Petersen, as director of the division of vector borne diseases at the Centers for Disease Control and Prevention, is one of the foremost experts in the world on the condition.

CNN: CDC expert gets West Nile bug -- literally

"JE is a vector-borne disease, " notes Yap Han Heng, a professor with the Malaysian Science University.

CNN: ON DEADLY GROUND

An unidentified 37-year-old man from the San Francisco Bay area died in late July, said Dr. Vicki Kramer, chief of the department's vector-borne disease section.

CNN: STORY HIGHLIGHTS

What health scientists are telling us is that climate change will bring increased asthma, more virulent allergens, medical emergencies from heat stress, the spread of water- and vector-borne diseases and increased severe weather events.

FORBES: What does Climate Change Have to Do With Health Care?