Experimental cryptosporidiosis in adult and neonatal rabbits.

Neonatal and adult New Zealand White rabbits were infected experimentally with Cryptosporidium parvum. No histologic evidence of infection was found in adult rabbits. However, increased levels of anti-cryptosporidial serum IgG were present, and multiple antigens were detected by serum on immunoblots. In neonates, variably severe, transient infection was present from Days 3 to 21 postinoculation. Serum IgG was initially elevated, decreased until Day 10 postinoculation, then progressively increased for the remainder of the study. A prominent 15 kilodalton antigen was detected on immunoblots using serum obtained on Days 14 until 28 postinoculation. Neonate anti-cryptosporidial fecal IgA were slightly elevated on Days 14 and 21 postinoculation.