Enhancing Ebola Virus Disease Surveillance and Prevention in Counties Without Confirmed Cases in Rural Liberia: Experiences from Sinoe County During the Flare-up in Monrovia, April to June, 2016

Vera Darling Weah; John S. Doedeh; Samson Q. Wiah; Emmanuel Nyema; Siafa Lombeh; Jeremias Naiene

doi:10.1371/currents.outbreaks.2b7f352af0866accbd7e5a82f165432a

Introduction: During the flare-ups of Ebola virus disease (EVD) in Liberia, Sinoe County reactivated the multi-sectorial EVD control strategy in order to be ready to respond to the eventual reintroduction of cases. This paper describes the impacts of the interventions implemented in Sinoe County during the last flare-up in Monrovia, from April 1 to June 9, 2016, using the resources provided during the original outbreak that ended a year ago.

Methods: We conducted a descriptive study to describe the key interventions implemented in Sinoe County, the capacity available, the implications for the reactivation of the multi-sectoral EVD control strategy, and the results of the same. We also conducted a cross-sectional study to analyze the impact of the interventions on the surveillance and on infection prevention and control (IPC).

Results: The attrition of the staff trained during the original outbreak was low, and most of the supplies, equipment, and infrastructure from the original outbreak remained available. With an additional USD 1755, improvements were observed in the IPC indicators of triage, which increased from a mean of 60% at the first assessment to 77% (P=0.002). Additionally, personnel/staff training improved from 78% to 89% (P=0.04). The percentage of EVD death alerts per expected deaths investigated increased from 26% to 63% (P<0.0001).

Discussion: The low attrition of the trained staff and the availability of most supplies, equipment, and infrastructure made the reactivation of the multi-sectoral EVD control strategy fast and affordable. The improvement of the EVD surveillance was possibly affected by the community engagement activities, awareness and mentoring of the health workers, and improved availability of clinicians in the facilities during the flare-up. The community engagement may contribute to the report of community-based events, specifically community deaths. The mentoring of the staff during the supportive supervisions also contributed to improve the IPC indicators.

Background: The 2014 West African Ebola Outbreak is so far the largest and deadliest recorded in history. The affected countries, Sierra Leone, Guinea, Liberia, and Nigeria, have been struggling to contain and to mitigate the outbreak. The ongoing rise in confirmed and suspected cases, 2615 as of 20 August 2014, is considered to increase the risk of international dissemination, especially because the epidemic is now affecting cities with major commercial airports.

Method: We use the Global Epidemic and Mobility Model to generate stochastic, individual based simulations of epidemic spread worldwide, yielding, among other measures, the incidence and seeding events at a daily resolution for 3,362 subpopulations in 220 countries. The mobility model integrates daily airline passenger traffic worldwide and the disease model includes the community, hospital, and burial transmission dynamic. We use a multimodel inference approach calibrated on data from 6 July to the date of 9 August 2014. The estimates obtained were used to generate a 3-month ensemble forecast that provides quantitative estimates of the local transmission of Ebola virus disease in West Africa and the probability of international spread if the containment measures are not successful at curtailing the outbreak.

Results: We model the short-term growth rate of the disease in the affected West African countries and estimate the basic reproductive number to be in the range 1.5 − 2.0 (interval at the 1/10 relative likelihood). We simulated the international spreading of the outbreak and provide the estimate for the probability of Ebola virus disease case importation in countries across the world. Results indicate that the short-term (3 and 6 weeks) probability of international spread outside the African region is small, but not negligible. The extension of the outbreak is more likely occurring in African countries, increasing the risk of international dissemination on a longer time scale.