Pathogens & People: Will global warming create new 'hot zones'? Maybe

Summer began with a heat wave, violent thunderstorms and a tornado or two.

Tornadoes tore up the Midwest. Fires burned in California. Record flooding covered parts of Iowa. Is it all another sign of global climate change? Maybe. Will a warmer world also lead to more infectious diseases? Yes and no.

Politicians and reporters hate an answer like that, but it really depends on what disease, and where, and sometimes who you ask.

For example, there was a recent surge in the number of cases of tick-borne encephalitis in the former Soviet states of Latvia, Estonia and Lithuania. The first impulse was to blame a warming climate...