Drug sensitivity of pleomorphic Trypanosoma rhodesiense

Differential susceptibility to DL-alpha-difluoromethylornithine in clinical isolates of Trypanosoma brucei rhodesiense

“…Key general issues that appear to be involved in the response of any trypanosome isolate to any drug are as follows: (i) the number of prior syringe passages, since repeated passage is often associated with increasing virulence; (ii) prior selection of resistant organisms by exposure to drug in vivo before the original samples were collected; (iii) the variable time different isolates require to establish infection in sites not accessible to the test drugs; (iv) the degree to which an isolate is able to evade the host immune response, since this will affect the usual synergism between a chemotherapeutic agent and the immune system (12,26); and (v) variable innate biochemical resistance to the drug. We attempted to minimize variables i through iv by beginning treatment 24 h postinfection, using outbred Swiss Webster mice throughout, and using inocula no more than two syringe passages removed from the original strain bank isolate.…”