para Lu. migonei indicó que la temperatura parece ser un factor limitante y la precipitación un factor favorecedor, lo cual coincidió con los resultados obtenidos a través de la Modelación de Nichos Ecológicóos de esta especie sobre 23 registros a nivel nacional. La correlación de incidencia de leishmaniasis cutánea-clima mostró que el mayor número de casos tiende a ocurrir, con un mes de retraso, en los meses de mayor precipitación. Estos datos pueden ser utiles al Ministerio de Salud ya que proveen información sólida sobre "cuándo", "dónde" y "cómo" implementar métodos de control de vectores en la Región Andina de Venezuela.

We studied some aspects of the bionomics of phlebotomine vectors of cutaneous leishmaniasis (CL) at El Carrizal, Municipality Tovar, Venezuela: Lutzomyia youngi, Lutzomyia spinicrassa and Lutzomyia migonei. Monthly catches were performed throughout 2008 using CDC and Shannon traps. We investigated: (i) species richness, (ii) relationships richness-traps-habitats (domestic, peri-domestic and forest), (iii) monthly fluctuations and relationship with climatic variables, (iv) relationship climatic factors-cutaneous leishmaniasis cases at El Carrizal and Municipality Tovar (2000-2008). Females in the Verrucarum group and males of Lu. youngi prevailed. Catches with CDC revealed the predominance of Lu. migonei outdoors where probably they maintains cutaneous leishmaniasis transmission, while females in the Verrucarum group would contribute to maintain it indoors. The greatest abundance of the three species occurred in November after the heaviest peak of rains. The correlation species-climate for Lu. migonei indicated that temperature seems a limiting factor and precipitation a favouring factor, which agreed with results obtained through Ecological Niche Modelling of this species over 23 records at national level. The correlation cutaneous leishmaniasis incidence-climate showed that the greatest number of cases tends to occur, with a month lag, in the months of most rainfall. These data may support the Ministry of Health, since they provide robust information about "when", "where" and "how" to implement target phlebotomine vectors control methods in the Andean Region of Venezuela.

Since the description of Lutzomyia longipalpis by Lutz and Neiva more than 100 years ago, much has been written in the scientific literature about this phlebotomine species. Soares and Turco (2003) and Lainson and Rangel (2005) have written extensive reviews focused on vector-host-parasite interactions and American visceral leishmaniasis ecology. However, during the last two decades, the success of Lu. longipalpis in colonising urban environments and its simultaneous geographical spreading have led to new theoretical and operational questions. Therefore, this review updates the general information about this species and notes the more challenging topics regarding the new scenario of urbanisation-spreading and its control in America. Here, we summarise the literature on these issues and the remaining unsolved questions, which pose recommendations for operational research.

We evaluated the effects of Leishmania spp infection on several population parameters of Lutzomyia longipalpis sensu lato and Lutzomyia pseudolongipalpis, vectors of visceral leishmaniasis in Venezuela, under experimental conditions during the first post-feeding period. Females of both species were allowed to feed and engorge on a suspension of fresh washed human red blood cells in foetal calf serum. These blood cells were either non-infected or infected with one of the four Leishmania spp strains and were offered through a chicken skin membrane. The longevity, life expectancy and the fecundity of uninfected flies were similar in both species, but the fertility was significantly lower in uninfected Lu. longipalpis females. In all cases, the infection of Lu. longipalpis and Lu. pseudolongipalpis by the Leishmania strains resulted in significant detrimental effects, which exerted a fitness cost expressed by reduced survival and life expectancy, as well as decreased fertility and fecundity compared with the control groups. Nevertheless, differences in these parameters were observed between these vector species depending on whether they were infected with the autochthonous Venezuelan Leishmania infantum strain (NESA) or the Brazilian reference strain (PP75). The experimental data obtained agree with field data on the natural infection of these vector species and the significance of this scenario is discussed.

