Food-borne Illness, Public Health, Shigella

Health officials investigate Shigellosis outbreak at Cascade Ridge Elementary School

Computer image of Shigella bacteria

From Public Health – Seattle & King County

Public Health is investigating an outbreak of shigellosis associated with the kindergarten classrooms at Cascade Ridge Elementary School in Issaquah.

All of the people who have been or are sick are students, school staff, or their family members. At this time, Public Health investigators have not identified any common foods, restaurants, or other sources among the people who got sick.

Since November 26, 2018, Public Health has learned of at least 16 people that became sick with symptoms consistent with shigellosis, including vomiting, diarrhea, and fever. Eight of the 16 sick people are adults and eight are children; most have already recovered. Illness onset dates range from November 4–29, 2018.

About Shigellosis

  • Shigellosis is an infectious disease caused by bacteria called Shigella.
  • Most who are infected with Shigella develop diarrhea, fever, and stomach cramps. Some people may have no symptoms at all.
  • Illness from Shigella usually resolves in 5–7 days, but recovered individuals may still spread the bacteria.
  • Ill persons with suspected shigellosis should not work in food handling, patient care, or childcare settings, and ill children with suspected shigellosis should not attend daycare until they have seen a healthcare provider and been tested for Shigella infection, even if their illness is mild.
  • Persons with Shigella infection who work in or attend these sensitive settings must be cleared by Public Health before returning.
  • People with mild cases of Shigellosis can still spread the infection. It’s important to have good handwashing and food safety practices at all times (see below).

Prevention: General advice for reducing risk of contracting Shigella:

  • Wash hands, cutting boards, and counters used for food preparation immediately after use to avoid cross contaminating other foods.
  • Wash hands thoroughly with soap after using the bathroom or changing diapers, and before preparing any food or eating.
  • Wait at least 24 hours after the last episode of vomiting and/or diarrhea before preparing any food for others.
  • Avoid sexual activity with those who have diarrhea or who recently (within the past several weeks) recovered from shigellosis

For more information about shigellosis here:

As part of the investigation, Environmental Health investigators visited the affected kindergarten classrooms and completed an inspection of the kitchen and cafeteria at Cascade Ridge Elementary on November 28, 2018. Investigators worked with the school nurse and principal to identify any other ill staff or students outside of the kindergarten classrooms.

The investigators did not identify any food handling practices in the kitchen that could increase the risk for Shigella infection among students or staff. No ill food workers were identified.

Recommendations for a thorough cleaning and disinfection of common areas and surfaces was given and completed by the school on November 28, 2018. Public Health will continue to work with Cascade Ridge Elementary School staff to help prevent additional people from becoming sick.

Four of the people who got sick tested positive for the Shigella bacteria and two of those four are confirmed to have Shigella sonnei. Though we do not have lab confirmation for the other people who got sick (and likely never will), their symptoms are suggestive of shigellosis as well.

The investigation is ongoing and Public Health will provide more information as it becomes available. Public Health officials are working closely and cooperatively with the Cascade Ridge Elementary School staff to communicate with parents/guardians of students who may be at risk and to prevent further spread of illness.

Shigella (shigellosis) can cause serious illness. If you or someone in your family works at or attends Cascade Ridge Elementary School and is currently experiencing similar symptoms, please follow-up with your health care provider and ask about stool testing.

Any school staff or children that are experiencing vomiting, diarrhea, or fever should stay home from school until they have been symptom free for at least 24 hours. The spread of Shigella can be stopped by frequent and careful handwashing with soap and water.