The results of a national study looking into rates of hepatitis in cities with large ethnic-minority communities were unveiled in Bradford yesterday.

The Department of Health-funded project looked into rates of hepatitis B and C in five areas of the country, including Bradford.

Known as silent killers, they both cause inflammation and scarring of the liver over a number of years. In most cases there are no symptoms.

The blood-borne viral infection is spread through unprotected sex, sharing contaminated needles, non-sterilised equipment for tattooing, acupuncture or body piercing, from an infected mother to her baby at birth or through a blood transfusion in a country where blood is not screened for blood-borne viruses.

Doctors fear there may be a ticking timebomb of people who have hepatitis B and C but do not know it.

Between October 2007 and August 2008 staff from Bradford Teaching Hospitals NHS Foundation Trust went out to mosques and community centres to test anyone who volunteered.

The results of the study were revealed at a conference at the Hilton Hotel, Bradford, yesterday. In Bradford 1,457 people were recruited to the study and data from 1,413 tests were analysed – 1,100 men and 313 women. There were 19 cases of hepatitis B (1.3 per cent) and five cases of hepatitis C (0.4 per cent). All are now in treatment.

The other areas where the study was conducted were East London, West London and Walsall and Sandwell. About 5,000 tests were carried out and in total there 72 cases of hepatitis C (1.4 per cent) were found and 58 cases of hepatitis B (1.1 per cent).

Dr Sulleman Moreea, consultant gastroenterologist at Bradford Royal Infirmary, said: “Hepatitis B and C are silent diseases.

“If we catch these diseases early, we can treat these people and prevent them from being ill in the future, saving them a lot of misery.”