SUMMARY
There were 7 confirmed cases of Ebola virus disease (EVD) reported in the week to 26 July: 4 in Guinea and 3 in Sierra Leone. This is the lowest weekly total for over a year, and comes after 8 consecutive weeks during which case incidence had plateaued at between 20 and 30 cases per week. Although this decline in case incidence is welcome, it is too early to tell whether it will be sustained. There have been several high-risk events in both Guinea and Sierra Leone in the past 14 days, and past experience has shown that it can take a single high-risk case or missed contact to spark a new cluster of cases. In addition, there are over 2000 contacts still within their 21-day follow-up period in Guinea, Liberia, and Sierra Leone, representing a substantial residual risk of further cases. Refinements to the response continue to yield improvements, with recent weeks seeing a higher proportion of cases arising from contacts and a lower proportion of cases identified post-mortem than at any time previously, but the continued occurrence of high-risk transmission events means that an increase in case incidence in the near term is a strong possibility.
In Guinea, cases were restricted to a small geographical area in Conakry (3 cases) and the nearby prefecture Coyah (1 case). The large prefecture of Forecariah, which has seen widespread transmission since the start of the year, reported no cases for the first time since January 2015, although there are still over 700 contacts under follow-up in the prefecture. For the first time in the outbreak, all cases reported from Guinea were registered contacts. All 3 of the cases from Conakry were registered contacts associated with a chain of transmission that originated in the prefecture of Dubreka. The remaining case from Coyah was a registered contact associated with a chain of transmission that originated in Forecariah. For the first time since September 2014, no EVD-positive community deaths were reported from Guinea.
No new cases were reported from Liberia in the week to 26 July. Of the 6 confirmed cases reported since 29 June, 2 have died, and the remaining 4 have now all been discharged after treatment. There are currently 33 contacts under follow-up in Liberia, all of whom will have completed the 21-day follow-up period by 2 August.
The 3 confirmed cases in Sierra Leone were reported from Freetown (2 cases) and Tonkolili (1 case). Both cases from Freetown were registered contacts who were residing in a voluntary quarantine facility at the time of symptom onset, and were rapidly isolated. The remaining case from Tonkolili, a district east of Freetown in the centre of the country, is assessed as posing a substantial risk of further transmission. The case travelled to Tonkolili from an area near the Magazine Wharf neighbourhood of Freetown on 16 July, and died on 23 July in a community hospital, where he was confirmed EVD-positive after post-mortem testing. The case visited at least two health facilities between 19 and 21 July, and over 500 contacts have been identified so far.
Investigations are ongoing to establish the source of infection and identify and trace all contacts.
One new health worker infection was reported from Conakry, Guinea, in the week to 26 July. Guinea has reported health worker infections in 5 of the past 6 weeks. No health worker infections were reported from Sierra Leone, but several health workers are listed as contacts of the case in Tonkolili. There have been a total of 880 confirmed health worker infections reported from Guinea, Liberia, and Sierra Leone since the start of the outbreak, with 510 reported deaths.