At least 100 people have died in an Ebola outbreak in the Democratic Republic of Congo, with more than 390 suspected cases, the head of the Africa Centres for Disease Control and Prevention told the BBC.

The World Health Organization (WHO) has declared the outbreak an international emergency.

The current outbreak is caused by the Bundibugyo strain of the Ebola virus, for which no approved vaccines or treatments are currently available.

According to the US Centers for Disease Control and Prevention (CDC), there are also two confirmed cases and one death in Uganda.

Sources told CBS News, the BBC’s US partner, that at least six American citizens have been exposed to the virus in DR Congo.

One American is reportedly showing symptoms, while three others are believed to have had high-risk exposure or contact. It is not yet confirmed whether any of them are infected.

The CDC said it is assisting in the “safe evacuation of a small number of Americans directly affected”, but did not disclose exact figures.

According to a health news outlet STAT, US authorities are reportedly arranging transport for the group to a secure quarantine location. One possibility mentioned is a US military base in Germany, although this has not been confirmed.

During a press briefing on Sunday, the CDC declined to answer specific questions about the American citizens involved.

On Monday, the agency said the risk to the United States remains relatively low, but added that preventive measures are being introduced to stop potential entry of the disease.

These measures include monitoring travellers from affected regions and imposing entry restrictions on non-US citizens who have been in Uganda, DR Congo, or South Sudan within the past 21 days.

The CDC also said it will cooperate with airlines and partners to conduct contact tracing, expand testing capacity, and strengthen hospital preparedness.

The United States has issued a Level 4 travel advisory — its highest warning level — advising against travel to DR Congo.

The WHO has classified the outbreak in eastern Ituri province as a public health emergency of international concern, though it does not meet the definition of a pandemic.

Officials warn it could become “a much larger outbreak” than currently detected, with a significant risk of regional spread.

The 2014–2016 Ebola outbreak in West Africa infected more than 28,600 people and remains the largest recorded outbreak since the virus was discovered in 1976. It spread to multiple countries, including the US, UK, and Italy, and caused 11,325 deaths.

Jean Kaseya, director-general of the Africa CDC, urged people to follow strict public health guidance, especially regarding burial practices.

“We don’t want people getting infected through funerals,” he told the BBC.

Traditional burial practices involving washing the bodies of the deceased contributed to transmission during earlier outbreaks.

The WHO has recommended cross-border screening between DR Congo and Uganda to prevent further spread, and has urged neighbouring countries to strengthen surveillance and preparedness.

Rwanda said it is tightening border screening as a precaution, while Nigeria stated it is closely monitoring the situation.