RESUMO
PURPOSE: Trypanosoma cruzi and Leishmania spp. coexist in several endemic areas, and there are few studies of Chagas disease and leishmaniasis coinfection worldwide; for this reason, the objective of this work was to determine the Chagas disease and leishmaniasis coinfection in several rural communities co-endemic for these diseases. METHODS: A total of 1107 human samples from six co-endemic rural communities of Cojedes state, Venezuela, were analyzed. Serum samples were evaluated by ELISA, indirect hemagglutination, and indirect immunofluorescence for Chagas disease diagnosis, and individuals were evaluated for leishmaniasis by leishmanin skin test (LST). Approximately, 30% of the individuals were also analyzed by PCR (blood clot samples) for T. cruzi and for Leishmania spp. RESULTS: The 14.7% of the individuals were positive to Trypanosoma cruzi infection by serology, and 25.8% were positive to Leishmania spp. current or past infection by LST. Among the group with PCR results, 7.8% were positive for T. cruzi, and 9.4% for Leishmania spp. The coinfection T. cruzi/Leishmania spp. was 6.5%. The T. cruzi DTUs of the positive blood clot samples were TcI, revealed using the molecular markers: (i) intergenic region of the miniexon, (ii) D7 divergent domain of the 24Sα rDNA, (iii) size-variable domain of the 18S rDNA, and (iv) hsp60-PCR-RFLP (EcoRV). The Leishmania species identified were L. (Leishmania) mexicana and L. (Viannia) braziliensis. CONCLUSION: A high prevalence was found for T. cruzi and Leishmania spp. single and coinfections in almost all communities studied, being these results of relevance for the implementation of control programs in co-endemic areas.
Assuntos
Doença de Chagas , Coinfecção , Leishmania , Leishmaniose , População Rural , Trypanosoma cruzi , Humanos , Venezuela/epidemiologia , Doença de Chagas/epidemiologia , Doença de Chagas/parasitologia , Coinfecção/parasitologia , Coinfecção/epidemiologia , Leishmaniose/epidemiologia , Leishmaniose/parasitologia , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificação , Adulto , Adolescente , Masculino , Criança , Feminino , Pessoa de Meia-Idade , Adulto Jovem , Animais , Leishmania/genética , Leishmania/isolamento & purificação , Leishmania/classificação , Pré-Escolar , Zoonoses/parasitologia , Zoonoses/epidemiologia , Idoso , Reação em Cadeia da Polimerase , Anticorpos Antiprotozoários/sangue , Lactente , Ensaio de Imunoadsorção EnzimáticaRESUMO
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.
Assuntos
DNA Espaçador Ribossômico/genética , Insetos Vetores/parasitologia , Leishmania braziliensis/genética , Leishmania guyanensis/genética , Leishmania mexicana/genética , Leishmaniose Cutânea/parasitologia , Psychodidae/parasitologia , Animais , Cães , Feminino , Humanos , Leishmania braziliensis/isolamento & purificação , Leishmania guyanensis/isolamento & purificação , Leishmania mexicana/isolamento & purificação , Leishmaniose Cutânea/transmissão , Tipagem Molecular , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , VenezuelaRESUMO
American trypanosomiasis and leishmaniases are diseases caused by protozoans of the Trypanosomatidae family. In Venezuela, although several endemic foci of both diseases coincide, there are no reports of coinfection in mammals. The molecular diagnosis of the coinfection T. cruzi-Leishmania spp. was done in 527 blood samples collected on filter paper of several species of mammals (Canis familiaris, Equus asinus, Didelphis marsupialis, Equus mulus, Rattus rattus, Equus caballus, Artibeus fraterculus, Felis catus, Sus scrofa, Bos taurus, Capra hircus and Sciurus granatensis) from the states Cojedes, Aragua, Anzoátegui, Guárico, Miranda and Capital District. The T. cruzi infection was determined through PCR amplification of DNA of kinetoplast minicircles (kDNA) and satellite DNA (sDNA). The Leishmania spp. infection was detected by Leishmania nested PCR (Ln-PCR), and ribosomal DNA internal transcribed spacer 1 PCR (ITS1-PCR). The percentage of infection by T. cruzi was 23.5%, by Leishmania spp. 12.9% and coinfection was 5.7%. D. marsupialis was the species with the highest percentage of infection for each parasitosis (T. cruzi 34.3%, Leishmania spp. 20.0%) and coinfection (14.3%). Anzoátegui was the state with the highest percentage of infection for each parasitosis (T. cruzi 64.9%, Leishmania spp. 64.9%) and coinfection (43.2%). Infections were determined in species not reported as natural reservoirs of T. cruzi (E. asinus and E. mulus) and of Leishmania spp. (E. mulus and S. scrofa). Coinfection was a frequent phenomenon in mammals in several co-endemic zones evaluated.
