The recent food poisoning incident in Kasaragod district, Kerala has been attributed to an outbreak of Shigella bacteria, according to news sources. The same bacteria had previously been observed in the Koyilandy district of Kerala in 2019. This article provides a comprehensive understanding of Shigella bacteria, including its defining characteristics, transmission methods, symptoms, treatments, and preventive measures.
Understanding Shigella Bacteria
Shigella is a genus of bacteria that causes shigellosis, an intestinal infection. It ranks second as a cause of diarrhea worldwide, after Rotavirus, and it’s the third leading cause of death among children under 5 years old. Annually, the estimated number of shigellosis episodes globally reaches 164.7 million.
Symptoms and Transmission of Shigellosis
Symptoms of shigellosis include diarrhea, fever, and stomach cramps, which can persist for a week. Shigella is predominantly transmitted through contact with contaminated food or water or through person-to-person interaction. Shigellosis commonly affects those in densely populated, low-income communities where sanitation and safe water supplies are inadequate. Its incubation period typically ranges from 1-4 days.
Different Strains of Shigella
The severity of shigellosis is determined by the infecting species of Shigella. For instance, infections with Shigella dysenteriae usually result in dysentery, which may also be triggered by an infection with Shigella flexneri. On the other hand, Shigella boydii and Shigella sonnei often cause self-limiting watery diarrhea.
Shigellosis Vaccines
Currently, no vaccines are available to prevent shigellosis. However, due to the escalating rate of multidrug resistance, notably fluoroquinolone resistance in Asian and African regions, Shigella has been designated as a medium-priority bacteria on the WHO Priority Pathogens List. This serves as an urgent call for research and development of novel and effective antibiotic treatments.
Treating Shigellosis
The primary goal in treating shigellosis is to maintain hydration and electrolyte balance. In young children, oral rehydration with a reduced osmolarity solution treats some dehydration and is preferable over intravenous fluids unless severe dehydration is present.
Role of Antibiotics and Public Hygiene
Although shigellosis is primarily self-healing, antibiotics are recommended to shorten the illness duration and prevent transmission. Currently, third-generation cephalosporins (ceftriaxone or cefixime) and macrolides (azithromycin) are the preferred drugs. Maintaining public hygiene can also play a significant role in controlling the spread of Shigella bacteria. Regular handwashing can reduce transmission rates by 70%. Public health control measures recommend excluding individuals with shigellosis from workplaces, food preparation areas, and childcare facilities to prevent further spread.
