MONMOUTH COUNTY - Health officials in Monmouth County are investigating more than 20 probable cases of mumps in the area.

Most of the 22 patients are adults between the ages of 30 and 50, and at least 21 of them have either been a patron or an employee at the night club D'Jais in Belmar during the last several weeks.

"A lot of the cases, people we've interviewed - they've been to parties, they've been in close contact with others," Monmouth public health coordinator Mike Meddis says.

Officials say one patient is pre-school age.

The viral illness spreads through saliva and can be passed to others through the air via coughs and sneezes and by sharing food and drinks.

Meddis says swelling of the neck under the jawline and ears is the most prominent symptom. Other symptoms include fever, fatigue, muscle aches, loss of appetite and headache.

Vaccines greatly reduce the chances of contracting mumps, but vaccinations are only 90 percent effective. The Monmouth County Health Department says it will be offering free mumps vaccines within the next few days.

A source of the infection has not yet been found.