<TABLE cellSpacing=0 cellPadding=0 width="100%" border=0><TBODY><TR>Oct 3, 2008
</TR><!-- headline one : start --><TR>Dengue via blood donor <!--10 min-->
</TR><!-- headline one : end --><TR>Donor had no symptoms; risk of such transmissions extremely low </TR><!-- Author --><TR><TD class="padlrt8 georgia11 darkgrey bold" colSpan=2>By Jessica Jaganathan
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<!-- START OF : div id="storytext"-->IN WHAT the health authorities say is the first case in Singapore, three people contracted the dengue virus from a blood donor last year.
Two men, aged 64 and 72, suffered fever, muscle pain and fluid build-up in their chests one to two days after receiving the blood, according to a report published in a medical journal yesterday. The third man, 74, was infected without suffering any symptoms.
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</TD></TR></TBODY></TABLE>All three were discharged from the National University Hospital (NUH) in good health, according to the article.
The 52-year-old repeat blood donor did not show any symptoms of dengue at the time of donation, wrote Associate Professor Paul Ananth Tambyah, head of infectious diseases at NUH and the National University of Singapore, in the New England Journal of Medicine.
The donation was made to NUH in July last year. The donor informed the blood bank when he developed fever the day after, which prompted a check on the three recipients of his blood products.
Dengue, which is endemic here, is typically transmitted through the bite of an infected mosquito, and not from person to person.
Since 2002, the Blood Services Group of the Health Sciences Authority (HSA) has taken precautions against dengue-infected blood, which it cannot screen directly. It defers blood donors showing symptoms, or who have been exposed through family and friends, it said.
It also asks donors to call back if they become ill, so their donations can be removed from the inventory.
Dengue patients are asked not to donate blood for six months after they have recovered fully.
Blood products are now screened for HIV, Hepatitis B, Hepatitis C and syphilis viruses.
But dengue has always been a concern because of its prevalence, according to Dr Mickey Koh, division director of patient services at HSA.
There is no licensed test kit available to screen donated blood for dengue, said the HSA.
Dengue patients are now diagnosed through a different test that cannot be used to test donated blood, a spokesman said.
One may be available in the future which measures the viral load in a patient's blood. It is now studying this with NUS Laboratories.
Prof Tambyah said in an e-mail to The Straits Times that the risk of dengue being transmitted through the blood supply was extremely low, 'probably less than one in a million'.
With such low risk, large numbers of screening tests on donors would need to be done to pick up even a single case of dengue. The price would be blood that is thrown away for no good reason because of false positive diagnoses being made by tests which are not foolproof.
Any decision to do such tests would be an economic, and not medical, one.
'There is a deeper issue with making people a little more confident in the blood supply especially as dengue is endemic in the region and we are a medical hub for people coming from non-endemic areas,' he said.
Dr Wong Sin Yew, an infectious diseases physician in private practice and former head of the Communicable Disease Centre said that much depended on donors calling back if they fell ill afterwards. If they did not, he said: 'That's when something falls through the cracks.'
The transmissions were not publicly known before they were published in the medical journal.
Dengue symptoms include high fever, headaches, joint and muscle pains, vomiting and rashes. There is currently no vaccine. The virus has infected 4,702 people in the first 39 weeks of the year, compared with 7,114 in the same period last year.
The three men who received the infected blood were being treated at NUH for diabetes, hypertension, heart disease, kidney failure and cancer.
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