Trypanosoma congolense, Broden, 1904.
Probable synonyms.—Trypanosoma dimorphon, Laveran and Mesnil, 1904; Trypanosoma nanum, Laveran, 1905; Trypanosoma pecorum, Bruce, 1910; Trypanosoma confusum, Montgomery, 1909.
This trypanosome causes disease among horses (e.g., Gambia horse sickness), cattle, sheep, goats, pigs, and dogs. It is widely distributed in Central Africa (e.g., Gambia, Congo, Uganda, Nyasaland), the strain probably being maintained naturally in big game. It is transmitted by various Glossinæ, and perhaps by Tabanus and Stomoxys. It is said to develop in the gut and proboscis of Glossina palpalis and G. morsitans. The trypanosome averages 13 µ to 14 µ in length and has no free flagellum (fig. 46). It is about 2 µ broad. Formerly T. nanum and T. pecorum were said to differ in their pathogenicity, the former being said not to infect the smaller laboratory animals. Yorke and Blacklock (1913), however, consider that the virulence varies and that these trypanosomes are probably the same.
Fig. 46.—Trypanosoma congolense. × 2,000. (Original. From preparation by Fantham.)
Fig. 47.—Trypanosoma uniforme. × 2,000. (Original. From preparation by Fantham.)
The T. dimorphon originally obtained by Dutton and Todd (1903) in Gambian horse sickness has been shown to be a mixture of T. vivax and T. congolense.