Genetic diversity of Aedes aegypti in the central-upper Paraná Cross-Border axis in Paraguay. / Diversidad genética de aedes aegypti en el eje transfronterizo Central-Alto Paraná en Paraguay.

OBJECTIVE: To determine the genetic diversity of Aedes aegypti in the Central-Alto Paraná cross-border road corridor of Paraguay, an area that has reports of dengue cases. MATERIALS AND METHODS: Twenty adult females were selected from hatching Ae. aegypti eggs from households geolocated in the departments of Alto Paraná, Caaguazú, Cordillera and Central, between 2018 and 2019. DNA was extracted from the tissue of females for amplifying their polymorphic patterns by random amplification of polymorphic DNA by PCR (RAPD-PCR), using primers H3 and B03 in order to identify genetic parameters of population diversity. The relationships between mosquito populations according to locality were observed by unpaired arithmetic mean analysis. We used DIVA-GIS 7.3.0 and MAXENT to analyze the suitable areas of actual and potential geographic distribution of these Ae. aegypti populations. RESULTS: Forty loci were identified by RAPD-PCR profiling, with moderate gene differentiation (Gst = 0.12). The cross-border corridor presented bioclimatic conditions for the presence of variant populations of Ae. aegypti, with precipitation in the warmest quarter and mean temperature in the driest quarter being determinant in the distribution. CONCLUSIONS: There is evidence of moderate genetic diversity in Ae. aegypti populations from areas that have reported dengue cases in the cross-border road corridor linking the Central and Alto Paraná departments of Paraguay. The study of genetic variability of Ae. aegypti is very useful for entomo-epidemiological surveillance and evaluation of possible resistance to chemical control.

OBJETIVOS: Conocer la diversidad genética de Aedes aegypti en el corredor vial transfronterizo Central-Alto Paraná de Paraguay, con registros de casos de dengue. MATERIALES Y MÉTODOS: Se seleccionaron veinte hembras adultas de la eclosión de huevos de Ae. aegypti procedentes de casas geolocalizadas en los departamentos de Alto Paraná, Caaguazú, Cordillera y Central, entre el 2018 y 2019. Se extrajo ADN del tejido de las hembras para amplificación aleatoria de sus patrones polimórficos mediante amplificación aleatoria del ADN polimórfico por PCR (RAPD-PCR), usando cebadores H3 y B03 a fin de conocer parámetros genéticos de diversidad poblacional. Las relaciones entre las poblaciones de mosquitos según la localidad fueron visualizadas mediante análisis no apareado de la media aritmética. Las áreas idóneas de distribución geográfica real y potencial de estas poblaciones de Ae. aegypti fueron analizadas mediante DIVA-GIS 7.3.0 y MAXENT. RESULTADOS: Se identificaron 40 loci mediante perfiles RAPD-PCR, con diferenciación génica moderada (Gst = 0,12). El corredor transfronterizo presentó condiciones bioclimáticas para la presencia de poblaciones variantes de Ae. aegypti, siendo determinantes en la distribución la precipitación del trimestre más cálido y la temperatura media del trimestre más seco. CONCLUSIONES: Se evidencia que existe diversidad genética moderada en las poblaciones de Ae. aegypti procedentes de zonas con registros de casos de dengue ubicadas en el corredor vial transfronterizo que une los departamentos Central y Alto Paraná de Paraguay. El estudio de variabilidad genética de Ae. aegypti es de gran utilidad para la vigilancia entomoepidemiológica y evaluación de posibles eventos de resistencia al control químico.