El Programa de Control de Leishmaniasis en Venezuela, a cargo del Servicio Autónomo Instituto de Biomedicina (IB) del Ministerio del Poder Popular para la Salud (MPPS), ha sido reforzado en los últimos años a través del fortalecimiento de la asistencia médica, en especial la consolidación de la base diagnóstica y una mayor interacción con los Servicios de Zoonosis para la LV. Sin embargo, indicadores entomológicos y epidemiológicos de la dispersión y en algunos casos urbanización, de la leishmaniasis cutánea (LC) y visceral (LV) han resaltado la necesidad del control antivectorial para un abordaje sistémico y transdisciplinario de este problema de salud, en el marco de la protección ambiental. Se presenta en este documento una revisión de los datos epidemiológicos, de los conocimientos sobre las especies de flebótomos incriminadas en la transmisión, su respuesta a los insecticidas y los ensayos de control conducidos en el país. Como perspectiva factible a corto plazo se propone un programa multisectorial en el cual concurran en primera instancia el IB, la Dirección General de Salud Ambiental (DGSA) y el Sector Educativo en una acción concertada para el control de leishmaniasis y Enfermedad de Chagas y leishmaniasis-malaria en áreas de co-endemicidad. Se hace especial énfasis en la necesidad de buenos programas educativos de salud que deben aplicarse antes de la selección de las medidas de control, de acuerdo a las características epidemiológicas y socio-culturales de la zona. Es importante tener en cuenta los conocimientos, actitudes y prácticas (CAP) de la población de riesgo con el fin de promover la aceptación del programa y de la participación comunitaria en la prevención de estas "enfermedades desatendidas", a través de la gestión ambiental y la protección personal. Sobre la base de estas premisas, estas acciones de lucha integrada, concertadas en un programa multisectorial, en el marco del enfoque Ecosalud conducirían hacia la optimización de los recursos y la sostenibilidad del programa en sí.

The Leishmaniasis Control Program in Venezuela, directed by the Institute of Biomedicine (IB) of the Ministry of Popular Power for Health (MPPH) has been strengthened in recent years by the improvement of health care, especially with regard to the establishment of diagnostic procedures and for Visceral Leishmaniasis (VL), tighter relations with the Zoonosis Department of the MPPH. However, entomological and epidemiological indicators of the dispersion, and in some cases urbanization, of cutaneous and visceral leishmaniasis (CL and VL, respectively) have highlighted the need for vector control in order to approach this health problem from a transdisciplinary systemic perspective in the context of environmental protection. We present a review of epidemiological data, our knowledge about the species of phlebotomine sand flies incriminated in transmission, and their response to insecticides and control assays undertaken in Venezuela. A multisectorial program managed between the Institute of Biomedicine (MPPH), the General Directorate of Environmental Health (GDEH) (MPPH) and the Education Sector (MPPE) for the control of leishmaniasis-Chagas disease and leishmaniasis-malaria in co-endemic areas, has been proposed as a feasible short term strategy. The need for high quality health education programs implemented according to the epidemiological and socio-cultural features of the regions, before control measures are selected, is also emphasized. It is important to take into account the knowledge, attitudes and practices (KAP) of the population at risk in order to a) ensure acceptance of the program and b) promote community participation, through environmental management and personal protection, for the prevention of these "neglected diseases". Based on this approach, these integrated control actions within a multi-sectorial program would lead towards the optimization of resources and the sustainability of the program itself.

El Boletín de Malariología y Salud Ambiental es una de las revistas más antiguas de Venezuela en el área de la Salud Pública. Durante 50 años de publicación ininterrumpida, sus páginas reflejan la ciencia, tecnología y acción sanitaria, que han contribuido a la prevención y control de las parasitosis y arbovirosis de mayor impacto en la población venezolana. Se reseñan autores y acontecimientos, que en las diferentes décadas han incidido en el devenir de esta revista. En los últimos años, su especificidad, pertinencia social y calidad científica la han hecho acreedora de inclusión en importantes índices internacionales, como Global Health, SciELO Venezuela y el WEB Science Citation Index ExpandedTM 2010. Por ende, gracias a la moderna tecnología de la comunicación, esta revista ha logrado una mayor participación a nivel ibero-americano y mayor visibilidad internacional. Dentro de este marco, se aprecia un renovado apoyo de la comunidad científica venezolana y del órgano patrocinador, Instituto de Altos Estudios "Dr. Arnoldo Gabaldon", en pro del Boletín de Malariología y Salud Ambiental, revista que ha contribuido a poner al alcance de todo el mundo, un importante acervo científico venezolano, de alto compromiso social en el ámbito de la Salud Pública.

The Boletín de Malariología y Salud Ambiental is one of Venezuela’s oldest journals in the area of Public Health. During 50 years of uninterrupted publication, its pages reflect the science, technology and environmental sanitation that have contributed to the prevention and control of parasitic and arborviral diseases with a greatest impact on the Venezuelan population. Authors and events are outlined, which, over the decades, have influenced the evolution of this journal. In recent years, high specificity, social relevance and scientific quality have earned its inclusion in major indexes such as Global Health, SciELO Venezuela and the WEB Science Citation Index ExpandedTM 2010. Thus, thanks to the modern communication technology, this magazine has achieved a greater participation of the Ibero-American scientists and wider visibility. Within this framework, we see a renewed support of the Venezuelan scientific community and its sponsor, the "Instituto de Altos Estudios Dr. Arnoldo Gabaldon" with the Boletin de Malariología y Salud Ambiental magazine, that has contributed to making available worldwide, a major Venezuelan scientific heritage, with high social commitment in the field of Public Health!.

