SUMMARY
Three new confirmed cases of Ebola virus disease (EVD) were reported in the week to 18 October, all of which were reported in Guinea. The country had reported zero cases for the previous 2 weeks. Of the 3 new cases, 1 was reported from the capital, Conakry, and 2 were reported from the subprefecture of Kaliah, Forecariah. Of note, 2 cases were not registered contacts, 1 of whom was identified after post-mortem testing of a community death. There are currently 246 contacts under follow-up in Guinea (70 of whom are high risk), and an additional 253 contacts identified during the past 42 days remain untraced. Therefore there remains a nearterm risk of further cases among both registered and untraced contacts. Sierra Leone reported zero cases for a fifth consecutive week.
Case incidence has remained at 5 confirmed cases or fewer per week for 12 consecutive weeks. Over the same period, transmission of the virus has been geographically confined to several small areas in western Guinea and Sierra Leone, marking a transition to a distinct, third phase of the epidemic. The phase-3 response1 coordinated by the Interagency Collaboration on Ebola2 builds on existing measures to drive case incidence to zero, and ensure a sustained end to EVD transmission. Enhanced capacity to rapidly identify a reintroduction (either from an area of active transmission or from an animal reservoir), or re-emergence of virus from a survivor, and capacity for testing and counselling as part of a comprehensive package to safeguard the welfare of survivors are central to the phase-3 response framework.
The case from Conakry, a 21-year-old male, was reported from the Ratoma area of the city. However, he is not a known contact of a previous case, and genomic analyses suggest he was not infected with the strain of Ebola virus responsible for the most recent cases in Conakry and Forecariah. Investigations to identify the origin of infection are ongoing. The first case identified from Forecariah, a 35-year-old woman, was not a registered contact, and was identified after post-mortem testing of a community death. However, genomic analyses suggest she is part of the same chain of transmission—the Ratoma chain—as the 4 cases that were reported from the same subprefecture in Forecariah during the week ending 27 September 2015. The second case identified from Forecariah is her 3-month-old child, and was a registered contact. Of 246 contacts under follow-up in Guinea on 18 October, 43 were located in Conakry with the remainder located in Forecariah.
In Sierra Leone, all contacts linked to the country’s 2 most recently active chains of transmission, Bombali and Kambia, have completed 21-day follow-up. In addition, the last case to receive treatment was confirmed free of EVD after a second consecutive negative test on 25 September. The country will be declared free of EVD transmission on 7 November if no further cases are reported. However, 2 high-risk contacts—one from Bombali and one from Kambia—remain untraced. Efforts to trace these contacts will continue until 42 days have elapsed since the last reported case in each district.
Robust surveillance measures are essential to ensure the rapid detection of any reintroduction or reemergence of EVD in currently unaffected areas. Nine operational laboratories in Guinea tested a total of 654 new and repeat samples in the week to 18 October. In Liberia, 1278 new and repeat samples were tested over the same period in the country’s 4 operational laboratories. 1592 new samples were collected in Sierra Leone and tested by 8 operational laboratories.