Sympatry influence in the interaction of Trypanosoma cruzi with triatomine

Abstract INTRODUCTION: Trypanosoma cruzi, the etiologic agent of Chagas disease, is widely distributed in nature, circulating between triatomine bugs and sylvatic mammals, and has large genetic diversity. Both the vector species and the genetic lineages of T. cruzi present a varied geographical distribution. This study aimed to verify the influence of sympatry in the interaction of T. cruzi with triatomines. Methods: The behavior of the strains PR2256 (T. cruzi II) and AM14 (T. cruzi IV) was studied in Triatoma sordida (TS) and Rhodnius robustus (RR). Eleven fifth-stage nymphs were fed by artificial xenodiagnosis with 5.6 × 103 blood trypomastigotes/0.1mL of each T. cruzi strain. Every 20 days, their excreta were examined for up to 100 days, and every 30 days, the intestinal content was examined for up to 120 days, by parasitological (fresh examination and differential count with Giemsa-stained smears) and molecular (PCR) methods. Rates of infectivity, metacyclogenesis and mortality, and mean number of parasites per insect and of excreted parasites were determined. RESULTS: Sympatric groups RR+AM14 and TS+PR2256 showed higher values of the four parameters, except for mortality rate, which was higher (27.3%) in the TS+AM14 group. General infectivity was 72.7%, which was mainly proven by PCR, showing the following decreasing order: RR+AM14 (100%), TS+PR2256 (81.8%), RR+PR2256 (72.7%) and TS+AM14 (36.4%). CONCLUSIONS: Our working hypothesis was confirmed once higher infectivity and vector capacity (flagellate production and elimination of infective metacyclic forms) were recorded in the groups that contained sympatric T. cruzi lineages and triatomine species.

Estudio comparativo de la susceptibilidad de cuatro especies del genero Rhodnius a la infección experimental con Trypanosoma cruzi / Comparative study of susceptibility of four species of genera Rhodnius to experimental infection with Trypanosoma cruzi in Venezuela

Con el objetivo de comparar su susceptibilidad, se infectaron experimentalmente con Trypanosoma cruzi especímenes de Rhodnius prolixus, Rhodnius robustus, Rhodnius neivai y Rhodnius neglectus. El análisis de varianza de Kruskall-Wallis con los datos agrupados por especie y por estadio reveló diferencias estadísticamente significativas entre las especies en cuanto al volumen de sangre ingerida, volumen de orina producida y número de parásitos desarrollados en orina y heces para cada estadio. Posteriormente la prueba de comparación múltiple de Mínima Diferencia Significativa demostró que R. prolixus ingirió el volumen más elevado de sangre mientras que R.neivai produjo el volumen de orina más elevado, seguido por R. robustus, R. prolixus y R. neglectus,en ese orden. Asimismo, R. neivai mostró el promedio más elevado de parásitos tanto en orina como en heces mientras que R. robustus y R. neglectus produjeron significativamente menos parásitos en orina y heces respectivamente. Las cuatro especies estudiadas son capaces de infectarse, multiplicar y excretar el parásito en su forma infectante, en todos los estadios

In order to compare their susceptibility to Trypanosoma cruzi specimens of Rhodnius prolixus, R.robustus, R. neivai and R. neglectus were experimentallyinfected with this parasite. Statistically significantdifferences among the species in the volume of bloodingested, volume of urine produced and number ofparasites in urine and grounds developed in each stage,were detected with a non parametric Kruskall-Wallisanalysis of variance, with the data grouped in speciesand instars. The Low Significative Difference posterioritest, shows that R. prolixus ingested the highest bloodvolume while R. neivai produced the highest urinevolume, followed by R. robustus, R. prolixus and R.neglectus. Likewise, R. neivai showed the highest averageof parasites in urine and feces, while R. robustus and R.neglectus showed significantly less parasites in urineand feces respectively. The four studied species are ableto infect, to multiply and to excrete the parasite in their infective form in all instars stages

Rhodnius zeledoni sp. nov. afim de Rhodnius paraensis Sherlock, Guitton & Miles, 1977 (Hemiptera, Reduviidae, Triatominae) / Rhodnius zeledoni sp. nov. afim de Rhodnius paraensis Sherlock, Guitton & Miles, 1977 (Hemiptera, Reduviidae, Triatominae)

A new species of Rhodnius is described and illustrated from a male specimen from northeastern Brazil. The specimen was found died and dried. This species can be distinguished from its similar congener R. paraensis Sherlock, Guitton & Miles by the greater size, the general aspect of the color of the body, by the uniform color of the legs, different proportions between the morphological structures of the head and the segments of the rostrum; also, in the male genitalia by the aspect of median process of pygophore, dorsal phallotheca plate and phallotheca process.

Uma nova espécie de Rhodnius é descrita e ilustrada baseada em um exemplar macho do nordeste brasileiro. O espécime foi encontrado morto e ressecado. Esta espécie pode ser separada da espécie afim, R. paraensis Sherlock, Guitton & Miles, pelo seu maior tamanho, pelo aspecto geral de coloração do corpo, pela cor uniforme das pernas, pelas diferentes proporções entre as estruturas morfológicas da cabeça e dos segmentos do rostro; ainda, na genitália masculina, pelo aspecto do processo mediano do pigóforo, do falosoma e de seu processo.

Los triatominae (hemiptera, reduviidae) / The triatominae (hemiptera, reduviidae)

Se señala la presencia de especies de Triatominae (Hemiptera, Reduviidae) en la zona centro del Perú constituido por los departamentos: Lima, Ica, Ayacucho, Apurimac, Huánuco, Pasco y Junín. Ellas son: Triatoma infestans, Panstrongylus geniculatus, Panstrongylus herreri, Rhodnius pictipes, Rhodnius robustus y Eratyrus mucronatus. La especie que tiene mayor distribución es Panstrongylus geniculatus. Los autores hallaron a Panstrongylus geniculatus infectado naturalmente con Trypanosoma sp