WHO has published Ebola Situation Report - 20 May 2015. Total cases are now 26,969 and deaths are 11,135. The summary:
• The week to 17 May saw the highest weekly total of confirmed cases of Ebola virus disease (EVD) for over a month, with 35 cases reported from Guinea and Sierra Leone. This is a substantial increase compared with 9 cases reported the previous week. The geographical area of transmission has also expanded compared with recent weeks, with a total of 6 districts reporting cases (3 in Guinea, 3 in Sierra Leone), compared with 3 the previous week (2 in Guinea, 1 in Sierra Leone). Capacity for improved community engagement, case investigation, and targeted, active surveillance continues to be strengthened in areas of continuing transmission to ensure that remaining chains of transmission are detected, contained, and brought to an end.
• Guinea reported a total of 27 cases, compared with 7 cases the previous week. The majority of cases were reported from the western prefectures of Dubreka (11 cases) and Forecariah (11 cases), with the remaining 5 cases reported from the north western prefecture of Boke, which borders Guinea-Bissau. The cases in Boke were tightly clustered in the coastal sub-prefecture of Kamsar, and initial investigations suggest they may have originated from a chain of transmission in Conakry. All 11 cases reported from Dubreka came from the sub-prefecture of Tanene. Although the exact origin of the cluster is unknown, retrospective investigation has linked most of the confirmed cases to 4 probable cases who attended a funeral of another probable case in Dubreka in mid-April, which may have been the source of the outbreak. Difficulty engaging local communities has made case investigation and contact tracing in the area challenging. In Forecariah, 11 cases were distributed across 6 of the prefecture’s 10 sub-prefectures. A total of 9 of the 27 cases reported from Guinea originated from an unknown source, indicating that chains of transmission continue to evade detection in several areas.
• 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. An epidemiological investigation team has also mobilized to ensure any contacts who cross the border are traced.
• In Sierra Leone, 8 confirmed cases were reported from Freetown (4 cases), Kambia (1 case), and Port Loko (3 cases). In Freetown, cases were clustered in 3 neighbourhoods in the north of the city near to the Moa Wharf area, which was the only part of Sierra Leone to report cases in the previous week. The single case in Kambia was reported from the Chiefdom of Magbema, which had been the main focus of transmission in the district in recent weeks. The 3 cases in the Port Loko Chiefdom of Kaffu Bullom are linked to a chain of transmission in Kambia. A total of 4 of the 8 cases reported from Sierra Leone were registered contacts of a previous case. An additional 3 cases were not registered contacts, but were found on further investigation to have had contact with a previous case. The remaining case, reported from Freetown, was identified after post-mortem testing of a community death. The source of infection is unknown, but the case was found in the Moa Wharf area.
• The last health worker infection in Guinea was reported on 6 April. However, a new health worker infection in Sierra Leone was laboratory confirmed on 14 May. The case is a Sierra Leone national who was working at an Ebola treatment centre near Freetown at the time of symptom onset. This is the same facility at which the recent Italian health worker case was stationed prior to their return to Italy. Investigations are ongoing into how both health workers came to be exposed to EVD. A total of 13 contacts are currently being monitored in Italy, none of whom are considered to have had a high-risk exposure. 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.