Shigellosis

Shigellosis, also known as bacillary dysentery, is an acute infectious disease caused by bacteria of the genus Shigella. There are four species that cause human disease: Shigella dysenteriae (serogroup A), Shigella flexneri (serogroup B), Shigella boydii (serogroup C), and Shigella sonnei (serogroup D). The disease primarily affects the gastrointestinal system, specifically the colon and rectum, where the bacteria invade the intestinal epithelium, causing intense inflammation and mucosal destruction. Transmission occurs via the fecal-oral route, often through contaminated food, water, or direct person-to-person contact. The infectious dose is remarkably low, making it highly contagious. Key symptoms include watery or bloody diarrhea (dysentery), abdominal cramps, fever, nausea, vomiting, and tenesmus (painful straining during bowel movements). The illness typically begins 1 to 3 days after exposure and is usually self-limiting, resolving within 5 to 7 days. However, severe cases, particularly those caused by Shigella dysenteriae type 1, can lead to serious complications including hemolytic uremic syndrome (HUS), toxic megacolon, intestinal perforation, seizures (especially in young children), severe dehydration, and septicemia. Children under 5 years of age, elderly individuals, and immunocompromised patients are at greatest risk for severe disease and complications. Treatment focuses on rehydration therapy (oral or intravenous) to replace fluid and electrolyte losses. Antibiotic therapy is recommended for moderate to severe cases and can shorten the duration and severity of illness. Commonly used antibiotics include fluoroquinolones (such as ciprofloxacin), azithromycin, and third-generation cephalosporins, though antimicrobial resistance is an increasing global concern. Prevention strategies include proper hand hygiene, safe water supply, adequate sanitation, and food safety measures. No vaccine is currently widely available, though several candidates are in development.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Shigellosis