(CNN) - The number of inmates quarantined at the Harris County Jail has increased in the last weeks since the mumps outbreak, which has already forced staff to isolate 14 symptomatic people, health officials said.
According to the Houston Health Department, there are more than 400 quarantined inmates, up from the 300 that were previously reported.
The first case appeared around May 17 and the other cases came along a couple of weeks later, as would be expected with the virus' incubation period of 12-to-25 days incubation period, officials said.
About 300 to 600 inmates who may have been in close proximity to the 14 -- such as cellmates of the ill -- have been temporarily quarantined in a certain cell block, even though they are not showing symptoms, said Chief Darryl Coleman, commander of the sheriff's criminal justice command.
The quarantine of the 414 is precautionary because infected people may spread the virus a couple of days before showing symptoms, officials said.
"We're going to navigate through this and make sure we take every precaution," Harris County Sheriff Ed Gonzalez said.
The jail has a population of about 8,000 inmates on any given day, Gonzalez said.
Mumps is caused by a virus
As of May 24, 1,002 cases of mumps were reported this year in the United States, according to the U.S. Centers for Disease Control and Prevention.
That's nearly on pace for the total for all of 2018 (2,251) but well under the rate for spikes in 2016 (6,366) and 2017 (6,109), the CDC says.
Mumps is a disease that is caused by a virus. It is spread through saliva or mucus by coughing, sneezing or talking, and by sharing eating utensils or cups. It can spread when an infected person touches items or surfaces that are then touched by someone else, who picks up the virus.
The best way to prevent mumps is with a vaccine. The measles, mumps and rubella (MMR) vaccine is 88% effective for mumps when two doses are given, the CDC says.
Outbreaks usually occur among people who have close contact with an infected person or persons, such as on college campuses and among sports teams.
Symptoms can appear 12 to 25 days after a person is infected and can include fever, headache, muscle aches, being tired and loss of appetite. The hallmark, though, is swollen glands under the ears that are tender. But not everyone has symptoms, especially if they are experiencing a mild case of the illness.
When there is a mumps outbreak in a facility where adults are detained, the U.S. Immigration and Customs Enforcement Health Service Corps recommends the vaccine be given "to detainees with known exposure to at least one laboratory-confirmed person with measles, mumps or rubella." It's also recommended that catch-up vaccinations be given to those younger than 18.
KPRC 2019/ CNN