A 74-year-old Sacramento County woman has died from West Nile Virus. 

The woman had been ill for some time, and started having symptoms of West Nile when she was hospitalized.

Kate Macaulay with the Sacramento County communicable Diseases coordinator says fever, weakness and headaches are symptoms of the virus, but they're not always present. 

"Many people have no symptoms at all, in fact, about 80 percent do not have any symptoms," Macaulay said. 

In Sacramento County, there are seven additional cases of possible West Nile under investigation.  

West Nile Virus is transmitted to humans and animals through mosquito bites.

Mosquitoes become infected when they feed on infected birds.