28 January 1998
INCREASED SURVEILLANCE FOR INFLUENZA SHOULD BE CONTINUED
While a World Health Organization (WHO) team found no human case of influenza A(H5N1) virus infection in Guangdong province in southern China during its mission there from 16 to 22 January, there is still a need to maintain intensified levels of surveillance for at least six months, because of the potential risk of adaptation of the H5N1 virus to humans.
"We were very impressed with the high quality of the surveillance activities which had been implemented by the Chinese Government in December 1997 and January 1998. The number of specimens collected for virus isolation from patients exhibiting flu-like symptoms has increased from 20 to 1000 samples per month, while key influenza laboratories, which are part of WHO's global influenza surveillance network, are strengthening their capabilities," said Dr Daniel Lavanchy, who heads the WHO programme on influenza surveillance and was a member of WHO's team in China.
Lavanchy noted that the increased surveillance was being implemented with the full support of local and central government. WHO, in collaboration with its Collaborating Centre for Reference and Research on Influenza at the Centers for Disease Control and Prevention in Atlanta, USA, has distributed H5N1 kits to laboratories in Guangzhou and Shenzhen in order to standardize laboratory diagnosis.
But Lavanchy stressed that, "even though, with the increased surveillance, no cases of human infection with H5N1 virus in Guangdong Province have been identified, there is still the need to remain vigilant, because if the H5N1 virus adapts to humans, it could lead to the transmission of a highly virulent strain from person to person."
The WHO team found that Guangdong Province Agriculture Bureau had found no trace of H5N1 among the samples taken in the annual routine surveillance for avian influenza in poultry breeder and chicken farms since 1994. The Bureau is planning to complement routine surveillance with additional surveys in 1998.
The mission, which was organized by the WHO Regional Office for the Western Pacific and WHO headquarters in Geneva in collaboration with the Ministry of Health of China, reported its findings at a meeting on 23 January 1998 in Beijing. It made more than 20 technical recommendations on surveillance in humans, and surveillance in animals, including laboratory surveillance. These recommendations include more training of staff, improved reporting of epidemiological data and expanding the scope for serological and virological investigations to include duck and geese and to cover more farms.
Dr Yin Dakui, the Chinese Vice-Minister of Health, said that China would be extending its collaboration with WHO on influenza, including H5N1.
The WHO mission started on 16 January at Guangzhou and visited Guangdong Provincial Health Bureau, Guangzhou and Shenzhen Municipal Health Bureaus, four epidemic prevention stations, hospitals, influenza surveillance sites, poultry farms, a wholesale market and animal quarantine laboratories. The mission was composed of 14 members. They came from WHO headquarters and the Regional Office for the Western Pacific; the Guangdong provincial health authority; health authorities and institutions in Beijing, Shenzhen and Hong Kong; the WHO Collaborating Centres at the Centers for Disease Prevention and Control (CDC), Atlanta, USA and at the National Institute for Infectious Diseases (NIID), Tokyo, Japan; the Department of Public Health, Kyushu University, Fukuoka, Japan; and the Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Texas, USA.
While the mission was in China, no new cases of H5N1 influenza in humans were reported from Hong Kong, Special Administrative Region of China, where onset of the last reported case was 28 December 1997.
Authorities in Hong Kong will resume importation of chickens from mainland China on 7 February 1998. Requirements for this will include additional inspection, and blood testing at chicken farms prior to export with complementary testing for avian influenza upon arrival in Hong Kong. Chickens will be segregated from live ducks/other water fowl at all levels to minimise the risk of transmission of the H5N1 virus from live ducks/other water fowl to live chickens.
WHO also stressed that there is no public health reason for other countries to ban the importation of chicken and chicken products from China, including Hong Kong.
Related stories:Influenza A8H5N1) Virus Found in Ducks and Geese (16 January, 1998)
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