Surveillance for Leishmania asymptomatic infection in endemic foci of cutaneous leishmaniasis in Venezuela: a combination of leishmanin skin test and PCR using blood clots improves detection and enables identification of species.

BACKGROUND: Little is known about the prevalence of asymptomatic leishmaniasis in Venezuela. The objective of this study was to quantify Leishmania asymptomatic infection in six endemic foci of cutaneous leishmaniasis (CL) in Portuguesa State, Venezuela, where no previous data were available. METHODS: Study of the prevalence of Leishmania asymptomatic infection was carried out in 841 individuals from six endemic foci of CL in the municipalities Sucre and Ospino, Portuguesa State. We applied the leishmanin skin test (LST) and the internal transcribed spacer 1 (ITS1) PCR to DNA from sera and blood clots of all LST-positive and 20% of LST-negative patients. RESULTS: Of 841 inhabitants tested by LST, 197 returned a positive reaction (23.42%); all of the LST-positives (197) and 121 negatives were screened by nested PCR using serum and blood clots. Among the LST-positive group, 2.54% were PCR-positive with sera, while 44.67% were positive with blood clots. In the LST-negative group, PCR was positive in 2.48% of serum samples and in 38.84% of blood clots. CONCLUSIONS: It is recommended that LST and PCR on blood clots are used together to detect exposure and asymptomatic infection and for identification of the Leishmania species.

Seasonal changes of the diurnal variation of precipitation in the upper Río Chagres basin, Panamá.

This study elucidated the characteristics of climatological seasonal changes in the diurnal variations of precipitation at four ground stations in the upper Río Chagres basin in the Panama Canal watershed. The seasonal changes differed among the stations, although they are located within an area of only 414 km2. Precipitation peaks in the early afternoon at 1500 local standard time (LST) were observed at all the stations. At Chamon, monthly-mean hourly precipitation at every hour exceeded 0.3 mm h-1 throughout November and December. The occurrence of morning precipitation in January and March distinguished the seasonal precipitation pattern at Esperanza from the pattern at the other stations. Analyses of the seasonal changes in the diurnal variation with pattern correlations and rotational empirical orthogonal functions grouped the stations into two pairs: no morning peak at Chico and Río Piedras in the downstream basin and morning peak at Chamon and Esperanza in the upstream basin.

Leishmaniasis cutánea americana en Venezuela, bienio 2008-2009 / American cutaneous leishmaniasis in Venezuela, biennium 2008-2009

Se presenta el reporte epidemiológico de la Leishmaniasis Cutánea Americana (LCA) en Venezuela para los años 2008-2009. Se describen las características epidemiológicas generales, junto a algunos aspectos clínico-inmunológicos de sus diferentes formas clínicas. Esto se logro a través del análisis de la base de datos del registro nacional de leishmaniasis del Instituto de Biomedicina. La información fue analizada con Epi Info 3.5.1 y Excel. Un total de 4.640 casos de las diferentes formas clínicas de leishmaniasis cutánea fueron diagnosticados en el periodo 2008-2009, una media de 2.320 casos por año, con una tasa promedio anual de 8,25 por 100.000 habitantes. Predomina el sexo masculino con una razón de masculinidad de 1,84 para el periodo en estudio. Casos en todas las edades, con predominio numérico en el grupo de 5 a 34 años, edad promedio fue de 31,09 y 33,91 años para 2008 y 2009 respectivamente. En cuanto a la ocupación 22,39 % corresponde a personas del sector agropecuario, seguido de estudiantes con 20,88% de los casos. Se registraron casos en todas las entidades federales menos en Nueva Esparta, en este periodo los estados con mayor número de casos fueron, Lara con 910 (19,61%), Miranda con 650 (14,01%) y Táchira con 488 (10,52%). En cuanto a las formas clínicas se observó un predominio franco de la leishmaniasis cutánea localizada con 97,84% de los casos (4.540/4.640). Mientras que las formas localizadas están distribuidas por todo el territorio nacional, las formas difusas predominan en el estado Lara (63,64%, 7/11), las formas Mucosas en los estados Bolívar (21,74%, 10/46), Portuguesa (15,22%, 7/46) y Miranda, Táchira, Zulia (10,87%, 5/46 c/u) y finalmente las formas intermedias en los estados Monagas (30,23%, 13/43), Miranda (18,60%, 8/43) y Táchira (13,95%, 6/43). Las características clínicas e inmunológicas estudiadas variaron de acuerdo con las diferentes formas clínicas. En promedio más del 90 % (93,39 % en el 2008 y 89,81 % en el 2009) de los casos fueron diagnosticados con frotis directo. 88,86 % de los casos recibieron como tratamiento de primera elección inmunoterapia. En conclusión se hace una descripción clínico-epidemiológica de la LCA en Venezuela para el periodo 2008-2009 y se compara con el patrón descrito con anterioridad.

