Written By: Satata Karmakar | Updated : June 9, 2026 12:43 PM IST
Medically Verified By: Dr. Vamshi V
Shigella kills 4-year-old in Kerala's Kozhikode (Representative image)
While a bout of stomach upset is often brushed off as a temporary nuisance, some gastrointestinal pathogens need far more caution. Shigella, a genus of highly infectious Gram-negative bacteria, is one of them. It causes an estimated 125 million cases of bacillary dysentery (shigellosis) worldwide every year, and it takes only a very small infectious dose (as few as 10 to 100 organisms) to cause severe illness.
A 4-year-old girl has reportedly died of complicated and severe symptoms of the highly contagious Shigella virus in Kozhikode, Kerala. On Tuesday, the officials stated that new positive cases of the disease are being reported from some parts of the state, leaving healthcare workers scrambling to contain the virus from spreading.
"A little girl named Nila from Thalakkulathur in Kozhikode, was admitted to Medical College Hospital with two other kids, all with confirmed Shigella. Sadly, while others bounced back, Nila didn't make it, making this Kerala's first known fatality from the disease. Afterwards, the state ramped up efforts to spot and prevent more cases," an official told the media.
For healthy adults, shigellosis is usually self-limiting. But in vulnerable populations, it can be a serious threat. Knowing who's most at risk, understanding potential systemic complications, and recognising when to escalate care can prevent serious morbidity and even death.
How a Shigella infection progresses depends a lot on the person's immune status and physiological reserves. In an exclusive interaction with TheHealthSite.com, Dr. Vamshi V, Consultant - Internal Medicine, Gleneagles AWARE Hospital, LB Nagar, Hyderabad, explained that three groups face a significantly higher risk of severe disease and poor outcomes:
Children make up the largest group affected by shigellosis. Their higher vulnerability comes from developing immune systems and behavioural factors. In daycare and preschool settings, person-to-person spread happens easily via the fecal-oral route because hand-hygiene habits are still developing.
Physiologically, children have less extracellular fluid volume than adults. That makes them especially prone to rapid, life-threatening dehydration from severe diarrhoea and vomiting.
In older patients, the natural age-related drop in immune function immunosenescence reduces the body's ability to clear the bacteria efficiently. Many seniors also have pre-existing chronic conditions like cardiovascular disease or chronic kidney disease.
The intense fluid and electrolyte shifts caused by Shigella can easily destabilise these fragile medical conditions, leading to acute kidney injury or cardiac events.
Patients with HIV, those on chemotherapy, and people taking long-term immunosuppressive therapy such as corticosteroids or biologics don't have the cellular defences needed to keep the infection confined to the colon's mucosal lining. In these cases, Shigella is far more likely to cross the intestinal barrier, causing persistent, hard-to-treat infections, mucosal ulceration, and a much higher risk of systemic bacteremia (bloodstream infection).
The classic signs of shigellosis are watery or bloody diarrhoea, severe abdominal cramping, and high fever. But the cytotoxins made by certain strains most notably the Shiga toxin from Shigella dysenteriae type 1 can trigger severe local and systemic complications that go well beyond simple gastroenteritis.
This is a life-threatening complication where severe inflammation paralyses the colonic smooth muscle, causing rapid dilation of the colon. As gas and faeces build up, the intestinal wall thins dramatically, creating an immediate risk of perforation, peritonitis (abdominal cavity infection), and overwhelming septic shock.
Mainly linked to Shiga-toxin producing strains, HUS is a triad of microangiopathic hemolytic anemia (destruction of red blood cells), thrombocytopenia (low platelet count), and acute kidney injury. The toxin enters the bloodstream and binds to endothelial receptors, causing widespread microscopic clots that block the kidneys' filtering units. HUS needs intensive supportive care, often including blood transfusions and temporary dialysis.
Usually appearing weeks after the gut symptoms have settled, reactive arthritis is an immune-mediated inflammatory response. It mainly affects large joints like knees and ankles and can come with conjunctivitis and urethritis a combination previously called Reiter's Syndrome.
Especially in young children, the high fever with shigellosis can trigger febrile seizures. In rarer, severe cases, encephalopathy (altered brain function) can occur, causing delirium, lethargy, or coma, even without major metabolic disturbances.
Telling the difference between mild viral gastroenteritis and severe Shigella infection is crucial for timely treatment. Get medical help promptly if any of these develop:
Stools with visible blood or mucus point to significant mucosal invasion and ulceration.
Marked lethargy, sunken eyes, dry mouth, reduced urine output (or fewer wet diapers in infants), and dizziness on standing.
Temperature above 101 F (38.5 C) that doesn't come down with antipyretics, suggesting systemic inflammation.
Localised or worsening tenderness that may signal a surgical abdomen or toxic megacolon.
Confusion, extreme lethargy, or seizures, especially in young children or elderly patients.
If a bacterial infection like shigellosis is suspected, avoid over-the-counter anti-motility drugs such as loperamide. These slow down intestinal transit and trap the bacteria and its toxins in the bowel, which can dangerously prolong the illness and raise the risk of toxic megacolon. Treatment should focus on aggressive oral or intravenous rehydration. Empirical antibiotic therapy should only be started under strict medical supervision due to rising global antimicrobial resistance.
