The new coronavirus: In search of the culprit

Virologist Klaus Stohr first had an inkling that trouble was brewing in November 2002. On a business trip to Beijing, the influenza programme manager for the World Health Organisation (WHO) was attending a routine meeting on China's flu vaccination policy. Stohr heard a report from a Guangdong health care worker that several people in the southern province had contracted a severe flu with unusual characteristics. The WHO requested a sample of the virus from the Chinese, but testing of the specimen received by the UN agency did not show anything out of the ordinary.1 By January 2003, Hong Kong virologists began to receive news of peculiar cases of pneumonia in neighbouring Guangdong. When health authorities in Guangdong announced on 10 February that a form of atypical pneumonia had infected 305 people since November 2002, five of whom had died, Hong Kong experts knew the situation across the border had to be watched closely. Scientists initially suspected that the mysterious disease was somehow linked to a flu that mainly affects birds, particularly fowl. Several geese in a Hong Kong park had recently died from the H5N1 virus. A team of scientists at the University of Hong Kong (HKU), led by Professor Malik Peiris and Dr. Guan Yi, had been studying this strain of influenza since the 1997 outbreak in Hong Kong. The outbreak began with the sudden death of thousands of farm chickens. When the virus crossed over toinfect humans, 18 people fell seriously ill with what was termed as the avian or bird flu. Six of the patients died.2 Hong Kong slaughtered over a million chickens and other poultry to stop the disease from spreading. Up until this point, scientists had believed that the bird influenza virus could not infect humans. The 1997 outbreak proved that the crossover from animal to human hosts was possible. The good news was that transmission from person to person was not efficient. Had it been more efficient, the avian flu would have affected many more people. The virus re-emerged in Hong Kong in 1999 but in a less severe form. On 11 February 2003, China's Ministry of Health informed the WHO of the atypical p n e u m o n i a outbreak in Guangdong. After the announcement, Hong Kong's Department of Health and the Hospital Authority (HA) set up a Working Group on Severe Community-acquired Pneumonia and launched an intensive surveillance operation to locate any unusual cases of severe pneumonia. Peiris' laboratory was one of the facilities involved in the investigation. The next day, China reported that the outbreak in Guangdong had affected six municipalities. But laboratory analysis of blood and saliva samples from patients did not indicate the presence of any influenza viruses. China informed the WHO on 14 February that similar cases in Guangdong had been reported as far back as 16 November 2002.3 Dr. Guan Yi and Dr. Zhen Bojian, colleagues in HKU's Department of Microbiology, travelled to Guangzhou to learn more about the outbreak and obtain samples for testing back in Hong Kong. A few days later, Hong Kong officials told the WHO that two people, a father and son, who had visited Fujian Province and travelled through Guangdong back to Hong Kong had contracted the H5N1 flu.4 The daughter of the family had developed the disease and died while in Fujian, where she was buried.5 Because of these cases, there was uncertainty as to whether the illness reported in Guangdong in February 2003 was a new disease or simply a return of the avian flu. Peiris and his team suspected the latter. They were therefore screening samples from flu patients for evidence of H5N1 infection. On 21 February, a Guangdong doctor, Liu Jianlun, arrived in Hong Kong. He was admitted to Kwong Wah Hospital the following day. Liu's brother-in-law, a Hong Kong resident, who had accompanied Liu shopping and sightseeing also became infected and was admitted to hospital. Kwong Wah sought the help of Professor Yuen Kwok-yung ofHKU as Liu had told staff that he had been in contact with suspected atypical pneumonia patients in Guangdong. Both Liu and his brotherin- law eventually died from the infection. There was insufficient evidence that these cases were different from other pneumonia cases. By the end of February, however, scientists became more certain that they were dealing with a new virus. "We stopped wondering and started worrying," Stohr said.6 On 5 March, Hong Kong's Department of Health announced it was investigating reports that healthcare workers were falling ill with atypical pneumonia at the Prince of Wales Hospital (PWH). At about the same time, reports of similar cases emerged in Hanoi, Singapore and Toronto. (Chapter 2 provides a detailed account of what happened at each of the hospitals in Hong Kong and in other cities.) In a 15 March global advisory, the WHO for the first time referred to the new disease as "Severe Acute Respiratory Syndrome." By this time, over 150 people in countries around the world had become infected with SARS. The WHO believed that what it was dealing with was the first readily transmissible disease to emerge in the twenty-first century.

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