The epidemiological report of American Cutaneous Leishmaniasis (ACL) in Venezuela for the years 2008-2009 is presented. It describes the general epidemiological characteristics, together with some clinical and immunological aspects of its different clinical forms. This was performed by analyzing the database of the leishmaniasis national registry of the Instituto de Biomedicina. The data was analyzed using Epi Info 3.5.1 and Excel. A total of 4,640 cases of different clinical forms of cutaneous leishmaniasis were diagnosed during 2008-2009, i. e. 2,320 cases per year with an average annual rate of 8.25 per 100,000 inhabitants. It is predominant in males, with a sex ratio of 1.84 for the period under study. Cases in all ages, with numerical predominance in the group of 5 to 34 years, mean age were 31.09 and 33.91 years for 2008 and 2009 respectively. Regarding the occupation, 22.39% are people of the agricultural sector, followed by students with 20.88% of cases. Cases were recorded in all states but Nueva Esparta, the states with the largest number of cases were Lara with 910 (19.61%), Miranda 650 (14.01%) and Táchira with 488 (10.52%). In terms of clinical forms, clear predominance was observed of localized cutaneous leishmaniasis with 97.84 % (4,540) cases. While localized forms are distributed nationwide, diffuse forms predominate in the Lara State (63.64%, 7/11), muco-cutaneous forms predominate in the States of Bolivar (21.74%, 10/46), Portuguesa (15.22%, 7/46) and Miranda, Táchira, Zulia (10.87%, 5/46 each one) and finally, the intermediate forms in the States of Monagas (30.23%, 13/43), Miranda (18.60%, 8/43) and Táchira (13.95%, 6/43). The clinical and immunological characteristics studied varied according to the different clinical forms. In average, more than 90% (93.39% in 2008 and 89.81% in 2009) of the cases were diagnosed with direct smear. 88.86% of the patients received immunotherapy as first choice treatment. In conclusion, a clinical-epidemiological description of the ACL in Venezuela for the period 2008-2009 was made and compared with the pattern previously described.

Inmunoterapia de la leishmaniasis cutánea: factores que influencian su efectividad / Immunotherapy of cutaneous leishmaniasis: factors that influence their effectiveness

En Venezuela se utiliza la inmunoterapia por su bondad terapéutica y operacional en el tratamiento de la leishmaniasis cutánea y se aprecian diferencias de su efectividad entre los servicios locales de salud que la emplean. En el estado Mérida, donde se tiene un bajo nivel de falla terapéutica, se desconocen los factores de riesgo ó de protección que la determinan. Por ello se planteó realizar un estudio epidemiológico de casos y controles para evaluar los factores individuales demográficos, clínicos, inmunológicos y adherencia terapéutica que influyen en dicha efectividad. El ajuste con regresión logística determinó según definición: a) Demográfica: como riesgo las edades extremas, tabaquismo y de oficio doméstico, con protección en el alfabeto educativamente, b) Clínica: como riesgo la forma intermedia, cinco o más lesiones, infección secundaria y ubicación en pié, con protección en la forma localizada y tamaño menor a 60 mm, c) Inmunológica: de riesgo las bajas respuestas a leishmánina y PPD, d) Adherencia terapéutica: son riesgo la aplicación tópica y aseo local inadecuados. Se concluye, hay factores de riesgo y protección que modelan la eficacia de la inmunoterapia, lo que en consecuencia demanda una dinámica vigilancia clínico-epidemiológica para potenciar dicha terapéutica.

Immunotherapy is used in Venezuela as treatment of cutaneous leishmaniasis and there are differences among the health services that use it. In Merida State there are a low proportion of failures, but the factors that are related to this failure are unknown. A case-control study was planned to evaluate the demographics, clinical, immunological factors and the treatment compliance that can be related to the effectiveness. Logistic regression showed that the factors related to failure were: a) demographics: lower and older ages, smoking, domestic labor and illiteracy; b) clinical: intermediate leishmaniasis, five or more lesions, aggregated infection, lesions in feet, and lesion size above 60 mm; c) Immunology: low reactivity to Montenegro and tuberculin tests; d) treatment compliance: use of incorrect topical substances and inadequate cleaning of ulcer. As a conclusion, there are several factors that influence treatment response, that require clinical and epidemiological surveillance to increase the effect of therapy.

