Yesterday the CDC announced 457 ill persons with confirmed Cyclospora infection from 29 states in 2015. Most of these persons—275 (60%) of 457—experienced onset of illness on or after May 1, 2015, and did not have a history of international travel within 2 weeks before illness onset. These 275 persons were from the following 22 states: Arkansas (2), California (2), Connecticut (3), Florida (11), Georgia (22), Illinois (6), Iowa (1), Kansas (2), Maryland (1), Massachusetts (9), Michigan (2), Missouri (1), Montana (3), Nebraska (1), New Jersey (6), New Mexico (1), New York (excluding NYC) (8), New York City (21), Texas (157), Utah (1), Virginia (3), Washington (2), and Wisconsin (10). Clusters of illness linked to restaurants or events have been identified in Texas (157 cases, according to CDC; 237 cases, according to the Texas Department of State Health Services), Wisconsin (10), and Georgia (22) beginning May 1, 2015. CDC added that cluster investigations are ongoing in Texas and Georgia. Canadian Public health officials are also warning about an outbreak of the intestinal illness Cyclospora, with 83 cases are being investigated across Canada. The cases became known between May 9 and July 18 and are mainly in Ontario, but there are also some infections in B.C., Alberta and Quebec.
What is Cyclospora?
Cyclospora is a parasite composed of one cell, too small to be seen without a microscope. The organism was previously thought to be a blue-green alga or a large form of Cryptosporidium. Cyclospora cayetanensis is the only species of this organism found in humans. The first known human cases of illness caused by Cyclospora infection (that is, cyclosporiasis) were first discovered in 1977. An increase in the number of cases being reported began in the mid-1980s, in part due to the availability of better diagnostic techniques. Over 15,000 cases are estimated to occur each year in the United States. The first outbreak in North America occurred in 1990 from contaminated water. Since then, several outbreaks of cyclosporiasis have been reported in the U.S. and Canada, many associated with eating fresh fruits or vegetables. In some developing countries, cyclosporiasis is common among the population and travelers to those areas have become infected as well.
Where does Cyclospora come from?
Cyclospora is spread by people ingesting water or food contaminated with infected stool. For example, exposure to contaminated water among farm workers may have been the original source in raspberry-associated outbreaks in North America.
Cyclospora needs time (one to several weeks) after being passed in a bowel movement to become infectious. Therefore, it is unlikely that Cyclospora is passed directly from one person to another. It is not known whether or not animals can be infected and pass infection to people.
What are the typical symptoms of Cyclospora infection?
Cyclospora infects the small intestine (bowel) and usually causes watery diarrhea, bloating, increased gas, stomach cramps, loss of appetite, nausea, low-grade fever, and fatigue. In some cases, vomiting, explosive diarrhea, muscle aches, and substantial weight loss can occur. Some people who are infected with Cyclospora do not have any symptoms. The time between becoming infected and becoming ill is usually about one week. If not treated, the illness may last from a few days up to six weeks. Symptoms also may recur one or more times (relapse). In addition, people who have previously been infected with Cyclospora can become infected again.
What are the serious and long-term risks of Cyclospora infection?
Cyclospora has been associated with a variety of chronic complications such as Guillain-Barre syndrome, reactive arthritis or Reiter’s syndrome, biliary disease, and acalculous cholecystitis. Since Cyclospora infections tend to respond to the appropriate treatment, complications are more likely to occur in individuals who are not treated or not treated promptly. Extraintestinal infection also appears to occur more commonly in individuals with a compromised immune system.
How is Cyclospora infection detected?
Your health care provider will ask you to submit stool specimens to see if you are infected. Because testing for Cyclospora infection can be difficult, you may be asked to submit several stool specimens over several days. Identification of this parasite in stool requires special laboratory tests that are not routinely done. Therefore, your health care provider should specifically request testing for Cyclospora if it is suspected. Your health care provider might have your stool checked for other organisms that can cause similar symptoms.
How is Cyclospora infection treated?
The recommended treatment for infection with Cyclospora is a combination of two antibiotics, trimethoprim-sulfamethoxazole, also known as Bactrim, Septra, or Cotrim. People who have diarrhea should rest and drink plenty of fluids. No alternative drugs have been identified yet for people with Cyclospora infection who are unable to take sulfa drugs. Some experimental studies, however, have suggested that ciprofloxacin or nitazoxanide may be effective, although to a lesser degree than trimethoprim-sulfamethoxazole. See your health care provider to discuss alternative treatment options.
How can Cyclospora infection be prevented?
Avoiding water or food that may be contaminated is advisable when traveling. Drinking bottled or boiled water and avoiding fresh ready-to-eat produce should help to reduce the risk of infection in regions with high rates of infection. Improving sanitary conditions in developing regions with poor environmental and economic conditions is likely to help to reduce exposure.
Washing fresh fruits and vegetables at home may help to remove some of the organisms, but Cyclospora may remain on produce even after washing.