Global Microbe Detectives Are Getting Better at Tracking Disease Outbreaks

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I was lucky — or unlucky — enough to have a front-row seat for one of the most surprising and frightening infectious disease outbreaks in recent history. I was working as a reporter in TIME’s Hong Kong office in March 2003, a moment when all the focus was on the soon-to-begin war in Iraq. But as early as February we had started hearing reports of a strange respiratory illness across the border in southern China, where people were supposedly crowding hospitals and disinfecting everything in sight. (The big clue — a run on vinegar in Guangzhou.) But that’s all we knew — and as we found out later, that was all that officials in Hong Kong and disease experts at the World Health Organization (WHO) in Geneva knew either.

The mainland Chinese government was suppressing information about the new disease, and it wasn’t until the government in Vietnam notified the WHO of cases of “atypical pneumonia” in a foreign doctor that the international agency had some official notice. But by that time the disease had spread to Hong Kong, and though the WHO put an emergency travel advisory out on March 15, it was too late. The disease that would be known as “severe acute respiratory syndrome,” or SARS, would eventually infect more than 8,000 people around the world and kill nearly 800. (Check out China Syndromea book by Karl Taro Greenfeld, my boss at the time in Hong Kong — for the definitive story of SARS.)

SARS became a symbol of success and failure for the disease detectives at the WHO. Success because a network of microbiologist and epidemiologists managed to isolate and sequence the coronavirus behind the disease incredibly quickly. (The work was actually done at the local University of Hong Kong, which beat the U.S. Centers for Disease Control to the prize — you can read about my visit to their lab in 2003 here.) Once the disease had spread, the global medical community mobilized to stop it, and in the end, kept SARS from getting out of control. But at the same time, outright denial on the part of the Chinese government and weak lines of communication within the WHO made the outbreak much worse than it might have been. Had the WHO more power to investigate reports of new diseases even without the support of national governments, SARS might never have become a household name.

The good news is that for all the complexities of working across borders, the WHO and the international medical establishment is getting better and faster at detecting disease outbreaks — in part because the WHO is, post-SARS, more open to indirect lines of communication. That’s the conclusion of a new study published today in the Proceedings of the National Academy of Science (PNAS). John Brownstein, an epidemiologist at Children’s Hospital Boston, led a team of colleagues who compiled WHO disease outbreak reports over the past 14 years. They found that the time lag between estimate beginning of a disease outbreak and discovery is now an average of 15 days, and has improved at a rate of about 7.3% a year since 1996. The timeliness of public communication of a new disease outbreak (the moment when the media is alerted) has improved as well, at about 6.2% a year, though it still lags behind disease detection by about a week. (Download a PDF of the study here.)

What’s behind the better disease detecting? Brownstein and his colleagues note that the Western Pacific region and Southeast Asia saw particular improvements — possibly due to the higher profile of outbreak reporting following SARS and then avian influenza, which hit Asia hard. Though the bird flu response, like SARS, was marred at first by secrecy on the part of governments afraid of the economic consequences of a H5N1 outbreak, those walls broke down over time. As Brownstein and his colleagues wrote: “This would be a promising improvement, as these regions include many of the world’s developing nations, which have faced challenges with newly emerging and reemerging infectious diseases, with surveillance capacity and reporting, and with potential economic consequences of reporting.”

Even more important might have been the establishment in 2000 of the WHO’s Global Outbreak Alert and Response Network (GOARN), a situation room within the WHO that tracks and counters emerging diseases. Also the WHO revised its outdated International Health Regulations in 2005, after both SARS and bird flu, to mandate that countries report “public health emergencies of international concern.” (Before the 2005 revision, there were only a handful of known diseases that required national reporting, allowing an emerging unknown disease like SARS to slip through the cracks.)

It’s not all perfect — the PNAS study notes that disease reporting still lags in Africa, which has been home to around half of the WHO’s reported disease outbreaks over the past 14 years. That’s due largely to insufficient surveillance resources and weak national governments, but it should be a priority to ensure that Africa can pull its weight — it’s more than possible that the next killer bug could come from the crowded streets of Lagos or Cairo.

The WHO and the world itself is better prepared for an emerging disease now than it was in the spring of 2003 — the largely successful response to H1N1/A pandemic flu, however checkered, is proof of that. But as we learned during SARS, when it comes to infectious disease the world is only as strong as its weakest link — and we’re all vulnerable.

Check out John Brownstein’s HealthMap iPhone app, which tracks disease outbreaks in real time.

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