Trypanosoma gambiense and T. lewisi: Increased vascular permeability and skin lesions in rabbits

Abstract

A vascular permeability-increasing factor, which has the characteristics of a protein, was demonstrated in extracts of Trypanosoma gambiense. The concentration of this factor required to produce a strong skin reaction experimentally appeared compatible with the numbers of trypanosomes (protein concentration) observed in the skin lesions. Trypanosoma lewisi was also shown to contain a vascular permeabilityincreasing factor, and produced a definite inflammatory reaction after the injection of living blood trypanosomes into the skin of rabbits. Early skin lesions (2 days) in rabbits produced by the intradermal injection of live T. gambiense were shown to contain greatly increased water content. It is suggested that a trypanosome toxin (a vascular permeability-increasing factor) causes edema of the skin, and at least partially accounts for the early pathologic changes in the skin.