Leishmaniasis cutánea americana en Venezuela: un análisis clínico epidemiológico a nivel nacional y por entidad federal, 1988-2007 / American cutaneous leishmaniasis in Venezuela: a clinical and epidemiological analysis at a national level and by federal entity, 1988-2007

Se describen las características epidemiológicas generales, junto a algunos aspectos clínico-inmunológicos, de las diferentes formas clínicas de leishmaniasis cutánea en Venezuela. Esto se logró a través de un estudio descriptivo retrospectivo de la base de datos del registro nacional de leishmaniasis en el Instituto de Biomedicina. La información fue analizada con EpiInfo 3.5.1, SPSS 11.0 y Excel. 47.762 casos de las diferentes formas clínicas de leishmaniasis cutánea fueron diagnosticados en el periodo 1988-2007, esto es 2.388 casos por año, con una tasa promedio anual de 10,5 por 100.000 habitantes. Predomina en sexo masculino con una razón de masculinidad que oscila entre 1,2 y 1,8. Casos en todas las edades, con predominio en el grupo de 15 a 24 años, edad promedio de 28 años. En cuanto a la ocupación 24,58 % corresponde a personas del sector agropecuario, seguido de estudiantes (21,40%) y Oficios del Hogar (18,47%). Se han registrado casos en todas las entidades federales, observándose regiones como los estados andinos (Trujillo y Mérida) con tasas superiores a 30 por 100.000 habitantes. La distribución según forma clínica fue: 97,94% (46.778) leishmaniasis cutánea localizada; 0,72% (346) leishmaniasis cutánea intermedia; 1,11% (531) leishmaniasis cutánea mucosa y 0,22% (107) leishmaniasis cutánea difusa. Las características clínicas e inmunológicas estudiadas variaron de acuerdo con las diferentes formas clínicas descritas. En conclusión, se hace una descripción clínico-epidemiológica de la leishmaniasis cutánea americana en Venezuela en base a los datos del registro de casos del Programa Nacional de Control de la Leishmaniasis. Esto sirve de apoyo al desarrollo de futuras investigaciones y para la mejora del propio registro con los consecuentes beneficios que ello puede traer al programa de control.

The general epidemiological characteristics are described, together with some clinical and immunological aspects of the different clinical forms of cutaneous leishmaniasis in Venezuela. This was accomplished through a descriptive retrospective study of the leishmaniasis national registry database of the Institute of Biomedicine. The information was analyzed with EpiInfo 3.5.1, SPSS 11.0 and Excel. 47,762 cases of different clinical forms of cutaneous leishmaniasis were diagnosed during the period 1988-2007, i.e. 2,388 cases per year, with an average annual rate of 10.5 per 100,000 inhabitants. It is predominant in males, with a sex ratio of between 1.2 and 1.8. There are cases in all ages, with predominance in the 15 to 24 years group, average age 28 years. In terms of occupation, 24.58% are people of the agricultural sector, followed by students (21.40%) and housewives (18.47%). Cases have been registered in all the federal entities, observing regions such as the Andean States (Trujillo and Merida) with rates above 30 per 100,000 inhabitants. Distribution according to clinical form was: 97.94% (46,778) localized cutaneous leishmaniasis; 0.72% (346) intermediate cutaneous leishmaniasis, 1.11% (531) mucocutaneous leishmaniasis and 0.22% (107) diffused cutaneous leishmaniasis. The clinical and immunological characteristics examined varied according to the different clinical forms described. In conclusion, a clinical and epidemiological description is made of the American cutaneous leishmaniasis in Venezuela, based on the data of the register of cases of the Leishmaniasis Control National Program. This serves to support the development of future research and improve the register with the consequent benefits is can bring to the control program.

Isolation and molecular identification of Leishmania chagasi from a bat (Carollia perspicillata) in northeastern Venezuela.

This report describes the isolation of a Leishmania chagasi strain from a bat (Carollia perspicillata), and its identification using biological methods and molecular characterization. The parasites were isolated in an artificial culture medium from a blood sample extracted from a bat heart. The isolate was then inoculated into the footpads of Balb/c mice, which subsequently developed a typical nodular leishmanial lesion; the parasites were confirmed as Leishmania by smear and histopathology. Molecular characterization of the parasites was performed by polymerase chain reaction with species-specific primers, kDNA restriction pattern following Hae III endonuclease digestion and dot blot hybridization using a kDNA probe. This report demonstrates that bats can be hosts for L. chagasi species and suggests the need for studies to determine whether they may be involved in foci of visceral leishmaniasis.