Características clínico-epidemiológicas de pacientes coinfectados con el virus de inmunodeficiencia humana y leishmaniasis visceral que acuden al Instituto de Medicina Tropical, durante los años 2016 al 2020

RESUMEN La coinfección por leishmaniasis visceral y VIH es una preocupación mundial debido al ascenso progresivo en los últimos años, en varias regiones del mundo. La progresión de ambas enfermedades conducen al deterioro del sistema inmune, y como resultado, al fracaso terapéutico. El presunto estudio tiene como objetivo describir las características clínico-epidemiológicas de pacientes coinfectados con el virus de inmunodeficiencia humana y leishmaniasis visceral que acuden al Instituto de Medicina Tropical, en el periodo del 2016 al 2020. Es un estudio observacional, descriptivo, de corte transversal, utilizando registros médicos de pacientes con el diagnóstico de leishmaniasis visceral y VIH. Se incluyeron 51 pacientes coinfectados, entre 19 y 65 años, 42 del sexo masculino (82,3 %); 37 procedentes del área Central. Los hallazgos clínicos mas frecuentes fueron el decaimiento del estado general y la fiebre. La mayoría de los pacientes tuvieron un recuento bajo de linfocitos tCD4 y valores elevados de carga viral de VIH. Nuestro trabajo contribuye a conocer el perfil epidemiológico de pacientes coinfectados para mejorar el diagnóstico temprano y consecuentemente el tratamiento médico precoz.

ABSTRACT Co-infection by visceral leishmaniasis and HIV is a global concern due to the progressive rise in recent years, in various regions of the world. The progression of both diseases leads to the deterioration of the immune system, and as a result, to therapeutic failure. The presumed study aims to describe the clinical-epidemiological characteristics of patients co-infected with the human immunodeficiency virus and visceral leishmaniasis who attend the Institute of Tropical Medicine, in the period from 2016 to 2020. It is an observational, descriptive, cross-sectional study, using medical records of patients diagnosed with visceral leishmaniasis and HIV. 51 coinfected patients were included, between 19 and 65 years old, 42 male (82.3%); 37 from the Central area. The most frequent clinical findings were a weakness and fever. Most of the patients had a low tCD4 lymphocyte count and high HIV viral load values. Our study contributes to knowing the epidemiological profile of coinfected patients to improve early diagnosis and consequently early medical treatment.

Diversidad genética de aedes aegypti en el eje transfronterizo Central-Alto Paraná en Paraguay / Genetic diversity of Aedes aegypti in the central-upper Paraná Cross-Border axis in Paraguay

RESUMEN Objetivos: Conocer la diversidad genética de Aedes aegypti en el corredor vial transfronterizo Central-Alto Paraná de Paraguay, con registros de casos de dengue. Materiales y métodos: Se seleccionaron veinte hembras adultas de la eclosión de huevos de Ae. aegypti procedentes de casas geolocalizadas en los departamentos de Alto Paraná, Caaguazú, Cordillera y Central, entre el 2018 y 2019. Se extrajo ADN del tejido de las hembras para amplificación aleatoria de sus patrones polimórficos mediante amplificación aleatoria del ADN polimórfico por PCR (RAPD-PCR), usando cebadores H3 y B03 a fin de conocer parámetros genéticos de diversidad poblacional. Las relaciones entre las poblaciones de mosquitos según la localidad fueron visualizadas mediante análisis no apareado de la media aritmética. Las áreas idóneas de distribución geográfica real y potencial de estas poblaciones de Ae. aegypti fueron analizadas mediante DIVA-GIS 7.3.0 y MAXENT. Resultados: Se identificaron 40 loci mediante perfiles RAPD-PCR, con diferenciación génica moderada (Gst = 0,12). El corredor transfronterizo presentó condiciones bioclimáticas para la presencia de poblaciones variantes de Ae. aegypti, siendo determinantes en la distribución la precipitación del trimestre más cálido y la temperatura media del trimestre más seco. Conclusiones: Se evidencia que existe diversidad genética moderada en las poblaciones de Ae. aegypti procedentes de zonas con registros de casos de dengue ubicadas en el corredor vial transfronterizo que une los departamentos Central y Alto Paraná de Paraguay. El estudio de variabilidad genética de Ae. aegypti es de gran utilidad para la vigilancia entomoepidemiológica y evaluación de posibles eventos de resistencia al control químico.

