HACKENSACK — The Bergen County Jail has been quarantined after five cases of mumps were diagnosed among the inmate population.

The cases were clinically diagnosed, but the tests had not been confirmed as of late Tuesday afternoon, a Bergen County Sheriff's Office spokesman said.

The first case was discovered at about 3:30 p.m. Monday, but the cause is not known, Bergen County Executive Jim Tedesco said at a Tuesday press conference.

"It cascaded after that," said Dr. Michael Hemsley, medical director of the jail.

The quarantine means that no new inmates will be accepted until the outbreak is over. Visitors and attorneys can still go to the jail but will not have direct access to the inmates.

People who would have been sent to Bergen County will instead go to the Hudson County Jail. Additional jails may be used going forward, Tedesco said.

The five inmates were from the general population, Tedesco and Hemsley said.

If no new cases are discovered, the quarantine will end 25 days from Tuesday.

Anyone at the jail who needs a mumps vaccination will receive one, Hemsley said.

"We will do everything to ensure the safety of our staff and inmates," Tedesco said.

The Bergen County Jail has housed immigration detainees for ICE for years. Most of those detained in Bergen have pending immigration cases in the Varick Street Immigration Court in New York.

Victor Salama, executive director of First Friends of New Jersey and New York, said one of the group's volunteers, who visits immigration detainees at the jail, was not allowed to conduct her visit around noon Tuesday, but the group did not know why she wasn’t allowed in.

“We haven’t confirmed anything, but earlier today one of our volunteers wasn’t able to visit the jail,’’ he said.

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Rosa Santana, the program coordinator for the organization, said that a few years ago a measles outbreak at the Elizabeth immigration detention center caused a quarantine at that facility for a week.

Although Bergen officials said the mumps cases were among the general population, Hudson County authorities are taking precautions with immigrant detainees. William O'Dea, a Hudson County freeholder, said officials were acting on advice from a Bergen County warden to check immigrant detainees who arrived May 18 and were on the same flight as those taken to Bergen County.

“We isolated the individuals that came in on the flight so we can check them. We are examining them, isolating them until we examine them,’’ O’Dea said. “So far, the ones that we have examined there have been no issues.”

How is mumps transmitted?

Mumps spreads through direct contact with saliva or respiratory droplets from the mouth, nose or throat. It can be spread through:

coughing, sneezing, or talking.

sharing items that may have saliva on them, such as water bottles or cups.

participating in close-contact activities with others, such as playing sports, dancing, or kissing.

using unwashed hands to touch objects or surfaces that are then touched by others.

Close quarters can make the disease more susceptible to spreading, according to the Centers for Disease Control and Prevention.

From Jan. 1 to late May, 42 states and Washington, D.C., reported 1,002 cases of mumps this year, according to the CDC.

The disease was greatly reduced once the mumps vaccine was introduced in 1989, but cases started increasing again in 2006.

Email: jongsma@northjersey.com