AVOIDING FOOD-BORNE ILLNESS.

Byline: Steven Pratt Chicago Tribune 

Most of the guests felt ill after a Lake Forest, Ill., dinner party in late May, but it took one woman's persistent complaints and a specialist in parasitic diseases to diagnose the group had been infected by the emerging protozoa Cyclospora caytenneis.

That is because information on cyclospora is scarce and tests for it are not yet routine. Only within the last decade has it been recognized as a health threat, and until recently most cases have been confined to or traced to poor and developing countries, such as Peru, Nepal, India and some tropical countries.

Transmitted through contaminated water or food, it can cause watery diarrhea, nausea, vomiting, cramps, appetite loss and low-grade fever that may last a month or longer. It also may return one or more times, researchers say. Although seldom fatal in healthy people, it has caused death in those with compromised immune systems.

When her symptoms failed to subside after three weeks, the woman sought help at two hospitals before seeing Dr. Scott Fridkin at the Infectious Disease Clinic in Rush Presbyterian Medical Center. A former investigator for the Centers for Disease Control and Prevention, Fridkin ordered specific tests and discovered the cyclospora protozoa.

Subsequent tests have confirmed 15 more recent cases of cyclospora among Chicago-area residents, 12 of whom had attended either the May 18 party in Lake Forest or a May 10 golf club luncheon in North Barrington, Ill.

Similar outbreaks have been reported in seven other states, including Texas, where 100 people at a gas company picnic in early May were infected from what investigators there traced to fresh strawberries.

Most Chicago-area victims also reported eating fresh strawberries or raspberries as well.

Not until recently did CDC officials in Atlanta confirm a link between Guatemalan raspberries and cyclospora.

One problem tracing the source is that it takes up to six days for symptoms to appear. By that time, it not only is difficult to pinpoint what foods were eaten, but those foods also usually have disappeared.

Like its cousin Cryptosporidium parvum - the protozoa that invaded Milwaukee's water in 1993, sickening 400,000 and killing more than 100 - cyclospora is ingested through the mouth in food or water, then reproduces in the human intestines and is excreted in the stool.

And like cryptosporidium, it will survive in water, moist dirt or on plants at a temperature of 77 degrees F or greater almost indefinitely, though it will not reproduce, present research shows.

But unlike cryptosporidium, it can be treated: Cyclospora will respond to the antibiotic combination trimethoprim-sulfamethoxazole, also known as Bactrim, Septra or Cotrim.

Although the symptoms may last for as long as 43 days, most people eventually recover. But left untreated it could be fatal to those with HIV, older people, the very young and others with compromised immune systems.

Although cryptosporidium can be transmitted directly from one infected person to another, that is not usually the case with cyclospora because it first must mature outside a host four to seven days before it becomes infectious.

Though the cyclospora organism was first reported in 1977, no research was published until 1986, when almost all reported cases were outside the United States.

Give fresh fruit a good cleaning

Thoroughly rinse fresh fruit and vegetables in clear, fresh water, especially if you plan to eat them raw, health officials recommend. That applies to all produce, whether it is to be peeled or not.

But if a fruit or vegetable is contaminated with a parasite such as cyclospora, even a good scrubbing is not guaranteed to make them safe, said Dr. Peter Schantz, deputy chief of epidemiology at the Centers for Disease Control in Atlanta. Only cooking or freezing will kill the bug.

Because of their surface texture and crevasses, berries can be more difficult to rinse than a plum or a peach, Schantz says.

Besides helping to eliminate parasites and microbial contamination, rinsing fruits will help remove dirt, dust and any residual pesticides.

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Photo: Thoroughly rinse fresh fruit and vegetables inclear, fresh water, especially if you plan to eat them raw, health officials recommend.

Chicago Tribune

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