For additional details, please see: UPDATED: FDA names Taylor Farms de Mexico in outbreak

UPDATED: FDA intensifies cyclospora outbreak investigation(UPDATED COVERAGE, 1:55 p.m.) With 466 cases of cyclospora parasite infections already confirmed and more cases being confirmed daily, the Food and Drug Administration has stepped up its traceback investigation into the packaged salad mix from a Taylor Farms facility in Mexico.

The agency now has 21 people — up from five a week ago — on the case at its headquarters. FDA specialists in 10 field offices across the country are also working on the outbreak investigation. As of Aug. 5, infections from the tropical, one-celled parasite had been confirmed in 16 states, according to the Centers for Disease Control and Prevention.

Investigators with FDA have already confirmed that Iowa and Nebraska health officials were correct when they linked outbreaks in their states to packaged salad mix from Taylor Farms de Mexico, S. de R.L. de C.V.

UPDATED: FDA intensifies cyclospora outbreak investigationAs of Aug. 8, the FDA’s investigation had not linked any illnesses to consumer packs of the salad mix sold in retail stores.

“As a result of the current investigation FDA is increasing its surveillance efforts on green leafy products exported to the U.S. from Mexico,” according to the agency’s Aug. 6 update.

Investigators are trying to determine if outbreaks in 14 other states are also related to the salad mix, or if there is another potential source. The salad was served at Rod Lobster and Olive Garden restaurants, which are part of the Darden Restaurants operation.

Darden's communications director Rich Jeffers said Aug. 7 that the company is cooperating with investigators.

"We respect their findings and will continue to work with them on this matter. Iowa and Nebraska health authorities have said this is not an ongoing outbreak and the product is no longer in the food supply in those states," Jeffers said.

The FDA update said the implicated salad mix is likely out of the supply chain by now because of its limited shelf life.

However, new illnesses continue to be confirmed because of the long-lasting nature of the cyclospora infections. Symptoms can last for up to three months in healthy people and a year in the elderly or immune-compromised patients.

Patricia Quinlisk, Iowa’s head epidemiologist and medical director of the state’s health department, said in a CDC weekly report that the use of traditional media and electronic media helped during the early days of the investigation.

She said electronic alerts sent to hospitals and other health care providers on July 3, coupled with mainstream media coverage beginning July 4 in Iowa and a series of 14 Twitter messages helped raise awareness among the public and doctors.

UPDATED: FDA intensifies cyclospora outbreak investigation“For example, one patient with severe vomiting and diarrhea was discharged without a diagnosis after a five-day hospital stay and extensive laboratory testing, only to relapse days later,” according to Quinlisk’s report.

“After reading (an alert), the patient’s health-care provider ordered cyclospora testing on the patient, and the result was positive. The patient was treated with trimethoprim-sulfamethoxazole, and the symptoms resolved.”

The use of electronic messaging and media attention in the early stages of the investigation encouraged testing that might not otherwise have been considered by health-care providers or their patients, the CDC report stated.

The CDC most recently updated the case count on Aug. 5, reporting 466 cases of infection from the following 16 states: Arkansas, Connecticut, Florida, Georgia, Iowa, Illinois, Kansas, Louisiana, Minnesota, Missouri, Nebraska, New Jersey, New York (including New York City), Ohio, Texas, and Wisconsin.