Laboratory and field evaluation of Schistosoma japonicum DNA vaccines in sheep and water buffalo in China

Vaccines are needed to control zoonotic Schistosoma japonicum infection and several vaccine candidates have now been identified. Two of these (Sj28GST and Sj23) have shown particular promise in sheep when injected with Freund 's adjuvants. The objective of the present work was to find a vaccine formu lation which may have potential for widespread use in the field. DNA vaccin e formulations of these antigens were produced and tested first in sheep un der laboratory conditions and then in both the laboratory and the field in water buffalo. In both host species partial protection as evidenced by a re duction in parasite counts in vaccinated compared with control animals was induced by both vaccines, and in water buffalo the vaccines were shown to b e partially protective in the field as well as in the laboratory. These res ults suggest that the two DNA vaccines tested here may have potential for l arge-scale field use. (C) 2001 Elsevier Science Ltd. All rights reserved.