The Glenn County residents are confirmed to have been infected with West Nile virus, and two required hospitalization.
A press release from the county Public Health Agency said the three were all adults, ranging in age from their 30s to 70s, living at undisclosed locations along the Interstate 5 corridor.
All had symptoms, and one had a severe illness that may the neuroinvasive form of the disease. Both who were hospitalized have now been released.
West Nile Virus activity is on the increase in Glenn County. Last week the Glenn County Mosquito and Vector Control District reported 35 percent of the mosquitoes trapped and tested were positive for West Nile virus, the highest percentage the District has seen in recent years.
Only 20 percent of people who are infected with West Nile virus develop even mild symptoms that may include fever, headaches, body aches, joint pain, vomiting, diarrhea or rash.
Less than 1 percent of infected people will develop serious illness such as encephalitis or meningitis (inflammation of the brain and surrounding tissues), which can be fatal.
Symptoms typically develop from three to 14 days after being bitten by an infected mosquito.
Preventing mosquito bites is the best way to ensure you do not become ill from West Nile Virus.
