First, the bad news. As of today, there’s been 8,914 cases and 4,457 reported deaths from ebola. There is no evidence that the outbreaks in Guinea, Sierra Leone or Liberia are coming under control. “It’s still moving geographically and it’s still increasing in capitols,” said Bruce Alyward, the WHO’s point person on Ebola response in a briefing to reporters this morning. So long as the outbreak is out of control in these countries, we can expect more imported cases elsewhere in the world, both the countries bordering the affected countries and here in the United States.
But even as the outbreak metastasizes in those three countries, the WHO is preparing to declare the outbreak over in two other West African countries: Nigeria and Senegal
Ebola was first brought to Nigeria by a sick Liberian on July 20. Nigeria’s patient zero resulted in twenty infections and eight deaths in two cities: Lagos and Port Harcourt. In late August, an infected student from Guinea brought ebola to Senegal. He survived and did not infect anyone else.
The incubation period for this ebola virus is at most 21 days. The WHO will declare an outbreak over 21 days after the last high risk exposure–which includes health care workers treating an infected patient. So, for the WHO to declare an outbreak over requires rigorous monitoring over 42 days with no new cases detected.
If no new cases emerge in Senegal, that 42 day period will be reached on Friday. And if no new cases emerge in Nigeria, the WHO will declare on Monday that the outbreak is over in Nigeria. In both instances, contact tracing, palliative care and rigorous infection controls have stopped the outbreak. This demonstrates that traditional epidemiological strategies to contain the outbreak can work, even in resource poor settings like Liberia, Sierra Leone and Guinea. It’s just a matter of getting the resources and political to scale up the response. Therein lies the rub.