The Boston Public Health Commission has confirmed that there are two definite cases and 10 probably cases of mumps in Boston.

Of the 12 total cases, 11 patients attend Northeastern University.

According to the Health Commission, mumps illness is caused by a virus that lives in a person’s nose, mouth, and throat. It can spread to others who are in close contact with a case through direct contact with infected saliva or through the air when an infected person coughs or sneezes. The most common symptoms are a low fever, headache, muscle pain and swelling in the salivary glands (located at the cheek, below the ear and under the jaw). Symptoms can appear 12 to 25 days after contact with an infected person. Those ill with mumps are most contagious 3 days before until 5 days after symptoms begin. Mumps is usually a mild illness but can cause serious problems in some people.

The Boston Public Health Commission encourages persons who were born after 1956 who may have been in contact with a person who has mumps to contact their healthcare provider and have their immunization status evaluated.

Anyone with symptoms of mumps should seek medical attention right away.

For more information, call the Boston Public Health Commission at 617-534-5611.

The Boston Globe has reported that four Northeastern University students may have the mumps, a once common childhood disease now thought to be virtually irrelevant because of the commonality of childhood vaccines.

The Globe, citing city public health officials, said that the results are not confirmed, but that two students came down with symptoms after returning from Ireland, where apparently a mumps outbreak has occurred.

All four students had been vaccinated against the disease, which is not 100 percent effective. The Globe says 10-20 percent of those vaccinated are still vulnerable to the disease.