Epidemiological update: New Ebola cluster in Guinea, 22 March 2016

epidemiological update

​​A new Ebola cluster has been announced in Guinea, just after Sierra Leone was declared free of the virus, and West Africa was declared to be Ebola-free.

On 17 March 2016, Guinean health officials reported three unexplained deaths that had occurred in recent weeks in the village of Korokpara, in the prefecture of N’Zérékoré. The investigation conducted by health authorities identified four close contacts among relatives who were showing symptoms suggestive of Ebola virus disease. On 18 March, WHO verified that two of them, a mother and her five-year-old son, had had laboratory tests confirmed for Ebola virus disease (EVD) and been admitted to a treatment facility. In addition, according to media, a young girl died at the N’Zérékoré EVD treatment centre on 21 March 2016. On 22 March, media reported an additional fatal case in Macenta prefecture, about 200 kilometres from the village of Korokpara. The man was a high-risk contact who travelled to Macenta to consult a healer and has since tested positive for Ebola, bringing the number of probable and confirmed Ebola deaths to five.

As of 22 March, 816 contacts have been identified, from 107 households in the immediate vicinity of the home of the confirmed and probable cases in Korokpara. More than 100 of the contacts are considered high-risk. In addition, over 50 contacts of the man who travelled to and died in the Macenta prefecture have been identified. Additional contact tracing and case investigation is underway.

Korokpara district, which is located in Guinée Forestière, 950 km from Conakry, has over 8 000 inhabitants and WHO has registered 10 EVD survivors there.

Guinea was under a 90-day enhanced surveillance scheme that was due to be completed by 31 March 2016. According to WHO, there are signs of reticence in the area so awareness campaigns are being organised in Korokpara and in the prefecture of N’Zérékoré. Further case-finding and response activities are ongoing, including vaccination of all contacts and contacts of contacts.

The detection of a new chain of transmission in Guinea is not unexpected and highlights the importance of maintaining heightened surveillance in the coming months as the risk of additional small outbreaks remains. Sporadic cases have been identified previously and are likely to be the result of the virus persisting in survivors even after recovery. However, a new introduction from the animal reservoir remains possible. Whole genome sequencing of the virus would supply additional information on the origin.