Epidemiology of rubella disease in south-west nigeria: trends and projection from measles case-based surveillance data

Abstract

Although surveillance for rubella does not exist in Nigeria, a measles case-based surveillance system was introduced in 2005 as one of the strategies for measles morbidity control, and included laboratory testing for confirmation of the disease. In this report, we provide the epidemiological distribution of rubella-confirmed cases reported from the south-west zone of the country, and predict the expected number of cases in the ensuing years. A descriptive analysis was carried out of rubella cases reported in the measles case-based surveillance data from the south-west zone of Nigeria for the period 2007-2012. Using an additive time series model, we predicted the expected number of cases until the year 2015. Four hundred and thirty-eight (5.4%) rubella cases were confirmed from 8 046 suspected measles cases. Cases were confirmed from all six states within the zone. The majority (87.3%) were individuals < 15 years of age and 40.9% were female. Seasonal variation existed, with peaks of infection in the first and third triannual periods of the year, while annual trends showed peaks in 2007 and 2010. Based on projections, there was a reduction in the number of expected cases. Rubella testing, in parallel with measles case-based surveillance, provides understanding of the epidemiology of rubella infection in south-west Nigeria.