[Trypanosomatidae of public health importance occurring in wild and synanthropic animals of rural Venezuela]. / Trypanosomatidae de importancia en salud pública en animales silvestres y sinantrópicos en un area rural del municipio Tovar del estado Mérida, Venezuela.

INTRODUCTION: Chagas disease and leishmaniasis are important public health problems due to their high frequency and broad distribution in Latin America. Understanding of the roles of reservoir animals is crucial for a global assessment of the epidemiology of these diseases. OBJECTIVE: To identify parasites classed as Trypanosomatidae as they occurred in sylvatic animals, and to establish rates of coinfection. MATERIALS AND METHODS: Sylvatic animals were systematically captured in the rural area of El Carrizal, Merida State, Venezuela, betweenJuly, 1998 and February, 2000. The captures were made in Tomahawk type homemade traps, placed 15 nights per month throughout the study period. Blood was extracted from each captured and anesthetized animal by means of cardiac puncture. The search for trypanosomatids was undertaken by fresh blood examination, Giemsa stained blood smears and by means of blood-agar culture. Occasional xenodiagnoses were made to check diagnostic accuracy. The isolates obtained in culture media were identified by restriction fragment analysis and hybridization with specific probes. RESULTS: Three species of sylvatic animals (n = 215) were captured: Rattus spp. (135), Sigmodon hispidus (73) and Didelphis marsupialis (7). From them, three species of Trypanosomatidae were identified: Leishmania (Viannia) guyanensis, Trypanosoma cruzi and Trypanosoma lewisi. Trypanosoma. cruzi was identified in D. marsupialis (4/7), S. hispidus (1/73) and Rattus spp. (1/ 135), whereas L. (V.) guyanensis and T. lewisi were identified only in Rattus spp., 1/135 and 12/ 135, respectively. CONCLUSIONS: The coexistence of these genetically related hemoflagellates in sylvatic hosts was important for understanding the immunological interactions that may be established in reservoir animals, and the possible implications that this may have for the susceptible host. Finally, the identification of L. (V.) guyanensis in Rattus spp and T. cruzi in S. hispidus constituted the first reports of this relationship in Venezuela.

Trypanosomatidae de importancia en salud pública en animales silvestres y sinantrópicos en un área rural del municipio Tovar del estado Mérida, Venezuela / Trypanosomatidae of public health importance occurring in wild and synanthropic animals of rural Venezuela

Introducción. La enfermedad de Chagas y la leishmaniasis son patologías de gran importancia en salud pública debido a su alta frecuencia y amplia distribución en América Latina. El estudio de los animales reservorios es vital para una comprensión global de estas enfermedades. Objetivo. En el presente trabajo nos propusimos identificar parásitos de la familia Trypanosomatidae en animales silvestres con la finalidad de establecer posibles relaciones debidas a la coinfección. Materiales y métodos. En El Carrizal, un área rural del estado Mérida, Venezuela, entre julio de 1998 y febrero de 2000 se realizaron capturas sistemáticas de animales silvestres con la finalidad de poner en evidencia la presencia de parásitos pertenecientes a la familia Trypanosomatidae. Las capturas fueron realizadas con trampas caseras tipo Tomahawk, colocadas 15 noches por mes durante el periodo del estudio. A los animales capturados se les practicó punción cardiaca bajo anestesia para extracción de sangre con la cual se realizaron los siguientes estudios: examen en fresco, extendido para coloración con Giemsa y cultivo en agar-sangre. Se realizaron algunos xenodiagnósticos. Los aislamientos obtenidos por medio de cultivo se identificaron por medio de análisis de restricción e hibridación con sondas específicas. Resultados. Se capturaron y estudiaron 215 animales pertenecientes a tres especies: Rattus spp. (135), Sigmodon hispidus (73) y Didelphis marsupialis (7). Igualmente, se identificaron tres especies de Trypanosomatidae: Leishmania (V) guyanensis, Trypanosoma cruzi y Trypanosoma lewisi. Mientras T. cruzi fue identificado en D. marsupialis (4/7), S. hispidus(1/73) y Rattus spp. (1/135), L.(V) guyanensis y T. lewisi sólo se identificaron en Rattus spp. (1/135 y 12/135, respectivamente). Conclusión. El estudio de la coexistencia de estas diferentes especies de flagelados genéticamente relacionados nos parece de importancia por las interacciones inmunológicas que se pueden establecer en los animales reservorios y las posibles implicaciones que esto puede tener en el huésped susceptible. Finalmente, las identificaciones de L.(V) guyanensis y T. cruzi en Rattus spp. y S. hispidus, respectivamente, son las primeras reportadas en Venezuela.

