Long-term survival of an urban fruit bat seropositive for Ebola and Lagos bat viruses

Abstract

Ebolaviruses (EBOV) (family Filoviridae) cause viral hemorrhagic fevers in humans and non-human primates when they spill over from their wildlife reservoir hosts with case fatality rates of up to 90%. Fruit bats may act as reservoirs of the Filoviridae. The migratory fruit bat, Eidolon helvum, is common across sub-Saharan Africa and lives in large colonies, often situated in cities. We screened sera from 262 E. helvum using indirect fluorescent tests for antibodies against EBOV subtype Zaire. We detected a seropositive bat from Accra, Ghana, and confirmed this using western blot analysis. The bat was also seropositive for Lagos bat virus, a Lyssavirus, by virus neutralization test. The bat was fitted with a radio transmitter and was last detected in Accra 13 months after release post-sampling, demonstrating long-term survival. Antibodies to filoviruses have not been previously demonstrated in E. helvum. Radio-telemetry data demonstrates long-term survival of an individual bat following exposure to viruses of families that can be highly pathogenic to other mammal species. Because E. helvum typically lives in large urban colonies and is a source of bushmeat in some regions, further studies should determine if this species forms a reservoir for EBOV from which spillover infections into the human population may occur.

Figure 1. Western blot analysis using a recombinant nucleoprotein protein of EBOV-Zaire.

The five bat sera (bat serum #46, 48, 49, 50 and 53, respectively) were tested at 1∶100. The positive control antibody (anti-RGS-His monoclonal antibody, Invitrogen, USA) in strip 6 was tested at 1∶600. The numbers on the left are molecular masses in kDa derived from the BenchMark Pre-stained molecular markers (Invitrogen, USA).

Figure 2. Weekly presence determined by radio-telemetry of the female Eidolon helvum in central Accra, Ghana.

The bat was determined to be seropositive against both Ebolavirus subtype Zaire and Lagos Bat Virus (Nigeria 1956 isolate). The bat was pregnant when sampled in January 2008. Monthly mean rainfall is shown in mm (data from World Weather Information Service).