Parasites at Risk – Insights from an Endangered Marsupial

Abstract

Parasites are the most abundant form of life on earth and are vital components of ecosystem health. Yet, it is only relatively recently that attention has been given to the risks of extinction that parasites face when their hosts, particularly wildlife, are endangered. In such circumstances, parasites that are host-specific with complicated life cycles are most at risk. Such extinction/coextinction events have been poorly documented, principally because of the difficulties of following such extinction processes in nature. Fortunately, we were presented with the rare opportunity to catalogue an endangered Australian marsupial's parasites; we present our near-complete catalogue here. We incorporate this catalogue into a predictive framework to understand which parasites might be most vulnerable to coextinction, which we hope will serve as a model for endangered hosts and their parasites elsewhere.

Phylogenetic uniqueness, not latitude, explains the diversity of avian blood parasite communities worldwide

“…Uncovering factors influencing parasite community assembly is important for predicting disease emergence, outcomes of reintroduction programmes and risks of host–parasite co‐extinction (Agosta et al, ; Lafferty, ; Moens & Pérez‐Tris, ; Thompson et al, ; Viggers et al, ). My global analysis of avian haemosporidian communities identified hotspots of diversity and uncovered consistent variation in biogeographical structure among parasite genera.…”

Altered parasite community structure in an endangered marsupial following translocation

“…Given the increased recent interest in conserving parasites, as well as their hosts, as integral components of biodiversity, the loss of parasite species during translocations represents an important risk that needs consideration in translocation protocols. Thompson et al (2018) provided a comprehensive list of woylie parasites and identified six species that appear to be host-specific and are in danger of extinction. Given that we identified three of these six species ( Ixodes woyliei , Eimeria woyliei and Potoroxyuris keninupensis ) plus a novel undescribed species of cestode during this study (Northover et al, unpublished data) and woylies are the most commonly translocated species in Australia (Morris et al, 2015), the consequences of host-specific parasite extinction require careful deliberation.…”

“…For woylies, more research is needed to understand the site-level drivers of parasite dynamics. Second, with increasing recognition of the intrinsic biodiversity value of parasites (Colwell et al, 2012; Thompson et al, 2018), the potential loss of host-parasite associations should be a serious consideration when planning fauna translocations. Finally, antiparasitic drugs should be applied prior to translocation only where there is a clear rationale for their use; field studies that examine the response of parasites following experimental manipulation are required to provide such justification.…”

“…For parasites with density-dependent transmission, translocation-induced changes to population density and host connectivity may enhance parasite transfer among hosts and increase disease prevalence within a population (Aiello et al, 2014). For rare host-specific parasites, fauna translocation may promote parasite extinction and loss of biodiversity (Moir et al, 2012; Dougherty et al, 2015; Thompson et al, 2018).…”

Exotic Parasite Threats to Australia’s Biosecurity—Trade, Health, and Conservation

“…As such, the dangers of local transmission of Trypanosoma cruzi in Australia should not be dismissed, given its emergence in the USA and involvement of native vectors. It should not be necessary to wait until a species is in danger of extinction before doing this [ 57 ], but such studies should be ongoing and the importance of doing so recognised by appropriate conservation agencies and granting agencies.…”