Iowa has seen an influx in cases of a food-borne illness, which can spread like wildfire when exposed.

In 2013, Iowa had 342 cases of shigella — bacteria closely related to salmonella that causes shigellosis. This was a 522 percent increase over the average number of cases for the past three years, according to the annual disease report released this month by the Iowa Department of Public Health.

The majority of cases were due to a community-wide outbreak in western Iowa beginning in September and lasting through the end of the year.

Shigella can be transmitted through food, including salads, raw vegetables, dairy products, and meat. These food items are usually contaminated by water obstructed with fecal matter or the unsanitary conditions of food handlers.

People who contract shigella can experience abdominal cramps, high fever, loss of appetite, nausea and vomiting, and painful bowel movements.

In severe cases, individuals affected may suffer convulsions, lethargy, and kidney failure.

Doug Beardsley, the director of the Johnson County Department of Public Health, said the outbreak was associated with a nationwide distribution of contaminated lettuce to restaurants.

“There was a huge spike in cases during that time period where restaurants were receiving contaminated lettuce,” Beardsley said. “That’s why the percentage increase for 2013 seems so drastic.”

He said this increase is associated with a single outbreak, and cases went back down after the lettuce-contamination was discovered, so it isn’t something to be concerned about in the future.

University of Iowa Hospitals and Clinics apokesman Tom Moore said he didn’t know if there was an abnormal increase in shigella cases for UIHC, but the hospital reports data directly to the Public Health Department.

He said it is difficult for the hospital to get specific numbers, but if there is a significant change reflected in Johnson County, it is possible it was reflected at UIHC.

Iowa’s Deputy State Epidemiologist Ann Garvey said the bacteria are very infectious, and it doesn’t take much exposure to spread from person-to-person.

“When [shigella] gets circulating in communities in high numbers, it’s extremely hard to stop,” Garvey said. “We’ll often see community-based outbreaks because of its infectious nature.”

She said there is no vaccine for the infection, and the department relies heavily on community-based initiatives to encourage cleanly habits for those cooking food for others.

“If you’re sick, please stay home,” Garvey said. “We ask the community members to wait until they are well again to handle food that is intended for others.”

The most recent National Shigella Surveillance Annual Report indicated 7,746 nationwide infections in 2012, according to the Centers for Disease Control and Prevention.

Garvey said shigella cases are common in the United States — additionally, many times individuals experience mild cases in which they may not get very sick and aren’t diagnosed.

“The actual number of shigella cases may be up to 20 times the number that are diagnosed,” she said. “So realistically, the U.S. is dealing with nearly 300,000 cases per year.”