The Ebola epidemic is still spreading in Guinea, Sierra Leone and Liberia and the number of cases in West Africa will exceed 9,000 this week, the World Health Organisation (WHO) said yesterday.

The death toll so far in the outbreak, first reported in Guinea in March, has reached 4,447 from a total of 8,914 cases, WHO Assistant Director General Bruce Aylward said.

While there are signs that rates of infection are slowing in some of the worst-hit areas, Aylward said the disease has now reached “more districts, counties and prefectures” than it had a month ago, and said case numbers would continue to rise.

A UN medical official who caught Ebola while working in Liberia died yesterday in St Georg Clinic in Leipzig, the German hospital where he was being treated.

The medic, who has not been named, arrived last week and was the third Ebola patient to be treated in Germany.

A health worker uses an infrared scanner to record the temperatures of passengers arriving at the international airport in Guatemala City.

Yesterday, Britain began screening passengers arriving at London’s busiest airport from West Africa for signs of the deadly Ebola virus.

The screening involves passengers who have travelled to the affected area filling out questionnaires to discover any possible exposure to the virus and undertaking temperature checks if necessary. By the end of next week the programme will be extended to London’s Gatwick airport and the Eurostar rail link to Europe.

Anyone found to have recent exposure to the virus, or who displays symptoms, will undergo a clinical assessment and be transferred to hospital if necessary, the government said.

The United States has begun a similar screening process at New York’s JFK airport and four other major US airports will begin screening later this week.

On Sunday a US health worker was confirmed as having caught the virus from a Liberian man being treated in Texas.

Doctors yesterday said the Spanish nurse with Ebola, the first person to contract the disease outside West Africa, is slightly better and she remains the only known case in the country.

Teresa Romero’s contracting of the disease in Spain sparked an outcry over how that happened in a high-security ward while the 44-year-old was treating two Ebola-infected priests who had been repatriated to Spain.