The number of cases of hepatitis C has increased by more than a third in two years, figures show.
There were 7,882 cases confirmed in England in 2010, rising to 10,873 in 2012, Public Health England (PHE) said.
Experts estimate there are around 160,000 people in England living with chronic hepatitis C, officials said.
Many of them are unaware they are infected.
The virus causes inflammation of the liver and, if left untreated, can result in liver disease, liver failure and even death.
Because the liver can still function when it is damaged, infected people can be unaware they have the disease because they suffer no symptoms.
The PHE figures, released ahead of World Hepatitis Day on Sunday, also show that hospital admissions for end stage liver disease and liver cancer caused by the infection increased from 574 in 1998 to 2,266 in 2012.
Dr Helen Harris, a hepatitis expert at PHE, said: “While there has been an increase in confirmed cases of hepatitis C infection, partly as a result of increased testing and partly because of improved laboratory reporting, sadly, many people chronically infected with hepatitis C remain unaware of their infection.
“For many, it can be several years or even decades before they develop symptoms.
“It is therefore vital to raise awareness about this condition so that more individuals are diagnosed and treated.
“Antiviral therapies exist that will clear the virus in most cases, yet only around 3% of the chronically infected population in England access them each year.
“Preliminary results from statistical models presented in the report suggest that numbers of hepatitis C-related end stage liver disease and liver cancer patients could be substantially reduced by increasing access to treatment.
“If the number of people being treated is doubled over the next 10 years, around 6,000 new cases of hepatitis C-related end stage liver disease could be averted over the next 30 years.”
In England, the most common way people catch the infection is by sharing injectable drugs equipment - accounting for nine in every 10 cases.
Less commonly, people can get hepatitis C through sex or being exposed to infected body fluids at work.
The World Health Organisation (WHO) says that viral hepatitis is a “silent epidemic” because so many people do not realise they are infected.
The five hepatitis viruses lead to 1.4 million deaths across the globe every year, WHO officials said.
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