Application of immunity in the control of parasitic disease

Abstract

The application and potential of immunological methods for the control of a number of parasitic diseases of domestic animals is reviewed. In particuar, East Coast fever and trypanosomiasis of cattle and haemonchosis of sheep are discussed at some length, while dictyocauliasis, babesiosis and C. bovis infection (all of cattle) are dealt with more briefly. To date, the only vaccines in large-scale production are those against Dictyocaulus viviparus, the bovine lungworm, and Babesia argentina and B. bigemina in cattle. Both are attenuated live vaccines with quite stringent methods of distribution in view of their limited shelf life. Perhaps part of their success is due to the fact that by the time the clinical disease is recognised and treatment initiated, the hosts have usually suffered a considerable check and may even be very ill. If this is the case, it seems not unreasonable to hope, in view of the progress already achieved, that a vaccine for East Coast fever may become available in the fairly near future. For trypanosomiasis and haemonchosis, the immediate outlook is less promising. With the former perhaps the best one can strive towards is a better appreciation of the role of chemotherapy in permitting the development of non-sterile immunity. In the latter, apart from the potential role of H. contortus-resistant breeds, there seems little option at present but to rely on prophylactic chemotherapy.