Construction of genomic libraries of Cryptosporidium parvum and identification of antigen-encoding genes. 
Genomic libraries have been constructed from bovine C. parvum DNA in the lambda ZAP and lambda DASH vectors.  Based on an estimated genome size of 2 x 10(4) kilobases (kb), each recombinant library contains greater than 10 genomic equivalents.  The average recombinant size for the lambda ZAP library is 2.1 kb and for the lambda DASH library is 14 kb.  We have identified genes to major antigens recognized by hyperimmune bovine antiserum.  These recombinants are currently being purified and characterized.  Limited DNA sequence analysis of random C. parvum clones confirms suggestions that the genome is quite AT-rich.  The DNA sequence of random lambda ZAP fusion proteins has identified a potential ATPase, a structural protein and a DNA-binding protein.