Protection of kids against Cryptosporidium parvum infection after immunization of dams with CP15-DNA

In this study the effectiveness of a DNA vaccine to confer protection again st cryptosporidiosis, an enteric infection of lifestock and humans, was eva luated. A vaccination protocol using a recombinant plasmid encoding the 15 kDa surface sporozoite protein of Cryptosporidium parvum was developed in a dult pregnant goats. The present study reports that nasal immunization of p regnant goats with CP15-DNA led to a transfer of immunity to offspring conf erring protection against C. parvum infection. Kids from CP15-DNA-vaccinate d dams shed significantly fewer oocysts and over a shorter period than did kids from unvaccinated goats. The low level of parasite development in prot ected kids did not affect their growth whereas unprotected kids grew much s lowly. There was still a significant difference in the weights of protected and unprotected kids after complete recovery. Anti-CP15 antibodies were pr esent in serum and colostrum from vaccinated goats. Nevertheless, the preci se immune mechanism of protection has still to be determined. This vaccine should reduce the economic losses due to cryptosporidiosis in ruminants, sp ecially in small ruminants (calves, lambs, kids). It has also the potential to reduce environmental contamination by reducing oocyst shedding. (C) 199 9 Elsevier Science Ltd. All rights reserved.