The last known chains of transmission in the Ebola virus in West Africa have been stamped out, but "more flare-ups" are expected, the World Health Organisation (WHO) said on Thursday, calling for continued strong surveillance.
The announcement by the UN health agency came 42 days, or two 21-day incubuation cyles of the virus, after the last confirmed patient in Liberia tested negative twice for the deadly disease that has killed more than 11,300 in two years.
Guinea, Liberia and Sierra Leone "remain at high risk of additional small outbreaks of Ebola", it said.
“Detecting and breaking every chain of transmission has been a monumental achievement,” Dr Margaret Chan, WHO Director-General, said in the statement.
“So much was needed and so much was accomplished by national authorities, heroic health workers, civil society, local and international organisations and generous partners. But our work is not done and vigilance is necessary to prevent new outbreaks.”
Dr Bruce Aylward, WHO’s Special Representative for the Ebola Response, said in the statement the organisation was now moving from "managing cases and patients to managing the residual risk of new infections".
"“The risk of re-introduction of infection is diminishing as the virus gradually clears from the survivor population, but we still anticipate more flare-ups and must be prepared for them," he said.
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"A massive effort is underway to ensure robust prevention, surveillance and response capacity across all three countries by the end of March.”
The WHO and other organisations are working with the governments of Guinea, Liberia and Sierra Leone to ensure survivors have access to medical and psychological care.
Survivors will also be provided with screening, counselling and education to help them reintegrate into family and community life, reduce stigma and minimise the risk of Ebola virus transmission, the statement said.
The Ebola epidemic killed 11,300 people and infected 28,500.
Key facts:
- The epidemic began in eastern Guinea in December 2013 and swept through Liberia and Sierra Leone. Liberia was the last nation to be declared Ebola-free
- The Ebola virus infected more than 28,600 people and killed 11,300 of them in the three worst affected nations - more cases and more deaths than in all previous outbreaks combined
- Ebola cases were also recorded in seven other countries, including the United States, Spain and Nigeria, but on a much smaller scale, totalling 36 cases and 15 deaths
- The World Health Organization (WHO) declared the West Africa Ebola outbreak a Public Health Emergency of International Concern on Aug. 8, 2014
- After a slow initial response, the WHO and nations ranging from Cuba to France poured in trained staff, field hospitals, laboratories and equipment to tackle the epidemic
- On average, around 50 per cent of humans infected in an outbreak die, though in past outbreaks the fatality rate has varied from 25 to 90 per cent
- The virus is transmitted to people from wild animals such as fruit bats and monkeys and spreads among humans through contact with bodily fluids of an infected person
- Medical experts believe new Ebola cases in Liberia after it had twice been declared Ebola-free were due to sexual contact as the virus lives in semen longer than the 21-day incubation period elsewhere in the body
- The worst affected countries were, at the start of the epidemic, recovering from years of conflict and instability and had weak health systems and a shortage of expertise and infrastructure
- The Ebola virus first appeared in 1976 in two simultaneous outbreaks, one in Nzara, South Sudan, the other in Yambuku, Democratic Republic of Congo, in a village near the River Ebola
Key developments in the three most severely affected countries:
Liberia
- Recorded more than 10,700 cases and 4,800 deaths
- Declared Ebola-free in May 2015 and September 2015, but each time a fresh cluster of cases appeared later.
- Declared Ebola-free on Jan. 14, 2016 Sierra Leone
- First case confirmed in May 2014
- Recorded about 14,100 cases and 4,000 deaths
- Declared Ebola-free on Nov. 7, 2015
Guinea
- The region's outbreak began in Gueckedou, eastern Guinea in December 2013
- Recorded more than 3,800 cases and 2,500 deaths
- Declared Ebola-free on Dec. 29, 2015
Sources: World Health Organization, Centers for Disease Control and Prevention, Reuters News, Thomson Reuters Foundation
