THE THOMAS FRANCIS, JR. MEDAL IN GLOBAL PUBLIC HEALTH

Technology Speeds Disease Transmission and Control

“It’s a global environment today,” said Matthew Boulton, associate professor of epidemiology and an associate dean at U-M’s School of Public Health. “What happens in Hong Kong one day can have implications in Michigan two weeks later, or even sooner.”

Technology has turbo-charged both the offense and defense in our timeless battle with infectious agents.

Just at the time scientists obtained computers that would allow them to track the spread of a disease outbreak with greater speed and accuracy, jet travel accelerated the rate at which an infectious agent can move around the globe.

Fifty years ago, mathematicians did most of the heavy data crunching of disease surveillance, by necessity, said Jim Koopman, a U-M professor of epidemiology who specializes in detailed analysis and projection of disease occurrence. But the advent of powerful desktop computers gave other scientists—epidemiologists, microbiologists and others—the ability to figure out where infectious agents were going.

The answer turned out to be ‘almost everywhere,’ thanks to more frequent, less expensive international jet travel, and the global economy.

“It’s a global environment today,” said Matthew Boulton, associate professor of epidemiology and an associate dean at U-M’s School of Public Health. “What happens in Hong Kong one day can have implications in Michigan two weeks later, or even sooner.”

Airport security can x-ray your shoes, but it can’t scan your bloodstream.

Disease detectives saw just how frightening this scenario can be with SARS, the 2003 outbreak of a new respiratory virus that killed about 10 percent of those it infected. Transmitted primarily by the droplets an infected person expels through coughing or sneezing, the Severe Acute Respiratory Syndrome traveled from Hong Kong to Toronto in a matter of hours.

The disease apparently began in China, with numerous people getting infected in a hotel and an apartment building. But then a 78-year-old woman who harbored the virus returned from a trip to Hong Kong in the tight quarters and enclosed airspace of an airplane bound for Toronto.

Not only did she transport the virus halfway around the world, but in doing so, unknowingly passed it on to others along the way. Anyone she coughed near, or who touched the lavatory door after she did, was potentially infected. More than 440 Canadians ended up infected with the virus, and 44 died. In a matter of months from its first documented appearance in 2002, the droplet-borne disease had spread from Guangdong Province, China to infect more than 8,000 people worldwide.

When Rift Valley Fever virus looked like it might make a move from its native Africa to North America last year, scientists rallied to figure out a plan of defense. Sonja Gerrard, assistant professor of epidemiology at U-M, said researchers long ago figured out how the virus works but with no vaccine against it, they needed to think about preventing transmission rather than dispensing drugs to would-be victims.

Improved transportation and communications and better disease surveillance have made protecting the public health a global effort because some of these emerging diseases have the potential to do global harm.

The National Institute of General Medical Sciences developed what it calls the Modeling Infectious Disease Agents System—or MIDAS—to monitor for signs of the potentially lethal H5N1 strain of influenza, which is being watched closely for its potential to become a global pandemic. Like SARS, this flu bug originates in Southeast Asia.

Koopman, who has collaborated with the developers of the MIDAS system, said scientists are worried enough about the threat H5N1 poses that they wanted to have an early-warning system in place to watch for it. The virus is moving from birds to humans, and is unusually deadly, but it has not yet learned to effectively transmit from person to person.

With the first few reports of H5N1 being passed between people and the number of bird-to-human cases still rising in Asia, the virus could be just a plane ride away from the United States.