Henipaviruses: Gaps in the Knowledge of Emergence

Abstract

Over the past 10 years many ''new'' viruses have been identified in Australia and the Asian region.The viruses have been isolated from, and/or identified in, a range of animals; some of these viruses are of veterinary and medical importance while others are new threats to biodiversity. Of these viruses, Hendra and Nipah viruses have emerged as significant zoonotic agents belonging to the family Paramyxoviridae and genusHenipavirus. These agents cause fatalities in a range of animals including horses, pigs, and humans. Both viruses have been isolated from flying foxes (genus Pteropus; suborder Megachiroptera), which are accepted as their natural hosts. Although some research has been undertaken on the viruses and their hosts, little is known about how these viruses emerge. We have attempted to investigate the current knowledge of the bat-Henipavirus ecology by discussing the range of bat viruses that exist (viral assemblage), the significance of evolving viruses, possible functional role(s) of viruses, the ecology of viruses and their hosts, and identifying possible drivers (selection pressures) that may culminate with the overlap of new potential viral hosts thereby facilitating the replication of fit viral populations in a new host-virus continuum(s). By undertaking such an analysis, we have attempted to identify key questions, which should be investigated if the factors involved in ''driving'' Henipavirus emergence are to be understood.

The relationship between physiological stress and wildlife disease: consequences for health and conservation

“…The epidemiology of HeV remains incompletely understood, particularly the host and environment factors driving spill-over events (Hyatt et al 2004;Smith et al 2011). Changes in flying fox ecology associated with anthropogenic stressors including climate change, habitat fragmentation and urbanisation, have been proposed as drivers of HeV disease dynamics (Bradley and Altizer 2007;Plowright et al 2011;Dietrich et al 2015).…”

One Health research and training in Australia and New Zealand

“…As a result there has not been a single human case of Hendra virus since 2009 (28), and only a small number of infrequent cases in horses (29). The research on Hendra virus also allowed Australian scientists to contribute to research on the closely related Nipah virus that emerged in Malaysia and Bangladesh (30). …”

Viral disease emergence in shrimp aquaculture: origins, impact and the effectiveness of health management strategies

“…Indeed, the absence of pathology or mortality may provide the virus with a better opportunity for replication and efficient ongoing transmission. Covert infections without disease commonly occur for viruses that have established a stable ecological niche (Hyatt et al. 2004; Walker 2004).…”

“…Human social and industrial activities that have been implicated in disease emergence include increased urbanisation, the globalisation of trade, cultural and behavioural changes, the population of new environments, climate change, and the establishment and growth of new industries or industrial practices (Brown 1997; Mayer 2000). Changes of this nature can allow a virus, through necessity or opportunity, to occupy a new niche in which the ecological balance is temporarily lost (Hyatt et al. 2004).…”