Zaire ebolavirus surveillance near the Bikoro region of the Democratic Republic of the Congo during the 2018 outbreak reveals presence of seropositive bats

On the 8th of May, 2018, an outbreak of Ebola virus disease (EVD) was declared, originating in the Bikoro region of the Democratic Republic of the Congo (DRC) near the border with neighboring Republic of the Congo (ROC). Frequent trade and migration occur between DRC and ROC-based communities residing along the Congo River. In June 2018, a field team was deployed to determine whether Zaire ebolavirus (Ebola virus (EBOV)) was contemporaneously circulating in local bats at the human-animal interface in ROC near the Bikoro EVD outbreak. Samples were collected from bats in the Cuvette and Likouala departments, ROC, bordering the Equateur Province in DRC where the Bikoro EVD outbreak was first detected. EBOV genomic material was not detected in bat-derived samples by targeted quantitative reverse transcription-polymerase chain reaction or by family-level consensus polymerase chain reaction; however, serological data suggests recent exposure to EBOV in bats in the region. We collected serum from 144 bats in the Cuvette department with 6.9% seropositivity against the EBOV glycoprotein and 14.3% seropositivity for serum collected from 27 fruit bats and one Molossinae in the Likouala department. We conclude that proactive investment in longitudinal sampling for filoviruses at the human-animal interface, coupled with ecological investigations are needed to identify EBOV wildlife reservoirs. Author summary Zaire ebolavirus (Ebola virus, (EBOV)), first characterized more than 40 years ago, is a causative agent of Ebola virus disease (EVD) which is associated with viral hemorrhagic fever. EBOV is thought to be transmitted to humans through contact with wildlife. Though bats are suspected to be the hosts that maintain EBOV in nature, it is currently not known which bat species serve as the reservoir. Identifying the wildlife species that maintain EBOV in nature would facilitate the development of strategies to mitigate the risk of EBOV transmission to humans from wildlife. In this manuscript, we describe the results of surveillance efforts to detect Ebola virus in wildlife near a contemporaneous outbreak of EBOV disease in humans. We detected evidence of recent EBOV infection in bats near the location of the EVD outbreak through serological techniques, but we did not find evidence of active EBOV infection in bats. These data support the need for more proactive surveillance in wildlife in EBOV endemic regions