Milan, June 11 - Italy leads Europe in cases of hepatitis C with 3% of the population infected, more than half of whom suffer from the most difficult variety to treat, leading experts said Tuesday. Some 1.6 million people carry the liver infection in Italy and 55% of them are afflicted with genotype 1, a particularly infectious strain of the disease, said doctors at the Premio Giornalistico Riccardo Tomassetti conference on virology in Milan. "At least one million Italians are chronic carriers of the infection," said Massimo Colombo, director of special treatments and organ transplants at Milan's Maggiore hospital. "One third of these people have developed or are developing serious liver infections". The majority of patients contracted the virus in the 1970s and 80s, Colombo said, with infected blood transfusions, or from health instruments such as hypodermic needles that were not sterilized. "But another 200-300,000 contracted the disease due to risky behaviour such as unprotected sex, piercings and tattoos. "In addition we should include a substantial number of migrants who come from areas with high levels of hepatitis C".