Trypanosoma vivax in the Americas: morphometry and host range

Abstract

The African Trypanosoma vivax is classically described as being club-shaped. However, slender forms are present in several stocks. In the Americas this basic club-shaped characteristic has also been observed, but is dependent on the host species. The South American T. vivax has a range length of 16 to 26.5 µm, and therefore appears shorter than the originally described species. Recent biometrical studies showed that the South American T. vivax varies from mean lengths of 15.86 to 23 µm and the minimum length reported is 11.34 µm. A description of morphometrical characteristics and host range of T. vivax in the Americas is presented since little information is currently available on the natural pathogenicity, epizootiology and morphology of the T. vivax like trypanosomes infecting domestic animals in the Americas.