The agency plans to deploy additional staff to the affected countries and will provide technical support including laboratory testing, contact tracing and surveillance through its country offices, said Satish Pillai, the CDC’s Ebola response incident manager, on a call with reporters Sunday. It has also activated its emergency response center. 

“The risk to the United States remains low,” Pillai said. The outbreak is caused by the Bundibugyo ebolavirus strain and has no approved vaccine or treatment. Infected people can transmit Ebola when they are symptomatic, he added. 

The actions come after the WHO declared the Ebola outbreak a public health emergency of international concern on Sunday — stopping short of a “pandemic emergency” declaration — as it looks to mobilize support against the rare strain of the virus. The WHO said the strain has likely been spreading undetected in the region for weeks. 

Congo has reported eight confirmed cases, 246 suspected infections and 80 suspected deaths in the Ituri province, according to the WHO. Uganda has recorded two infections and one death among travelers from Congo. 

The CDC did not confirm whether Americans in Congo have been exposed to the virus.

The agency was notified of the outbreak in Congo on May 14 and the Uganda outbreak on May 15, Pillai said. The Atlanta-based agency is identifying employees to deploy to the countries early this week and add to the more than 30 people already on staff in each country, Pillai said. 

The agency has also posted two travel health notices for Americans to practice enhanced precautions. The impacted countries have exit screening strategies in place at local airports to monitor infections, and the US is adding measures to identify symptomatic people at ports of entry, Pillai said.  

The cross-border transmission, unexplained clusters of deaths and major uncertainty about the scale of the outbreak caused the WHO to designate the outbreak as the highest level of international concern. 

“This event is considered extraordinary,” WHO Director-General Tedros Adhanom Ghebreyesus said in the declaration, which is intended to mobilize international funding and response efforts. It’s the first declaration of this type since mpox was designated a global health emergency in 2024. 

Read More: How Ebola Outbreak Is Testing Congo After US Aid Cuts: Explainer

The CDC is also working to contain an outbreak of hantavirus linked to a cruise ship that has killed three people. Currently, 41 people who were exposed to the virus are being monitored.

The Fortune 500 Innovation Forum will convene Fortune 500 executives, U.S. policy officials, top founders, and thought leaders to help define what’s next for the American economy, Nov. 16-17 in Detroit. Apply here.