ABSTRACT Objective: To determine the genetic diversity of Aedes aegypti in the Central-Alto Paraná cross-border road corridor of Paraguay, an area that has reports of dengue cases. Materials and methods: Twenty adult females were selected from hatching Ae. aegypti eggs from households geolocated in the departments of Alto Paraná, Caaguazú, Cordillera and Central, between 2018 and 2019. DNA was extracted from the tissue of females for amplifying their polymorphic patterns by random amplification of polymorphic DNA by PCR (RAPD-PCR), using primers H3 and B03 in order to identify genetic parameters of population diversity. The relationships between mosquito populations according to locality were observed by unpaired arithmetic mean analysis. We used DIVA-GIS 7.3.0 and MAXENT to analyze the suitable areas of actual and potential geographic distribution of these Ae. aegypti populations. Results: Forty loci were identified by RAPD-PCR profiling, with moderate gene differentiation (Gst = 0.12). The cross-border corridor presented bioclimatic conditions for the presence of variant populations of Ae. aegypti, with precipitation in the warmest quarter and mean temperature in the driest quarter being determinant in the distribution. Conclusions: There is evidence of moderate genetic diversity in Ae. aegypti populations from areas that have reported dengue cases in the cross-border road corridor linking the Central and Alto Paraná departments of Paraguay. The study of genetic variability of Ae. aegypti is very useful for entomo-epidemiological surveillance and evaluation of possible resistance to chemical control.

Susceptibilidad a deltametrina de Aedes (Stegomyia) aegypti (Linnaeus 1676) (Diptera: Culicidae) y determinación de áreas de influencia para su presencia en un municipio del Departamento Central, Paraguay / Susceptibility to deltametrin of Aedes (Stegomyia) aegypti(Linnaeus 1676) (Diptera: Culicidae) and determination from areas of influence for its presence in a municipality of the Centraldepartment, Paraguay

RESUMEN Introducción. Paraguay es un país endémico para el dengue y la intervención primaria para esta arbovirosis es el control químico de su vector Aedes aegypti, siendo necesario estudiar su resistencia frente a insecticidas utilizados para el control y conocer su sostenibilidad en espacio y tiempo. Objetivo. Determinar la susceptibilidad de poblaciones silvestres de Ae. aegypti procedentes de Villa Elisa-Central, frente al adulticida deltametrina y conocer el área potencial de distribución de estas poblacionesresistentes/susceptibles. Metodología. Se utilizaron mosquitos Ae. aegypti adultos de la Filial 1 obtenidos de ovitrampas colocadas en viviendas geo-localizadas entre diciembre 2017-marzo 2018. Las hembras resultantes de la cría en condiciones ad hoc en laboratorio fueron expuestas a concentraciones crecientes del insecticida. La distribución real de las poblaciones de mosquitos y su área de influencia, fueron modeladas mediante DIVA-GIS. Resultados. La mortalidad promedio observada para cada dosis de deltametrina fue: 5,3% para (0,03%); 47,4% para (0,15%) y 61,2% para (0,3). Se observó áreas de influencia para la presencia de Ae. aegypti. Conclusión. los valores correspondientes a la mortalidad resultaron inferiores al 98%, lo cual fue indicativo de resistencia a dosis diagnóstica. El modelo de distribución geográfica de la población evaluada demostró la existencia de áreas idóneas con condiciones bioclimáticas óptimas (niveles de precipitación, temperatura y humedad), propicias para la aparición de reservorios de agua y presencia del vector, tanto en Villa Elisa, como en los distritos localizados en la periferia tales como San Lorenzo, Lambaré, Ñemby, San Antonio y Fernando de la Mora.

