Faecal-oral transmission of Shigella occurs when:

Infected respiratory droplets are inhaled into another person's lungs

Material contaminated with infected stool reaches another person's mouth

A mosquito transfers bacteria from one person's bloodstream to another

Bacteria enter through a skin wound during contact with contaminated soil

What is the main purpose of oral rehydration solution during diarrhoeal illness?

Directly identifying the bacterial species in a laboratory sample

Giving permanent immunity against every intestinal infection

Replacing water and electrolyte losses

Destroying bacteria on kitchen surfaces before cooking

Shigellosis in Keralam: Tracing Infection and Interrupting Faecal–Oral Transmission

Why in news?

Health authorities in Kozhikode and Malappuram districts of Keralam intensified surveillance after laboratory-confirmed Shigella infections. ETV Bharat reported the cases on 7 November 2026, citing district health officials. They included infections among schoolchildren in Vadakara and people treated in the Nilambur area. Health teams were testing food and water samples to investigate the sources. Shigellosis is an intestinal infection that can spread through contaminated hands, food and water. Finding the source helps teams stop further exposure.

What causes shigellosis?

Shigellosis is an intestinal infection caused by Shigella bacteria. The bacteria reach the digestive tract when a person swallows material contaminated with the stool of an infected person. Only a small amount of the bacteria can cause illness, which makes careful hygiene especially important during an outbreak.

Four species cause the infection: Shigella sonnei, Shigella flexneri, Shigella boydii and Shigella dysenteriae. The symptoms commonly include diarrhoea, fever, stomach pain and an urge to pass stool even when the bowels are empty. Diarrhoea can contain blood. Children younger than five are particularly likely to develop shigellosis, although people of any age can be infected.

How the infection spreads

The main mechanism is faecal–oral transmission. Bacteria leave an infected person in stool. Contaminated hands, surfaces, food or water can then carry them to another person’s mouth. For example, inadequate handwashing after using the toilet can contaminate food during preparation. The food then becomes a vehicle through which someone swallows the bacteria.

Three connected cards show bacteria in infected stool, transfer through contaminated hands, surfaces, food or water, and swallowing the bacteria; hygiene interrupts this route. — Faecal–oral transmission of Shigella. Clarity original diagram; sources: CDC and WHO.

Close contact can also allow infection to spread between people. Schools and childcare settings bring many children into shared spaces, where hand hygiene and clean facilities help interrupt transmission. Investigators therefore examine both common exposures, such as a shared meal, and opportunities for further spread.

Investigating the district clusters

Kozhikode and Malappuram lie in the northern part of Keralam, the state long known as Kerala, along India’s southwestern coast. The reported Vadakara cases involved schoolchildren. In Malappuram, officials described cases from the Nilambur area after people fell ill following meals.

The report distinguished people with symptoms from cases confirmed by laboratory testing. Food and water sampling was part of the investigation into the source. Officials also described inspections of food outlets, water chlorination and distribution of oral rehydration solution.

Preventing spread and managing illness

Handwashing with soap and water is particularly useful after using the toilet and before preparing food or eating. Safe drinking water, hygienic food handling and cleaning contaminated surfaces reduce opportunities for bacteria to move between people. A person with diarrhoea should avoid preparing food for others while ill.

Diarrhoea causes the body to lose water and salts. Oral rehydration solution replaces these losses through a mixture of water, glucose and electrolytes. Clinical care is especially important for bloody or prolonged diarrhoea and severe abdominal pain. Severe infections can require antibiotics selected by a healthcare professional. Laboratory testing helps identify which antibiotics are likely to work because some Shigella strains are resistant to particular medicines.

Conclusion

The district response connects case detection with practical control of transmission. Testing helps investigators identify infections and examine shared exposures, while safe water, food hygiene and handwashing reduce the routes through which the bacteria spread.