Rubella outbreak amongst residential students in a military vocational school of Malaysia

An outbreak of rubella occurred amongst 303 newly recruited residential Form IV students in a military vocational training school in Malaysia. Of the 303 Form IV students, 77 gave a history of acute illness. Rubella specific IgM was detected in the sera of 46.5% (141/303) whereas rubella specific IgG was detected in 100% of all Form IV students. Sixty five students with no clinical history of acute illness during the outbreak period had detectable rubella IgM in their sera and rubella specific IgM was detected in the sera of all symptomatic students except one. Maculopapular rash was the commonest presenting clinical feature among students with acute rubella infection in this outbreak (97.4%) followed by fever (88.2%). The duration of rash ranged from one to nine days with a mean of 4.6 days. Of the 65 students that had both fever and rash, 56 (85.2%) students had maculopapular skin eruption on the same day as the date of onset of fever, six (9.2%) developed the rash a day after the onset of fever and three (4.6%) had the rash after two days of fever. The duration of fever ranged from one to eight days with a mean of 3.5 days. The duration of conjunctivitis ranged from one to four days with a mean of 2.3 days, and all those who developed conjunctivitis had mild eye-discharge without photophobia. The duration of arthralgia ranged from one to three days with a mean of 2.1 days. The commonest type of joints affected was knee joints (66.7%, 12/18), followed by elbow and shoulder joints (27.8%, 5/18) and wrist joints (5.6%, 1/18). A good clinical history of the temporal relationship between the occurrence of rash and fever during the outbreak could easily differentiate rubella illness from that of measles.