Clinical observation on three nigerian breeds of sheep experimentally infected with trypanosoma viva

Abstract EN

Livestock production has been continually challenged with trypanosomes of which Trypanosoma vivax is the most pathogenic cause and the least studied in sub-Saharan Africa.

Five sheep of each of the three Nigerian breeds, viz: West African Dwarf (WAD), Yankassa and Ouda were intravenously infected with 2.5 × 106 Trypanosoma vivax per milliliter and monitored until the Packed Cell Volume (PCV) declined to 15% when they were treated with diminazene aceturate.

Three animals of each breed served as an uninfected control.

The parameters monitored were parasitemia, clinical signs, bodyweight, and PCV.

Levels of parasitemia were not significantly different across the breeds.

Thirteen out of fifteen infected sheep had fever three days pi, followed by signs of pale mucous membranes, enlarged lymph nodes, serous nasal discharge, loss of weight, and dullness at various days pi in all the infected sheep.

There were no significant (p>0.05) differences between the weight of all infected animals in the three breeds.

The mean PCV of infected sheep was significantly (P<0.05) lower than that of non-infected sheep as from 14 days pi to 21 days pi in all the breeds of sheep.

The least decline in PCV occurred in WAD sheep (20.92%) compared to Yankassa (31.65%) and Ouda (30.36%).

The field strain of mouse-infective T.

vivax used had 99% homology with the diagnostic antigen gene of T.

vivax (L25129 T and U43183) from GenBank.

All the three Nigerian breeds of sheep are susceptible to T.

vivax infection and WAD sheep are more tolerant (resilience) to T.

vivax infection than Yankassa and Ouda sheep.