Life cycle of Cryptosporidium muris in two rodents with different responses to parasitization.

This study focuses on mapping the life cycle of Cryptosporidium muris in two laboratory rodents; BALB/c mice and the southern multimammate rat Mastomys coucha, differing in their prepatent and patent periods. Both rodents were simultaneously experimentally inoculated with viable oocysts of C. muris (strain TS03). Animals were dissected and screened for the presence of the parasite using a combined morphological approach and nested PCR (SSU rRNA) at different times after inoculation. The occurrence of first developmental stages of C. muris in stomach was detected at 2 center dot 5 days post-infection (dpi). The presence of Type II merogony, appearing 36h later than Type I merogony, was confirmed in both rodents. Oocysts exhibiting different size and thickness of their wall were observed from 5dpi onwards in stomachs of both host models. The early phase of parasitization in BALB/c mice progressed rapidly, with a prepatent period of 7 center dot 5-10 days; whereas in M. coucha, the developmental stages of C. muris were first observed 12h later in comparison with BALB/c mice and prepatent period was longer (18-21 days). Similarly, the patent periods of BALB/c mice and M. coucha differed considerably, i.e. 10-15 days vs chronic infection throughout the life of the host, respectively.