Researchers in the United States say they have discovered that people infected with hepatitis C can be cured with existing treatments.
Hepatitis C is usually contracted through infected blood; it can cause cirrhosis, liver failure or cancer but if diagnosed early treatment is usually effective; however many people are unaware they are carrying the infection and it is often discovered almost by accident.
Improved testing procedures have meant that over the last ten years the number of people diagnosed with hepatitis C has increased dramatically.
Experts believe more than 3.9 million Americans, and around 250,000 people in the UK have symptoms of hepatitis C infection; many of these will clear up naturally but it is thought the actual numbers could much higher as nine out of ten people are unaware they are infected.
As it can be years before symptoms appear, campaigns have been encouraging those at risk to get tested even if the risk scenario was years ago.
At risk is anyone who ever shared equipment for injecting drugs, even years ago, even if they only did it once or twice; those who had a blood transfusion before screening was introduced in 1991 or those who shared banknotes or straws to snort cocaine.
The current standard therapy uses pegylated interferon and ribavirin which are known to work initially, but it had been unclear whether the virus could return.
Following a long-term study of 1,000 patients Professor Mitchell Shiffman, chief of hepatology at the Virginia Commonwealth University Medical School, and his team have found the therapy removed all detectable virus in 99% of patients.
The study found that after successful treatment with injections of pegylated interferon alone or in combination with ribavirin, only eight patients tested positive for the virus in the following seven years.
The researchers however do say that whether those patients had suffered a relapse or been reinfected has not as yet been established and experts while they have welcomed the news say some patients will still suffer from painful symptoms such as aches in their joints and feeling tired.
Professor Shiffman says the results are encouraging as it is rare in the treatment of life-threatening viral diseases that patients can be told they may be cured.