Discussion

African trypanosomes are single-celled extracellular protozoan parasites that are transmitted via the tsetse fly vector across sub-Saharan Africa. Mammalian infection begins when the tsetse fly injects trypanosomes into the skin. The parasites invade the circulatory and lymphatic systems, reaching the draining lymph nodes and disseminate systemically. How this occurs is not known. Chemokines play important roles in attracting leukocytes towards the lymphatics and lymph nodes.To investigate how trypanosomes migrate from the bite site to the draining lymph nodes, we determined whether chemokines act as chemoattractants for trypanosomes. As certain chemokines also possess antimicrobial properties, including against the protozoan parasite Leishmania mexicana ,we tested their potential cytotoxic effects against T. b. brucei . Our data showed that these chemokines do not induce chemotaxis of T. b. brucei . The motility characteristics of the parasites were also not affected. Moreover, these chemokines do not exert any trypanostatic effects on trypanosomes. This data suggests trypanosomes use alternative cues to reach the lymphatics post-infection. Identifying the mechanisms involved in establishing African trypanosome infections in the skin and their systemic dissemination will aid the development of novel approaches to block disease transmission.