La Enfermedad de Chagas es una "enfermedad desatendida" que afecta a millones de personas en América Latina. En este trabajo se hace una revisión de los logros pasados y retos actuales del Programa de Control de la Enfermedad de Chagas (PCECh) en Venezuela, presentándose resultados de investigaciones recientes. Implementado en la década de 1960 con el objetivo de interrumpir la transmisión intradoméstica mantenida por Rhodnius prolixus, el PCECh se basó en el uso en gran escala de insecticidas de acción residual, la implementación del Programa de Vivienda Rural y el Programa de Mejoramiento de la Vivienda Campesina (MIVICA), y la introducción del examen rutinario de Trypanosoma cruzi utilizando la técnica de ELISA en los bancos de sangre. Tras cuatro décadas se ha logrado una reducción drástica del índice de prevalencia de la infección a nivel nacional de 44,5% a 8,9%. Sin embargo, la presión de la reinfestación por R. prolixus selváticos y la tendencia a la domiciliación de especies silvestres como Panstrongylus geniculatus han dado lugar a nuevos escenarios epidemiológicos que plantean nuevos retos. Frente a estas situaciones, es imperiosa la necesidad de reorientar sobre bases científicas las acciones de monitoreo, prevención y control. Mejorar la atención médica al paciente chagásico e incrementar los esfuerzos para incorporar la participación comunitaria a la vigilancia entomológica, aspectos no abordados en el pasado, deben ser además considerados como una prioridad urgente dentro de una política integral del PCECh en Venezuela.

Chagas disease is a "neglected disease" affecting millions of people in Latin America. A review is made of the past successes and current challenges of the Chagas disease Control Program in Venezuela (PCECh), and results of recent research are presented. Officially implemented in the decade of 1960 with the aim of interrupting the intra-domestic transmission maintained by Rhodnius prolixus, the PCECh was mainly based on the large-scale use of insecticide spraying, the construction or improving of rural houses and the introduction of routine screening in public hospital blood banks for Trypanosoma cruzi using the ELISA test. After four decades, a drastic reduction of the prevalence of infection from 44.5% to 8.9% has been achieved. However, the pressure of house re-infestation by sylvan R. prolixus, and trends of domestication of other sylvan species, such as Panstrongylus geniculatus, have given rise to new epidemiological scenarios that pose new challenges. Because of this situation, re-examining how best to target monitoring and control efforts on scientific bases is of great urgency. Additionally, efforts to improve health education and community participation for a more efficient epidemiological surveillance as well as medical attention to Chagas patients, not undertaken in the past, are currently considered as a new and urgent priority of a comprehensive Chagas disease Control Program policy in Venezuela.

A doença de Chagas é uma "doença negligenciada" que afecta milhões de pessõas na América Latina e na Venezuela. Neste trabalho faz-se uma revisão dos sucessos do passado e os desafios actuais do Programa de Controlo da Doença de Chagas na Venezuela (PCECh). Mais ainda, apresentam-se resultados de investigações recentes. Este programa foi implementado oficialmente em 1960, com o objectivo de interromper a transmissão intra-doméstica mantida por Rhodnius prolixus, baseou-se principalmente no uso em grande escala de insecticidas de acção residual, construção ou melhoramento das habitações rurais e introdução em todos os bancos de sangue dos Hospitais públicos como rotina, a pesquisa da infecção por Trypanosoma cruzi utilizando a técnica de ELISA. Quarenta anos depois do início do PCECh, obteve-se uma redução drástica da prevalência da infecção de 44,5% para 8,9%. Contudo, a pressão da re-infestação por R. prolixus silváticos e a tendência para a domiciliação de outras espécies silvestres, como Panstrongylus geniculatus, levaram ao aparecimento de novos cenários epidemiológicos. Analisar novamente como melhor dirigir sobre bases científicas, as acções de monitorização e controlo es agora uma prioridade. Também devem-se estimular os esforços para melhorar a educação para a saúde e a participação comunitária para uma vigilância epidemiológica mais eficiente. Mas, a atenção médica integrada ao paciente chagásica não abordada no passado, es agora considerada como uma necessidade urgente dentro de uma política integral do Programa de Controlo da Doença de Chagas.

