The following correction was printed in the Guardian's Corrections and clarifications column, Monday October 17 2005

In the article below we said that interferon was a tablet to be taken daily. It is an injection given one or three times a week.

What is it?
A form of liver inflammation caused by the hepatitis C virus. Doctors say it's on the increase.

How can I get it?
It is transmitted by exposure to infected blood. There is a smaller risk of infection through sexual contact, poor hygiene at tattoo parlours or shared toothbrushes and razors. There is no vaccine, unlike hepatitis A and B.

How can I tell?
Symptoms might show only once the liver is scarred by cirrhosis, but include jaundice, abdominal pain, fatigue, loss of appetite, nausea and vomiting, dark urine and generalised itching. A simple blood test can detect the virus.

What treatment is available?
Conventional treatment involves a combination of tablets taken daily, such as interferon and ibavirin, which costs up to £12,000 for a year's supply. There are alternative treatments, including herbs and botanicals such as milk thistle and licorice root.