On January 22, the World Health Organisation will hold an emergency meeting to discuss the situation arising out of the outbreak of a mystery respiratory illness, which has killed at least four people and infected more than 200 in China. With cases also being reported in Japan, South Korea and Thailand, the outbreak has revived memories of the SARS epidemic — caused by a coronavirus — that killed nearly 800 people and infected more than 8,000 others across the world in 2002-2003. Preliminary analysis of the new virus’s genetic code reveals that it is more closely related to SARS than any other coronavirus detected in humans in the past 20 years. And, though experts suggest that the new flu may not be as lethal as SARS, there are enough reasons for health authorities around the world to be vigilant.

The infection, initially transmitted from animals, was first detected in Wuhan province in mid-December. Some reports have hinted that the virus spread from a seafood market in Wuhan. But the fact that several people who contracted the flu never visited the market has complicated the search of the disease’s origins. Chinese researchers now believe that, given the large number of cases, the likelihood of human-to-human transmission is large. But the failure to isolate the animals that transmit the virus in the first place could compromise efforts to contain the outbreak.

In 2016, the WHO reported that more than 75 per cent of the new diseases that have affected humans over the last decade have been caused by pathogens hosted by animals or from products of animal origin. Population pressure and clearing vegetation, whether for agriculture or urban expansion, is bringing humans, domestic animals and poultry into closer contact with animals known to be carriers of diseases — rodents, primates and bats. And when humans and animals share space, they also share microbiology. The genetic make-up of most viruses allows them to jump from an animal host to humans. It also allows them to adapt to a foreign environment — such as the human immune system — and makes several resistant to drugs. Compounding this public health challenge are the forces of globalisation, especially the speed and volume of global air travel. For example, after originating in China, the SARS virus traversed nearly 30 countries in less than a year. That is why health authorities across the world should be careful in case of the new coronavirus. The outbreak in Wuhan has coincided with the Chinese Lunar New Year — vacation time in China, when millions of Chinese travel across the world.