WHO Declares Emergency Over Rare Ebola Strain

The outbreak is caused by the Bundibugyo strain, a rare type of Ebola seen in only two earlier outbreaks. Each of those killed roughly one in three of the people infected. Worryingly, there is no approved vaccine for this strain and no targeted treatment. Antibody therapies such as Inmazeb and Ebanga were developed for the more common Zaire ebolavirus, and it is unclear whether they work against Bundibugyo. Experts believe the virus spread undetected for weeks before it was identified on 24 April. Containment is especially hard because the centre of the outbreak, the DRC's Ituri province, has been damaged by years of armed conflict.

Health agencies are responding through contact tracing, isolating patients, safe burials and community engagement, which scientists say are vital to stopping the disease. The WHO has released almost $4m and is shipping protective equipment and medicine. Several American citizens exposed to the virus have been evacuated to Europe for monitoring. The Guardian reported that the United States, once a leader in outbreak response, has been largely absent after deep cuts to global health funding. African health officials have urged neighbouring countries to strengthen screening rather than impose "fear-driven" travel bans.