Mumps Outbreak in Copperbelt Province, Zambia: Epidemiological Characteristics
Mumps are known to occur in Zambia, but outbreaks are rare. Here we report on a recent mumps outbreak, between January and September, 2015.
The study was to verify the existence and extent of mumps outbreak in Copperbelt province; to describe the epidemiological characteristics of the outbreak; to identify risk factors associated with the illness; to confirm the etiology of the outbreak through appropriate laboratory testing; to inform disease control strategy and advocate for mumps, measles and rubella vaccine in Zambia, which has not yet been implemented.
A case report. Clinical records of cases suspected of mumps in the district were reviewed. Cases covered the first 36 weeks of 2015 (January to September, 2015). Charts were generated to capture the epidemic curve. Detailed analysis using data from Luanshya was carried, by calculating relative risk for the demographic factors and place of residence.
Between week 1 and 36 of 2015, a total of 1651 cases of mumps were reported. The primary case was a four year old male child, and was diagnosed in the first week of January. Week 14 and 19 reported the highest number of cases, but the cases plateaued in week 33. Laboratory analysis provided a test positivity rate of 70%. Most cases (71%) were children aged between 1 and 9 years of age. This group was at least 3 times higher at risk than those <20 years.
Several factors may have contributed to the emergence of mumps outbreaks including intense exposures, overwhelming protection offered by the vaccine, combined with non-optimal vaccine coverage, low immunogenicity and waning immunity. It is therefore recommended that, first, continued surveillance be maintained so that cases are identified, contacts are traced, and inform implementation of appropriate infection control measures. Second, continued Information, Education and Communication (IEC) on good hygiene practices, modes of transmission and risk factors in schools and other public places is recommended. Third, there is need to establish local emergency health services linking schools and health facilities. Furthermore, health authorities should make concerted efforts to enable diagnostic tests for mumps within the country, while at the same time we advocate for Measles, Mumps & Rubella (MMR) vaccine in Zambia.