Submitted to: Emerging Infectious Diseases
Publication Type: Abstract Only
Publication Acceptance Date: July 7, 2000
Publication Date: N/A
Technical Abstract: Cryptosporidium parvum poses a waterborne and foodborne threat to public health. At present, human and bovine isolates have been identified as human pathogens but no technique exists, other than oral inoculation of neonatal or immunosuppressed mice, to measure the viability of C. parvum oocysts in environmental specimens. Research in our laboratory has shown that intracellular amylopectin levels decrease during storage at temperatures from 5 to 30oC. Recent studies in our laboratory using RT-PCR have shown that mRNA levels for amyloglucosidase (CPAG) decrease during storage of C. parvum oocysts. Our results clearly show that oocysts stored for 9 months or more do not contain CPAG mRNA. Furthermore, the CPAG mRNA levels correlate with parasite infectivity and fecundity in neonatal mice. Given that amylopectin is an energy source for C. parvum oocysts, it is possible that blockage or loss of amylopectin synthesis may render the parasite incapable of existing for long periods of time in the environment or possessing the energy stores needed to excyst and enter host cells.