WHO issues alert over atypical pneumonia outbreaks in Asia

Mar 13, 2003 (CIDRAP News) – The World Health Organization has issued an alert over outbreaks of severe respiratory illness, including atypical pneumonia, that it has been investigating since mid-February in Vietnam, Hong Kong, and mainland China.

The Chinese government reported in mid-February that 305 cases of atypical pneumonia, with five deaths, occurred in China's Guangdong Province, which adjoins Hong Kong Special Administrative Area (SAR) of China, according to a WHO statement issued yesterday. In addition, clusters of cases have occurred in one hospital in Hanoi, Vietnam, and another in Hong Kong

WHO said it is investigating the possibility of a link between the outbreaks and two recent human cases of avian influenza A(H5N1) in Hong Kong. Those cases involved a 33-year-old man, who died, and his 9-year-old son, who was hospitalized but recovered, according to US and Hong Kong health officials.

"Until more is known about the cause of these outbreaks, WHO recommends patients with atypical pneumonia symptoms who may be related to these outbreaks be isolated with barrier nursing techniques," the WHO statement said. "At the same time, WHO recommends that any suspect cases be reported to national health authorities." Officials said hospital workers caring for the patients seem to be at highest risk for contracting the illness.

The outbreak in Vietnam began with one patient who was hospitalized with severe respiratory symptoms shortly after arriving in Hanoi from Shanghai and Hong Kong, WHO reported. After he was admitted, about 20 hospital workers became sick with a similar flu-like illness, featuring rapid onset of fever, muscle aches, headache, and sore throat. In some cases this progressed to bilateral pneumonia, for which some patients required breathing assistance. "Some patients are recovering but some patients remain critically ill," the statement said.

The hospital outbreak in Hong Kong was reported just yesterday, according to the WHO. In screening of 50 healthcare workers there, 23 were found to have a febrile illness and were admitted to the hospital for observation. Eight of those patients have had early signs of pneumonia on chest x-rays. Three other healthcare workers reported on their own to hospitals with a febrile illness, and two of them had radiographic signs of pneumonia.

The outbreaks in Hanoi and Hong Kong appear to be confined to the hospitals, and no link has been found between the two outbreaks, WHO reported. Meanwhile, the cause of the outbreak in Guangdong Province of China, which adjoins Hong King, is still under investigation.

The influenza A(H5N1) cases in Hong Kong occurred in a local family while they were visiting Fujian Province in mainland China, according to reports by the US Centers for Disease Control and Prevention (CDC) and the Hong Kong SAR Department of Health. The 33-year-old father died Feb 17, after the family's return to Hong Kong. Influenza A(H5N1) was confirmed in him and in his nine-year-old son. An eight-year-old daughter died while the family was in China, and other family members had respiratory symptoms, but the cause of those illnesses was not known.

The father and son probably acquired the infection directly from chickens, according to Dr Yeoh Eng-kiong, Hong Kong's secretary for health, welfare, and food. "There is no evidence of human to human spread," Eng-kiong said, as reported in a transcript on the health department's Web site.

WHO said laboratories in Japan and the United States are testing specimens from Vietnam and Hong Kong to determine if the avian influenza cases and the three outbreaks of atypical pneumonia are related. No link has been found so far, officials said.

A CDC statement said the two Hong Kong cases mark the first time since 1997 that human influenza A(H5N1) cases have been seen anywhere in the world. In the 1997 outbreak in Hong Kong, 18 people were hospitalized with the disease, and six died. Those cases resulted mostly from direct contact with birds; "efficient, sustained transmission of the virus from person to person did not occur," the CDC said.

See also:

WHO alert statement

CDC report on human cases of avian influenza

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