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Mumps is an acute but usually mild viral infection of
childhood, characterized by swollen and inflamed salivary glands (most
often the parotids).
Less often the virus attacks the pancreas, ovaries,
testes, and other organs.
Mump virus is a highly contagious paramyxovirus that is
commonly transmitted in respiratory droplets.
A vaccine made from attenuated live mumps virus has
reduced the frequency.
Most adults are immune. Nonimmune adults who acquire
the infection may have a painful and debilitating illness.
The incubation period is 2 to 4 weeks, after which
fever, headache, malaise, and swelling and inflammation of the
salivary glands follow.
Swelling and other acute symptoms usually subside within 2 weeks.
Mumps is usually diagnosed clinically from swollen
salivary glands and confirmed by finding rising titers to mumps virus
in the serum of convalescent patients.
The histologic features of the swollen parotid glands
include diffuse interstitial edema and an inflammatory infiltrate
composed of histiocytes, lymphocytes, and plasma cells.
This infiltrate may compress the acini and ducts, and
the exudate may also spill into the epithelial layers.
Other organs may be affected whether the salivary
glands are swollen or not.
The most common complication is a painful orchitis with
parenchymal hemorrhage. The tunica albuginea tightly contains the swollen
testis, which may result in necrosis of seminiferous tubules, local
hemorrhage, and microinfartions sometimes leaving permanent fibrous
scars. Mumps orchitis is usually unilateral and thus rarely
causes male sterility.
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Infection of the pancreas leads to pancreatitis,
characterized by necrosis of pancreatic and fat cells.
Up to 10% of
patients can develop aseptic meningitis ; a less common but more
serious complication is encephalitis, which can result in death or
disability.
Hemagglutinin-neuraminidase
(HN) is the major surface antigen and is known to elicit neutralizing
antibodies.
Traditional mumps
virus detection methods are often insensitive, lengthy, and
cumbersome. Early serological diagnosis often relies on detection of
anti-mumps IgM, which may be absent in the first 10 days of illness.
Some laboratories use molecular methods that are based on nested
polymerase chain reaction.
According to one
study - Real-time PCR on oral samples was considered to be the
investigation of choice for mumps infection. Mumps virus detection in
urine by any of the PCRs used was less successful. Real-time PCR on
CSF samples was considered a promising adjunct for diagnosis of mumps
meningitis, especially in an age group with high incidence of mumps.
Countries already
using mumps vaccine should monitor immunization coverage and establish
routine mumps surveillance with investigation of outbreaks. Where
mumps is targeted for elimination, countries need to add a second dose
of mumps vaccine for children, keeping in mind that the disease may
still occur in susceptible adults.
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