Humoral antibody response and oocyst shedding after experimental infection of histocompatible newborn and weaned piglets with Cryptosporidium parvum.

Experimental inoculations (mono- and multi-inoculations) with C parvum isolated from a diarrheic child and maintained on calves, were performed on 2 histocompatible miniature (d/d haplotype) weaned 4-week-old piglets and 2 newborn piglets. In each group, 1 piglet received water at the moment of inoculation and served as a negative control. Our results showed that the piglet strain used was resistant to cryptosporidiosis. No clinical sign or oocyst shedding were observed in newborn piglets. A very weak shedding was noticed on day 6 (D6) post-inoculation in inoculated weaned piglets. Using ELISA, inoculated weaned piglets showed a peak of G, M and total antibodies on D10. Specific IgA antibody production peaked on D20. During the experiment on newborn piglets, no peak of specific IgA production was detected. Using immunoblotting, sera of both inoculated weaned piglets and one inoculated newborn piglet were shown to recognize a 14.5-16.5 kDa protein. A 23 kDa antigen was recognized by all 3 uninoculated and inoculated weaned piglets. A difference between mono and multi-inoculations was not clearly demonstrated. Age did not play any role. This pig strain does not seem to be a good model to induce acute cryptosporidiosis.