Rare virus linked to Japanese occupation
JAPANESE soldiers occupying Hong Kong during World War II appear to have left some residents with a hereditary virus related to AIDS.
The potentially deadly HTLV-1, which can lead to leukaemia, has appeared in the blood of a small number of donors to the Hong Kong Red Cross Blood Bank.
University of Hong Kong Reader in Medicine Dr Raymond Liang Hin-suen said he was examining cases of HTLV-1, a rare virus usually found only in Japan and the Caribbean.
Dr Liang said he had seen a patient last year who tested positive to the virus and developed a leukaemia lymphoma. She has since died.
Dr Liang's research team, surprised by the discovery of HTLV-1 in Hong Kong Chinese blood donors, scrutinised the organisms found in their blood.
'It appears they are from Japan - the DNA sequencing is almost identical to the Japanese strain,' Dr Liang said.
'At the moment, we cannot identify their mode of transmission; they have not had blood transfusions, they do not have unusual sexual histories, they are not drug addicts.
'But because of the Japanese occupation of Hong Kong and China, it may be that they contracted it from their parents. A casual contact does not pick up the virus; it has to be a prolonged, intimate contact.
'The occupation of Hong Kong would be the only period I can think of where Japan had this kind of contact with Hong Kong.' A research team was studying why Hong Kong people were more prone to T-cell leukaemia and examining HTLV-1's links with other diseases.
'In a small proportion of AIDS victims in Hong Kong, they develop blood cancer as well. It is still closely related; it is kind of a cousin,' Dr Liang said.
'We believe there is a good possibility there may be other related diseases.' The blood bank began screening donations almost two years ago, and has come across five cases of HTLV-1 infection among about 100,000 donors.
'There is controversy over whether or not we should spend money screening for that virus, because it's not common,' Dr Liang said.
'But we know something that can prevent a fatal disease from spreading and we should do so.' The HIV virus was briefly named HTLV-3 in the early 1980s, because doctors initially mistook it for the same organism.
'It is a virus closely related to AIDS; the mode of transmission is quite similar to the AIDS virus and hepatitis B,' Dr Liang said.
'HTLV was the first virus known to cause blood cancer in humans.
'This virus causes T-cell leukaemia.
'In Chinese, we are seeing quite a high level of T-cell malignancies, compared to Western areas.
'In Westerners it is 10 per cent; we are seeing 30 per cent.' T-cell leukaemia tumours were more aggressive, more widespread and more difficult to cure than the common B-cell strain.
Red Cross Blood Bank consultant Dr Liu Hing-wing said it cost about $900,000 to screen for HTLV-1 in the 180,000 units of blood donated each year.
