Dozens of cases of cyclospora have been diagnosed in Texas but the source remains a mystery.

When Christine first fell ill the weekend before Fourth of July, she says she thought she had food poisoning.

“My stomach was feeling like it was actually being wrung out like a wet towel,” she describes. “That just happened so frequently, I was doubled over in pain.”

Christine, who didn't want to use her last name, assumed the symptoms would go away. When they didn’t, she ended up in her doctor’s office.

“She said, ‘I don’t even need to see you, go straight down to the emergency room,’” Christine remembers.

The diagnosis: cyclospora, a nasty parasite that’s part of a vicious cycle. It all starts when the parasite gets introduced to the food chain, usually when dirty, infected water is used on produce. If you eat it, you get violently ill and could even spread it by accident, perpetuating that cycle.

“I want everyone to be aware that it is a contact-spread parasite,” Christine warns. “Wash your produce. Wash your hands after you handle produce.”

Nearly a month after getting treatment, Christine can finally eat solid foods again, though she’s starting slowly with soups.

Now she wants to know how she got cyclospora. So do local and state health workers.

The Houston Health Department has gotten 19 reports of the parasite since May.

A spokesperson with Harris County Public Health says they received nine probable or confirmed cases between June 4 and July 5. There are three cases still pending investigation.

The Texas Department of State Health Services reports there have also been: Three cases in Fort Bend County; two in Galveston County and one in Montgomery County.

RELATED: Source of Texas cyclospora cases still a mystery

“We don’t have an idea of where it’s coming from so far. That’s the importance of us doing an investigation,” said Houston Health Department spokesman Porfidio Villareal.

Until there’s a concrete answer, Christine says she and her family are taking extra precautions, which include using hand sanitizer in the grocery store and every time they touch produce.

“Be very, very careful,” she warns.

Symptoms of cyclosporiasis usually begin two to 14 days after eating or drinking contaminated food or water. It causes severe diarrhea that can last weeks to months and may relapse.

Additional symptoms may include anorexia, fatigue, weight loss, abdominal cramps, bloating, increased gas, nausea, vomiting and low-grade fever.

Cyclosporiasis can occur at any time of the year, but most of the reported cases and outbreaks in the United States occur during spring and summer months, particularly during May through August.

Past outbreaks in the U.S. have been associated with imported fresh produce, including fresh cilantro, pre-packaged salad mix, raspberries, basil, snow peas and mesclun lettuce. Thorough washing of fresh produce is recommended, but may not eliminate the risk of transmission since Cyclospora can be difficult to wash off all types of produce.