Henipavirus Neutralising Antibodies in an Isolated Island Population of African Fruit Bats

Abstract

Isolated islands provide valuable opportunities to study the persistence of viruses in wildlife populations, including population size thresholds such as the critical community size. The straw-coloured fruit bat, Eidolon helvum, has been identified as a reservoir for henipaviruses (serological evidence) and Lagos bat virus (LBV; virus isolation and serological evidence) in continental Africa. Here, we sampled from a remote population of E. helvum annobonensis fruit bats on Annobón island in the Gulf of Guinea to investigate whether antibodies to these viruses also exist in this isolated subspecies. Henipavirus serological analyses (Luminex multiplexed binding and inhibition assays, virus neutralisation tests and western blots) and lyssavirus serological analyses (LBV: modified Fluorescent Antibody Virus Neutralisation test, LBV and Mokola virus: lentivirus pseudovirus neutralisation assay) were undertaken on 73 and 70 samples respectively. Given the isolation of fruit bats on Annobón and their lack of connectivity with other populations, it was expected that the population size on the island would be too small to allow persistence of viruses that are thought to cause acute and immunising infections. However, the presence of antibodies against henipaviruses was detected using the Luminex binding assay and confirmed using alternative assays. Neutralising antibodies to LBV were detected in one bat using both assays. We demonstrate clear evidence for exposure of multiple individuals to henipaviruses in this remote population of E. helvum annobonensis fruit bats on Annobón island. The situation is less clear for LBV. Seroprevalences to henipaviruses and LBV in Annobón are notably different to those in E. helvum in continental locations studied using the same sampling techniques and assays. Whilst cross-sectional serological studies in wildlife populations cannot provide details on viral dynamics within populations, valuable information on the presence or absence of viruses may be obtained and utilised for informing future studies.

Henipavirus microsphere immuno-assays for detection of antibodies against Hendra virus

“…While progressive validation of this approach remains dependent on the availability of infrequent positive samples generated in episodic outbreaks, the Luminex assay have been shown to perform better than the conventional ELISAs currently in use at AAHL in terms of both sensitivity and specificity. The results supplement other serological studies in Australia and Africa which have utilised Luminex serology assays to demonstrate evidence for henipavirus infection (Bossart et al, 2005(Bossart et al, , 2007Hayman et al, 2011;Peel et al, 2012Peel et al, , 2013Dups et al, 2012;Playford et al, 2010). In particular, this study has explored more extensively the relative performance characteristics of ELISAs and Luminex and evaluated more recent developments in assessments of post-infection canine sera and post vaccination equine sera.…”

“…The detection of HeV-specific antibodies in sera from convalescent horses following HeV infection in Australia using the henipavirus Luminex binding and blocking assays was first described by Bossart et al (2007). In addition, these Luminex assays have been used for further serological studies to detect henipavirus antibodies in bats and other species internationally including; West African fruit bats and domestic pigs (Hayman et al, 2008;Hayman et al, 2011;Peel et al, 2012Peel et al, , 2013, Pteropid bats in Papua New Guinea (Breed et al, 2010) and Pteropus vampyrus bats in Indonesia (Sendow et al, 2013). Recently, the Luminex microsphere assay was used to assess HeV infection in the mouse model (Dups et al, 2012) and to confirm HeV infection in human cases by Queensland Health (Playford et al, 2010).…”

Nipah Virus Matrix Protein Influences Fusogenicity and Is Essential for Particle Infectivity and Stability

“…It causes sporadic outbreaks of deadly encephalitic disease in humans in Malaysia, Singapore, India, and Bangladesh (1,2). Cross-reactive antibodies against NiV and other related henipaviruses have been detected in bats and pigs as far afield as Africa and other parts of Southeast Asia, indicating that these viruses circulate quite widely (3)(4)(5)(6)(7)(8)(9)(10).…”

Attachment Protein G of an African Bat Henipavirus Is Differentially Restricted in Chiropteran and Nonchiropteran Cells

“…The detection of cross-neutralizing antibodies and genomic RNA in bats of the species Eidolon helvum indicated that henipaviruses are also present in African fruit bats (14)(15)(16)(17). Cross-reacting antibodies were also reported for domestic pig populations in Ghana, suggesting that the occurrence of henipavirus infections may not be restricted to bats (18).…”

“…Cross-reacting antibodies were also reported for domestic pig populations in Ghana, suggesting that the occurrence of henipavirus infections may not be restricted to bats (18). So far, all efforts to isolate an African henipavirus have failed, which makes it difficult to assess the zoonotic potential of these viruses (14)(15)(16)(17)(18).…”