ABSTRACT Introduction. Paraguay is an endemic country for dengue and the primary intervention for this arbovirus is the chemical control of its vector Aedes aegypti, being necessary to study its resistance against insecticides used for control and to know its sustainability in space and time. Objective. To determine the susceptibility of wild populations of Ae. aegypti from Villa Elisa-Central, against the adulticide deltamethrin and to know the potential area of ​​distribution of these resistant/susceptible populations. Methodology. Mosquitoes Ae. aegypti adults from Filial 1 obtained from ovitraps placed in geo-located dwellings between December 2017 and March 2018. The females resulting from rearing under ad hoc conditions in the laboratory were exposed to increasing concentrations of the insecticide. The actual distribution of mosquito populations and their area of ​​influence were modeled using DIVA-GIS. Results. The average mortality observed for each dose of deltamethrin was: 5.3% for (0.03%); 47.4% for (0.15%) and 61.2% for (0.3). Areas of influence were observed for the presence of Ae. aegypti. Conclusion. The values ​​corresponding to mortality were lower than 98%, which was indicative of resistance to diagnostic dose. The geographic distribution model of the evaluated population demonstrated the existence of suitable areas with optimal bioclimatic conditions (levels of precipitation, temperature and humidity), conducive to the appearance of water reservoirs and the presence of the vector, both in Villa Elisa and in the districts located on the outskirts such as San Lorenzo, Lambaré, Ñemby, San Antonio and Fernando de la Mora.

Características clínico-epidemiológicas de leishmaniasis visceral canina en un área endémica de Paraguay / Clinical-epidemiological characteristics of visceral leishmaniasis in dogs from an endemic area in Paraguay

RESUMEN Objetivo Describir las características clínico-epidemiológicas asociadas a la transmisión de leishmaniosis visceral canina en un área endémica del departamento de Caaguazú, Paraguay. Materiales y Métodos El estudio fue descriptivo observacional, de corte transversal. Se evaluaron 324 caninos seleccionados de 110 viviendas. Se realizó el examen clínico; se obtuvo aspirado de ganglio para el examen directo y muestra de sangre para la posterior detección de anticuerpos anti-Leishmania revelados en tiras inmunocromatográfias. Resultados El 4,9% de la población canina dio positivo con antígeno recombinante rK39. Por la técnica de tinción con Giemsa, se obtuvo 4,3% de canes positivos, de los cuales 37,5% presentaron signos clínicos evidentes. Los signos más frecuentes encontrados en los perros infectados fueron adelgazamiento, onicogrifosis y alopecia (25%). La seroprevalencia fue mayor en perros entre 2 y 4 años de raza mestiza. Conclusiones Los signos clínicos presentes confirmaron la infección parasitaria y el hallazgo indica el rol de los caninos en la epidemiologia de la leishmaniosis en Caaguazú, así como el riesgo que representan para la transmisión. Los resultados obtenidos podrían ayudar a formular un sistema de monitoreo y contribuir con la vigilancia de la leishmaniosis canina en la zona.

ABSTRACT Objective To describe the clinical-epidemiological characteristics associated with the transmission of visceral leishmaniasis in dogs in an endemic area from Caaguazú department, Paraguay. Materials and Methods Cross-sectional study that included 324 dogs from 110 houses. Clinical examination was performed; ganglion aspirate was obtained for direct exa-mination and blood sample for further detection of anti-Leishmania antibodies by rk39 recombinant antigen immunochromatographic strips. Results 4.9% of the canine population resulted positive for rk39 recombinant antigen. By the Giemsa staining technique, 4.3% of positive dogs were obtained, of which 37.5% presented evident clinical signs. The most frequent signs found in infected dogs were thinning, onychogryphosis and alopecia (25%). Seroprevalence was higher in mixed breed dogs between 2 and 4 years old. Conclusion The clinical signs confirmed the parasitic infection, and the finding indicates the role of canines in the epidemiology of leishmaniasis in Caaguazú as well as the risk that they represent for transmission. These results may help to formulate a monitoring system and contribute to the surveillance of canine leishmaniasis in the zone.

Chagas Disease Vectors of Paraguay: Entomoepidemiological Aspects of Triatoma sordida (Stål, 1859) and Development of an Identification Key for Paraguayan Triatomines Based on Cytogenetics Data.

