Emerging myxosporean parasites of Australian frogs take a ride with fresh fruit transport

Abstract

BackgroundThe spread of wildlife pathogens into new geographical ranges or populations is a conservation concern for endangered species. Cystodiscus australis and Cystodiscus axonis are two species of myxosporean parasites infecting Australian frogs and tadpoles that have been recently recognised as important disease agents impacting amphibian conservation. Yet despite their importance to wildlife health, the mechanism of emergence for these parasites is unknown. We hypothesise that these parasites are capable of being accidentally translocated with their amphibian hosts in fresh produce (agricultural, horticultural and industrial) shipments into naïve environments and host populations.MethodsWe surveyed 33 Australian “Banana box” frogs from Sydney fruit markets during 2011 using faecal smears and multiplex species specific PCR on DNA isolated from frog faeces or using histopathology to demonstrate the presence of both C. australis and C. axonis.ResultsOne of the “Banana box” frogs, the Dainty green tree frog (Litoria gracilenta) was positive for C. australis and C. axonis in its faeces and continuously shed the parasites for eight months.ConclusionsWe present a possible mechanism for the emergence of Cystodiscus parasites and a non-invasive screening method to be used as a diagnostic test. In the future, vigilance and communication between wildlife managers/researchers and veterinarians will provide valuable information about these parasites, their host range and true distribution. This will aid risk management assessments for threatened populations within the range of Cystodiscus parasites and ultimately enhance conservation efforts.

Sphaeromyxids form part of a diverse group of myxosporeans infecting the hepatic biliary systems of a wide range of host organisms

“…Myxosporeans from the hepatic biliary clade infecting gall bladders of invasive amphibians, such as the cane toad ( Bufo marinus ) in Australia, are known to spread to numerous endemic species [32,33], again indicating the very low host specificity found in this group of myxosporeans. The spread of wildlife pathogens into new geographical ranges or populations is a conservation concern for endangered species of which amphibian decline is one of the most dramatic examples.…”

Finding Them Before They Find Us: Informatics, Parasites, and Environments in Accelerating Climate Change

“…At this time, there is growing interest in parasites as we begin to understand more and more that there are direct connections among climate change, biodiversity dynamics, and emerging infectious disease (EID). Parasites occupy a central role in efforts to develop proactive protocols for monitoring changes in ecosystem structure and for detecting the potential for emerging disease in resident and colonizing host species, be they human, livestock, or wildlife (Daszak et al, 2000;Brooks and Hoberg, 2006, 2008Patz et al, 2008;Agosta et al, 2010;Hoberg, 2010;Weaver et al, 2010;Hartigan et al, 2012;Altizer et al, 2013;Hoberg and Brooks, 2013). Parasites, especially those with specialized transmission dynamics, including complex life cycles, are not only agents of disease in humans, food-animal resources, crops, and wildlife, they are also powerful representations of the ecological and historical context of the diseases they cause (Dobson and Hudson, 1986;Dobson and May, 1986a, b;Dobson and Carper, 1992;Hoberg, 1997;Dobson and Foufopoulos, 2001;Marcogliese, 2001Marcogliese, , 2005Nieberding and Olivieri, 2007;Hoberg and Brooks, 2008;Rosenthal, 2008;Lafferty, 2009;Kilpatrick, 2011;Kuris, 2012).…”

Myxozoans on the Move: Dispersal Modes, Exotic Species and Emerging Diseases

“…The survival of such potential hosts during transport is promoted by refrigeration, faster shipping times and open trade agreements. The only demonstrated example of a myxozoan being dispersed through accidental transport of infected hosts was where myxozoaninfected amphibians were transported extensively within and beyond Australian borders in banana boxes (Hartigan et al 2012). …”