Developments in anti-tick vaccines

Abstract

The tick infestations lead to severe irritation of the animals, discomfort, pyrexia, paralysis, worry, toxicosis, anaemia and transmit the different haemoprotozoan diseases resulting in huge economic losses to the livestock industry worldwide due to their global distribution. Hence, most of the ticks in a dairy cattle or buffaloes and sheep-goat are controlled mainly by the chemotherapeutic agents called acaricides to increase the production and productivity of these animals. Chemical control, albeit predominant, has been hampered by poor utilization of active agents, indiscriminative utilization and sub-therapeutic dosages, thus leading to development of resistance and requiring the use of greater concentrations of active compounds and extra regular application, year by year. Moreover, due to the development of multidrug resistance in ticks in livestock, there is a need for development of the vaccines against the ticks. In the global market, different vaccines against bacteria and viruses are available but vaccines against the ticks are very few. Vaccines may help control ticks by non-chemical ways, thereby, reducing acaricide resistance. The release of commercial recombinant vaccine against the cattle tick Boophilus microplus, plays a significant role as a novel control measure of cattle ticks, due to the feasibility of vaccination. A number of factors create some hindrances to the progress towards usable, commercially available vaccines, thereby, limiting their use. However, Gavac and TickGard are available commercially worldwide. Vaccine candidates which act against tick vectors and pathogens transmitted by ticks, are discussed in the present communication.