London: A gut bug, H. pylori, which infects half the global population and causes gastritis, gastric and duodenal ulcers and stomach cancer, has been found to protect against allergy-induced asthma.

Scientists from the University of Zurich, Switzerland and Johannes Gutenberg University, Germany, now reveal that the dramatic increase in asthma could be tied with the disappearance of H. pylori from Western societies. Asthma symptoms are shortness of breath, wheezing, coughing, etc.

H. pylori is often killed off with antibiotics as a precaution, even if the patient does not have any complaints or symptoms, reports the Journal of Clinical Investigation.

When researchers infected mice with H. pylori, a day or two after birth, they developed tolerance to the bug and took strong, asthma-inducing allergens in their stride, according to a Zurich statement.

Mice that were not infected with H. pylori until they had reached adulthood, however, had a much weaker defence.

(Agencies)