Explained: What is Shigella? The bacteria that killed Kerala girl due to food poisoning

After having identified the highly contagious bacteria causing shigellosis, the Kerala health department on May 3 identified Shigella bacteria as the cause of the food poisoning case in Kasaragod claiming the life of a 16-year-old girl and leading to nearly 20 others being admitted to hospital.

The case came to the fore after bacteria was confirmed in the blood and faeces of people undergoing treatment after they reportedly consumed chicken shawarma from an eating joint at Cheruvathur in Kasaragod in the preceding week. 

Subsequently, Kerala Police arrested the owner and staff members of the eatery. Food poisoning is a highly common occurrence, however, Shigella infection appears to be a fairly uncommon infection. 

What is Shigella & how does Shigellosis spread?

Primarily affecting the intestine of a person, the bacteria is said to cause severe diarrhoea (sometimes bloody), stomach pain, abdomen ache and fever. The bacteria belong to an enterobacter family, which is a group of bacteria that reside in the intestines as not all of them cause human disease.

According to the Unites States' Centers for Disease Control and Prevention, "Shigellosis is a highly contagious diarrheal disease caused by a group of bacteria called Shigella. Outbreaks of Shigella infection can occur from environmental,1 food,2, 3 water,4–9 or person-to- person10 exposure (see References section). Anyone can get sick from a Shigella infection. However, groups that may be at particular risk include children, travellers, men who have sex with men, and people with weakened immune systems."

Do people die of infection from Shigella?

It is not very common for patients suffering from Shigellosis to die but doctors have said that the bacteria generally would not kill a person. However, in the case of a person with a weak immune system or restricted pathogen, chances for fatality are fairly high. Out of four species of Shigella bacteria, the CDC has held that 'Shigella dysenteriae type 1 can be deadly'.

What are the symptoms of Shigella infection?

Most patients with Shigella infection experience diarrhoea (sometimes bloody), stomach pain, abdomen ache and fever. The symptoms, as per the CDC, usually start 1-2 days after infection and lasts for 7 days. As per the CDC, "In some cases, bowel habits (frequency and consistency of stool) do not return to normal for several months."

What precautions must one take to avoid Shigella infection? 

Akin to the prevention of other usual food poisonings, the measures to prevent a shigella infection are similar to any food or water-borne infection. Doctors advise that one must wash their hands thoroughly before any meal and one must ensure that the source of drinking water is clean while fruits and vegetables are clean and fresh too.