Disease Carriers

Bacteria: Shigella

The genus Shigella is composed of four serogroups: dysenteriae, flexneri, boydii, and sonnei. All four species can cause diarrhea, which is frequently bloody, as well as classical dysentery. Infection is generally person to person but illness can also occur from ingesting contaminated food or water. Shigellosis is found primarily in environments where hygiene is difficult to maintain, such as day care centers. This organism is a large problem in underdeveloped countries where it is responsible for high rates of morbidity and mortality.

A transmission electron micrograph of Shigella, negatively stained to enhance contrast.