At 693, the Centers for Disease Control says there are more reported cases of West Nile virus so far this year than any year since the disease was first detected in the U.S. in 1999. Half of those cases have been in Texas where 14 of the 26 deaths from the mosquito. Because of a lag in the confirmation of cases by the CDC, the Texas health department reports 465 cases and 17 deaths. This has prompted Dallas Mayor Mike Rawlings to declare an emergency, which will allow aerial spraying of pesticide to start this week. There is no clear reason why the number of cases in Texas is so high, but Christine Mann, a spokeswoman for the Texas health department said that it could be related to a warmer winter and rainy spring that has contributed to a high mosquito population.