"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

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