The World Health Organisation on Sunday said it had begun vaccinating frontline health workers and contacts of people infected with Ebola virus in the Democratic Republic of the Congo's Kasai Province, where an outbreak has been declared.

The WHO said an initial 400 doses of the Ervebo Ebola vaccine from the country's stockpile of 2,000 doses have been delivered to Bulape, which is the outbreak's epicentre.

The International Coordinating Group on Vaccine Provision has approved the dispatch of some 45,000 additional Ebola vaccine doses to Congo, the organisation said.

The outbreak, the country's first in three years, was declared in early September. Congo's dense tropical forests are a natural reservoir for the Ebola virus, which causes fever, body aches, and diarrhoea, and can linger in the body of survivors only to resurface years later.

The latest data from the health ministry in Kinshasa said there were 32 suspected cases, 20 confirmed cases and 16 deaths.

Containing the outbreak is "possible, but it will be challenging if we miss the window of opportunity," WHO Programme Area Manager Patrick Otim told a Geneva briefing last week, calling for more support for the government and other partners.

Several aid workers have told Reuters that Congo could struggle to mount an effective response given recent cuts to foreign assistance and the dismantling of the U.S. Agency for International Development under President Donald Trump.

Otim said the outbreak may expand, noting that one new case was confirmed 70 km from the current epicentre and that there was a moderate risk of it spreading to other countries, in particular neighbouring Angola.