Field Trial of a Thermostable Peste des petits ruminants (PPR) Vaccine in a Semi-Arid Zone of Nigeria

The field trial of a candidate thermostable Peste des petits ruminants (PPR) vaccine was carried out in flocks of sheep and goats under the extensive system of management. The immune response of vaccinated animals was determined using the neutralisation test to detect PPR virus specific antibody. Vaccinated animals seroconverted and a four-fold or more rise in antibody titre were observed between pre-vaccination and post-vaccination antibodies. The vaccine elicited significant antibody response in goats through the different routes of administration (intramuscular, intranasal, intraocular, subcutaneous and orally), but was poorly transmitted between the vaccinees and in-contact animals. The sheep responded poorly to the vaccine administered through most of the routes, except for those vaccinated through intramuscular and subcutaneous routes that seroconverted significantly (≥4 fold rise). The vaccine retained a potent titre of 3.1 log10 TCID50 for more than 8 hours after reconstitution in PBS at room temperature. Based on the response of goats to oral vaccination, it is suggested that the vaccine could be administered on the field through the oral routes and has the potential to be adapted to a feed-based administration for wider application to the scattered livestock populations under the extensive system of management.