Hong Kong saw a record number of new HIV infection in 2012, the Department of Health said on Wednesday.

A total of 513 new infections of Human Immunodeficiency Virus (HIV) were reported last year, a 17 per cent increase from the previous high of 438 cases recorded in 2011.

The new cases take the cumulative total of HIV infections reported in Hong Kong to 5,783 since the first case in 1984.

Dr Wong Ka-hing, a consultant with the Centre for Health Protection, said at a press conference that sexual contact was the major mode of transmission last year.

Of the 513 new cases last year:

• 254 were the result of infection via homosexual or bisexual sexual activity
• 126 via heterosexual
• 7 acquired the virus through drug injection
• 1 through perinatal (mother-to-baby) transmission
• 1 via blood or blood product transmission outside Hong Kong

The transmission routes of the remaining 124 cases have had yet to be determined due to inadequate information.

In the fourth quarter 2012, 120 people – 93 men and 27 women – tested positive for HIV.

The same quarter also saw 25 new cases of HIV-infected patients develop into Acquired Immune Deficiency Syndrome (Aids), bringing to 1,353 the total number of locally confirmed AIDS cases.

Without treatment, about half of the HIV-infected people will progress to Aids within 10 years.