Immunological control of ectoparasites: past achievements and future research priorities

Recombinant vaccines are available for the control of the tick Boophilus microplus, while progress has been made in the development of vaccines against Lucilia cuprina and Chrysomya bezziana. Literature suggests that the control of other ectoparasites is feasible, either through the duplication in a vaccine of naturally acquired immunity or through 'concealed' antigen vaccines. Major deficiencies in our current knowledge however point to possible research opportunities for the future. The identification of protective antigens from all species is proceeding slowly, particularly for the antigens of naturally acquired immunity. Our capacity to produce effective recombinant antigens has progressed greatly, though there remains a major difficulty where some or all of the protective effect is due to immunogenic oligosaccharide. Our understanding of protective mechanisms is limited. The delivery of the appropriate immunological response remains difficult. Nevertheless, some of the most critical areas of ignorance are in basic biological issues: factors which affect the susceptibility of particular pest species to immunological attack and the implications of vaccine-induced effects for pest and disease control under field conditions. Increasingly too, effective pest control is likely to demand the integration of a variety of control technologies. The study of this integration is in its infancy.