Marburg virus in Egyptian Rousettus bats in Guinea: Investigation of Marburg virus outbreak origin in 2021.

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. Author summary: In 2020, MARV was first detected in fruit bats in Sierra Leone (West Africa). One year later, first outbreak of MARV in West Africa was registered in the neighboring Guinea after a man's death in the Temessadou M'bokét village. The source of the outbreak has not been identified. It is known, that the reservoir animal of MARV is the cave-dwelling bat Rousettus aegyptiacus, and typically, MARV disease outbreaks emerge after a visit of the index patient to a cave or mine. In our work, we studied bats in the vicinity of this village for the presence of the MARV. A cave hosting a colony of R. aegyptiacus was found close to the Temessadou M'bokét village (~4.5 km). Sampling and PCR screening of the bats from the colony identified three MARV-positive bats. The cave is inaccessible to humans; therefore, the index patient could not have been infected upon visit. We assume that the patient was infected outside the cave after direct or indirect contact with an infected bat of the same colony. These results provide the basis for preventive measures against new MARV outbreaks in Guinea. [ABSTRACT FROM AUTHOR]