The County Health and Human Services Agency (HHSA) confirmed a woman from Spring Valley tested positive for the West Nile Virus on Friday.
The woman is the first confirmed case in San Diego County this year, according to a county statement. In 2016, 22 cases were reported and two people died.
The woman described symptoms of rash and headache four days after traveling outside the country, but county officials were prompted to issue a warning because symptoms can occur anywhere from two to 14 days after being bitten by a mosquito, according to the county.
The virus mainly affects birds but can be transferred to humans by mosquitos.
Many people bitten by infected mosquitos will never experience any symptoms. However, those who do may experience headache, fever, nausea, rashes, fatigue or swollen glands, according to the statement. In rare cases the virus can make a person extremely sick and become deadly.
In California, 231 people have been reported ill from the West Nile virus this year, and 12 people have died.
This year San Diego County reported 32 dead birds, eight batches of mosquitos and one horse that tested positive for West Nile virus.
San Diego County officials encourage residents to protect themselves from mosquitos by using insect repellent or wearing pants and long sleeves when outdoors and removing possible breeding sources such as water fountains, horse troughs, rain gutters and toys that collect water.
Increased mosquito activity, being bitten during daylight hours, dead birds and mosquito breeding sources can be reported to the Vector Control Program at (858) 694-2888 or by emailing firstname.lastname@example.org.
For more information, visit the county's website, “Fight the Bite.”