Ecological and Reproductive Cycles Drive Henipavirus Seroprevalence in the African Straw-Coloured Fruit Bat (Eidolon helvum).

Bats are known to host zoonotic viruses, including henipaviruses that cause high fatality rates in humans (Nipah virus and Hendra virus). However, the determinants of zoonotic spillover are generally unknown, as the ecological and demographic drivers of viral circulation in bats are difficult to ascertain without longitudinal data. Here we analyse serological data collected from African straw-coloured fruit bats (Eidolon helvum) in Ghana over the course of 2 years and across four sites, comprising three wild roosts and one captive colony. We focus on antibody affinity to five henipavirus antigens: Ghanaian bat henipavirus (GhV), Nipah virus (NiV), Hendra virus (HeV), Mojiang virus (MojV) and Cedar virus (CedV). In the wild roosts, we detected seasonal variations in henipavirus antibody binding, possibly associated with bat life-history cycles and migration patterns. In the captive colony, we identified increases in antibody affinity levels among pregnant bats, suggesting possible shifts in the immune system during pregnancy. These bats then pass maternal antibodies to their pups, which wane before antibody affinity levels rise later in life following initial infections and/or reactivation of latent infections. These results improve our understanding of the links between bat ecology and viral circulation, including for GhV, a locally-circulating African henipavirus.