[Comparison of the life cycles of Rhodnius colombiensis Moreno, Jurberg & Galvão, 1999 and R. prolixus Stal, 1872 (Hemiptera, Reduviidae, Triatominae) under laboratory conditions]. / Comparación del ciclo de vida de Rhodnius colombiensis Moreno, Jurberg & Galvão, 1999 y Rhodnius prolixus Stal, 1872 (Hemiptera, Reduviidae, Triatominae) en condiciones de laboratorio.

INTRODUCTION: Rhodnius colombiensis is a sylvatic triatomine associated with wine palm trees (Attalea butyracea) in the high basin of the Magdalena river (Colombia). The frequent invasion of these vectors into human dwellings and the high prevalences of natural infection with Trypanosoma cruzi of these insects suggest an important role in the transmission of Chagas disease. OBJECTIVE: The length of the life cycles of R. colombiensis and R. prolixus under laboratory conditions were compared. MATERIALS AND METHODS: Ninety-two individuals for each species were studied. The mean duration time of each stage, the number of bloodmeals for each stage, the percentage of mortality, the cause of death, the mean of eggs laid by female, the number of fertile eggs and the longevity of adults were recorded. RESULTS: The mean duration time of all stages of R. colombiensis was higher than in R. prolixus, producing significant differences in the overall time from egg to adult. The mean of total eggs and fertile eggs showed significant differences, being higher in R. prolixus than in R. colombiensis. The total mortality was 31.5% for R. colombiensis and 6.5% for R. prolixus. The longevity of females was higher in R. prolixus. CONCLUSIONS: The stages of R. prolixus are of relatively short duration. In general, the nymphs take fewer bloodmeals than R. colombiensis, the adults take more bloodmeals and oviposit a larger number of fertile eggs, and females have a greater longevity. These parameters indicated that R. prolixus has superior reproductive success in comparison with R. colombiensis under the experimental conditions used. These new life cycle data of R. colombiensis will be useful for maintenance of laboratory colonies.

[Trypanosoma rangeli parasite-vector-vertebrate interactions and their relationship to the systematics and epidemiology of American trypanosomiasis]. / Interacción tripanosoma-vector-vertebrado y su relación con la sistemática y la epidemiología de la tripanosomiasis Americana.

INTRODUCTION: Trypanosoma rangeli is a species of trypanosome second to T. cruzi, that is infective to humans in Latin America. Variability in the biological, biochemical and molecular characteristics between different isolates isolates of this parasite have been recorded. OBJECTIVE: Morphological and molecular characteristics were recorded from strains of T. rangeli that were isolated from different species of Rhodnius and maintained in different vertebrate species. MATERIALS AND METHODS: Nineteen strains of T. rangeli were isolated from R. prolixus, R. pallescens and R. colombiensis in Colombia, R. ecuadoriensis in Peru and R. pallescens in Panama. Polymorphism of blood trypomastigotes in ICR mice was evaluated and pleomorphism of P53 strain of T. rangeli KP1(-) inoculated in mouse, marsupial and canine was studied. RAPD analysis (randomly amplified polymorphic DNA analysis) of 12 strains isolated from four species of Rhodnius was performed. RESULT: Based on the total length of blood trypomastigotes, three discrete groups were observed. The P53 strain showed significant differences in the size of blood trypomastigotes in mouse, marsupial and canine. RAPD analysis showed that the strains segregated into two branches corresponding to strains of T. rangeli KP1(+) and T. rangeli KP1(-). All strains of T. rangeli KP1(-) clustered according to the species of Rhodnius from which they were isolated. CONCLUSION: These data reveal, for the first time, a close association amongst T. rangeli strains and Rhodnius species, confirming that each species of Rhodnius transmits to vertebrate hosts a parasite population with clear phenotypic and genotypic differences. This is further evidence that supports the concept of clonal evolution of these parasites.

[Giardia duodenalis genotypes found in the Instituto Colombiano de Bienestar Familiar day care centers and dogs in Ibagué, Colombia]. / Genotipos de Giardia duodenalis en muestras de niños de las guarderías del Instituto Colombiano de Bienestar Familiar y de perros en Ibagué, Colombia.

