Health experts are turning their attention to learning lessons from one of the deadliest West Nile outbreaks in U.S. history.
Federal authorities are collecting data and examining factors for the mosquito-borne illness that killed more than 240 in the U.S. -- about a third of them in Texas. Meanwhile, Dallas County, the epicenter of the outbreak, has begun year-round mosquito surveillance and testing.
What remains unclear is whether experts will be able to shed light on what caused it, why parts of Texas were so severely affected and if the next major surge can be forecast.
Dr. Lyle Petersen of the Centers for Disease Control and Prevention questions whether experts will ever be able to sort it out.