Molecular epidemiology of cutaneous leishmaniasis in Venezuela.

This paper discusses the utility of a set of primers (3J1, 3J2) designed from a repetitive nuclear deoxyribonucleic acid sequence for the diagnosis of Leishmania braziliensis infection in samples obtained from humans, insect vectors and mammalian reservoir hosts from different endemic areas in Venezuela. A high incidence of Leishmania (Viannia) braziliensis infection was found in the endemic areas studied. The sensitivity and specificity of the primers used were adequate for the identification of the natural vectors and reservoir hosts of L. (V.) braziliensis. The polymerase chain reaction was more sensitive than culture and stained smear examination in the diagnosis of cutaneous leishmaniasis, detecting 80% of cases compared to 42% and 72%, respectively.

Cotton rats (Sigmodon hispidus) and black rats (Rattus rattus) as possible reservoirs of Leishmania spp. in Lara State, Venezuela.

A total of 519 wild animals belonging to eleven species were collected during a two year study in a cutaneous leishmaniasis endemic area in Venezuela (La Matica, Lara State). The animals were captured in home-made Tomahawk-like traps baited with maize, bananas or other available local fruits, and parasites were isolated from 27 specimens. Two different species were found naturally infected with flagellates, i.e., cotton rats (Sigmodon hispidus) and black rats (Rattus rattus). Characterization of the parasites using PCR, kDNA restriction pattern and hybridization with species-specific probes revealed the presence of Leishmania (L.) mexicana in three of the black rats and Leishmania (V.) braziliensis in two others. The latter species was also identified in the single positive specimen of S. hispidus. The results suggested both species of animals as possible reservoirs of Leishmania sp.

Cotton rats (Sigmodon hispidus) and black rats (Rattus rattus) as possible reservoirs of Leishmania spp. in Lara State, Venezuela

A total of 519 wild animals belonging to eleven species were collected during a two year study in a cutaneous leishmaniasis endemic area in Venezuela (La Matica, Lara State). The animals were captured in home-made Tomahawk-like traps baited with maize, bananas or other available local fruits, and parasites were isolated from 27 specimens. Two different species were found naturally infected with flagellates, i.e., cotton rats (Sigmodon hispidus) and black rats (Rattus rattus). Characterization of the parasites using PCR, kDNA restriction pattern and hybridization with species-specific probes revealed the presence of Leishmania (L.) mexicana in three of the black rats and Leishmania (V.) braziliensis in two others. The latter species was also identified in the single positive specimen of S. hispidus. The results suggested both species of animals as possible reservoirs of Leishmania sp

Desarrollo de inmunoterapia de la leishmaniasis cutánea americana en el Instituto de Biomedicina / The development of inmunotherapy of american cutaneous leishmaniasis at the Instituto de Biomedicina

El desarrollo de la inmunoterapia de la leishmaniasis cutánea americana en el Instituto de Biomedicina, fue un proceso complejo de más de dos décadas que involucró diversas disciplinas. Un aspecto importante fue la comparación de la leishmaniasis cutánea difusa con otras formas clínicas. Este estudio comparativo constituyó la base para proponer un espectro para la leishmaniasis cutánea americana, que se presentó en el Simposium CIBA 20 en 1974. Otra etapa importante fue el estudio de la prueba de competencia, respuesta macrofágica del enfermo de leishmaniasis cutánea difusa a la inyección intradérmica de una suspensión de promastigotes de cultivo de Lishmania. Comparando esta respuesta con la respuesta de estos mismos enfermos a la inyección intradérmica de bacilos de Calmette-Guerin pudimos demostrar que al mezclar ambos antígenos (promastigotes de Leishmania con bacilos de Calmette-Guerin) en una prueba intradérmica, se obtenía un nódulo de estructura tuberculoide con desaparición de los parásitos inoculados; esto sugirió una vacuna combinada para inmunoterapia de leishmaniasis. Esta vacuan fue estudiada en 217 pacientes con leishmaniasis cutánea localizada, en una experiencia doble ciego al azar, en el que se estudió comparativamente la inmunoterapia con quimioterapia, con meglumine antimoniato y con basilos de Calmette-Guerin solos. Los resultados demostraron que no había diferencias estadísticamente significativas entre el tratamiento con inmunoterapia o quimioterapia