Chestertown, MD — Juan Lin, professor of physics at Washington College, intends to spend the next four years with Influenza A. He hasn't come down with a particularly bad case of the flu. Rather, as part of a team armed with a $676,000 grant from the National Institutes of Health, he and colleagues from Princeton University and two universities in Denmark will study how the flu spreads, with an eye toward controlling it.
Using demographic and molecular information on flu epidemics, Lin and collaborators will model how influenza spreads over time and space. "From the models, we hope to be able to understand the effects of vaccinations and the possibilities for controlling outbreaks of the flu," he says. The challenges to understanding the wily virus are great. "We're working on multiple fronts. We have to look at transmission, or how well flu spreads from person to person, and the susceptibility of the host, which is the actual infection and subsequent immune response. These characteristics affect how flu travels through a population and across distances," Lin says. "For instance, in the fall of 1997 a virulent flu strain developed in Hong Kong. Although several people who contracted it died, ultimately not many people became infected with it." That's because the Hong Kong flu's transmission from person to person was weak.
The team will also examine how different strains of a sub-type cross-react with one another and how those reactions affect the effectiveness of flu vaccines. Rarely does the flu virus undergo a radical shift—gene changes inside the nucleus—like the pandemic of 1918 that killed 20 to 40 million people. Shifts occur only once every 40 to 70 years. However, the influenza virus escapes immune surveillance by mutating rapidly. Lin says, "In regular epidemics only the outside molecular structure of influenza changes."
Lin also says that modern travel makes flu outbreaks more difficult to control and track. A person in an infectious phase of the disease flying from London to Baltimore, for example, can expose passengers sitting close by. When those passengers debark, they bring the flu with them. "The germ responsible for the latest outbreak in America, Influenza A, is also known as the Sydney/05/97 virus for its origins in Australia," Lin says.
Lin, who has been studying the dynamics of disease and epidemiology since 1994, finds applying physical and mathematical ideas to the modeling of the disease "a very challenging intellectual process." He says, "Collaborative research between physicists, mathematicians and biologists is becoming more important because quantitative models can be useful to further understanding of vital problems having social and ecological consequences."
The results of the team's research are about four years away. But those battling this year's epidemic can take some comfort that efforts are underway to tame the flu in the future.