Genetical and biological characteristics of gastric Cryptosporidium spp.

We investigated gastric types of Cryptosporidium. We isolated C. muris type oocysts from beef cattle in Miyagi, Japan, and the type was a novel type because of the difference of the infectivity to mice compared to that isolated in the U.S. We denoted it as C. andersoni Kawatabi type. It parasitized in the abomasum of cattle and the stomach of SCID mice, and had a relatively low infectivity to cattle. We also isolated Cryptosporidium from large Japanese field mice that parasitized to the stomach. The infectivity of the isolate to wild and laboratory mice was slightly different from that of C. muris. Phylogenetic analysis of DNA sequence of the 18S rRNA indicated that the isolate was a member of the C. muris cluster. This isolate was denoted as Cryptosporidium muris Japanese field mouse genotype as a novel genotype of C. muris.