By: Pooja Sharma
New Delhi-based Hilleman Laboratories, an equal joint partnership between MSD and Wellcome Trust signed an MOU with Kolkata-based NIECD (National Institute of Cholera and Enteric Diseases), a part of Indian Council of Medical Research to develop and commercialize vaccines for Shigella and other diarrheal diseases. Both of these companies aim to complete the project by 2024 and make available a full-fledged vaccine, which will be one of its kind in the world.
NICED’s main purpose up until now has been to improvise and develop techniques to control, prevent, and treat existing infections. On the other hand, Hilleman is known to devise and optimize existing vaccinations and make them available in areas with lesser access to these types of resources. Now that both of them have partnered, the development of a vaccine for this disease is a reality. This is great news as Shigella is already becoming resistant to the existing antibiotics. Yes, Shigella is now a part of the antibiotic-resistant superbugs group. Considering the growing concern of antimicrobial resistant superbugs threatening our society, vaccination is the only way through which a disease can be completely eradicated.
Last month Rockville, the USA-based company Protein LLC also reported their first steps towards developing a room-temperature stable oral vaccine for Shigella and Anthrax. The vaccines were successful in protecting mice against the lethal Shigellosis after immunization with Protein Potential’s TyOraSs vaccine, formulated with an acid-stabilized form of Ty21a. NICED and Hilleman are also working to develop an oral vaccine, which will target four strains of bacteria of Shigella. Many other companies have also been working to develop a vaccination for Shigellosis including Path, based in Washington and Immuron, an Australian based Biotech company.
The Shigella Concern
Shigella is responsible for 80 million infections (500,000 in the United States) and 700,000 deaths worldwide. It’s the most fatal organism that affects children after Rotavirus. It causes severe diarrhea (occasionally bloody), fever, and stomach pain. According to Global Burden of Disease Report, diarrheal diseases are a cause of 1.3 million deaths in all age groups.
One study done by Harvard also showed the implications on development of vaccination program for the disease. It also explained how Shigella is able to successfully develop antimicrobial resistance against so many antibiotics. The study touched on how Shigella so effectively transfers from the mouth to the colon. It states that, after passing through bile salts, it creates a complete wreck in the intestines – resulting in severe diarrhea. The researchers are aiming to understand the complete survival mechanism of Shigella in the human body, along with how it forms resistance to antibiotics, so as to have an effective treatment. And in the future, the creation of a vaccination to the virus. The researchers found out how pathogen’s gene expression change upon exposure to bile salts and how antibiotic resistance can further fuel up virulence gene expression in the bacteria that makes it more easier for it to survive. Furthermore, the study revealed that bacteria not only resists bile salts, but also uses the liquid to its advantage. It stated that the longer exposure to bile salts led to the formation of biofilms (communities of bacteria) that form a protective coating to survive harsh conditions.
Hence, the function of bile in Shigella infection development will not only have significant perks for Shigella vaccine and treatment program, but will also benefit the overall antibiotic resistant danger.
What is Shigella?
Shigella is spread when a person consumes infected food, water or comes in contact with someone who has Shigella contaminated feces. It easily spreads through the contaminated feces and is very contagious. So, exposure to even the tiniest amount of infected feces can easily result in a person becoming getting sickened by Shigella. Since, Shigella travels from mouth to colon and also stays in the abdomen for a while, it can take around 2-3 days for the symptoms to appear and sometimes even a week. It directly attacks large intestine and causes damage to its walls like swelling and ulcers. Diarrhea or any other effects can last for 3-7 days. It’s important to stay hydrated during the time and consult your doctor from time to time. Children, people with weakened immune systems, or those who suffer from severe cases of Shigellosis may have to be hospitalized.
The worst part about having suffered from Shigellosis is the after effects. They include:
- Post Infection arthritis which includes: joint pain and irritation of the eyes.
- Seizures: Seizures after Shigellosis are more common in children who suffer from this infection in their childhood. The reason of why this occurs is, however, still not known.
- Blood Stream Infections: This infection is very rare and generally occurs in people with weakened immune functions. It is caused when the germs or other bacteria pass through the wall of intestine (which is already weakened after the infection) to the blood stream.
Other side effects include: impaired physical and cognitive development, kidney damage, and poor digestive health. The degree of these after effects might vary in people with some struggling through it for the rest of their life.
What Causes Shigellosis, and How can I Prevent It?
The most common causes of Shigella include:
- Toddlers who haven’t been properly potty trained or their family members.
- Vegetables and fruits become infected if there is infected feces around the field. Flies can also carry it and spread it to the crops.
- Infection in restaurant food can occur if the food service workers do not wash their hands after using the restroom, which might result in an outbreak.
- Swimming in lakes, pools, etc. can cause shigellosis too. This happens if there is any sewage water that contaminated the water or if someone infected by Shigella swim in the water.
Since, Shigella is so contagious that it’s so recommended that you practice good personal hygiene if there is anyone around you who is suffering from Shigellosis, especially if you are a parent to an infected child. If you are yourself suffering from Shigella make sure that you wash your hands and avoid cooking food for others until you feel better or until doctor has done your stool check and given you a green light.
To protect yourself from Shigella on a daily basis, wash your hands properly if you have been to a public place or after changing your child’s diaper. Also, make sure that you don’t swallow water in public pools, lakes, etc. Reading international guidelines, especially if you are travelling to a country that have high rates of illnesses and infections from Shigella, is also a good idea.