Attempted protection of zebu cattle against trypanosomiasis using a multi-stabilate vaccine.

The protective value of double vaccination with 11 recently isolated stabilates of Trypanosoma congolense given either as live or dead organisms, followed by trypanocidal therapy, was assessed in zebu cattle subsequently challenged by nine of the original stabilates. Both vaccination regimens failed to prevent the animals becoming parasitaemic and eventually succumbing to the infection, although the mean survival times and prepatent periods of the calves which received the live vaccine were longer than those of both the groups which had received the dead vaccine and the challenge controls.