Estudios de los patrones del exocorión en insectos, utilizando microscopia electrónica de barrido (MEB), refieren que las diferencias entre éstos son marcadores taxonómicos útiles para separar especies relacionadas. En el presente trabajo se examinó el patrón del exocorión del huevo de dos poblaciones venezolanas de Lutzomyia longipalpis s.l., principal vector de la leishmaniasis visceral americana, una procedente del Estado Trujillo y la otra del Estado Guárico. El esculpido del exocorión del material estudiado estuvo caracterizado por un patrón de crestas paralelas, pero el huevo de la población de Trujillo presentó irregularidades y crestas conectadas, mientras que en la población del Guárico, las crestas son más regulares y no se observaron conexiones. Siendo L. longipalpis un complejo de especies, es necesario realizar estudios comparativos con otras poblaciones del complejo de diferentes paises neotropicales, incluyendo Lutzomyia pseudolongipalpis, la primera especie descrita en el complejo, para tratar de dilucidar el significado de estas diferencias y su utilidad como herramienta taxonómica para este complejo.

Scanning electron microscope (SEM) studies of eggshell morphology have shown that differences between related species of insects are reliable taxonomic markers. In the present study, the eggshell fine structure of two Venezuelan populations of Lutzomyia longipalpis s.l., vector of American visceral leishmaniasis, was examined by SEM. Newly laid eggs of L. longipalpis s.l.were obtained from a colony from Trujillo state a nd from field females collected in Guárico state. The chorionic egg sculpturing of both populations was characterized as a pattern of parallel ridging, but in the population from Trujillo the pattern was irregular and the ridges appeared connected, while those from Guarico were more regular and no connections were observed. As L. longipalpis s.l. is recognised as a species complex, further studies are needed to compare the chorionic sculpturing of eggs from different populations of L. longipalpis in Venezuela and other Neotropic countries, including L. pseudolongipalpis, the first described species in the complex, in order to clarify the significance of such differences and the usefulness of the eggshell chorionic sculpturing as a taxonomic tool in the complex.

La estratificación de riesgo para priorizar las acciones de control en función de optimización de recursos, es de gran importancia dentro de las actividades de vigilancia epidemiológica para el control de la Enfermedad de Chagas. Para esto es necesario contar con un método para la detección de la infestación intradomiciliaria por triatominos vectores, que sea de alta sensibilidad, especialmente en condiciones de baja densidad. En este estudio se compararon los resultados obtenidos con 5 métodos de capturas de vectores, 2 de búsqueda pasiva: caja Gómez-Nuñez y papel A4 Bond colocados en el dormitorio principal de las casas, 2 de búsqueda activa por personal técnico especializado: captura directa y captura con un excitante (cypermetrina+tetrametrina) durante ½ hora y por último la recolección efectuada durante un mes por los habitantes, oportunamente entrenados. El estudio se realizó en 11 localidades y 200 casas del Estado Portuguesa y 29 localidades y 350 casas del Estado Barinas. No se encontraron diferencias estadísticamente significativas entre los resultados obtenidos con los diferentes métodos en los dos estados. Sobre el total de las 550 casas exploradas, 132 fueron positivas: en 131 (99,2%) la presencia de triatominos fue detectada por lo habitantes vs. 5,3% por búsqueda activa; 3,38 por la caja Gómez-Nuñez; 3,03% por búsqueda con excitante y 0% por la hoja de papel. Se colectaron en total 5 especies y 563 individuos. Rhodnius prolixus fue la especie predominante seguido por Triatoma maculata, Panstrongylus geniculatus y R. pictipes. Se calcularon índices entomológicos de dispersión, de colonización y de infección a Trypanosoma cruzi para cada localidad. Los datos obtenidos soportan la hipótesis de un nuevo escenario epidemiológico en Venezuela donde, en las localidades en las cuales se ha interrumpido el ciclo intradoméstico, la transmisión es fundamentalmente mantenida por R. prolixus visitantes procedentes de las palmeras cercanas. Se demuestra de forma inequívoca y se resalta la importancia de la incorporación de la participación comunitaria en la vigilancia epidemiológica dentro del Programa de Control de la Enfermedad de Chagas.

