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The Centre for Health Protection (CHP) of the Department of Health announced today (September 30) that tests on blood samples obtained from the 2-year-old girl suspected to have locally acquired dengue fever showed negative results.
A spokesman for CHP explained that the initial IgM test for dengue fever using ELISA technique is a sensitive test but may show false positive result in someone who is not actually suffering from dengue fever.
Although initial sample collected from the 2-year-old girl on September 22 tested positive for IgM by ELISA technique, blood samples taken at 22 days and 28 days after onset of symptoms did not show any rise in dengue antibody level and thus dengue fever was excluded.
Meanwhile, blood specimens of the girl's father and her 2 sisters also tested negative for dengue fever virus. Her mother and 2 domestic helpers have tested negative earlier.
Further tests for the other 3 suspected local cases involving family members of the 46-year-old man (47-year-old wife, 8-year-old son and 18-year-old son), who was the first local case, confirmed that they have been suffering from dengue fever.
The CHP has received information from over 862 persons by either questionnaire or interview in the vicinity of Deep Water Bay and Stubbs Road. Other than the earlier reported suspected cases (2-year-old girl and 3 family members of the confirmed case), 3 reported history of symptoms of fever but were already asymptomatic.
Blood samples from 86 local residents (including the 2-year-old girl and 3 family members of the confirmed case) in the region were collected for laboratory analysis.
"All results so far were negative for dengue fever virus (excluding the 2-year-old girl and 3 family members of the confirmed case). No other reports about newly confirmed or suspected local cases were received," he said.
As at 5pm today, the CHP's enquiry hotline (2125 1122) has received a total of 63 enquiries. Its operating hours will be adjusted to 9am to 1pm for the public holiday tomorrow and the adjoining weekend in view of the small number of enquiries, but the normal hours of 9am to 5 pm will resume on Monday (October 4).
A health talk on dengue fever will be held by the CHP and the Food and Environmental Hygiene Department tomorrow afternoon for residents of Wan Chai.
Investigation continues.
Ends/Thursday, September 30, 2010
Issued at HKT 21:01
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