In 2021, a patient died from Marburg virus (MARV) disease in Guinea and it was the first confirmed case in West Africa. The origin of the outbreak has not been identified. It was revealed that the patient didn’t travel anywhere before the illness. Prior to outbreak, MARV had been found in bats in the neighboring Sierra Leone, but never in Guinea. Therefore, the origin of infection is unclear: was it an autochthonous case with spillover from a local population of bats or an imported case with spillover from fruit bats foraging/migrating from Sierra Leone? In this paper, we studied Rousettus aegyptiacus in Guinea as the possible source of MARV infection caused the patient death in 2021 in Guinea. We caught bats in 32 sites of Guéckédou prefecture, including seven caves and 25 locations of the flight path. A total of 501 fruit bats (Pteropodidae) were captured, including 66 R. aegyptiacus. The PCR screening showed three positive MARV R. aegyptiacus, roosting in two caves discovered in Guéckédou prefecture. After Sanger sequencing and phylogenetic analyses it was shown that found MARV belongs to the Angola-like lineage but it is not identical to the isolate obtained during the outbreak of 2021.

In 2021, a patient died from Marburg virus (MARV) disease in Guinea, which was the first confirmed case in West Africa. The source of the outbreak has not been identified. It was revealed only that the patient had not traveled anywhere before the illness. Prior to this outbreak, MARV had been found in bats in the neighboring Sierra Leone. In Guinea, this virus has never been found before. Therefore, the question of the source of infection arose: was it an autochthonous case with spillover from a local population of bats or an imported case with spillover from fruit bats foraging/migrating from Sierra Leone? In this paper, we aimed to conduct a study ofRousettus aegyptiacusin Guinea and determine the source of the most likely infection of a patient who died from Marburg virus disease in 2021 in Guinea. We caught bats at 32 sites in Guéckédou prefecture, including seven caves and 25 locations on the flight path. A total of 501 fruit bats (Pteropodidae) were captured, including 66R. aegyptiacus. The subsequent screening showed three PCR-positive MARV bats. We have found and described two caves in Guéckédou prefecture where MARV-positiveR. aegyptiacusroost. Sequencing has shown that at least two different MARV genetic variants circulate inR. aegyptiacusin Guinea: an Angola-like strain and MARV strains of major marburgvirus lineages.