Ending Ebola before the rainy season is imperative, says Peter Jan Graaff, New Acting Head of United Nations Mission for Ebola Emergency Response (UNMEER).

A statement issued by UNMEER said Graaff, in his first week in office, affirmed his commitment to stopping the Ebola outbreak in West Africa though the timeline for doing so is tight.

“We have made great progress in fighting the virus, but we are not done yet,” said Graaff.

“The rainy season is fast approaching, which will complicate efforts to contain the disease. We have a very small window of opportunity and that window is closing fast. We can’t risk falling behind the virus again. We need to stay ahead of it and eliminate it before it is too late,” he said.

Graaff had since October 2014 served as Ebola Crisis Manager for Liberia, during which time the country’s Ebola case numbers dropped to zero.

The statement said Liberia was currently counting down to May 9 when it would be declared free of the Ebola Virus Disease if no new cases presented themselves.

“Until we reach zero cases in every country, Ebola still poses a threat to the region, and to the world. We must keep up our efforts over the next few weeks to trace and treat every last case,” Graaff stated.

The statement said as of April 24, a total of 26,101 confirmed, probable and suspected cases of Ebola had been reported in Guinea, Liberia and Sierra Leone, with 10,824 deaths.

According to the World Health Organisation (WHO), the decline in confirmed cases had halted over the last three weeks.

It said in the week to April 19, 33 confirmed cases were reported, compared with 37 and 30 in the preceding weeks.

Graaff succeeded Ismail Ould Cheikh Ahmed of Mauritania, who had served in the role since January 4, 2015. Ould Cheikh Ahmed was recently appointed the Secretary-General’s Special Envoy for Yemen.

“Peter led Liberia to much success and I’m confident he can achieve the same results in Guinea and Sierra Leone,” said Ould Cheikh Ahmed.

“The world is behind UNMEER, and UNMEER is behind the Ebola affected countries. Together, we will get to zero cases,” he said.

Prior to joining UNMEER, Graaff had worked extensively with the WHO across Africa, in Afghanistan and in Haiti.

He also led the Civil Affairs and Development team for the United Nations Assistance Mission in Afghanistan.