Ugandan authorities yesterday ordered the closure of their border with Congo “with immediate effect” as suspected cases of a rare type of Ebola surge towards 1,000 there and others emerge at home.

The measure, which goes against World Health Organization guidance, underscores growing fears of contagion in this East African country that, like Congo, has experience responding to Ebola outbreaks but is now facing a strain — Bundibugyo — for which there are no approved medicines or vaccines.

A local Ebola task force made the decision after Ugandan health workers were exposed to the virus by Congolese patients who crossed the border before the outbreak was declared on May 15.