Serum Neutralisation profiles of Straw-Coloured Fruit Bats (Eidolon helvum) against four Lineages of Lagos Bat Lyssavirus

Abstract

Purpose: Bats are the natural reservoir hosts for many viral zoonotic pathogens including lyssaviruses that can cause the fatal disease rabies. Lagos bat lyssavirus (LBV), a member of phylogroup II lyssaviruses, has been classified into four lineages (A, B, C and D). There is minimal information of LBV lineages circulating in fruit bat populations in Nigeria, despite that the bat lyssavirus (LBV-B) was first isolated in Nigeria in 1956. This study was undertaken to assess the levels of neutralising antibodies against four lineages of LBVs in straw-coloured fruit bats (Eidolon helvum) in Makurdi, Nigeria. Methods & Materials: Serum samples (n=180) were collected during two consecutive seasons between (November 2017 – March 2018 and November 2018 – March 2019) from terminally bled bats captured for human consumption and tested using a modified fluorescent antibody virus neutralisation (mFAVN) assay. Results: The data showed that a high number of bat sera (73%) neutralised at least one lineage of LBV with the reciprocal titre values ranging from 9 – > 420.89. Many sera (n=107) neutralised more than one lineages of LBV while 24 serum samples neutralised only one lineage, i.e. LBV-A (n=17), LBV-D (n=6), LBV-C (n=1) and LBV-B (n=0). Conclusion: The high seroprevalence of neutralising antibodies suggested that the exposures to LBVs were common and LBV- A (and possibly C and D) were circulating amongst those bats whereas LBV-B was unlikely to be present. The infected bats could pose a danger to their handlers and consumers.