Measles outbreak investigation - District 3, Grand Bassa County, Liberia, 2016

Introduction : measles is a contagious but vaccine-preventable disease. Children under five years are susceptible and prone to more complications, including death. In December 2015, the District 3 Health Team received reports of eight suspected measles patients in Yah Town, which has a population of 2,324. Objectives of the investigation were to confirm, determine extent and identify source of the outbreak to implement control measures. Methods : we examined the suspected cases and conducted active case search using the case definition; any person living in District 3 with fever and maculopapular rash plus one of the following; cough, coryza or redness of the eye from November 1, 2015. We reviewed hospital records and vaccination records of affected people and conducted laboratory testing for measles. We took control actions based on our findings. Results : all eight reported cases met the case definition for suspected measles. A total number of 19 patients were identified, with onset of symptoms from November 2015 to January 2016. All patients lived in Yah Town. Median age was 8 years (range: 1-22 years), with only one being under 5years. 53% (10) were males. Only 5% (1) of 19 patients had been vaccinated against measles. Five (26%) tested positive for Measles IgM. The index case was a 15-year old male whose symptoms started on November 12, 2015. He had no history of travel or contact. There were no deaths. Conclusion : a measles outbreak was confirmed in Yah Town which lasted for two months, with attack rate of 13 per 1000 and no deaths. The source of outbreak was not established. Patients were treated with Vitamin A and mop-up immunization was conducted to cover 378 children aged less than 5 years in Yah Town. Contact tracing and community awareness was carried out in the communities. The outbreak was declared over mid-February 2016.