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DETECTION OF CYCLOSPORA CAYETANESIS USING A QUANTITATIVE REAL-TIME PCR ASSAY
Citation:
Manju Varma, M., Jeff D. Hester, F. Frank W. Schaefer III, M. Michael W. Ware, AND H. H. D. Alan Lindquist. DETECTION OF CYCLOSPORA CAYETANESIS USING A QUANTITATIVE REAL-TIME PCR ASSAY. JOURNAL OF MICROBIOLOGICAL METHODS 53(1):27-36, (2003).
Impact/Purpose:
The main objective is to develop a method to detect Cyclospora in water.
Description:
Cyclosporal cayetanensis, a coccidian parasite of humans, has been recognized worldwide as an emerging pathogen in both immunocompromised (Ortega et al.1993) and immunocompetent individuals (Berlin et al.1994). Presently, humans apear to be the primary host for this parasite (Eberhard et al.2000). Clinical manifestations associated with C. cayetanensis can include prolonged diarrhea, nausea, abdominal cramps, anorexia, weight loss, and other symptoms of gastronenteritis. The transmission form of C. cayetanensis is an environmentally resistant, 8-10 um spherical oocyst that contains two ovoid sporocysts each of which contains two sporoxoites. Cyclospora cayetanensis oocysts shed in the feces of an infected host are not infectious until they become sporulated. Depending on a variety of environmental factors such as temperature and humidity, sporulation occurs after approximately two weeks outside the host.
A striking feature of this parasite is its seasonality. In some areas, during the rainy season, infection rates are high, decreasing to undetectable levels during the dry season. While the mode of transmission has not been completely elucidated, most cases of cyclosporiasis in the United States have been associated with consumption of fruits and vegatables that may have become contaminated after contact with tainted water (Berline et al.1994; Herwaldt and Ackers 1997). Since the epidemiology of this disease is still in doubt, it would be valuable to have sensitive and specific tools to detect and quantify the presence of this organism in the environment. These tools might also lead to the development of more sensitive and specific clinical diagnostic methods.