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.”
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
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.
Hall RL. Clin Infect Dis. 2012;54:S411-S417. .
Ms. Hall reports no relevant financial