Cryopreservation of Trypanosoma brucei gambiense in a commercial cryomedium developed for bull semen

There have been major advances in the formulation of cryomedia for spermatozoa owing to their economic importance. In this study, the suitability of the commercial cryomedium Triladyl® developed for bull semen was evaluated for the cryopreservation of Trypanosoma brucei gambiense. Cryopreservation efficacy was determined by direct counting of motile trypanosomes and by viability assessment using in vitro and in vivo methods. Culture medium containing 10% glycerol was used as the control. Trypanosomes cryopreserved in Triladyl demonstrated a higher in vitro viability than those in culture medium with 10% glycerol. Similar results were obtained in vivo in immunosuppressed Mastomys natalensis. Trypanosomes cryopreserved in Triladyl showed better growth characteristics than those in culture medium with glycerol. It can be concluded that the use of Triladyl in the cryopreservation of T. b. gambiense leads to a better survival of the trypanosomes which could lead to an improved isolation of T. b. gambiense from sleeping sickness patients.