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USE OF LONG ACTING STEROID METHYLPREDNISOLONE ACETATE FOR THE PROLONGATION OF CRYPTOSPORIDIUM SP. IN MICE
Citation:
Miller, T. A. AND F W. Schaefer III. USE OF LONG ACTING STEROID METHYLPREDNISOLONE ACETATE FOR THE PROLONGATION OF CRYPTOSPORIDIUM SP. IN MICE. Presented at VII International Workshops on Opportunistic Protists (IWOP), Cincinnati, OH, June 13-16, 2001.
Impact/Purpose:
Determine the infective dose of Cryptosporidium in the immunocompromised host to see if it differs from that in the immunocompetent host.
Description:
Current protocols for Cryptosporidium sp. propagation in mice vary according to the strain and age of mouse as well as the species of Cryptosporidium. Cryptosporidium muris is a natural parasite of mice, but only neonatal mice are susceptible to C. parvum infection. Published C. parvum protocols for adult mice usually involve the use of the water soluble form of dexamethazone, administered daily or every other day, either ad libitum in the drinking water or by intra peritoneal injection. Uniformity of doses a problem with any water bottle delivery system. Also, excessive animal handling and labor costs are significant with daily injections.
In an attempt to decrease handling problems and dosing variations a single injection method was developed. A single injection of Methylprednisolone Acetate (DepoMedrol - Pharmacia-UpJohn) is sufficient to allow a Cryptosporidium parvum infection in adult CF-1 mice. The effective dose appears to increase with the age and weight of the mouse. In mice naturally infected with Cryptosporidium muris a single dose prior to infection will prolong the shedding of oocysts. A single dose after the prepatient period will radically incrase the number of oocysts produced per mouse as well as prolong the shedding interval.