london some variants of the common food bug called listeria monocytogenes appear to have an enhanced ability to increase the risk of serious heart diseases a new study has claimed researchers at the university of illinois chicago found thatsomedeadly strainsofthe bug are uniquely adapted to invade heart tissues of people with preexisting heart problems or who have had heart valve replacements in a study on mice the scientists discovered that the animals infected with the strains had up to 15 times more bacteria in their hearts than those exposed to other forms of listeria the findings the researchers said could help develop new ways of identifying the strains and protect those most at risk the daily mail reported listeria monocytogenes is widespread in the environment living in soil and vegetation and exists harmlessly in the the guts of at least 5 of healthy people according to the researchers the bacteria has an unusual ability to grow in low temperatures and can be found in a wide range of foods including soft cheeses cold meat products raw vegetables fish salads and unpasteurised milk listeria infections may cause nothing worse than flulike symptoms and a upset stomach or lead to serious illness involving the blood and nervous system research showed some listeria strains had modified surface proteins which helped them home in on the heart the scientists are now working on developing diagnostic tests based on bacterial genetic markers