Key Facts
Kerala is grappling with a significant shigellosis outbreak first detected in late March 2026. As of June 12, the Kerala health department has confirmed 132 cases and approximately 75 probable cases. Three deaths have been reported, including two children under five years old.
What is Shigellosis?
Shigellosis is a contagious diarrhoeal disease caused by the gram-negative bacterium Shigella. Symptoms include fever, abdominal cramps, and bloody diarrhoea (dysentery). The bacterium was first isolated by Japanese bacteriologist Kiyoshi Shiga in 1897 following a severe dysentery epidemic in Japan.
Transmission and Risk Factors
Transmission occurs mainly via the faeco-oral route — ingesting tiny amounts of faecal matter through contaminated food, water, or hands. As few as 10–100 bacteria can cause infection. Globally, Shigella causes an estimated 80–165 million infections and about 600,000 deaths annually, mostly among children under five in sub-Saharan Africa and South Asia.
According to experts Neelam Taneja and Abhishek Mewara, writing in a medical journal, “Though humans and primates are the primary reservoir of shigella, it has been isolated from various sources — aquatic bodies (rivers, surface waters as well as coastal waters), free living amoebae, insects, birds and wild animals.” They note that several Indian water bodies harbour Shigella, making fish from sewage-contaminated water a potential source. Even swimming or bathing in contaminated water, or eating crops grown in contaminated soil/water, can cause infection.
While no one is immune, certain groups are at higher risk. “Globally, the incidence of shigellosis is highest among children under five. The incidence of shigellosis has been reported to increase steadily after the age of 40,” Taneja and Mewara add.
Outbreak Details in Kerala
The current outbreak began in late March 2026 in Kuttikkattoor, Kozhikode district, where a three-year-old girl died and over 60 residents, mostly children, fell ill. Subsequently, clusters emerged in Wayanad, Malappuram, and Kannur districts. A major cluster at a Wayanad school led to over 300 children being hospitalised. Experts have traced infections to contaminated water and food sources, along with poor hygiene in communal settings like schools.
Kerala has faced shigellosis outbreaks before: in 2009, over 300 people were infected; in December 2020, an outbreak in Kozhikode killed an 11-year-old and infected 40 others; and in May 2022, a mass food poisoning incident in Kasaragod hospitalised 30 people and killed a 16-year-old girl.
Treatment and Antibiotic Resistance
Mild shigellosis usually resolves with hydration, but severe cases require antibiotics to shorten illness and prevent complications, according to the U.S. Centers for Disease Control. However, some antibiotics are ineffective against certain Shigella strains. Laboratory tests are needed to identify effective drugs.
Taneja and Mewara warn that “there is a nationwide presence of multi-drug resistant shigella developing rapid resistance to most antibiotics available. Thus, judicious use of antibiotics is among the most essential measures to combat shigellosis.” Continuous surveillance of antibiotic resistance is crucial to update local antibiograms and guide appropriate treatment.
What Readers Should Know
- Practice good hand hygiene, especially before eating and after using the toilet.
- Ensure drinking water is safe; avoid swimming in potentially contaminated water bodies.
- Wash fruits and vegetables thoroughly.
- Seek medical attention if you develop fever, abdominal cramps, or bloody diarrhoea.
Frequently Asked Questions
What is shigellosis?
Shigellosis is a diarrhoeal disease caused by Shigella bacteria, marked by fever, abdominal cramps, and bloody diarrhoea.
How is shigella transmitted?
Transmission is primarily faeco-oral, through contaminated food, water, or hands. As few as 10-100 bacteria can cause infection.
Why is antibiotic resistance a concern?
Multi-drug resistant shigella is spreading in India, limiting treatment options. Judicious antibiotic use and surveillance are critical.