Shigella

This family of bacteria causes Shigellosis, or bacillary dysentery, a foodborne illness found in humans. Shigella symptoms usually start 24 to 50 hours after infection, and include stomach cramping, vomiting, bloody diarrhea, and fever. The illness lasts 5 to 7 days, the time it takes for the body to rid itself of all the bacteria. If the infection is mild, the victim is likely to recover fairly quickly, but antibiotics may bring a quicker resolution. Antidiarrheal agents such as Imodium should not be used, as they may actually prolong the disease process. People who experience severe diarrhea may require a number of months before their bowel habits have entirely returned to normal.

The Shigella bacteria are especially potent; as few as one hundred bacteria can produce an infection in a person. Children under two are particularly vulnerable, and may experience more severe symptoms, including seizures, and more often require hospitalization. Children age 2 to 4 are most likely to be infected, especially in day care centers, if proper hygiene is not observed.

The bacterium was discovered by in 1898 by Japanese scientist Kiyoshi Shiga, for whom it is named. Of the four major strains of Shigella, two thirds of the Shigella infections in the US are caused by Shigella sonnei, or Group D Shigella. Almost all the remaining infections are caused by Shigella flexneri.

Shigella is a frequent cause of foodborne illness. Food poisoning from the Shigella shigellosis bacterial infection, or bacillary dysentery, is transmitted from person to person in infected feces. The bacteria remain in the stools of an infected person for more than a week after the symptoms have resolved. The commonest routes of transmission are eating raw vegetables grown in a field that has been contaminated by sewage and food handlers who have not adequately washed their hands after using the bathroom. Parents and others who assist young children with diapers or toileting may inadvertently contract the disease from an infected child.

Every year about 14,000 cases of Shigellosis are reported in the US. Because only the severest cases tend to be reported, and milder cases often go undiagnosed, the Centers for Disease Control estimate that the actual number of Shigella infections may be as much as twenty times the number reported. Shigella infections tend to increase during the summer months, and taper during winter.

The most effective prevention against Shigella infections is careful hand washing. In child care settings, child care workers changing diapers need to take particular care in disposing of diapers and cleaning changing areas with antibacterial wipes, Lysol, or a diluted bleach solution. Food handlers should be thoroughly trained in food hygiene, and if infected, they should not be permitted to work with food until they are demonstrably free of the disease.