Emerging viruses: coming in on a wrinkled wing and a prayer

Abstract

The role that bats have played in the emergence of several new infectious diseases has been under review. Bats have been identified as the reservoir hosts of newly emergent viruses such as Nipah virus, Hendra virus, and severe acute respiratory syndrome-like coronaviruses. This article expands on recent findings about bats and viruses and their relevance to human infections. It briefly reviews the history of chiropteran viruses and discusses their emergence in the context of geography, phylogeny, and ecology. The public health and trade impacts of several outbreaks are also discussed. Finally, we attempt to predict where, when, and why we may see the emergence of new chiropteran viruses.

Figure 1

Electron micrographs of some recently discovered bat viruses. A, Negative contrast image of Hendra virus representative of the order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Henipavirus. B, Ultrathin section of Nipah virus representative of the order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Henipavirus. C, Ultrathin section of Tioman virus, order Mononegavirales, family Paramyxoviridae, subfamily Paramyxovirinae, genus Rubulavirus; arrows, viruses; arrowhead, surface projections. D, Negative contrast image of Pulau virus, family Reoviridae, genus Orthoreovirus. E, Negative contrast image of severe acute respiratory syndrome virus–like coronavirus representative of the order Nidovirales, family Coronoviridae, genus Coronavirus. F, Ultrathin section of Pulau virus, family Reoviridae, genus Orthoreovirus. G, Negative contrast image of Australian bat lyssavirus, order Mononegavirales, family Rhabdoviridae, genus Lyssavirus. Bars, 100 nm.

Figure 2

Bat orthoreoviruses: viruses belonging to the genus Orthoreovirus, family Reoviridae, isolated from bats belonging to the genus Pteropus, family Pteropodidae. Nelson Bay virus was isolated from Pteropus poliocephalus in Nelson Bay, New South Wales, Australia [20]. Broome virus was isolated from Pteropus alecto in Broome, Western Australia (Cummins, Lunt and Wang, personal communication). Pulau virus was isolated from Pteropus hypomelanus on Tioman Island, Malaysia [18].

Figure 3

Pteropus bats and associated viruses: viruses isolated from bats in Southeast Asia and the closely related viruses isolated from bats in Australia. Also listed are some of the Pteropus species found in these different regions. Note that this list is not exhaustive, and some species of bats can be found in both regions.