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Wednesday 11 June 2003

Like measles virus, mumps virus is a member of the paramyxovirus family. Mumps virus has two types of surface glycoproteins, one with hemagglutinin and neuraminidase activities and the other with cell fusion and hemolytic activities.

Mumps viruses enter the upper respiratory tract through inhalation of respiratory droplets, spread to draining lymph nodes where they replicate in lymphocytes (preferentially in activated T cells), and then spread through the blood to the salivary and other glands.

Mumps virus infects salivary gland ductal epithelial cells, resulting in desquamation of involved cells, edema, and inflammation that leads to the classic signs of mumps: salivary gland pain and swelling.

Mumps virus also can spread to other sites, including the central nervous system, testis and ovary, and pancreas. Aseptic meningitis is the most common extrasalivary gland complication of mumps infection, occurring in about 10% of cases. The mumps vaccine has reduced the incidence of mumps by 99% in the United States.


In mumps parotitis, which is bilateral in 70% of cases, affected glands are enlarged, have a doughy consistency, and are moist, glistening, and reddish brown on cross-section. On microscopic examination, the gland interstitium is edematous and diffusely infiltrated by macrophages, lymphocytes, and plasma cells, which compress acini and ducts.

Neutrophils and necrotic debris may fill the ductal lumen and cause focal damage to the ductal epithelium.

In mumps orchitis, testicular swelling may be marked, caused by edema, mononuclear cell infiltration, and focal hemorrhages. Because the testis is tightly contained within the tunica albuginea, parenchymal swelling may compromise the blood supply and cause areas of infarction.

Sterility, when it occurs, is caused by scars and atrophy of the testis after resolution of viral infection.

In the enzyme-rich pancreas, lesions may be destructive, causing parenchymal and fat necrosis and neutrophil-rich inflammation. Mumps encephalitis causes perivenous demyelination and perivascular mononuclear cuffing.


- mumps parotidis
- mumps orchitis