Small world makes West Nile virus spread

TBy Jeffrey Kahn

they jokingly say the state bird of Minnesota is the mosquito, but the joke isn’t so funny these days now that West Nile virus – carried by the buzzing pests – has infiltrated the state.

The virus infects birds, which are then bitten by mosquitoes that can transmit the virus from birds to humans. The virus was first identified in the United States three years ago in New York. Since then, it has been spreading across the country, appearing as far west as the Dakotas and as south as Texas.

The spread of a so-called “emerging disease” such as West Nile virus raises questions of public health prevention and protection and reminds us that diseases don’t pay attention to territorial boundaries. How should we prepare for diseases such as West Nile virus, and what lessons can we draw from it?

It used to be that infectious diseases of the less-developed world were the domain of international public health efforts, with less direct relevance in the United States and other developed countries.

But cheap and plentiful air travel has changed all that. Now an infected traveler or a wayward mosquito carried on a plane can unknowingly bring a disease to any place on the globe in a matter of hours.

This makes West Nile virus in Africa not only a local issue but also an international one. Public health professionals have long argued that helping to treat illness and disease around the globe is everybody’s problem – as a matter of human rights, economic development and good global partnership.

Unfortunately, these arguments tend to lose their urgency when it’s the plight of citizens in far-flung countries. The issue takes on a different dimension when birds in Central Park carry a potentially deadly disease.

What we need to realize is that public health threats know no borders.

Threats can take the shape of a bird flying hundreds of miles from New York City to the Southern coast. But it can also mean a jetliner flying thousands of miles from sub-Saharan Africa to North America.

So is it only a public health emergency when people are dying in Louisiana? Or should we think of diseases such as West Nile, malaria and numerous others as part of a global issue that warrants research and funding?

It’s good practice to make people aware about how to avoid mosquito-borne illness and to support programs for treating people who do get sick.

The take-home message is that the world is small and getting smaller when it comes to infectious diseases. We should view a public health problem in Africa or Asia today as one that could be ours to confront tomorrow.

So it’s wrong to think that isolation, containment, distance or anything else separates us from what is going on in China, India or Africa. We’re beginning to understand public health is everyone’s problem, no matter the name of the country in which it is currently an issue.

Jeffrey Kahn, Ph.D., MPH, is the director of the Center for Bioethics at the University. He welcomes comments at [email protected]. This column also appeared on, where Dr. Kahn writes the biweekly feature “Ethics Matters”. For more information about the Center for Bioethics, visit