Detection of Marburg Virus Antibodies 25 Years After Outbreak in Watsa, Democratic Republic of the Congo.

Abstract

Orthomarburgvirus marburgense (MARV) causes infrequent but often fatal disease in humans, with recent outbreaks expanding into new regions including Tanzania, Rwanda and Ethiopia. To date, 18 Marburg virus disease (MVD) outbreaks have been reported, primarily in Sub-Saharan Africa. From 1998-2000, a large MVD outbreak in Watsa/Durba region, Democratic Republic of the Congo (DRC), resulted in 154 confirmed cases and 128 deaths (83% case fatality rate). Given the ongoing public health risks posed by MARV, the lack of approved vaccines and therapeutics, and unpredictable frequency of future outbreaks, this study aimed to assess the prevalence of anti-MARV antibodies in Watsa/Durba. Samples collected in May 2023, (n=313) included known MVD survivors (n=5), close contacts (n=22) and other residents (n=286). A multiplex immunoassay, was used to assess seroreactivity to MARV antigens and other pan-filovirus targets. Among the Watsa/Durba cohort, 4.5% and 1.6% were seroreactive to MARV glycoprotein (GP) and VP40, respectively, including only one known MVD survivor. No significant associations were found between MARV seroreactivity and risk factors such as travel to Uganda, receiving injections or employment as a gold miner. Of those 14 MARV GP-reactive individuals, 85.7% were cross-reactive to other filoviral targets. This detected seroprevalence among individuals with no known history of exposure may indicate continued exposure to MARV or MARV-like antigens almost 25 years after the conclusion of the outbreak. Beyond MARV reactivity, detected cross-reactivity to pan-filovirus targets further emphasize a need for increased surveillance, and the potential for asymptomatic, undetected cases in the region.