The dynamics of the cellular reactions elicited in the skin of goats by Glossina morsitans morsitans infected with Trypanosoma (Nannomonas) congolense or T. (Duttonella) vivax.

Local skin reactions were elicited in goats by tsetse infected with either T. (N.) congolense of T. (D.) vivax. For the former trypanosomes, the skin reaction was detected initially 7 days after challenge and was maximal 3 days later. Histologically, the cellular response involved an initial influx of polymorphonuclear leucocytes (PMN) which was followed by a substantial infiltration of lymphocytes and macrophages. Large numbers of plasma cells remained in the skin reaction during its decline. Moderate numbers of parasites were observed in lesion at the height of the reaction. T. (D.) vivax provoked a small nodular skin reaction which became apparent 7 days after challenge. The cellular response, which peaked on day 9, contained large numbers of lymphocytes and macrophages and only a small contribution from PMN. Only small numbers of trypanosomes were observed in the chancre. The skin reaction elicited in goats by T. (N.) congolense, T. (D.) vivax or T. (T.) brucei were mutually distinct in their morphological appearance and size at the peak of the response, and in the interval required after challenge to attain maximum dimensions.