Cholera affects lakhs of people in developing countries like India, Africa etc. The microbe (Vibrio Cholerae) that causes it, is carried through water, stool, and food where it can remain live for over a week. Reaching the present cholera vaccine, which is short lived, to remote regions in poor countries presents a huge challenge.
They often need refrigerating, and medical workers need to be on hand to give injections. The work by immunologist Hiroshi Kiyono and his team at Tokyo University addresses these challenges.

They've found away of genetically engineering a strain of rice which contains a vaccine against cholera. The rice can be ground up and made into a pillor capsule, which will remain potent at room temperature forup to two years. This genetically modified 'rice' could provide developing countries with a cheap and effective treatment against cholera. Once the clinical trials are successfully concluded, it could reduce the cost of storing and transporting vaccines by hundreds of millions of dollars every year.

The bacteria that cause cholera infect the gut and bloody the stool of victims. It travels from host to host in water and on washed food, where it can persist for almost a week.

The present cholera vaccines provide short-lived protection.

The Japanese researchers have created a strain of rice that can act as a vaccine and last for more than a year and a half at room temperature. They inserted the genetic material from the microbe responsible for producing cholera toxin into a rice plant, whose genome has recently been sequenced. The plants produced the toxin and when the rice grains were fed to mice fortrials, they provoked immunity from the diarrhea-causing bacterium.

"We are considering rice as a new vaccine production and storage system, and natural vaccine delivery vehicle," Kiyono says.

The vaccine expressed in rice, or rice-based vaccine, will become a new form of vaccine production and delivery to fight cholera. Rice offers several advantages over traditional vaccines: it does not require needles, purification or refrigeration. In fact, the rice remained potent after 18months of storage at room temperature and the vaccine did not dissolve when exposed to powerful acids in the stomach, the researchers report in the Proceedings of the National Academy of Sciences, USA .

Dr Kiyono says rice is a good candidate for vaccine delivery. Because rice grains contain varying amounts of the vaccine (roughly30 micrograms per seed) a tablet or capsule has to be created to make sure people get the proper dose. The rice plants would also have to be grown under carefully controlled conditions to ensure appropriate vaccine production.

Such rice-based vaccines need not be limited to fight cholera. The same technique could be used to create rice grains bearing protection against the flu, botulism or anthrax, among other diseases. The day may not be far when a bowl of rice may keep certain diseases away.

Article Courtesy » Executive Knowledge Lines

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