More data needed to understand risk factors for Cyclospora infection

Recent data from the Foodborne Diseases Active Surveillance Network suggest that cases of Cyclospora cayetanensis appeared to be concentrated in two sites of the 10 studied.

“Because one of those sites also reported the most international travel-associated cases, it’s likely that differences in testing rates and/or sensitivity of testing methods in part account for the wide variation in number of reported cases among sites,” Rebecca Hall, MPH, of the division of parasitic diseases and malaria of the CDC, told Infectious Disease News. “It is not known whether there are differences in rates of exposure or infection among the sites.”

Rebecca Hall

Hall and colleagues from the CDC and the Connecticut and New York Emerging Infections Programs looked at data on Cyclospora infection reported to FoodNet between 1997 and 2009. The study included 10 sites that account for about 15% of the US population.

There were 370 cases of Cyclospora infection reported, and 70.3% were in Connecticut and Georgia. According to the researchers, these two sites comprised 29% of the entire FoodNet population on average during the 13-year study period.

Although positive stool specimens were found throughout the year, more than half of the cases occurred during June and July. During the period from 2004 to 2009, 48.6% of the cases reported were associated with international travel, known outbreaks or both.

“Compared with some other emerging foodborne enteric pathogens, we are lacking very basic knowledge about the biology and epidemiology of Cyclospora,” Hall said. “For example, we do not know the ideal environmental conditions — such as time, temperature and humidity — under which Cyclospora oocysts sporulate and become infective.”

Hall said investigations have implicated fresh produce commodities as vehicles of Cyclospora infection in US outbreaks, but there is little knowledge of the risk factors for travel-associated or non-outbreak-associated US cases. Also, there is little knowledge about the biology of Cyclospora in part because there is a lack of infective organisms with which to conduct laboratory research.

References:

Hall RL. Clin Infect Dis. 2012;54:S411-S417. .

Disclosures:

Ms. Hall reports no relevant financial disclosures.