Effect of Peste des petits ruminants Vaccination on Clinico-haematological Parameters of West African Dwarf Sheep Experimentally Infected with Trypanosoma congolense

Aim: The research was conducted to determine the clinico-haematological parameters and impacts of Peste des petits ruminants (PPR) vaccination and trypanocidal treatment in Trypanosoma congolense infected West African Dwarf (WAD) sheep.

Methodology: Twenty (20) WAD sheep were grouped into five (5) (A-E), each containing four (4) sheep. Group A (Gp A) was the unvaccinated and uninfected control. Groups B, C, D and E were first vaccinated with PPR vaccine, after which D and E were infected with T. congolense one (1) week post-vaccination, and then C and D were treated three (3) weeks post-infection.

Results: A prepatant period of 12-14 days was recorded. The infection was characterized by fluctuating parasitaemia and pyrexia, decreased appetite, slight pale mucous membrane, starry hair coat and enlargement of prescapular and perfermoral lymph nodes. There was no significant change (P>0.05) in the mean body weight and pulse rate of the infected sheep. Decreased packed cell volume (PCV), haemoglobin concentration (Hb conc) and total erythrocyte count (TEC) were observed in the infected sheep. Leucocytosis associated with lymphocytosis which was similar in the infected and uninfected sheep were observed in all the vaccinated sheep starting from two weeks post vaccination. The vaccination had no effect on clinical (temperature, pulse rate, weight gain) and red blood cell (mean PCV, Hb conc and TEC) parameters. Following treatment with diminazene aceturate, the infected and treated sheep became aparasitaemic within 24 hours post treatment and there was no relapse infection. The declines in the clinical and haematological parameters of the infected sheep were reversed by treatment.

Conclusion: Vaccination caused a marked leucocytosis due to lymphocytosis in both infected and uninfected animals and also had no impact on the clinical parameters assessed which is an indication that PPR vaccination had no untoward effect on the animals.