A 74-year-old, Sacramento County woman died July 26 from the West Nile Virus.
The Sacramento County Department of Public Health says the woman had a compromised immune system, which put her at greater risk of infection from the virus.
Kate McAuley is the Immunization and Communicable Disease Coordinator for the County. She says 80-percent of people who are bitten by mosquitoes carrying the virus develop no symptoms.
"If a person is going to become sick with symptoms, it's usually between two-and-fourteen days, but normally it's the shorter of that -within about a week."
McAuley says the virus is capable of causing encephalitis or meningitis.
"For some people who do become ill, it can be a fever-type of illness. And then for a small -about 1- percent of the people have an infection that affects their neurological system and that's the most severe."
This is the first reported death from West Nile in Sacramento County this year. There was one death from the virus reported last year.
The Sacramento-Yolo Mosquito and Vector Control District has conducted more than 200 backpack and truck spraying operations for mosquitoes in the two counties in the past two months.
The district plans aerial spraying for tonight and Thursday in Davis and Woodland from 8 o'clock to midnight.