Orange County health officials on Wednesday urged anyone who touched a dead bat in Newport Beach or Orange to immediately contact medical experts.
Test results showed the bats had been infected with rabies.
"We want to identify anyone who's been exposed before they've developed symptoms," said Deanne Thompson, spokeswoman for the county health department. "If you start to show symptoms, you definitely have big problems."
The two rabid California brown bats were found Monday afternoon: one near the bike trail at University Drive and Jamboree Road in Newport Beach at 6 p.m., the other at 3:30 p.m. near the Bank of America, 2680 N. Tustin Ave.
They are the 10th and 11th rabid bats found in the county this year.
"It's certainly on the high side," said Dr. Hildy Meyers, medical director of epidemiology for the county.
Rabid bats have been found in Irvine, Tustin, Los Alamitos and San Clemente. Health care agency officials on average find three to 10 bats with rabies a year, about 10% those tested for the virus tested, she said.
After being infected by a rabid bat, humans often die within days of developing flu-like symptoms, according to the U.S. Centers for Disease Control and Prevention. At first, people may experience fever, discomfort, headaches and weakness and possibly irritation at the site of infection.
The virus attaches itself to a nerve and travels to the brain, where it destroys tissue, county officials said.
A person may start to become anxious, confused or agitated, experience delirium, hallucinations or insomnia, the CDC website reports.
In the last stages, a person may salivate much more, have difficulty swallowing and develop a fear of water.
Rabies can't be passed on through skin-to-skin contact, Meyers said.
Typically, infection occurs from a bite or open wound and rarely through the eyes or mouth.
Meyers said symptoms typically develop three weeks to a couple of months after exposure.
If you think you had contact with bats or have been exposed to rabies, contact Orange County Public Health Epidemiology at (714) 834-8180.
Rabies' vaccination involves four vaccine shots in the arm over two weeks and one rabies antivirus shot.
Anyone who has spotted a wild or stray animal is asked to call OC Animal Care at (714) 935-6848.
Infection prevention tips:
Avoid contact with all wild animals
Vaccinate your cats and dogs
Don't sleep with unscreened windows or doors
If bats are seen inside the house or building, close off the area and contact animal control
Don't leave pet food outside
Immediately wash all animal bites
Report all bites and stray animals to OC Animal Care