Kenya has quarantined 10 people who came into contact with a man who died of Ebola after traveling from the Democratic Republic of Congo, while authorities seek 57 additional contacts.

The case has raised concerns about border screening after the patient traveled through several cities in Congo, Uganda and Kenya while reportedly sick for about a month without being detected.

Health officials say the patient may have taken medication that masked his fever, while Africa CDC officials noted that temperature checks are currently the main screening method because rapid Ebola testing is not available at border crossings.

Kenyan authorities have increased surveillance at airports and border crossings, designated four hospitals to treat Ebola patients and screened more than 650,000 travelers, while urging the public not to panic, the BBC has reported.

The outbreak involves the rare Bundibugyo strain of Ebola, and regional health officials are urging stronger cooperation among East African countries to prevent the disease from spreading.