Assuntos
Doença de Chagas/veterinária , Coinfecção/epidemiologia , Reservatórios de Doenças/veterinária , Leishmaniose/veterinária , Mamíferos/parasitologia , Animais , Animais Domésticos/parasitologia , Animais Selvagens/parasitologia , Doença de Chagas/diagnóstico , Doença de Chagas/epidemiologia , Coinfecção/parasitologia , Reservatórios de Doenças/parasitologia , Doenças Endêmicas , Leishmania/genética , Leishmania/isolamento & purificação , Leishmaniose/diagnóstico , Leishmaniose/epidemiologia , Trypanosoma cruzi/genética , Trypanosoma cruzi/isolamento & purificação , Venezuela/epidemiologiaRESUMO
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.
Assuntos
Humanos , Leishmania , Leishmania/parasitologia , Polimorfismo de Fragmento de Restrição , Reação em Cadeia da PolimeraseRESUMO
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.
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.
RESUMO
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.
Assuntos
Animais , Insetos Vetores/classificação , Psychodidae/classificação , Controle de Insetos , América Latina , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/transmissão , UrbanizaçãoRESUMO
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.
Assuntos
Insetos Vetores/classificação , Psychodidae/classificação , Animais , Controle de Insetos , América Latina , Leishmaniose Cutânea/transmissão , Leishmaniose Visceral/transmissão , UrbanizaçãoRESUMO
We evaluated the effects of
Assuntos
Animais , Feminino , Interações Hospedeiro-Parasita , Insetos Vetores/parasitologia , Leishmania/fisiologia , Psychodidae/parasitologia , Galinhas , Fertilidade/fisiologia , Insetos Vetores/fisiologia , Expectativa de Vida , Psychodidae/fisiologia , VenezuelaRESUMO
We evaluated the effects of Leishmaniaspp infection on several population parameters of Lutzomyia longipalpis sensu lato andLutzomyia 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 fourLeishmaniaspp 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 Leishmaniastrains 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.
Assuntos
Interações Hospedeiro-Parasita , Insetos Vetores/parasitologia , Leishmania/fisiologia , Psychodidae/parasitologia , Animais , Galinhas , Feminino , Fertilidade/fisiologia , Insetos Vetores/fisiologia , Expectativa de Vida , Psychodidae/fisiologia , VenezuelaRESUMO
BACKGROUND: Rhodnius prolixus is the main vector of Chagas disease in Venezuela. Here, domestic infestations of poor quality rural housing have persisted despite four decades of vector control. This is in contrast to the Southern Cone region of South America, where the main vector, Triatoma infestans, has been eliminated over large areas. The repeated colonisation of houses by silvatic populations of R. prolixus potentially explains the control difficulties. However, controversy surrounds the existence of silvatic R. prolixus: it has been suggested that all silvatic populations are in fact Rhodnius robustus, a related species of minor epidemiological importance. Here we investigate, by direct sequencing (mtcytb, D2) and by microsatellite analysis, 1) the identity of silvatic Rhodnius and 2) whether silvatic populations of Rhodnius are isolated from domestic populations. METHODS AND FINDINGS: Direct sequencing confirmed the presence of R. prolixus in palms and that silvatic bugs can colonise houses, with house and palm specimens sharing seven cytb haplotypes. Additionally, mitochondrial introgression was detected between R. robustus and R. prolixus, indicating a previous hybridisation event. The use of ten polymorphic microsatellite loci revealed a lack of genetic structure between silvatic and domestic ecotopes (non-significant F(ST) values), which is indicative of unrestricted gene flow. CONCLUSIONS: Our analyses demonstrate that silvatic R. prolixus presents an unquestionable threat to the control of Chagas disease in Venezuela. The design of improved control strategies is essential for successful long term control and could include modified spraying and surveillance practices, together with housing improvements.
