Mumps virus is a
member of the Paramyxoviridae family, transmitted
primarily by droplet spread during coughing and sneezing as well as by direct
contact with the saliva of an infected person.
Symptoms of mumps infection typically appear 16 to 18 days
after exposure. A person is most infectious from two days before symptoms
appear to five days after.
Almost half (40%) of those infected with mumps develop facial swelling
(parotitis) on either one or both sides of the face. Half of these may only have respiratory
symptoms, which contributes to the difficulty in diagnosing mumps. Complications
include deafness and, in persons past puberty, orchitis (inflammation of one or both testicles) in 20%
to 30% of males and oophoritis (inflammation of one or both ovaries) in 5% of females.
Two doses of mumps-containing vaccine are
required to be fully immunized against mumps. In Ontario, one dose of a
combined measles, mumps, rubella (MMR) vaccine is currently given on or after
the first birthday followed by a second dose at four to six years. Due to historical changes in vaccine programs
in Ontario, there is a cohort of individuals born around 1991 or earlier who likely
received only one dose of MMR vaccine who would not have acquired natural
immunity through infection. Mumps, is
a reportable infection and although uncommon does still occur in Ontario.