(CNN) -- An outbreak of the deadly ebola virus in the Democratic Republic of Congo has prompted neighboring Angola to close its border with that country, Angola's state news agency reported Tuesday.
Angolan Health Minister Jose Van-Dunem announced the "suspension of migratory movements" at the country's north-eastern border Sunday, the Angop news agency reported.
The World Health Organization reports 41 suspected cases of the deadly fever in Congo since November 27. Thirteen people have died, and 183 cases are under observation. Two people are being held in quarantine.
The handling of dead monkeys may be the source of the outbreak, the WHO suspects, according to Angop.
Diosdado Nsue-Micawg, the WHO representative in the Angolan capital of Luanda, said the health agency does not know the source of the virus, but fears that hunters and women who visit the forest might have been in contact with infected monkeys.
The outbreak is centered in the western Kassi province of the Democratic Republic of Congo, which has been reporting intermittent cases of the disease since 1976, according to Angop.