Ohio's Cyclospora case count has nearly doubled in one week, and the Centers for Disease Control and Prevention has sent investigators to the state to help manage an outbreak that has already surpassed the previous U.S. record of roughly 1,500 cases, according to CNN.

More than 2,500 Ohioans have reported illness from the parasite as of Friday, up from 1,274 cases reported the week of July 16, according to WLWT Cincinnati. The state has not specified whether that figure includes only confirmed cases or also probable ones. Hamilton County's count rose to 24. No deaths have been reported statewide, though Ohio has logged at least 88 hospitalizations, according to CNN.

The CDC's warning to avoid shredded iceberg lettuce at Taco Bell locations in Ohio remains in effect. West Chester Township and Liberty Township have multiple Taco Bell locations within the warning zone, as the Herald reported July 17.

CDC team on the ground

Gwen Biggerstaff, deputy director of the CDC's Division of Foodborne, Waterborne, and Environmental Diseases, confirmed the deployment to WLWT on Friday.

"They'll be helping with case interviews with data management, those kinds of things to support the great work that the Ohio Department of Health does every day," Biggerstaff said.

Biggerstaff told WLWT the team plans to stay two to three weeks. She said case numbers will keep climbing because reporting lags can stretch up to six weeks between when someone eats contaminated food, develops symptoms, and is officially counted.

Nine states linked to recalled lettuce

The CDC has linked cases across all nine states to shredded iceberg lettuce from Taylor Farms' facility in Guanajuato, Mexico, according to the agency's investigation page updated Friday. The affected states are Ohio, Indiana, Kentucky, Michigan, West Virginia, Illinois, Kansas, Oklahoma and Pennsylvania.

The CDC has tallied 1,947 people infected who reported eating at Taco Bell in those states, with illness onset dates ranging from Monday, June 22 through Monday, July 20, according to CNBC.

Taylor Farms issued a voluntary recall of all iceberg lettuce sourced from its Mexico facility. Sysco, the nation's largest food distributor, halted distribution of all Taylor Farms iceberg lettuce from Mexico, according to the Chicago Tribune. Taco Bell said in a July 19 statement that it removed the affected ingredient from its supply chain nationwide.

What residents should know

The CDC advises anyone who purchased recalled Taylor Farms iceberg lettuce to throw it out or return it. Routine stool tests do not include a Cyclospora-specific test, so residents who suspect illness should ask their doctor to order one, according to the Ohio Department of Health.

Symptoms include watery diarrhea, loss of appetite, weight loss, cramping, bloating, nausea and fatigue. They can take up to two weeks to appear after eating contaminated food.

Cooking food to 158°F kills the parasite. Person-to-person spread is very unlikely, according to the CDC.

The Ohio Department of Health updates its case count dashboard each Thursday; the next scheduled update is July 30.