Among the epidemiological surveillance activities, risk stratification is needed in order to establish priorities in the Chagas disease control program for the purpose of resource optimization. It is therefore necessary to rely on a method of high sensitivity for the detection of domestic infestation by triatomine vectors, mainly in situations of low density. In this study the results obtained with 5 capture methods were compared, 2 of passive search: Gomez-Nuñez boxes and A4 bond paper located on the walls of the bedrooms, 2 methods of active search carried out by trained personnel: direct capture without and direct search with the aid of a flushing agent (cypermethrin + tetrametrhrin) and the collection of live triatomine vectors by the inhabitants, during 1 month. The study was carried out in 11 localities and 200 houses of Portuguesa State and in 29 localities and 350 houses in Barinas State. Results obtained with the different methods were not significantly different in the 2 states. Of the total of 550 houses explored, 132 were positive, in 131 (99.2%) the presence of bugs was detected by the inhabitants vs. 5.3% by active search: 3.38% by Gomez-Nuñez boxes; 3.03% by flushing out search and 0% by paper. Five species and 563 individuals were collected: Rhodnius prolixus was the predominant species, followed by Triatoma maculata, Panstrongylus geniculatus and R. pictipes. The epidemiological indices of dispersion, colonization and infection to Trypanosoma cruzi were calculated for each locality. Results support the hypothesis of a new epidemiological scenario where, in the localities in which the domestic cycle has been interrupted, the transmission is primarily maintained by visiting R. prolixus coming in from nearby palms. The unequivocal importance of community participation in the epidemiological surveillance in the Control Program of Chagas disease in Venezuela is pointed out.

Antennal sensilla patterns were used to analyze population variation of domestic Rhodnius prolixus from six departments and states representing three biogeographical regions of Colombia and Venezuela. Discriminant analysis of the patterns of mechanoreceptors and of three types of chemoreceptors on the pedicel and flagellar segments showed clear differentiation between R. prolixus populations east and west of the Andean Cordillera. The distribution of thick and thin-walled trichoids on the second flagellar segment also showed correlation with latitude, but this was not seen in the patterns of other sensilla. The results of the sensilla patterns appear to be reflecting biogeographic features or population isolation rather than characters associated with different habitats and lend support to the idea that domestic R. prolixus originated in the eastern region of the Andes.

Predictions that deforestation would reduce American cutaneous leishmaniasis incidence have proved incorrect. Presentations at a recent international workshop, instead, demonstrated frequent domestication of transmission throughout Latin America. While posing new threats, this process also increases the effectiveness of vector control in and around houses. New approaches for sand fly control and effective targeting of resources are reviewed.

Este trabalho revisa o conhecimento atual sobre a epidemiologia da leishmaniose na Venezuela, Colômbia, Equador, Peru e Bolívia, países nos quais a doença é endêmica, tanto nos Andes quanto na Amazônia. Os vetores flebótomos pertencem a vários subgêneros e ao grupo Verrucarum. A maioria dos casos de infecção humana é causada pelos parasitas Leishmania do subgênero Viannia. As infecções humanas por Leishmania provocam lesões cutâneas, com uma minoria de infecções por L. (Viannia) levando à leishmaniose mucocutânea. Tanto a leishmaniose visceral quanto a leishmaniose cutânea difusa são raras. Em cada país, parte significativa da transmissão de Leishmania ocorre no intra ou peridomicílio, muitas vezes próximo à lavoura de café ou cacau. Não se sabe ao certo quais são os hospedeiros reservatórios para os ciclos de transmissão doméstica. Discute-se a carga da doença provocada pela leishmaniose na região, chamando atenção para os coeficientes de incidência e para a variabilidade dos sintomas. Tal informação fornecerá uma base racional, visando priorizar os recursos voltados para o controle da doença e selecionar esquemas terapêuticos. Os autores também descrevem a variação na ecologia da transmissão, delineando as variáveis que poderiam afetar a definição de estratégias preventivas.

This paper reviews the current knowledge of leishmaniasis epidemiology in Venezuela, Colombia, Ecuador, Peru, and Bolivia. In all 5 countries leishmaniasis is endemic in both the Andean highlands and the Amazon basin. The sandfly vectors belong to subgenera Helcocyrtomyia, Nyssomiya, Lutzomyia, and Psychodopygus, and the Verrucarum group. Most human infections are caused by Leishmania in the Viannia subgenus. Human Leishmania infections cause cutaneous lesions, with a minority of L. (Viannia) infections leading to mucocutaneous leishmaniasis. Visceral leishmaniasis and diffuse cutaneous leishmaniasis are both rare. In each country a significant proportion of Leishmania transmission is in or around houses, often close to coffee or cacao plantations. Reservoir hosts for domestic transmission cycles are uncertain. The paper first addresses the burden of disease caused by leishmaniasis, focusing on both incidence rates and on the variability in symptoms. Such information should provide a rational basis for prioritizing control resources, and for selecting therapy regimes. Secondly, we describe the variation in transmission ecology, outlining those variables which might affect the prevention strategies. Finally, we look at the current control strategies and review the recent studies on control.