An invasive vector of zoonotic disease sustained by anthropogenic resources: the raccoon dog in northern Europe.

Karmen Süld,Egle Soe,Leidi Laurimaa,John Davison,Harri Valdmann,Urmas Saarma,Tara C Smith

doi:10.1371/journal.pone.0096358

Abstract

The raccoon dog (Nyctereutes procyonoides) is an introduced species in Europe with a continually expanding range. Since the species is capable of affecting local ecosystems and is a vector for a number of severe zoonotic diseases, it is important to understand its food habits. Raccoon dog diet was studied in Estonia by examining the contents of 223 stomach samples collected during the coldest period of the year, August to March, in 2010–2012. The most frequently consumed food categories were anthropogenic plants (e.g. cereals, fruits; FO = 56.1%) and carrion (e.g. carcasses of artiodactyls and carnivores; FO = 48.4%). Carrion was also the only food category that was consumed significantly more frequently by raccoon dogs exhibiting symptoms of sarcoptic mange than by uninfected animals. Small mammals, which represent intermediate hosts for the zoonotic tapeworm Echinococcus multilocularis, were more commonly recorded in samples also containing anthropogenic plants than expected by chance. Comparison of raccoon dog and red fox (Vulpes vulpes) diet in Estonia revealed higher overlap than found elsewhere in Europe, with ‘carrion’ and ‘anthropogenic plants’ making up the bulk of both species’ diet; however, raccoon dogs were more omnivorous than red foxes. Our results suggest that while the use of most food categories reflects the phenology of natural food sources, ‘anthropogenic plants’ and ‘carrion’ provide an essential resource for raccoon dogs during the coldest period of the year, with the latter resource especially important for individuals infected with sarcoptic mange. Since both of these food categories and small mammals are often found at supplementary feeding sites for wild boar (Sus scrofa), this game management practice may facilitate high densities of mesocarnivores and promote the spread of some severe zoonotic diseases, including alveolar echinococcosis, trichinellosis, rabies and sarcoptic mange.

Highlights

Introduced terrestrial vertebrates are often species with generalist feeding habits and short generation times, allowing them to adapt to different environments and cause a range of ecological and economic problems [1]
Ungulate carcasses are primarily left by large carnivores - ungulates are preferred prey of grey wolf (Canis lupus) and Eurasian lynx (Lynx lynx) in Estonia [30,31] - and by hunters
Previous studies from Lithuania [32,33], Belarus [34], Poland [35], Russia [36] and Finland [37] have shown that during their short active periods in winter, raccoon dogs mainly rely on ungulate carcasses

Summary

Introduction

Introduced terrestrial vertebrates are often species with generalist feeding habits and short generation times, allowing them to adapt to different environments and cause a range of ecological and economic problems [1]. Genovesi et al [2] reported 117 alien mammal species in Europe, of which at least 58 are known to cause environmental or health problems, and 27 have been found to directly affect native species. One of the most successful invasive carnivores in Europe is the raccoon dog (Nyctereutes procyonoides) [3], which is suspected of causing damage to native fauna through its feeding habits. In Estonia it has been identified as a vector for rabies [9], trichinellosis [10], sarcoptic mange and alveolar echinococcosis. Sarcoptic mange is known to impose considerable nutritional stress on individual animals [13] and severely reduce population densities of wild canids, especially red foxes and raccoon dogs [3]

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Conclusion