Mumps Outbreak in a Private Primary School, Phrae Province, June-August 2007

Abstract

           During June - August 2007, a mumps outbreak occurred in a private primary school in Mueang district, Phrae province. Most cases (93.62%) were pre-kindergarten and kindergarten students. An investigation team conducted an investigation to define characteristics of the outbreak and prevent spreading of the disease. In all, 506 mumps case reports in Phrae province were reviewed and active case finding was undertaken. The investigation team confirmed diagnosis and used questionnaires to collect patients’ information. Suspected case was defined as a person in the school who had swelling or tenderness of one or more salivary glands between June 1 and August 31, 2007. Suspected patients who had laboratory confirmation by mumps IgM met confirmed case definition. Environmental study was done by exploration and mapping. From June 1 to August 31, 2007, 47 cases were identified, all were OPD cases. Of the 35 cases whose blood specimens were taken, 33 were positive for mumps IgM with 1.5:1 male to female ratio. The mean age was 5.2 years (SD 1.3 years) and median of age 5.08 years (range 2.7-20 years). Attack rate was 2.78 percent (pre kindergarten and kindergarten 8.04%, grade 1-6 0.18%, teacher 1.25%). The epidemic curve suggested propagated source outbreak. Main symptoms were parotitis (mostly submaxillary gland) and fever. Mumps outbreak in this school spread from an index case to his teacher and friends presumably by droplets. Possible route was using same glasses for drinking and tooth brushing. Public health officers immunized primary students who have not had received MMR vaccine. The school was closed for 11 days and continued surveillance for one week. After school reopened, there was no any new mumps cases.

Key words: mumps, school, Thailand