Diagnostic evaluation of PCR on dried blood samples from goats experimentally infected with Trypanosoma brucei brucei

In seven goats experimentally infected with a pleomorphic clone of Trypanosoma brucei brucei, parasitaemia was monitored weekly for 6 weeks by wet blood film and microhaematocrit buffy coat examination. Dried blood samples on filter paper were concomitantly collected and tested by PCR using three different primer sets, putatively specific for Trypanozoon, T. vivax and T. congolense. With the originally designed ORPHON5J Trypanozoon primers, PCR tests became positive after 1 week (six animals) or 2 weeks (one animal) of infection and remained consistently positive until the end of the experiments, thus yielding an overall positivity rate of 97%, as compared with 74% for all parasitological tests together. The T. vivax and T. congolense primers yielded no positive PCR results.