Approximately 150,000 people are living with Chagas disease in Paraguay. Although the country has been since 2008 considered as one of the countries that succeeded in interrupted the vector transmission of Chagas by Triatoma infestans in houses of the eastern region, there are nine other species notified in the country that are potential vectors and also deserve attention from vector control programs. Thus, we carried out an entomoepidemiological study of T. sordida in the eastern and western regions of the country and we developed an identification key for Paraguay's triatomines based on cytogenetic data. Between the years 2003 to 2004, 271 specimens of T. sordida were captured in domestic, peridomestic, and wild ecotopes, with 131 insects caught in the eastern (Alto Paraguay, Boquerón and Pte. Hayes) and 140 in the western region of Paraguay (Guairá and Paraguarí). High rates of peridomicillary infestation were observed for both regions. Besides that, the natural infection of the captured insects was detected by optical microscopy in 12% and 10%, and by PCR in 21% and 20% in the eastern and western regions, respectively. Based on cytogenetic data from nine of ten species notified in Paraguay, an identification key was developed to differentiate all taxa. Thus, given the vectorial importance of T. sordida, we highlight the need for continued attention from Paraguay's vector control programs for this species. Further, we provide a taxonomic key that assists in the correct classification of Paraguayan triatomines.

Parasitosis intestinales en niños de edad escolar de una institución educativa de Fernando de la Mora, Paraguay / Intestinal parasites in school - age children of an educational institution in Fernando de la Mora, Paraguay

La infección intestinal parasitaria afecta principalmente a la población infantil y constituye una de las enfermedades de mayor prevalencia en las comunidades empobrecidas de los países en desarrollo. El objetivo del trabajo fue determinar la prevalencia de parásitos intestinales en niños de edad escolar de una institución educativa del municipio de Fernando de la Mora. Se realizó un estudio observacional, descriptivo de corte transversal, de abril a julio del 2017. Se procesaron muestras fecales de40 niños de 6 a 11 años de edad, procedentes de una escuela pública de la zona sur de Fernando de la Mora. Las muestras obtenidas se fijaron en formol 10%, transportadas y procesadas mediante examen directo y por el método de Ritchie en el laboratorio de Microbiología de la carrera de Biología de la UNA. Se empleó el análisis univariado para calcular frecuencias y para determinar asociaciones entre variables el análisis bivariado prueba de Chi2. La prevalencia fue del 27% y se encontró infección por cinco especies de parásitos. Los parásitos encontrados fueron; Blastocystis hominis (18%), Giardia lamblia (10%), Chilomastix mesnili (10%), Balantidium coli (5%) y huevos de Ascaris lumbricoides (10%). Predominó el multiparasitismo (18%) y se encontró asociación significativa entre el nivel de grado escolar y la infección parasitaria (p=0,04). Se demostró la alta prevalencia de infección parasitaria para el grupo de niños escolares que participaron del estudio. Los resultados reafirman la importancia del constante seguimiento y control de las parasitosis a nivel local y nacional.

Parasitic intestinal infection mainly affects children and is one of the most prevalent diseases in impoverished communities in developing countries. The objective of the work was to determine the prevalence of intestinal parasites in school-age children from an educational institution in the municipality of Fernando de la Mora. An observational, descriptive cross-sectional study was carried out during the period from April to July 2017. Fecal samples from 40 children between 6 and 11 years old, from a public school in Fernando de la Mora, were processed. The obtained samples were fixed in 10% formalin, transported and processed by direct examination and by the Ritchie method in the Microbiology laboratory of the Biology degree program at UNA. Univariate analysis was used to calculate frequencies and bivariate by Chi 2 test to determine associations between variables. The prevalence was 27% and infection was determined by five species of parasites. The high prevalence of parasitic infection was demonstrated for the group of school children who participated in the study. The parasites found were; Blastocystis hominis (18%), Giardia lamblia (10%), Chilomastix mesnili (10%), Balantidium coli (5%) and Ascaris lumbricoides eggs (10%). Multiparasitism predominated (18%) and a significant association was found between grade level and parasitic infection (p = 0.04). The results reaffirm the importance of constant monitoring and control of parasites at the local and national level.

Dispersion of Leishmania (Leishmania) infantum in central-southern Brazil: Evidence from an integrative approach.

