MORPHOLOGICAL AND GENETIC-CHARACTERIZATION OF CRYPTOSPORIDIUM OOCYSTSFROM DOMESTIC CATS

Faecal samples were collected from domestic cats in the metropolitan a rea of the city of Perth, Western Australia, and screened for the pres ence of Cryptosporidium by both microscopy and PCR. Of 162 samples scr eened, two were positive for Cryptosporidium (a prevalence of 1.2%). S ample Ct33 was from an 18-month-old female and sample Ct131 from a 12- month-old female. Morphological studies revealed oocysts with an avera ge size of 4.6x4.0 mu m, smaller in size than isolates typically seen in humans (5.0x4.5 mu m). Sequence analysis of PCR products showed seq uences from cat isolates to be different to previously sequenced human and calf isolates, with cat isolates exhibiting 8.1% sequence diverge nce from these isolates. Phylogenetic analysis grouped the cat isolate s into a distinct group, separate from other C. parvum isolates and Cr yptosporidium species. These results lend support to the existence of a cat-adapted Cryptosporidium strain or species. (C) 1998 Elsevier Sci ence B.V.