In the past three months, an unusually high number of people have contracted Shigella sonnei infections in Douglas County, Nebraska, prompting a safety warning by the local health department. Normally, the area sees about 31 confirmed cases of shigellosis (the infection caused by Shigella bacteria) each year, according to the Douglas County Health Department. This year, however, 50 cases have been confirmed since May. Of these 50 cases, 41 percent occurred in children under the age of 5. A further 29 percent of victims were between 5 and 9 years old. The majority of the cases (62 percent) were associated with child care settings. Due to the high incidence of this disease, DCHD is issuing a warning to residents of the county, which includes the city of Omaha. The Health Department warned those who have been sick not to swim in pools or water parks for a week following recovery, and reminded everyone to be vigilant about hand washing. “Hand washing is absolutely critical to controlling any disease that involves diarrhea,” said DCHD Health Director Dr. Adi Pour in a statement Wednesday. “It is especially important to wash your hands with soap for at least 20 seconds after changing diapers or using the bathroom, since it takes only a small exposure to pass along the disease.” Infection can occur after ingestion of fewer than 100 of the bacteria, which thrive in the human intestine and are spread through fecal matter via person-to-person contact or through contaminated food. Symptoms of Shigella infection usually begin 1 to 3 days after exposure to the bacteria and include diarrhea, fever, stomach cramps and rectal spasms. Diarrhea is bloody in 25 to 50 percent of cases. If you think you may have contracted shigellosis, contact your healthcare provider.