BROOKLYN - An outbreak of mumps that began in Rockland County has spread to Orthodox, Jewish neighborhoods in Brooklyn, officials say.

The illness was transmitted during a summer camp in the Catskills in August 2009, parent Malky Porgesz said. This is the largest mumps outbreak in 20 years.

Doctors at the Ezra Medical Center have seen a steady number of cases since the outbreak began. Vaccination can prevent the mumps but does not guarantee immunity.

Symptoms of the disease include swelling, fever, headache and swollen glands. Doctors said anyone with these symptoms should visit the emergency room immediately.