SUMMARY
-There were 12 confirmed cases of Ebola virus disease (EVD) reported in the week to 24 May: 9 from Guinea and 3 from Sierra Leone. A total of 5 districts (3 in Guinea, 2 in Sierra Leone) reported at least one confirmed case, compared with 6 districts the previous week. The west-Guinean prefecture of Forecariah reported the most cases of any one district, and continues to present the greatest challenge in terms of response, with multiple chains of transmission over a wide geographical area (4 sub-prefectures), and the continued occurrence of cases from unknown sources of infection.
-Cases from Guinea were reported from the western prefectures of Dubreka (3 cases) and Forecariah (5 cases), with a single case reported from the north-western prefecture of Boke, which borders Guinea-Bissau. In line with the previous week, cases in Boke and Dubreka were concentrated in the sub-prefectures of Kamsar and Tanene, respectively. The 5 cases reported from Forecariah were reported from 4 different sub-prefectures. A 4-day targeted case-finding and sensitisation campaign concluded in Forecariah on 19 May. During the course of the campaign multidisciplinary teams trained in case detection and social mobilisation visited 8023 homes, and contacted 38 557 people.
Of the 9 cases reported from Guinea, 7 were known contacts of a previous case, 1 (in Forecariah) arose from an unknown source of infection, and one case was not a registered contact of a previous case but, on further investigation, does have an epidemiological link to a known chain of transmission in Forecariah. The case that arose from an unknown source of infection was 1 of 3 cases in Guinea identified after post-mortem testing of community deaths. A total of 13 unsafe burials were reported in the week to 24 May, representing 4% of 335 reported burials: a decrease compared with 25 (6%) of 386 reported burials the previous week, and a marked decrease compared with 163 (43%) of 375 reported burials during the week ending 19 April 2015.
Because of the proximity to Guinea-Bissau of the recent cluster of cases in the Guinean prefecture of Boke, a response team from Guinea-Bissau has been deployed to the border to assess points of entry. Investigations are ongoing to trace a contact who attended the funeral of a case in Boke, and who is thought to have returned to a fishing community in Guinea-Bissau.
In Sierra Leone, 3 confirmed cases were reported from Freetown (2 cases), and Port Loko (1 case). In Freetown, cases were reported from two densely populated neighbourhoods, Kroo Town and ward 350, in the north and east of the city, respectively. Both cases are known contacts of recent cases, and are linked to the chain of transmission originating in Moa Wharf. One of the cases was in voluntary quarantine at the time of symptom onset, and was transferred to a nearby Ebola Treatment Centre. The second case was a high-risk contact of a previous case from Moa Wharf. After being lost to follow-up, the case developed symptoms on 15 May and was subsequently relocated to a community care centre in ward 350, and treated for malaria on 19 May.
Intensive efforts are under way to identify all contacts associated with this case, and many high-risk contacts are currently in voluntary quarantine. The single case in Port Loko was reported from the chiefdom of Kaffu Bullom, and is thought to be linked to a chain of transmission from the northern district of Kambia. Having been a focus of transmission several weeks ago, Kambia has not reported a confirmed case for 10 consecutive days as at 24 May. The last health worker infection in Guinea was reported on 6 April, and 14 May in Sierra Leone. There have been a total of 869 confirmed health worker infections reported from Guinea, Liberia, and Sierra Leone since the start of the outbreak, with 507 reported deaths.