The Centers for Disease Control and Prevention (CDC) will tap $107m in emergency funding for Ebola outbreak response in the Democratic Republic of the Congo (DRC) and Uganda, officials said on Thursday.

The continued Ebola outbreak in the DRC comes as Canada, Mexico and the US jointly host the Fifa World Cup, attracting visitors from around the world. The officials said the outbreak, now the third largest on record, required “strong immediate support”, but that the global risk remained low.

“Specifically, and consistent with that modeling, we are now already approaching 1,000 confirmed cases across 31 health zones in DRC,” Dr Satish K Pillai, incident manager for the CDC’s Ebola response, said in a briefing with reporters on Thursday, “There are 31 cases in Kampala, Uganda.”

Pillai said the CDC had 23 field staff supporting disease investigations and 125 staff members across the DRC and Uganda, and that CDC staff hold twice-weekly calls with the US World Cup host cities. To date, officials said local health authorities had mostly faced illnesses typical of large, Super Bowl-style events, such as heat-related illnesses.

An outbreak of Bundibugyo viral disease (BVD) began roughly one month ago along the western border of the DRC and the eastern border of Uganda. BVD is a rare zoonotic species of Ebola, a hemorrhagic fever. The disease killed between 30% and 50% of those infected in recent outbreaks in Congo and Uganda.

African health officials warn the outbreak could become the worst on record and take a year to contain at current infection rates. The worst Ebola outbreak on record infected more than 28,000 people and killed 11,000 between 2014 and 2016 in west Africa and the eastern DRC. The CDC reported 837 confirmed cases in the DRC and 19 confirmed cases in Uganda as of 15 June. Across both countries, 198 people have died.

Although the risk within the DRC and Uganda is high, global risk is low. The disease is transmitted from person to person through direct contact with blood, bodily secretions and contaminated surfaces. This is in contrast to airborne diseases, such as Covid-19 and measles, which are considered far more contagious.

Despite low global risk, the US is one of 22 counties that imposed travel restrictions on people coming from these countries, which have been criticized as impeding the response to the outbreak. Efforts to contain the disease have been hampered by mistrust and shortages of personal protective equipment and vehicles to transport dead bodies.

Emergency funding from the CDC would add to the roughly $910m already pledged to combat the Ebola outbreak, less than 10% of which has been received from donors, according to African health leaders.

“CDC activities are focused on controlling the outbreak in the Democratic Republic of Congo, controlling the outbreak in Uganda and ensuring our domestic readiness to respond in the unlikely event of cases,” said Pillai.