SUMMARY
A total of 9 confirmed cases of Ebola virus disease (EVD) was reported in the week to 10 May: the lowest weekly total this year. Guinea reported a total of 7 cases, Sierra Leone reported 2. For the first time since the beginning of the outbreak in Sierra Leone, the country reported zero confirmed cases for more than 2 consecutive days in the week to 10 May. As at 12 May, Sierra Leone has reported 8 consecutive days without a confirmed case. The EVD outbreak in Liberia was declared over on 9 May, after 42 complete days elapsed since the burial of the last confirmed case. The country has now entered a 3-month period of heightened vigilance. WHO will maintain an enhanced presence in the country until the end of 2015, with a particular focus on areas that border Guinea and Sierra Leone.
Of 55 districts in Guinea, Liberia, and Sierra Leone that have reported one or more confirmed cases of EVD since the outbreak began, 43 have not reported a case for over 6 weeks.
Of the 7 confirmed cases reported from Guinea, 6 were reported from the prefecture of Forecariah, which has been the focus of transmission for several weeks. Of those 6 cases, 4 were reported from the central sub-prefecture of Moussayah, which borders the Sierra Leonean district of Kambia. Kaliah and Sikhourou, the sub-prefectures to the west and north-east of Moussayah, respectively, each reported 1 confirmed case. The remaining case in Guinea was reported from Dubreka prefecture. The case was identified post mortem in a community setting. Investigations have as yet been unable to establish a link with a previously reported case.
In total, 4 of the 7 cases reported from Guinea in the week to 10 May were identified after post-mortem testing. One of the 7 cases was a registered contact of a previously reported case. A total of 529 laboratory samples were tested in the week to 10 May, although this total includes both initial and repeat testing. The number of reported unsafe burials declined for a third consecutive week, to 23 out of 368 reported community deaths. These indicators suggest that tracking transmission chains is still challenging, and there remains a possibility of an increase in case incidence and/or geographical spread in coming weeks. The absence of an established epidemiological link between the case in Dubreka and a known chain of transmission is of particular concern. Preliminary reports from the prefecture since 10 May indicate that the case has resulted in at least 3 additional confirmed cases.
Both cases reported from Sierra Leone occurred in the Moa Wharf area of the East 1 Chiefdom of the capital, Freetown. The cases are a mother and her 10-year old daughter, both of whom are known contacts of a previous case in the Moa Wharf area, and were under quarantine at the time of symptom onset. After treatment at the Ebola Treatment Centre in Hastings, the mother has now tested negative for EVD for a second time. The daughter is still EVD-positive and remains in treatment.
For the fourth consecutive week, no health worker infections were reported in the week to 10 May. There have been a total of 868 confirmed health worker infections reported from Guinea, Liberia, and Sierra Leone since the start of the outbreak, with 507 reported deaths. However, on 12 May WHO received notification of a laboratory-confirmed EVD case in Italy. The case is a volunteer health worker who returned to Italy from Sierra Leone on 7 May. The patient developed symptoms on 10 May, and was transported on 11 May to the infectious diseases ward of the Hospital of Sassari, Sardinia. Clinical samples were confirmed as EVD positive on 12 May, and the patient was securely transferred to the National Institute for Infectious Diseases in Rome. Because onset of symptoms occurred 72 hours after the case’s last flight, contact tracing of passengers who shared flights with the case is not considered necessary.