An Invasive Vector of Zoonotic Disease Sustained by Anthropogenic Resources: The Raccoon Dog in Northern Europe

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.

Echinococcus multilocularis in foxes and raccoon dogs: an increasing concern for Baltic countries

“…These data highlight the importance of the feeding behaviour; in fact, amphibian-transmitted parasite species were more prevalent in raccoon dogs than in foxes, in which rodent-transmitted parasites prevailed [37]. In Estonia, a difference between the raccoon dog diet and the fox diet was observed in the cold period of the year, revealing anthropogenic plants and carrions as the most important food sources for raccoon dogs, while foxes consumed significantly more arvicolid rodents [38]. …”

Winter severity or supplementary feeding—which matters more for wild boar?

“…While supplementary feeding can, if implemented appropriately, be used to deter wild boar from potential damage areas (Calenge et al 2004), excessive feeding can result in increased damage to farmland (Schley et al 2008) and is ineffective during the period when crops are most vulnerable to damage by wild boar (Geisser and Reyer 2004). Supplementary feeding sites also attract nest predators of ground-nesting birds (Oja 2012), including invasive raccoon dogs, whose diet in Estonia largely consists of items of anthropogenic origin (56 %, frequency of occurrence; Süld et al 2014). Additionally, a recent study from Spain revealed that the density of feeding sites is related to the probability and intensity of infection of wild boar with gastrointestinal parasites (Navarro-Gonzalez et al 2013).…”

Direct and indirect effects of anthropogenic bird food on population dynamics of a songbird

“…Our study provides additional evidence that anthropogenic food can affect population dynamics, which could in turn have profound ramifications for community structure through interspecific interactions (Robb et al, 2008;Süld et al, 2014). For example, eastern populations of house finches that are supported by bird feeding could negatively impact other species.…”

“…Clustered, predictable resources like feeding tables and bird feeders produce unnaturally high concentrations of foragers (Adams et al, 2006;Daniels and Kirkpatrick, 2006), which could lead to higher mortality rates (i.e., negative effects) by attracting predators or increasing disease transmission (Brittingham and Temple, 1986;Dunn and Tessaglia, 1994;Süld et al, 2014). Conversely, anthropogenic foods could have positive indirect effects.…”