The coronavirus that is spreading in and from China, known as the Wuhan virus after the city in which it was first detected, demonstrates how impossible it is to constrain the outbreak of a new disease vector—and how important it is to try anyway. This virus emerged in a highly developed area, was quickly recognized as a novel disease, and was met with prompt action. Even so, cases are now in at least six countries, including the United States.
As of Wednesday morning, more than 20 million people in China are under travel restrictions, part of an effort to contain the outbreak. But with confirmation that the Wuhan virus is readily communicable person-to-person, it seems likely that it will continue to spread to other locations. So far it seems to be less lethal, in its current form, than the related SARS virus, which was identified in 2003. But that isn’t particularly comforting.
The outbreak that began near the city of Wuhan is caused by a coronavirus, one of a number of viruses in a poorly understood group that also includes SARS. These viruses are thought to have their primary reservoir in bats, but, unlike many viruses, they seem highly catholic in their choices of hosts. Everything from humans to farm animals to civets seems to be amenable to SARS. The Wuhan virus may be equally flexible. And the ease with which the new virus is apparently spread through the air, or through superficial contact, suggests that it may be transferred even more readily than the SARS virus, which killed at least 800 in its initial outbreak.
But then, when it emerged—also from China—in 2002, SARS also looked very damn scary. It spread to over 30 countries in that first wave, and the fatality rate approached 10%. In particular, an outbreak in Toronto, where 250 cases piled up in just a couple of weeks, and the fatality rate closed on 20%, was particularly frightening, as it suggested that even a well-funded, industrialized-nation facility had no means of dealing with the emerging disease.
That was true. However, it was also true that the Toronto situation was made worse through basic mistakes and failure to take the most basic precautions. That first round of SARS infections fizzled out over a period of weeks, much to the delight—and the surprise—of many epidemiologists who had begun to seriously sweat the possibilities. SARS has re-emerged several times as a cluster of single cases, but has never again repeated the 2002 pattern of infection and spread.
It would be more reassuring if the reason that SARS suddenly spread, and that it just as suddenly stopped, was better understood. One factor that seems to have played a roll is that SARS was simply not that transmissible. Many of the outbreaks seemed to have happened in situations where either the water supply or other elements of infrastructure assisted in the spread. Unfortunately, early patterns indicate that the Wuhan virus is more easily transmitted than SARS. In one instance, dealing with a single patient appears to have spread the virus to 14 caregivers. Researchers are trying to determine how that happened.
As of Thursday, there have been 17 deaths associated with the Wuhan outbreak. Every one of them is unfortunate, but many seem to be among the elderly or otherwise ill who are subject to greater risk from pulmonary infections of all sorts. At the moment, the greatest damage appears to be to China’s economy, as travel restrictions, shuttered stores, and simple fear are keeping millions at home. Hopefully, that will be the only damage.
It’s also notable that officials everywhere have been faster to act, faster to impose restrictions, and faster to identify the underlying cause of the outbreak than they had been in the case of SARS. Restricting the spread of an emerging disease remains a near-impossible task., but health officials around the world are giving it a really extraordinary try.