Assuntos
Habitação , Insetos Vetores/fisiologia , Biologia Molecular/métodos , Rhodnius/fisiologia , Animais , Doença de Chagas/epidemiologia , Doença de Chagas/prevenção & controle , Feminino , Insetos Vetores/genética , Insetos Vetores/crescimento & desenvolvimento , Insetos Vetores/parasitologia , Masculino , Repetições de Microssatélites/genética , Rhodnius/genética , Rhodnius/crescimento & desenvolvimento , Rhodnius/parasitologia , Análise de Sequência de DNA , Venezuela/epidemiologiaRESUMO
Reportes recientes de infecciones humanas por Trypanosoma cruzi y casos agudos y crónicos de Enfermedad de Chagas en la región amazónica en países limítrofes, llaman a la reflexión acerca de la necesidad de una investigación sobre la posible presencia de infección/enfermedad en los habitantes de la región amazónica Venezolana. La abundancia de reservorios y vectores y nuevos factores de riesgo como la deforestación, minería, migración poblacional y nuevos asentamientos podrían favorecer en los momentos actuales la circulación del parásito. El entrenamiento y aprovechamiento del personal de Salud destacado en las Demarcaciones y las Redes de Ambulatorios en los Estados Amazonas y Bolívar para detectar infección a T. cruzi a todo febril que acuda a la consulta en esos centros, especialmente para diagnóstico de malaria, podría a corto plazo y a un costo reducido, proveer datos sobre la situación epidemiológica de la infección/enfermedad de Chagas en la región amazónica venezolana
Assuntos
Animais , Infecções , Trypanosoma cruzi , Vetores de DoençasRESUMO
Conocimientos, aptitudes y prácticas (CAP) hacia las enfermedades por parte de la población a riesgo, son variables importantes a investigar en los estudios previos a la aplicación de las medidas de control y la vigilancia epidemiológica. Dentro del marco de un estudio de seroprevalencia a Tripanosoma cruzi en dos estados de Venezuela con diferente historia de Programa de Control de la enfermedad de Chagas (PCECh), se obtuvo información sobre el conocimiento que tienen las personas sobre el vector y la enfermedad. Se encuestaron 1.236 jefes de familia en el Estado Barinas y 1.015 en el Estado Portuguesa. En el primer estado, el 48,7 por ciento vivía en ranchos adecuados para la colonización y el establecimiento del vector y el 51,3 por ciento en casas , mientras que en Portuguesa el 22,4 por ciento vivía en ranchos y el 77,6 por ciento en casas respectivamente. En el Estado Barinas, donde las actividades del PCECh se han llevado a cabo esporádicamente sólo en la última década, las personas conocen porque han visto más el vector dentro y alrededor de las viviendas, sin embargo no lo relacionan con, ni conocen la enfermedad. En cambio, en Portuguesa, donde el PCECh se ha llevado a cabo desde su inicio, a principio de los '60, las personas conocen menos al chipo probablemente porque haya sido más controlado, pero saben más sobre la enfermedad y han conocido más personas que la han padecido. Sin embargo, en ambos estados una gran proporción de las personas no contestó las preguntas. Esto indica la necesidad de implementar un sistema adecuado de Educación para el conocimiento y el desarrollo de aptitudes y prácticas en la población para la prevención y control de la enfermedad y evaluar su impacto en la vigilancia epidemiológica a través de la participación comunitaria, menos costosa y más sostenible