Dirty needles = Hep C contamination; See China Drug addiction and the practice of reusing unsterile needles leads to the spread of Hepatitis C. https://www.msn.com/en-us/health/medical/china-has-the-worlds-biggest-hepatitis-c-problem-says-who/ar-AAGTwQf China now has the world's largest burden of hepatitis C -- an estimated 8.9 million people, or 0.6% of the overall population -- according to a WHO study released in March. Many of them will die from it: China accounts for more then half of the world's annual liver cancer fatalities caused by hepatitis C, according to the study.