Currently, we are experiencing unprecedented declines in biodiversity around the globe in what biologists have named the sixth mass extinction. Whilst habitat loss and ongoing anthropogenic environmental change are the biggest threats currently facing the natural world, emerging infectious diseases are partially responsible for large scale declines of many different taxa. For example, in bats, the emerging pathogen,
Pseudogymnoascus destructans, the causative agent of White Nose Syndrome, has caused the ongoing decline in many bat species in North America. Other vertebrates such as amphibians and reptiles are not immune to the negative effects of emerging infections. While both amphibian and reptilian populations around the globe are in decline, infectious diseases are thought to be a major contributing factor, especially in amphibians. The emergence of
Batrachochytrium dendrobatidis (Bd), often called the amphibian chytrid fungus, has been linked to the decline of hundreds of species, and the extinction of several dozen amphibian species. Another pathogenic fungus in the
Batrachochytrium genus was identified in 2013, after causing an unprecedented enigmatic decline in fire salamanders in the Netherlands.
Batrachochytrium salamandrivorans (Bsal) now threatens salamander species around the world, although for now it is confined to Europe and Asia.
In reptiles, another fungus has emerged,
Ophidiomyces ophiodiicola, the causative agent of ophidiomycosis (formerly known as Snake Fungal Disease), has emerged in a strikingly short amount of time resulting in population level declines in many North American snake species. Ophidiomyces has since been found in Europe and may have a near global distribution although ongoing monitoring and surveillance is needed to confirm this.
Several viruses have been recently discovered in reptiles and appear to be causing significant disease and even threatening populations. Viruses in the order Nidovirales, family Tobaniviridae have caused outbreaks of severe respiratory disease in captive snakes, and related viruses are also likely responsible for deaths of Bellinger river turtles in Australia that threaten the survival of that species. Ranaviruses are emerging pathogens of both amphibians and reptiles, found across the globe that have the ability to affect several species of conservation concern.
As well as living in a time of drastic biodiversity loss, we are also living in a world where global trade has never been higher. It is through these pathways that such diseases emerge, finding new hosts or being transported to different continents where their pathogenic potential may finally be realised. However there are a large number of bacterial, fungal, protozoan, and viral infectious agents that affect amphibians and reptiles that we know relatively little about. In this issue we seek submissions that examine all aspects of emerging infections and diseases in amphibians and reptiles, including but not limited to field studies, modelling approaches to understand infection dynamics, treatment methods, pathological investigations, and new diagnostic techniques.
We would like to acknowledge that Steven Allain, Durrell Institute of Conservation and Ecology at the University of Kent (Canterbury, UK), acts as coordinator and has contributed to the preparation of the proposal for this Research Topic.Topic Editor PD Dr.med.vet. Rachel E. Marschang is employed by Laboklin & Co. KG. The other Topic Editor declares no competing interest with regard to the Research Topic subject.