Vector Control officials set traps near El Sol Science and Arts Academy and Frances Willard Intermediate School. Authorities believe the cats are hosts of the fleas that are infected with typhus.
Orange County officials believe the fleas caused a person living in the area to contract typhus. That person was hospitalized last month but has since made a full recovery.
Since then, Vector Control officials have been setting traps and passing out literature to prevent the spread of the disease. There have been no other confirmed cases of the disease.
"We do have a colony of them that live up here. It's not uncommon for them to live in this area. It's heavily populated, so there are a lot of food sources for them out here, and so they stay where they know where they have the food," said Cpl. Sondra Berg, Santa Ana Police Animal Services supervisor.
Typhus is usually spread through infected fleas. Symptoms surface about a week or two after exposure and can include high fever, body aches or rashes. It can be fatal if it's not treated by antibiotics, which is why authorities are taking this very seriously.
Vector Control officials want to catch as many feral cats as possible at the two campuses.
The cats are taken to Vector Control. The fleas on each cat, possum or other animal will be counted. The normal range is about 50 to 100 fleas. If there are 200 or more, that's considered serious.
The animals will be tested, then released into the same neighborhood or euthanized, according to Vector Control.
Since there are very few labs that test for typhus, results could take a month to two months.
Vector Control is evaluating possible flea-eradication solutions, including spraying.
School officials said the traps were placed in areas not accessible by students.
"There is no reason at this point in time for any worry, any outward concern. This is cautionary," said Michael Bishop with the Santa Ana Unified School District. School officials have alerted parents about the issue last Friday, and they plan on sending out informational letters in Spanish on Tuesday.
Pet owners are being told to treat their pets with anti-flea medication and to not leave any pet food outside, which could attract other animals.
The last typhus outbreak in Southern California was in 2006.