Officials in Congo said the man who became the second confirmed Ebola case in Goma has died on Wednesday in what's become the second-deadliest outbreak of the disease in history.

There appeared to be no link between the man's case and the previous one in Goma nearly three weeks ago, said Jean-Jacques Muyembe, a local Ebola response coordinator, on Tuesday when the diagnosis was confirmed.

The man arrived on July 13 from a mining area in northeastern Congo's Ituri province and started showing symptoms on July 22. He died at an Ebola treatment center in Goma, more than 300 miles from Ituri.

Goma, a city of more than 2 million people, is on Congo's heavily traveled border with Rwanda and has an international airport. For months health officials had feared that an Ebola case would be confirmed there. Days after the first Goma case was announced, the World Health Organization declared the Ebola outbreak a rare global emergency.

Health experts are investigating exactly when and where the latest victim contracted the disease, Dr. Michael Ryan, executive director WHO's health emergencies program, told reporters during a telephone briefing from Geneva on Wednesday. Prior to showing severe symptoms, he had traveled through regions at the epicenter of the outbreak.

The man had been treated at home for five days before being taken to a health facility Goma, putting others at risk of exposure, Ryan said. "Right now, all of the potential contacts are being identified and vaccinated," he added.

More than 1,700 people have been killed in the outbreak despite the widespread use of an experimental but effective Ebola vaccine. Containing the outbreak faces unprecedented challenges amid attacks by rebel groups and resistance by wary community residents in a region of Congo that had never experienced an Ebola outbreak before.

Muyembe and other officials on Tuesday sought to reassure both Goma residents and neighboring countries that measures were being taken to strengthen surveillance for Ebola at border posts and elsewhere. Neighboring Rwanda, Uganda and South Sudan began vaccinating health workers weeks or months ago.

The declaration of a global health emergency — the fifth in history — brought a surge of millions of dollars in new pledges by international donors but some health workers say a new approach is needed to combat misunderstandings in the community. Far too many people in this outbreak are still dying at home, they say.

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