Leishmania (Leishmania) infantum is the zoonotic agent of visceral leishmaniasis (VL), a disease with a global distribution. The transmission scenario of VL has been undergoing changes worldwide, with the biologic cycle invading urbanized areas and dispersing the parasites into other previously free areas. The epidemiological cycle in Brazil has dispersed from the Northeast to other regions of the country. In this study, an integrative approach, including genotyping Brazilian strains of L. (L.) infantum for 14 microsatellite markers and reviewing historical records of the disease, was used to assess dispersion routes throughout central-southern Brazil. Our results support three L. (L.) infantum dispersion routes: A) dispersion from Bolivia to the states of Mato Grosso, Mato Grosso do Sul and São Paulo via the Bolivia-Brazil gas pipeline from 1998 to 2005; B) VL dispersion from Paraguay to the Brazilian side of the triple border (Foz do Iguaçu and Santa Terezinha de Itaipu) during after 2012; and C) emergence of a new L. (L.) infantum cluster in western Santa Catarina State and its dispersion to southern Paraná State (municipality of Pato Branco), after 2013. Hypotheses regarding possible entries of Leishmania (L.) infantum into the area of the triple border are presented and discussed. Understanding how VL has dispersed is vital to the development of control measures for this disease and to avoid future dispersion events.

Effect of antibiotic prophylaxis on Coagulase-negative Staphylococcus virulence factor profiles in patients undergoing cataract surgery.

PURPOSE: In this prospective study, multiplex polymerase chain reaction (PCR) was used to identify genes encoding virulence factors (ica, atlE and mecA) in Coagulase-negative Staphylococcus (CNS) isolates from the ocular microbiota of patients undergoing cataract surgery and to investigate possible changes in the CNS profile due to antibiotic prophylaxis. METHODS: Between 09/2011 and 08/2013, patients undergoing cataract surgery were recruited at the Department of Ophthalmology, National University of Asuncion, Paraguay. In the eye to be operated on, patients received moxifloxacin 0.5 % eye drops four times at the day before surgery and a last drop 1 hour before surgery (T1). The other eye remained as control (T0). Conjunctival swabs were taken from both eyes 1 hour after the last drop. The presence of genes encoding biofilm formation (ica and atlE) and methicillin resistance (mecA) was detected by a multiplex PCR. RESULTS: Of the 162 patients (162 study eyes, 162 fellow eye as control group), 87 (53.7 %) eyes were positive for CNS at T0 yielding 96 CNS isolates; 70 eyes (43.2 %) were positive at T1 yielding 77 CNS isolates. For this study, 43 CNS isolates (44.8 %) from T0 and 45 (64.3 %) from T1 were used. Of the total isolates, 81.8 % (72/88) had at least one virulence factor gene (37/43 from T0 and 35/45 from T1) (p = 0.314). Simultaneous detection of ica and atlE genes was higher in T0 (58.0 %) than T1 (46.7 %), but the difference was not significant (p = 0.28). CONCLUSION: A high frequency of genes encoding virulence factors was observed in the coagulase-negative Staphylococcus isolates. The use of moxifloxacin did not significantly modify the CNS virulence factor profiles.

Estandarización de la técnica de PCR-RFLP de la región ITS1, para la caracterización molecular de leishmania (L) infantum, en muestras caninas / Standardization of PCR-RFLP technique of the ITS-1 region for leishmania (L) infantum molecular characterization in canine samples

