In November 2002, the residents of Guangdong Province in China began to experience symptoms of a viral respiratory disease. In the middle of February, 2003, a doctor who had treated some of these patients started to show symptoms. In the beginning of March, he died in a Hong Kong hospital. One day later, a Canadian woman who had been vacationing in Hong Kong died in a Toronto hospital. Several members of her immediate family were determined to have been infected as well.
By mid-March, cases had cropped up in Canada, Germany, Taiwan, Thailand, the United Kingdom, Hong Kong, mainland China, Vietnam, and Singapore with initial death tolls estimated well over 200. SARS (Severe Acute Respiratory Syndrome) had arrived on the global stage.
[By the way, much of the chronological details on the SARS epidemic in this post come from this excellent timeline published on the WHO website.]Rapid global travel combined with a disease that health care officials were unable to effectively treat or even diagnose led to a spreading pandemic. This situation caused the World Health Organization (WHO) to issue more restrictive travel advisories than at any time in its history. Major hospitals in Toronto shut down, tourism to Hong Kong dropped by as much as 80 percent, and economic effects of varying sizes were felt all around the globe.
Fortunately, the impact on the U.S. was quite small, despite the volume of traffic to and from Asia, and none of the handful of domestic cases led to any deaths.
For several months now, I have been casually monitoring reports on a respiratory disease outbreak that has been developing in the Arabian Peninsula. Some things are known about this condition, many are not. One basic fact is that it belongs to a family known as Coronaviruses, the same family that houses SARS and the common cold.
Although this small outbreak has not yet reached the threshold of an epidemic, there are some things that should cause some concern.
First and most simply, it is a novel disease. A lack of information about the disease is itself a cause for concern.
Second, although we do not yet know how quickly it might spread, evidence is beginning to mount that it may spread easily. This is largely conjecture, but a recent paper in the Journal of Microbiology begins to hint at such a possibility. In particular, the results of the research indicate that the new disease does not use the same receptors as SARS, and therefore may be more easily transmitted. The reason for this is that while the particular pathology of the SARS virus caused significant mortality among the infected, it was not highly contagious. This was partly because it affected tissues deep in the lungs and was not coughed out as readily as an upper respiratory infection.
Third, among the (admittedly small) set of cases now confirmed, at least two are from a single household. This could either mean that they were exposed to the same animal host, or that the virus is being transmitted from human to human. A post on the Nature website suggests that it is likely that the natural host or reservoir for the virus is in bats, although there may be an intermediate host – pigs, rats, etc.
Fourth, and finally (for now at least), is the severity of the illness. Several people have died, and in addition to the severe respiratory symptoms, patients have also experienced severe kidney damage and undergone renal failure.
It is extremely unlikely that the only cases are the ones that have already been identified. More likely is that there is an asymptomatic presentation of the disease, or at least less severe, and individuals carrying it are not aware. This does not necessarily mean that they are contagious, as human-to-human transmission is still unclear. However, as shown by the SARS scenario, international travel can rapidly spread both disease and social disruption.
Why should Baltimoreans be concerned? For the same reason that Torontonians became concerned about SARS. SARS was a crisis for Toronto not because Toronto is particularly susceptible to disease, or that it has a higher traffic volume to Beijing than other cities in the world, but because it had airports and hospitals and a significant population. Toronto was simply unlucky, and any (or many) other North American cities could have been in the same situation.
Baltimore has an airport, hospitals, and a large population. Conventions, sports events and tourism bring a great deal of people to our city, to say nothing of the thousands of commuters that travel between Baltimore and Annapolis, Washington D.C., Arlington, Bethesda, and the rest of the Metro region. Baltimore also sends and receives many travelers from Philadelphia and the New York/New Jersey area on a daily basis.
[Ironically, I just heard this story about the spread of disease correlated with commerce on American Public Media’s Marketplace, heard locally on WYPR at 6:30 PM]Solutions? They may be hard to come by. Surveillance is incredibly important, of course. These cases could be the first of many in a growing epidemic, and the fact that they have been observed and monitored so early in the outbreak could make a huge difference in the outcome.
In terms of factors that we can control, however, it might be useful to look back again at the SARS epidemic of 2003. Behavioral economics were a major component of the costs of SARS. Perceived risk of falling ill or even dying of the disease was far higher than the actual risk of contracting the disease. Humans risk perception is notoriously poor, and is compounded by ambiguous or misleading public information campaigns.
The best solution may be to ensure effective communication of information. People respond well to honesty, and local and national governments should keep that in mind when considering how and when to provide information on a disease outbreak.
Next time, Does this train make me look fat?
