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Shigellosis

 What is shigellosis?

Shigellosis is an illness caused by bacteria called Shigella that cause diarrhea in humans. Shigellosis can be quite severe, especially in young children, the elderly, and those with weakened immune systems.

How common is shigellosis?

There are approximately 1000 reported cases of shigellosis in California each year. There may be many more unreported cases in people who did not seek medical care or did not submit fecal specimens for testing. Shigellosis is more common in summer than in winter. Young children are the most likely to get shigellosis. Shigellosis is more common in developing countries or in settings where hygiene is poor and is a cause of "traveler’s diarrhea".

How do people get shigellosis?

Infected persons can shed Shigella in their feces while they are sick and for more than a week afterwards, and can spread the bacteria if they do not wash their hands well enough after using the toilet. Direct or indirect contact with an infected person’s feces, even a very small amount that may not be visible, can make someone sick. Ways that people become infected with Shigella include:
  • Person-to-person contact, especially among contacts of infected children who are not completely toilet trained. Many outbreaks have occurred in child care settings, and many cases are related to the spread of illness in families with young children. 
  • Consumption of food or liquids contaminated by an infected person; food items that have been sources of outbreaks have included vegetables that are usually eaten raw, raw oysters, and commercially prepared food products. 
  • Swallowing untreated recreational water contaminated with Shigella; this includes lakes, pools, and water park play fountains. 
  • Exposure to the feces of an infected person during sexual contact.

Outbreaks have also been reported among men who have sex with men, and among people living in crowded conditions with poor hygiene, such as jails and refugee camps.

What are the symptoms of shigellosis?

Symptoms of shigellosis include diarrhea, which is often bloody, fever, and abdominal cramps. Symptoms usually occur within four days after exposure to Shigella, and last five to seven days. Some people with shigellosis have very few or no symptoms, but can still pass Shigella to others. Most people with shigellosis recover completely. A small number of people can develop more serious complications, including bloodstream infections, seizures, kidney failure or arthritis.

How is shigellosis diagnosed?

Your health care provider can order a test of your feces for Shigella. Shigella may also be found in blood but that is uncommon.

How is shigellosis treated?

People with mild shigellosis usually recover without treatment. It is important to drink enough fluids to prevent dehydration. For more severe infections, a health care provider can prescribe an appropriate antibiotic to treat shigellosis. Antibiotic-resistant Shigella has become increasingly common; therefore, health care providers should make treatment decisions based on culture results.

What can a person do to prevent shigellosis?

  • Wash hands with soap and water carefully and frequently, especially after using the bathroom, after changing diapers, and before preparing foods or beverages. 
  • Make sure toddlers and small children wash their hands properly after they use the toilet. 
  • If a diapered child has shigellosis, dispose of soiled diapers properly and disinfect diaper changing areas with diluted household bleach or bactericidal wipes after using them. 
  • Keep children with diarrhea out of child care settings. 
  • Do not prepare food for others if you have diarrhea.
  • Do not take part in recreational water activities (such as swimming) if you have diarrhea.
  • Carefully wash vegetables that will be eaten raw. 
  • When traveling in developing countries, drink only treated or boiled water and eat only cooked hot foods or fruits you peel yourself.
  • Avoid fecal exposure during sex.

What is public health doing about shigellosis?

The California Department of Public Health (CDPH) and local health departments (LHDs) monitor shigellosis in California. Because shigellosis is a disease that can be easily spread to other people, health care providers are required by law to report cases of shigellosis to the LHD. In order to protect the public, California state law requires that LHDs restrict the activities of persons with shigellosis in certain settings. This includes but is not limited to workers in day care settings, food-related businesses, and health care workers with direct patient contact. These persons should not resume these activities until they have been evaluated by their local health department and have been cleared to return to work. Children with shigellosis may also be restricted from attending daycare until they have been cleared to return by their local health department.
CDPH and LHDs monitor for and investigate outbreaks of shigellosis to identify the source(s) of contamination and take control measures to prevent ongoing infections. If a number of cases occur in a day care center, or if a community-wide outbreak occurs, the local public health department can help educate the community to promote appropriate hygiene measures.

Where can I get more information on shigellosis?

  • Your health care provider 
  • Your local health department 
  • The U.S. Centers for Disease Control and Prevention has information on their shigella webpage

Updated July 2015 ​ ​​
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