The Escherichia coli bacteria - known as E. coli - kills two to three million children around the world each year. It causes severe diarrhea, which can lead to fatal dehydration. While rehydration therapy can treat the symptoms, researcher Mahdi Saeed of Michigan State University explains there is no way to prevent people from being infected again and again.

"There is no immunity. You're exposed today and within 48 hours, you're exposed again, and you're going to develop the same thing. And in third-world countries, children 5 years and younger are very, very susceptible to dehydration."

It turns out that E. coli can re-infect people so easily because it produces such a small toxin that it is not recognized as a danger by the body's defense system. Saeed is testing the first-ever vaccine against this deadly strain.

He says the key breakthrough in developing a vaccine was to attach the toxin to something bigger so it did trigger an immune response.

"We chemically modified a carrier protein to accept the toxin in a way that it preserves its biological activity and that we were successful in doing."

Saeed and his team tested this approach on mice and found the biological activity of the toxin increased by more than 40 percent, leading to its recognition by the body's immune system. When they immunized a group of 10 rabbits, the vaccine led to the production of the highest neutralizing antibody ever reported for this type of the toxin.

Saeed says - in addition to children - air travelers, cruise ship passengers, troops stationed overseas and even livestock could all benefit.

"Diarrheal disease has a great impact on children in the third-world countries or developing countries. Less here for children, but for travelers, it is a menace. For animals it is, for our troops elsewhere, for those who gather in big crowds - this vaccine can offer some significant help."

Clinical trials on humans could begin later this year. Right now, the vaccine is administered through a shot, but the ultimate goal is to develop a skin patch.