La leishmaniasis es una enfermedad producida por protozoarios parásitos del género Leishmania. Estos parásitos infectan a hospedadores mamíferos, entre los cuales los perros han sido implicados como reservorios del parásito. Este trabajo planteó estandarizar la técnica de la PCR-RFLP luego de la amplificación de la región ITS1 de Leishmania spp, como herramienta útil para la detección y caracterización molecular. Se utilizaron promastigotes de cultivo y muestras de biopsias procedentes de perros con leishmaniasis visceral previamente diagnosticados en el Centro Antirrábico Nacional. La región ITS1 del ADN genómico nuclear de Leishmania spp. fue amplificada utilizando los cebadores LITSR y L5,8S. La técnica ITS1 PCR-RFLP aplicada, permitió la detección de Leishmania (L) infantum en 10/10 aislados de parásitos mantenidos en medio NNN, en 10/18 muestras de bazo y 10/18 muestras de ganglio linfático poplíteo. Las condiciones óptimas de reacción fueron 0,2 mM de dNTPs, 0,1 pmol de cada cebador y 1U de Taq polimerasa. La sensibilidad de la PCR fue de 3 ng/µL de ADN en aislados de cultivo NNN y 60 ng/µL de ADN en muestras de biopsias, mientras que la especificidad fue de 100% para la detección de Leishmania sp. La enzima de restricción Hae III, determinó fragmentos de 184, 72 y 55 pb., que resultaron específicos para la especie Leishmania (L.) infantum. El marcador utilizado resultó confiable para la detección y caracterización de Leishmania sp. en perros procedentes de zonas endémicas, lo cual podría ser útil para verificar las especies de parásitos circulantes entre los perros.

Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania. The separasites infect to mammalian hosts, including canines that have been implicated as reservoirs of the parasite. The aim of this research was to standardize the technique of PCR RFLP after amplification of the ITS1 region of Leishmania (Leishmania) infantum, as a useful tool for detection and molecular characterization. Promastigotes from culture and biopsies from dogs with visceral Leishmaniasis previously diagnosed by the Centro Antirrábico Nacional. The ITS1 region of the genomic DNA of Leishmania sp. was amplified using LITSR and L5,8S primers. The technique ITS1 PCR-RFLP applied, allowed the detection of Leishmania (L.) infantum in 10/10 of the isolates from parasites maintained in NNN culture medium, in 10/18 samples from spleen and 10/18 samples from popliteal lymph node. Optimal reaction conditions were 0.2 mM dNTPs, 0.1 pmol of each primer and 1U of Taq polymerase. The sensitivity of PCR was 3 ng/µL DNA in isolates of parasites from NNNculture medium and 60 ng/µL DNA in biopsy samples while the specificity was 100% for the detection of DNA of Leishmania sp. The restriction enzyme Hae III determined fragments of184, 72 and 55 bp., which were specific to Leishmania (L.) infantum. The marker used isreliable for the detection and characterization of Leishmania sp. in dogs from endemic areas, which could be useful to verify the species of parasites circulating among animals.

Genetic and Morphometric Variability of Triatoma sordida (Hemiptera: Reduviidae) from the Eastern and Western Regions of Paraguay.

Triatoma sordida is widely distributed throughout the Chaco and the Eastern Region of Paraguay. It is associated to palm trees and artificial ecotopes located in peridomestic environments. The aim of this work was to determine genetic and morphometric variability and feeding behavior among population of T. sordida captured in domicile and peridomicile areas of Paraguay. Feeding contents and levels of genetic and morphometric variation were determined in 124 T. sordida from domicile and peridomicile populations of San Pedro and Paraguarí departments of the Eastern Region and Boquerón and Presidente Hayes departments of the Western region using Double Diffusion Gel, random amplified polymorphic DNA (RAPD), and head and wings morphometry. Morphometric analysis revealed isolation of populations by geographic region and larger size in triatomine populations from the Western Region. RAPD showed no specific patterns for domicile and peridomicile populations. The estimator of diversity (F ST; 0.08) and high gene flow obtained (N m; 5.7) did not allow the establishment of genetic differentiation within the same region. The blood meal source showed that poultry feeding was 38% of host preferences, and human blood was the second feeding preference (24%) in the insects from the Eastern Region while poultry feeding was predominant in those from the Western Region (30%). This work showed homogeneity between T. sordida populations of the same region and between domicile and peridomicile. The genetic diversity was determined among T. sordida populations of both geographical regions suggesting differentiation associated to eco-geographical isolation by distance. It is important to notice that pattern feedings were different between the two regions. Further studies should be focused on how phenetic and genetic variations could be related to the adaptation capacity of these triatomine populations to domicile, increasing their vector potentiality in the transmission of Chagas disease.