Trypanosoma Evansi: An Experimental Infection In Mice

The experiments were aimed at creating sufficient infectious material to infect three groups of sow with Trypanosoma evansi and to evaluate whether there is a relationship between clinical signs and the level of parasites in the blood. The following experiment was done:\nTwo different groups of mice were intra-peritoneally inoculated with Trypanosoma evansi. When the mice reached high parasitemia, they were humanely euthanized and blood was taken by cardiac puncture. Blood containing the parasites was frozen with a Sylab IceCube Control Rated Freezer 14S, with different freezing media (DMSO and glycerol) and containers (cryo-tubes and straws). Samples were equally divided over the different media and containers. \nAfter freezing, there was no difference found in the motility after freezing, between the different media or different containers.\nThe second group of mice showed a longer prepatent period and a fast increase of parasites to the peak parasitemia. The first group showed a prepatent period from 2-4 days, the second group from 5-7 days. \nThere was no significant difference in parasitemia pattern between the groups.\nThere was no correlation (P > 0.05), between clinical signs and the level of parasites in the blood, for group 1 and group 2.\nSo, therefore to predict the time of high parasitemia by clinical signs, isn’t a reliable method.