Tripomastigotes sanguícolas de Trypanosoma vivax y Trypanosoma evansi obtenidos de infecciones experimentales en ovejas y ratones respectivamente, fueron utilizados para purificar y caracterizar proteínas citosólicas mediante el método de partición con Tritón X-114. Los resultados revelan diferencias en los patrones proteicos entre las dos especies. Asimismo, las reacciones antigénicas mediante Western blot utilizando suero de animales naturalmente infectados, permitió discriminar las infecciones entre ambos parásitos. Se sugiere la utilización de esta metodología como una prueba diagnóstica confiable.

Trypanosoma vivax and Trypanosoma evansi blood trypomastigotes, obtained respectively from sheep and mice experimentally infected, were used to isolate and characterize proteins using the partition Triton X-114 method. Results showed a different protein pattern between the 2 species. Additionally, results by Western blot, using sera from naturally infected animals, revealed specific discrimination between these two species of Trypanosoma. The potential use of this method as a reliable diagnostic tool is suggested.

Se registra la detección de infecciones subclínicas por Trypanosoma vivax en bovinos asintomáticos de fincas ganaderas de Mérida, Venezuela. El diagnóstico fue realizado utilizando métodos parasitológicos (examen microscópico de muestra fresca, micro-capilar y láminas coloreadas); bioquímicos (Western blot) y moleculares (PCR) en muestras sanguíneas. Se advierte sobre el riesgo potencial que infecciones asintomáticas, ocultas o inaparentes pudieran representar para los rebaños bovinos. Se discute su significado y su importancia epizootiológica para regiones ganaderas del país.

Subclinic infections of Trypanosoma vivax were detected in symptomless animals from cattle farms in Merida, Venezuela. Parasitological (microscopical examination of: fresh, capillary tubes and stained slides-blood samples); biochemical (Western blot) and molecular (PCR) methods were used for diagnosis in blood sample. The significance, potential risk and epizootiological importance, are discussed.

A massive and homogeneous amount of amastigote-like forms was detected in the stomodeal valve (SV) and the thoracic mid-gut (TMG) of Leishmania major-infected Phlebotomus papatasi, which received a second blood meal 13 to 21 days post-infection on healthy anaesthetized hamsters. After re-feeding, the infected sand flies were dissected out to examine the morphology of the parasite in SV, TMG and the abdominal mid-gut (AMG). Different promastigote forms were seen in the infected flies. Among these included typical promastigotes (nectomonads and haptomonads), paramastigotes, metacyclic promastigotes and, in some samples, the here-reported amastigote-like forms. The Leishmania amastigote-like forms were detected in the SV of sand flies with 14, 18 and 21 days of infection as well as in the TMG at 13 and 18 days post-infection. However, the amastigote-like forms were not detected in the AMG. Factors such as the acidic pH predominating the TMG and the SV, as well as the temperature of the ingested blood, among others, are suggested as contributing to the transformation of the typical promastigotes into the amastigote-like forms. The significance of this finding is discussed and the possible biological advantage for transmission of Leishmania is considered.