North South East West Nile

The first cases of West Nile virus were not reported in North American until 1999. Now it has spread across the entire United States and into Canada. Today, Governor Schwarzenegger declared a state of emergency in three California counties after four deaths and three times as many cases of infection as were reported last year. Scientists have long warned that global warming would contribute to the spread of mosquito-borne tropical diseases to both higher latitudes and higher elevations as rising temperatures made the areas more hospitable to the insects. But the rate of spreading has surprised even the experts. As Harvard Medical School's Dr. Paul Epstein told the Washington Post last year:

"Things we projected to occur in 2080 are happening in 2006. What we didn't get is how fast and how big it is, and the degree to which the biological systems would respond. Our mistake was in underestimation."