Laboratory and field studies for the control of Chagas disease vectors using the fungus Metarhizium anisopliae.

Chagas disease is one of the most important insect-vectored diseases in Brazil. The entomopathogenic fungus Metarhizium anisopliae was evaluated against nymphs and adults of Panstrongylus megistus, Triatoma infestans, and T. sordida. Pathogenicity tests at saturated humidity demonstrated high susceptibility to fungal infection. The shortest estimates of 50% lethal time (LT50 ) for P. megistus varied from 4.6 (isolate E9) to 4.8 days (genetically modified strain 157p). For T. infestans, the shortest LT50 was 6.3 (E9) and 7.3 days (157p). For T. sordida, the shortest LT50 was 8.0 days (157p). The lethal concentration sufficient to kill 50% of T. infestans (LC50 ) was 1.9 × 107 conidia/ml for strain 157p. In three chicken coops that were sprayed with M. anisopliae, nymphs especially were well controlled, with a great population reduction of 38.5% after 17 days. Therefore M. anisopliae performed well, controlling Triatominae in both laboratory and field studies.

[Diversity of Triatominae (Hemiptera: Reduviidae) in Santander, Colombia: Epidemiological implications].

INTRODUCTION: Domestic and wild triatomines in the department of Santander have an epidemiological impact, as recently they have been linked to outbreaks of acute Chagas disease. The analysis of their diversity and temporal variation contributes to the understanding of their biology and ecology in one of the most endemic areas of the country. OBJECTIVES: To analyze triatominae diversity in two regions of Santander. MATERIALS AND METHODS: We analyzed the triatomine records for Santander contained in the CINTROP-UIS entomology lab database. We grouped the information for two regions: the Middle Magdalena area and the Andean region, and for each one we designed species accumulation and range-abundance curves, we calculated diversity and equality indices, and we analyzed colonization and temporal variation or persistence of the community. RESULTS: Ninety five percent of triatomines came from the Andean area and 4.57% from Magdalena Medio, with nine and ten species each. The dominant species in the Andean area were Rhodnius prolixus and Triatoma dimidiata while in Magdalena Medio they were Rhodnius pallescens and Panstrongylus geniculatus. We found a greater diversity and richness in Middle Magdalena compared to the Andean area. The temporal variation showed persistence of communities over time. CONCLUSIONS: Results revealed differences in the diversity of the two regions and the potential of wild species to occupy artificial ecotopes. Triatomines intrusion and the recent involvement of wild species in the transmission of Trypanosoma cruzi emphasize the need to further investigate the ecology of these vectors in order to guide population control strategies.

Diversidad de Triatominae (Hemiptera: Reduviidae) en Santander, Colombia: implicaciones epidemiológicas / Diversity of Triatominae (Hemiptera: Reduviidae) in Santander, Colombia: Epidemiological implications

Resumen Introducción: Los triatominos domiciliados y silvestres constituyen un problema de impacto epidemiológico en el departamento de Santander, pues se han asociado recientemente con brotes agudos de la enfermedad de Chagas, por lo cual el análisis de su diversidad y variación temporal contribuye al conocimiento de su biología y ecología en una de las áreas más endémicas del país. Objetivo: Analizar la diversidad de triatominos en dos regiones de Santander. Materiales y métodos: Se analizó la información de la base de datos del Laboratorio de Entomología del Centro de Investigaciones en Enfermedades Tropicales de la Universidad Industrial de Santander (CINTROP-UIS), la cual contiene registros de triatominos en Santander. La información se separó en dos regiones, el Magdalena Medio y la zona andina, para cada una de las cuales se diseñaron curvas de acumulación de especies y de rango de abundancia, se calcularon los índices de diversidad y de igualdad, se analizó la colonización y se evaluó la variación temporal o persistencia de la comunidad. Resultados: El 95 % de los triatominos provenía de la zona andina y, el 4,57 %, del Magdalena Medio, con nueve y diez especies, respectivamente. Se encontró mayor diversidad y riqueza en el Magdalena Medio en comparación con la zona andina. Las especies dominantes en la zona andina fueron Rhodnius prolixus y Triatoma dimidiata, mientras que en Magdalena Medio fueron Rhodnius pallescens y Panstrongylus geniculatus. La variación temporal mostró persistencia de las comunidades en el tiempo. Conclusiones:. Los resultados evidenciaron diferencias en la diversidad de las dos regiones, además del potencial de las especies silvestres para ocupar ecótopos artificiales. La intrusión de triatominos y la reciente incriminación de especies silvestres en la transmisión de Trypanosoma cruzi, indican la necesidad de un mayor conocimiento de la ecología de estos vectores para orientar las estrategias de control.

