Evidence for declining numbers of Ebola cases--Montserrado County, Liberia, June-October 2014

Abstract

The epidemic of Ebola virus disease (Ebola) in West Africa that began in March 2014 has caused approximately 13,200 suspected, probable, and confirmed cases, including approximately 6,500 in Liberia. About 50% of Liberia's reported cases have been in Montserrado County (population 1.5 million), the most populous county, which contains the capital city, Monrovia. To examine the course of the Ebola epidemic in Montserrado County, data on Ebola treatment unit (ETU) admissions, laboratory testing of patient blood samples, and collection of dead bodies were analyzed. Each of the three data sources indicated consistent declines of 53%-73% following a peak incidence in mid-September. The declines in ETU admissions, percentage of patients with reverse transcription-polymerase chain reaction (RT-PCR) test results positive for Ebola, and dead bodies are the first evidence of reduction in disease after implementation of multiple prevention and response measures. The possible contributions of these interventions to the decline is not yet fully understood or corroborated. A reduction in cases suggests some progress; however, eliminating Ebola transmission is the critical goal and will require greatly intensified efforts for complete, high-quality surveillance to direct and drive the rapid intervention, tracking, and response efforts that remain essential.

FIGURE 1

Number of admissions to Ebola treatment units (ETUs),* by week and case status — Montserrado County, Liberia, June 13–October 26, 2014 * ETUs located in Montserrado County are ELWA (Eternal Love Winning Africa)-2, ELWA-3, Island Clinic, and JFK (John F. Kennedy) ETUs. ELWA-2 began operating on July 20, ELWA-3 and JFK began operating on August 17 (week 34), Island Clinic began operating on September 20 (week 38), and JFK closed on October 7 (week 41). ^† Includes cases that have been confirmed with ETU documentation of positive Ebola reverse transcription–polymerase chain reaction (RT-PCR) results, as well as those probable and suspect cases for which there are no ETU-documented negative RT-PCR results.

FIGURE 2

Number of patients with RT-PCR tests performed (bars) and percentage of patients with Ebola-positive test results (line), by week — Montserrado County, Liberia, August 18–October 26, 2014* Abbreviation: RT-PCR = reverse transcription–polymerase chain reaction. * Laboratory results are calculated per patient by week of first positive test performed. Repeat tests for a given individual were removed. CDC/National Institutes of Health and Island Clinic laboratories began operating on August 20 (week 34) and October 2 (week 40), respectively. The Liberian Institute of Biomedical Research laboratory began testing specimens on August 7 (week 32); however, data from before week 34 were excluded because of the lack of sufficient information to identify multiple samples from individual patients.

FIGURE 3

Number of bodies collected by IFRC and ELWA-3, by week — Montserrado County, Liberia, July 28–October 26, 2014 Abbreviations: IFRC = International Federation of Red Cross and Red Crescent Societies; ELWA = Eternal Love Winning Africa.