Effects of anti-tick vaccines, recombinant serine protease inhibitors (RAS-1-2) and RIM 36 antigens against Rhipicephalus appendiculatus ticks’ feeding on Zebu cattle in Uganda
A preliminary trial of a cocktail of recombinant RAS-1-2 and RIM 36 antigens was conducted in Uganda to assess the effects of ant-tick vaccines against Rhipicephalus appendiculatus tick feeding on Zebu cattle under both experimental and natural conditions. Under experimental conditions, over a period of 28 days, the vaccinated group (n = 5) registered a mean female tick engorgement weight of 147.7 ± 41.8, mean tick egg weight of 90.5 ± 37.9, mean egg hatchability rate of 87.0 ± 12.1 and mean days ticks took to drop off of 6.4 ± 0.4 as opposed to the unvaccinated group (n =5) that had a mean female tick engorgement weight of 175.4 ± 63.0, mean tick egg weight of 99.7 ± 39.4, mean egg hatchability rate of 100 ± 9.6 and mean days ticks took to drop off of 6.4 ± 0.4. Upon exposure to natural tick challenge over a period of 61 days, there was no difference in total tick counts between the vaccinated group (mean tick count= 2-9) and non-vaccinated group (Mean tick count = 2-9) for the first 38 days. However, thereafter over a period of 23 days, tick counts for the vaccinated group (mean tick count = 3) were consistently much lower than those of the non-vaccinated group (mean tick count = 6) on exposure to natural tick challenge. In conclusion, the study revealed that a cocktail of recombinant RAS-1-2 and RIM 36 antigens had effect against tick feeding on Zebu cattle under both experimental and natural conditions with an efficacy rate of 65 % against R. appendiculatus under experimental conditions.
Key words: Anti-tick vaccines; RAS-1-2; RIM 36; R. appendiculatus; Zebu cattle; Uganda