Researchers at the University of Cambridge have produced a new vaccine that can be swallowed by travellers to help them fight the bacteria that causes the illness.
Delhi belly, or traveller's tummy, affects an estimated 10 million people each year and up to half of all international travellers suffer from it in some form. It is most common in India and other tropical countries, The Telegraph reported.
Professor Nigel Slater, who has led the work at the University of Cambridge's department of chemical engineering and biotechnology, said they were planning to start clinical trials of the vaccine later this year.
"The vaccine we have produced is a powder so it is very stable and does not need to be kept in cold storage or carries any of the problems associated with needles," he said.
"It is currently targeting two main bacteria the E coli that causes Delhi belly and Salmonella that causes typhoid.
The scientists have found that they can introduce a small segment of DNA into harmless Salmonella bacteria so they look like enterotoxigenic E coli to the immune system.
These bacteria can be grown in vessels to form a kind of slurry that can then be spray dried with hot gas to turn it into a powder.
This leaves the bacteria in suspended animation until it is dehydrated in the stomach after being swallowed by the patient.
The resin absorbs the bile, allowing the bacteria to be rehydrated so it can then pass through the lining of the small intestine and induce an immune response.
"As we are creating immunity at the site where an infection from enterotoxigenic E coli would normally first occur - in the digestive system - it allows the immune system to be primed against it at the first line of defence," Slater said.
The scientists, who are working with a drug company Prokarium to develop the vaccine, also hope to produce vaccines against other bacteria including Clostridium difficile.
