Shigella is the bacterium that causes the foodborne illness shigellosis. The CDC (Center for Disease and Prevention) estimate that 18,000 Americans suffer from shigellosis infections each year, though the actual number is probably significantly higher, due to most mild cases going unreported. Symptoms, which usually appear within two days of exposure, do not often last longer than a week, and include diarrhea (which may be bloody), fever, stomach cramps, bloating, difficulty in having bowel movements, depression, and lethargy.
Severe cases are much more likely to affect those with compromised immune systems, elderly persons, and children. These may include seizures due to high fevers and severe diarrhea that requires hospitalization. Along with severe dehydration, another possible complication is the development of Reiter’s Syndrome, sometimes called reactive arthritis. Symptoms, which occur between 1-3 weeks following the infection, include pain in the joints (particularly fingers, toes, ankles, knees and hips), irritation of the eyes (conjunctivitis), and painful urination. Most recover in less than 1 year, but in some it can lead to chronic arthritis. It should be noted that other foodborne illness which cause gastroenteritis, such as Camplobacter and Salmonella, may also cause Reiter’s Syndrome. Additional complications arise if the infection spreads from the intestines to the bloodstream and other parts of the body.
Shigella is spread by the fecal to oral route, commonly by the consumption of contaminated food. Contaminated food often bears no indication that it carries the infection, looking, tasting, and smelling completely normal. Some means of contamination and transmission include:
- Infected persons not properly washing their hands before preparing food
- Food grown in areas that are contaminated by sewage
- Flies, which can spread the disease by breeding in feces and then contaminating food
- Contact with contaminated water (swimming or drinking). Water may become contaminated due to sewage runoff or contact with an infected person
Shigella is quite contagious and only a few organisms are necessary to spread infection, therefore group setting (day care centers, for example) are particularly susceptible to outbreaks. Children between the ages of two and four are most likely to contract the disease, primarily because of their poor hygiene. It may also be spread by asymptomatic individuals, who are unaware of their own infection. Shigella can also linger in the intestines, even after symptoms have disappeared, and be found in the stool weeks later.
A shigella infection can be diagnosed by means of specifically requested lab test on a stool sample. Upon diagnosis, further tests may be given to determine the details of the infection, in order to better select the antibiotic for treatment. Mild cases usually go without treatment. One of the reasons for this is that shigella is increasingly resistant to antibiotic treatment. However, more severe cases are treated with antibiotics and will shorten the length of the illness. It is NOT advisable to use anti-diarrheal medications, such as Imodium, while infected, because they can compound the illness.
Basic steps for reducing the likelihood of contracting a shigella infection involve good hygiene and basic sanitary measures. Recommendations from the CDC include:
- Frequent and thorough washing of the hands in hot water with soap
- Insistence that children wash their hands frequently with hot water and soap (especially in daycare centers)
- Those infected should not be in contact with uninfected persons (this is particularly true for children)
- Those infected should not prepare food until it is certain that they no longer carry the bacterium
- After changing the diaper of an infected child, it should be disposed of in a closed-lid garbage can, the changing table surface should be disinfected, and hands should be washed thoroughly
- There should be no direct or indirect contact between reptiles and children or individuals with compromised immune systems
- If in a developing country, only drink water that has been treated or boiled, do not use ice, eat only hot cooked foods and fruits that you peel yourself