All you need to know about: shigellosis

An outbreak of shigellosis, or shigella infection has been reported in Kerala, with one death and 15 cases across the State this month. A three-year-old girl from the Kuttikkattoor region of Kozhikode district reportedly died of the infection, triggering widespread concern and leading to doctors calling for personal hygiene measures to be followed stringently.

Here is all you need to know about the infection:

What is shigellosis?

Shigellosis is an infection caused by the Shigella bacteria. It is highly contagious, causes acute diarrhoea, and can affect anyone, but children under five are particularly susceptible. It is one of the leading bacterial causes of diarrhoea worldwide. Humans are the only natural reservoir of the Shigella bacteria.

How is it transmitted?

The infection is transmitted through direct, close contact with infected individuals, through the faecal-oral route and through sexual contact. It can also spread through contaminated food and water or contact with faeces of an infected person — for instance, while changing a diaper.

In Kerala, with summer having begun, and vacations approaching doctors have cautioned residents about unsafe food and water.

Risk factors include being under the age of five, having a weakened immune system, travelling to an area with unsafe food or water, living in crowded areas or in long-term care facilities or group settings/homes and experiencing homelessness.

What are the signs and symptoms?

The incubation period with Shigella is generally one to four days. The most common symptoms is diarrhoea, which can be bloody, contain mucus and last for a prolonged period of three days or more. Other symptoms include stomach cramps, vomiting, fever and feeling the need to pass stool even when the bowels are empty. Symptoms usually last for five to seven days.

Globally, the estimated annual incidence of shigellosis is 188 million cases. Approximately 164,000 cases result in death, a significant number of these being children under five.

How is it treated?

Shigellosis is typically self-limiting, which means in most mild cases, symptoms resolve themselves with supportive care at home including consuming fluids and resting. For more severe cases, diagnosis would involve a physical examination and testing of stool samples to check for the infection. Medicines, including antibiotics may be prescribed for a serious infection. The disease may be more severe in young children, older adults, immune-compromised individuals or malnourished persons.

It is important to consult a doctor before taking any medicine, as some diarrhoea medicines are not recommended for a shigella infection and some medicines are not recommended for children. If antibiotics are prescribed, it is important to complete the entire course. It is also crucial to stay hydrated, and children may need oral rehydration salts (ORS) to aid in this.

Can shigellosis cause complications?

While most often, the shigella infection clears up, in some cases, it could cause complications. Dehydration is one major complication, which can be caused due to constant diarrhoea. This severe loss of fluids can be dangerous, even leading to death. Some children with shigella infections may experience seizures, though it is unclear if it is the infection or the fever that causes the seizures. Other less common complications include the infection entering the bloodstream, reactive arthritis or an inflammation of the joints triggered by the infection, rectal prolapse, where part of the large intestine slips outs of the anus, and haemolytic uremic syndrome, in which the blood vessels of the kidneys get damaged.

What are the concerns around shigella and AMR?

There is currently no approved vaccine for shigellosis though several candidates are undergoing clinical trials. An important concern that has arisen, however, is antimicrobial resistance, or AMR. According to the United States’ Centers for Disease Control and Prevention (CDC), antimicrobial-resistant Shigella infections have been rising since 2016 and these infections may be harder to treat, may cost more to treat and may last longer, increasing the chance that Shigella may spread to other people.

In India too, this has become a serious concern: several studies have documented growing AMR when it comes to shigellosis, with some highlighting multi-drug resistance, bringing to the fore, the need to not only identify new drugs but also strengthen public health measures such as access to clean food, water and optimal sanitation.

Published – March 27, 2026 04:21 pm IST