Abstract Introduction: Domestic and wild triatomines in the department of Santander have an epidemiological impact, as recently they have been linked to outbreaks of acute Chagas disease. The analysis of their diversity and temporal variation contributes to the understanding of their biology and ecology in one of the most endemic areas of the country. Objectives: To analyze triatominae diversity in two regions of Santander. Materials and methods: We analyzed the triatomine records for Santander contained in the CINTROPUIS entomology lab database. We grouped the information for two regions: the Middle Magdalena area and the Andean region, and for each one we designed species accumulation and range-abundance curves, we calculated diversity and equality indices, and we analyzed colonization and temporal variation or persistence of the community. Results: Ninety five percent of triatomines came from the Andean area and 4.57% from Magdalena Medio, with nine and ten species each. The dominant species in the Andean area were Rhodnius prolixus and Triatoma dimidiata while in Magdalena Medio they were Rhodnius pallescens and Panstrongylus geniculatus. We found a greater diversity and richness in Middle Magdalena compared to the Andean area. The temporal variation showed persistence of communities over time. Conclusions: Results revealed differences in the diversity of the two regions and the potential of wild species to occupy artificial ecotopes. Triatomines intrusion and the recent involvement of wild species in the transmission of Trypanosoma cruzi emphasize the need to further investigate the ecology of these vectors in order to guide population control strategies.

Panstrongylus rufotuberculatus (Hemiptera, Reduviidae, Triatominae) infectado con Trypanosoma cruzi en el estado Anzoátegui (Venezuela) / Panstrongylus rufotuberculatus (Hemiptera, Reduviidae, Triatominae) infected with Trypanosoma cruzi in the state of Anzoátegui (Venezuela) Antonio Morocoima

En el caserío rural Mundo Nuevo, municipio Pedro María Freites, estado Anzoátegui (Venezuela) se capturaron en la pared externa de una vivienda cuatro ejemplares adultos de Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera, Reduviidae, Triatominae), uno de los cuales mostró infección por Trypanosoma cruzi, evidenciada por examen directo del contenido intestinal. El comportamiento del aislado en ratones NMRI presentó parasitismo tisular en 47% de 12 tejidos estudiados. La especie T. cruzi fue confirmada por PCR-ADNk y PCR ADN satélite. Se demuestra por primera vez la presencia de esta especie silvestre en el estado Anzoátegui.

In the rural village Mundo Nuevo, municipality Pedro Maria Freites, Anzoátegui state (Venezuela), four adults of Panstrongylus rufotuberculatus (Champion, 1899) (Hemiptera, Reduviidae, Triatominae) were captured in the external wall of a human dwelling. One triatomine was infected by Trypanosoma cruzi. The isolate inoculated in NMRI mice showed parasites in 47% of 11 studied tissues. T.cruzi was confirmed by PCR-kDNA and PCR satellite DNA.The presence of this species represents, to our knowledge,the first report for this state.

Panstrongylus rufotuberculatus (Champion, 1899) naturalmente infectados con Trypanosoma cruzi en el estado Miranda, Venezuela / Panstrongylus rufotuberculatus (Champion, 1899) naturally infected with Trypanosoma cruzi in Miranda state, Venezuela

Dos ejemplares de Panstrongylus rufotuberculatus fueron capturados en una vivienda de El Hatillo, estado Miranda. En ambos se confirma la presencia de Trypanosoma cruzi. Se estudian algunos parámetros biológicos para estimar el comportamiento de uno de los aislados (Pr), encontrándose que tanto el cultivo en medios acelulares como la inoculación en ratones fueron exitosos. Así mismo, 73,3% de los Rhodnius de laboratorio se infectaron y 30,6% de los parásitos presentaron metaciclogénesis, mientras que in vitro se obtuvo 25,5%. La identificación molecular correspondió a T. cruzi. Este hallazgo es importante debido a la posible emergencia de esta especie silvestre que por alteración antrópica de sus hábitats naturales puede estar en proceso de dispersión, penetración y domiciliación de las viviendas, implicando la posibilidad de transmisión del parásito al ser humano y animales domésticos.

Two specimens of Panstrongylus rufotuberculatus were captured in a house in El Hatillo, Estado Miranda. In both specimens the presence of Trypanosoma cruzi was confirmed. We studied some biological parameters for estimating the behavior of the isolates, finding in both that cell-free culture media as inoculation in mice were successful. Also, 73.3% of Rhodnius prolixus fed on infected mice became infected and 30.6% of the parasites developed to metacyclic forms whereas in vitro only 25.5% was obtained. Furthermore, the molecular identification corresponded to T. cruzi. This finding is important due to the possible emergence of wild species by anthropogenic alteration of their natural habitats, and this may become a process of dispersion, penetration and clearance of houses, implying the possibility of transmitting the parasite to humans and pets.

Pathogenicity of Evlachovaea sp (Hyphomycetes), a new species isolated from Triatoma sordida, in Chagas' disease vectors.

Evlachovaea sp was tested on nymphs of 5 Triatoma spp 5 Rhodnius spp, Panstrongylus herreri and Dipetalogaster maximus at 25 degrees C, 75% humidity and humidity >98%. Most species showed susceptibility to fungal infection at high humidity. Mortality was reduced at 75% humidity. Fungal development was observed on 69.5% of cadavers.

Entomopathogenic effect of Aspergillus giganteus and Penicillium corylophilum on two triatomine vectors of Chagas disease.

Two strains, Penicillium corylophilum and Aspergillus giganteus, of the most frequent species found in a survey of triatomines, were used for bioassays in the second and fourth nymphs stage of Triatoma infestans and Panstrongylus megistus. Two procedures, bite and pulverization, were used and compared. A. giganteus was most effective, causing mortality in at least 50% of the nymphs of the two species tested with exception of the nymphs of the fourth stage of P. megistus. Variation in entomopathogenic capacity of the fungal species were observed in the experiments. The two procedures used proved effective.