Onmanorama Explains | Kerala Shigella outbreak: 135 cases & 3 deaths, what drives the disease?

Kerala is witnessing a rise in cases of Shigella. Till June 13, there have been 59 confirmed cases and two deaths, according to the figures from the Integrated Disease Surveillance Programme. With this, the total number of cases has reached 135, with three deaths recorded since January 2026. Three new cases were recently confirmed in Pozhikkara in Kollam district, Thrissur Corporation area, and Panakkad in Malappuram district.

What is Shigella?
Shigella is a bacterial infection that causes severe food poisoning and bacillary dysentery. The disease spreads through the faecal-oral route, via contaminated food and water, as well as direct person-to-person contact.

Health experts warn that even a small number of bacteria can cause infection, with as few as 10 to 100 organisms constituting an infectious dose. Because Shigella can survive gastric acid, micro-contamination from unwashed hands, shared toys in anganwadis, or a single contaminated well can trigger widespread clusters of infection.

Symptoms usually appear within one to four days and include severe diarrhoea, which may contain blood or mucus, stomach cramps, fever, chills, and a frequent urge to pass stool.

Experts say rising temperatures may also be contributing to the spread of Shigella and other diarrhoeal diseases. Studies have shown that even a one-degree increase in long-term global temperatures can lead to a higher baseline incidence of diarrhoeal infections, particularly among vulnerable populations.

Why Shigella spreads so easily?
Warmer conditions accelerate the growth and replication of bacteria such as Shigella and Vibrio, while also supporting larger populations of disease-carrying vectors, especially houseflies. These factors can increase the risk of contamination and facilitate the spread of infections through food and water.

The bacteria can survive for extended periods in water, such as two weeks in tap water, 20 days in well water, 17 days on paper and clothes and for about a month in soil, making proper hygiene and sanitation critical in preventing its spread.

Health authorities also warn that infected individuals may continue to shed the bacteria for up to four weeks after recovery, increasing the risk of transmission. Treatment mainly focuses on preventing dehydration through adequate fluid and electrolyte replacement. Antibiotics are generally reserved for severe cases

The Kerala Health Department has directed hotels and restaurants to provide only boiled, cooled, or chlorinated drinking water. The use of commercial ice in drinking water has been prohibited, and food safety inspections have been intensified across the state. Officials have advised the public to wash hands thoroughly with soap, consume safe drinking water, and avoid eating from unhygienic food outlets. Anyone experiencing symptoms is urged to seek medical attention promptly.