INTRODUCTION: Eight Giardia duodenalis genotypes (A-H) have been described to date. Genotypes A and B have been isolated from humans and a wide range of mammals; however, genotypes C-H have shown greater host specificity. OBJECTIVE: Identifying G. duodenalis genotypes from cysts in faeces obtained from children attending the Instituto Colombiano de Bienestar Familiar (ICBF) day care centres and from dogs in Ibagué by PCR-RFLP targeting both the b -giardin and glutamate dehydrogenase genes. MATERIALS AND METHODS: Cysts from G. duodenalis positive samples were concentrated, DNA was extracted and the b -giardin and glutamate dehydrogenase genes were analysed by PCR-RFLP. The MHOM/CO/04/G40 strain was used as positive control (this was obtained from the Grupo de Parasitología at the Instituto Nacional de Salud ). RESULTS: Of the total human samples, 11/23 (48%) were genotyped as A and 12/23 (52%) as B; PCR-RFLP revealed that four canine samples were genotypes C and D, these being host-specific. CONCLUSIONS: Only genotypes associated with human infection (AII, BIII and BIV) were found in the children and host-specific genotypes were observed in canines (C and D). No interaction could be established between animal and human transmission cycles due to the small canine sample size and as the former did not come into contact with children attending ICBF day-care centres.

Genotipos de Giardia duodenalis en muestras de niños de las guarderías del Instituto Colombiano de Bienestar Familiar y de perros en Ibagué, Colombia / Giardia duodenalis genotypes found in the Instituto Colombiano de Bienestar Familiar day care centers and dogs in Ibagué, Colombia

Introducción. Se han descrito ocho genotipos de Giardia duodenalis, del A al H. Los genotipos A y B se han aislado de humanos y de una gran variedad de mamíferos; sin embargo, los genotipos del C al H han mostrado mayor especificidad de huésped. Objetivo. Identificar los genotipos de G. duodenalis a partir de quistes obtenidos en heces de niños de las guarderías del Instituto Colombiano de Bienestar Familiar (ICBF) y de perros en Ibagué, mediante PCR-RFLP de los genes de la beta giardina y la glutamato deshidrogenasa. Materiales y métodos. Los quistes de las muestras positivas para G. duodenalis fueron sometidos a concentración; se extrajo su ADN y se efectuó el análisis de PCR-RFLP de los genes de la beta giardina y de la glutamato deshidrogenasa. Como control positivo se utilizó la cepa MHOM/CO/04/G40 procedente del Grupo de Parasitología del Instituto Nacional de Salud. Resultados. De las muestras tomadas de niños, 11/23 (48 %) correspondieron al genotipo A y, 12/23 (52 %), al genotipo B. Cuatro muestras de perros presentaron los genotipos C y D, específicos de este huésped. Conclusiones. En los niños solamente se encontraron los genotipos asociados a infecciones humanas (AII, BIII y BIV) y en los perros, los genotipos específicos para este huésped (C y D). Debido al reducido tamaño de las muestras analizadas provenientes de perros, y dado que estos no estuvieron en contacto con los niños de las guarderías del ICBF, no fue posible determinar una interacción entre el ciclo de transmisión de los humanos y el de los animales.

Introduction: Eight Giardia duodenalis genotypes (A-H) have been described to date. Genotypes A and B have been isolated from humans and a wide range of mammals; however, genotypes C-H have shown greater host specificity. Objective: Identifying G. duodenalis genotypes from cysts in faeces obtained from children attending the Instituto Colombiano de Bienestar Familiar (ICBF) day care centres and from dogs in Ibagué by PCR-RFLP targeting both the b -giardin and glutamate dehydrogenase genes. Materials and methods: Cysts from G. duodenalis positive samples were concentrated, DNA was extracted and the b -giardin and glutamate dehydrogenase genes were analysed by PCR-RFLP. The MHOM/CO/04/G40 strain was used as positive control (this was obtained from the Grupo de Parasitología at the Instituto Nacional de Salud ). Results: Of the total human samples, 11/23 (48%) were genotyped as A and 12/23 (52%) as B; PCR-RFLP revealed that four canine samples were genotypes C and D, these being host-specific. Conclusions: Only genotypes associated with human infection (AII, BIII and BIV) were found in the children and host-specific genotypes were observed in canines (C and D). No interaction could be established between animal and human transmission cycles due to the small canine sample size and as the former did not come into contact with children attending ICBF day-care centres.