As spring approaches and temperatures rise, growing mosquito populations will increase the risk for deadly mosquito-borne diseases, including West Nile virus (WNV) and equine encephalomyelitis (sleeping sickness).

Since its discovery in the United States in 1999, WNV has spread rapidly across the country and poses a significant health threat to humans, horses, and other animals.

“The North American West Nile virus epidemic persists,” said Lyle Petersen, MD, MPH, Director of Vector-Borne Infectious Diseases for the Federal Centers for Disease Control and Prevention, when addressing the seventh National Conference on West Nile Virus in the United States held in San Francisco, Calif., in February.

Unseasonably warm weather and mild winter conditions, which have been experienced in many parts of the country this year, may lead to an increased threat of WNV. Torrential rains in other parts of the United States further complicate the risk