BRAZZAVILLE (Reuters) – Congo Republic has confirmed a case of yellow fever near the border with an Angolan enclave, the health ministry said on Tuesday, and has warned of “an emerging event of epidemic proportions”.

In all, 186 suspected cases have been detected this year, many of which were in the western commercial hub of Pointe Noire, the head of the government’s epidemics unit Lambert Kitembo told Reuters.

He said eight blood samples were sent to Democratic Republic of Congo (DRC) for testing last month, one of which came back positive. It was then officially confirmed last week at a laboratory in Senegal.

The sometimes deadly mosquito-borne virus causes fever, body aches and nausea and can quickly spread in areas with large unvaccinated populations.

A major outbreak in 2016 in Angola and the DRC killed more than 400 people, and was believed to have infected thousands more before it was brought under control through an extensive vaccination campaign.

The confirmed victim in the case of yellow fever in Congo Republic had traveled in Tchiamba Nzassi district, which lies along the border with the Angolan enclave of Cabinda, two weeks prior to the onset of his symptoms, the World Health Organization (WHO) said in a weekly report.

No deaths have been reported but the situation is being taken seriously by health officials, Kitembo said. He did not say whether authorities had plans to test other blood samples.

“Congo, in general, and the departments of Pointe Noire and Koulou in particular … are experiencing since the start of 2018 an emerging event of epidemic proportions,” the health ministry said in a statement dated last week.

The WHO said that the confirmed case was detected early last month at a health center in Pointe Noire, where the patient with fever and jaundice was admitted for treatment.

(Reporting by Christian Elion and Roch Bouka; Additional reporting by Tom Miles in Geneva; Writing by Sofia Christensen; Editing by Aaron Ross and Andrew Bolton)