Lagos bat lyssavirus (LBV) is a negative‑sense single‑stranded RNA virus belonging to the genus Lyssavirus. It was first isolated from a fruit bat in Lagos, Nigeria in 1956 and is one of several rabies‑related lyssaviruses endemic to Africa. LBV is genetically distinct from classical rabies virus and groups within phylogroup II.
Reservoirs, transmission and characteristics
LBV circulates in Old World fruit bats, with reported hosts including Eidolon helvum, Rousettus aegyptiacus and Epomophorus wahlbergi. The virus is maintained in these bats without causing obvious disease and is rarely detected; only a handful of isolations have been reported since its discovery. Transmission likely occurs via bites or contact with infected saliva, but no laboratory‑confirmed human infections have been documented. Like other lyssaviruses, LBV virions are enveloped and bullet‑shaped, containing a genome of approximately 12 kb that encodes five proteins (N, P, M, G and L). Experimental studies suggest that LBV may cause rabies‑like encephalitis in mammals, and current rabies vaccines may offer limited cross‑protection because LBV is phylogenetically distant from rabies virus. Diagnostic confirmation relies on virus isolation or reverse‑transcription PCR from brain tissue or saliva. Because of its rarity, the ecology, seasonality and spill‑over potential of LBV remain poorly understood.
Bats and surveillance findings
Since the initial isolation in Lagos, subsequent detections of Lagos bat lyssavirus have occurred sporadically in West and southern Africa. Surveillance studies have found LBV antibodies or viral RNA in straw‑coloured fruit bats (Eidolon helvum) roosting in urban areas, Egyptian fruit bats and Wahlberg’s epauletted fruit bats. No confirmed human cases have been reported, but several incidents have involved people being bitten or scratched by rabid‑acting fruit bats. In one outbreak in Ghana, multiple bats tested positive for LBV, raising concerns about its distribution and spill‑over risk. While phylogenetic analyses reveal four distinct lineages, their pathogenicity in non‑bat hosts remains unclear. Public health guidelines therefore recommend treating any bite or exposure to African fruit bats as a potential rabies exposure and administering post‑exposure prophylaxis until laboratory testing can rule out infection.
Lagos bat lyssavirus is a rare bat‑associated lyssavirus in Africa. Its limited detection and unknown capacity to cause human disease make it a subject of ongoing research. Awareness of bat exposures and adherence to rabies prophylaxis guidelines remain essential for preventing possible spill‑over.
Related Terms: Rabies Lyssavirus, Mokola Lyssavirus, Duvenhage Lyssavirus, Rotavirus H, Colorado Tick Fever Virus