Multiparasite communities in animals and humans: frequency, structure and pathogenic significance.

Cyclospora cayetanensis, a coccidian parasite that causes protracted, relapsing gastroenteritis, has a short recorded history. In retrospect, the first 3 documented human cases of Cyclospora infection were diagnosed in 1977 and 1978. However, not much was published about the organism until the 1990s. One of the surprises has been the fact that a parasite that likely requires days to weeks outside the host to become infectious has repeatedly caused foodborne outbreaks, including large multistate outbreaks in the United States and Canada. In this review, I discuss what has been learned about this enigmatic parasite since its discovery and what some of the remaining questions are. My focus is the foodborne and waterborne outbreaks of cyclosporiasis that were documented from 1990 through 1999. The occurrence of the outbreaks highlights the need for health care personnel to consider that seemingly isolated cases of infection could be part of widespread outbreaks and should be reported to public health officials. Health care personnel should also be aware that stool specimens examined for ova and parasites usually are not examined for Cyclospora unless such testing is specifically requested and that Cyclospora infection is treatable with trimethoprim-sulfamethoxazole.

Cyclospora cayetanensis : a review, focusing on the outbreaks of cyclosporiasis in the 1990s.

The coccidian parasite Cyclospora cayetanensis is recognized as an emerging pathogen that causes protracted diarrhea in humans. The first cases of Cyclospora infection were reported in the late 1970s and were observed among expatriates and travelers in regions where infections are endemic. Since then, Cyclospora has been considered a cause of traveler's diarrhea. Epidemiological investigations were reported and examined in areas of endemicity even before the true identity of Cyclospora was elucidated. Cyclospora was fully characterized in the early 1990s, but it was not until the 1995 Cyclospora outbreak in the United States and Canada that it caught the attention of the public and physicians. The biology, clinical presentation, epidemiology, diagnosis, treatment, and control of cyclosporiasis are reviewed, with a focus on diagnostic assays currently being used for clinical and environmental samples. Challenges and limitations in working with Cyclospora are also discussed.

Update on Cyclospora cayetanensis, a Food-Borne and Waterborne Parasite

Cryptosporidium parvum and Cyclospora cayetanensis: a review of laboratory methods for detection of these waterborne parasites.

Ingestion of raw vegetables represented an important mean of transmission of several infectious diseases. No previous surveys have been conducted to evaluate the prevalence of parasitic contaminati...

Detection of parasites in commonly consumed raw vegetables

Cyclospora cayetanensis, a newly emerging parasite, is endemic in Nepal. A total of 2,123 stool specimens were collected from 3 health care facilities based on clinical symptoms during the period between 1995 to October, 1998. Out of these specimens, cayetanensis oocysts were found in 632 (29.8%). To identify possible sources for Cyclospora infection, drinking water, sewage water, green-leafy vegetables including fecal samples of various animals were collected and examined. The vegetable leaves were washed in distilled water then the washings, sewage water and drinking water were centrifuged and the sediment were examined microscopically. As a result, oocyst of Cyclospora were identified in sewage water and vegetable washings on four different occasions in June, August, October and November. The positive results were also confirmed as C. cayetanensis by development of 2 sporocysts after 2 week incubation period in potassium dichromate. A survey of 196 domestic animals from the same areas demonstrated that two chickens were positive for Cyclospora-like organism and others were negative. Although further studies are needed to clarify the direct link between Cyclospora infection and these sources, the results suggest that sewage water, green leafy vegetables are possible sources of infection and chickens could be possible reservoir host of Cyclospora in Nepal.

Study of Cyclospora cayetanensis in health care facilities, sewage water and green leafy vegetables in Nepal.

Food consumption and nutrient intake and their relationship among nepalese

Three hundred and fifty-four soft, loose or watery stool specimens from patients with acute diarrhoea were screened for the presence of Cryptosporidium oocysts. A modified Ziehl Neelsen with DMSO staining method was used for detecting Cryptosporidium oocysts in the stool samples. The oocysts were identified in 24 (6.8%) of the samples, while 46 samples (13%) showed mixed infections. Children aged between 2 and 10 years were mostly infected by this parasite, while infection was more prevalent in females than in males for all the age groups. These findings suggest that Cryptosporidium is one of the important aetiologic agents of diarrhoea in this population and should be looked for during laboratory investigation of diarrhoeal stool samples.

Mathura P. Shrestha

Papers

Study of Cyclospora cayetanensis in health care facilities, sewage water and green leafy vegetables in Nepal.

Food consumption and nutrient intake and their relationship among nepalese

Prevalence of Cryptosporidium infection and diarrhoea in Nepal.

The serum status of tocopherol and retinol and their relation to lipids in persons aged 10–72 in Nepal

Evaluation of the iron status in Nepalese living in Southern Nepal