Shigella Diarrhea Infection: Causes, Symptoms, Diagnosis & Vaccine

Shigella Infection Image Courtesy - Youtube

Shigella or shigellosis infection is one of the leading bacterial causes of diarrhea in the whole world which causes about 80 million to 165 million cases in a year. It causes around 74000 to 600000 deaths in a year. It is one of the top four pathogens that cause severe diarrhea in African and South Asian children. It can be passed through direct contact with the bacteria in human excreta, like not washing hands properly after going to the toilet, swimming in contaminated water or by eating contaminated food. Shigella infection is most common among children between the ages of 1 to 5 years. A mild case may clear up on its own in a week. However treatment is needed when it lasts longer with severe symptoms.

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Severe symptoms of Shigella can include one or more of the following –

#Rectal prolapse
#Hemolytic uremic syndrome
#Toxic mega colon
#Reactive arthritis.

For the last 60 years researchers have been trying to develop a proper vaccine for Shigella. However despite intensive research no effective vaccine has yet been developed. Innovative approaches based on the mechanism of the shigella bacteria have developed over the years by understanding the immune systems response to this bacteria. So far over 50 serotypes of shigella have been discovered and these 50 serotypes belong to 4 serogroups or species.

Shigella Statistics
Some Statistics About Shigella

In a recent development, a Delhi based vaccine research organization called Hilleman Laboratories have made an agreement with the Kolkata-based National Institute of Cholera and Enteric Diseases(NICED) to develop and commercialize an effective vaccine to fight the shigella bacteria. This agreement has been made with the objective to completely develop a vaccine by 2024 as said by the Hilleman labs chief executive officer Mr. Devinder Gill.

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In February 2017, the World Health Organization released a list of antibiotic resistant bacteria that pose a great threat to human health. In this list, shigella bacteria came second followed by Rotavirus which is also a very common infection-causing bacteria among children.

Shigella Infectious Bacteria
Shigella is a Highly Infectious Bacteria Image Courtesy – Slide Share

According to the Director of National Institute for Cholera and Enteric Diseases Shanta Dutta, there is currently no approved vaccine for Shigella. however some companies and institutes like the GSK vaccines institute for Global Health are already working on such a vaccine.

So far, the main focus of Hilleman Laboratories was to optimize existing vaccines but with this agreement the company will now make efforts to develop a totally new line of treatment. Hilleman Labs in collaboration with NICED will begin testing its vaccine on human candidates.

Usually when we think about vaccines, syringes come to mind but unlike other vaccines the shigella vaccines which is under development will be oral vaccines. This vaccine is capable of targeting 4 different strains of the bacteria.

This agreement, apart from being beneficial for faster progress, is also an improvement on manufacturing. The hilleman laboratories’ existing heat and manufacturing technology might end up being incorporated in the vaccine development project. The potential market size for the shigella vaccine is estimated to be 1.4 billion dollars worldwide.

Although, Hilleman Laboratories did not disclose as to how much they would be investing, but according to Mr. Gill, a project like this may require a funding of about 50 to 100 million dollars.



About Sachin Vashisht 34 Articles
An engineer by qualification, a writer by passion.