Severe impact of sarcoptic mange on the movements and space use for one of its most important vector species, the raccoon dog.

Sarcoptic mange is a highly contagious zoonotic skin disease that can have severe effect on population dynamics of many wild mammals. However, very little is known about its effect on the activity and space use of infected animals. In this study we equipped two raccoon dogs (Nyctereutes procyonoides) in a mange outbreak area with radio-collars and observed the spatial and temporal effects of sarcoptic mange to these individuals. Initially, the raccoon dogs had no external symptoms of mange infection, but developed these during the study period. One of the raccoon dogs died just 32 and the other 52days after collaring. During a relatively short period before their death, there was an abrupt and drastic decline in their home range size. For one of the animals it started about 1 month before its death and the home range size reduced >1000×, whereas for the other raccoon dog it took place within the last week, decreasing >200×. The daily covered distances also declined considerably. These results indicate that at the later stage sarcoptic mange affected the physiological state of the diseased animals so forcefully that made them almost immobile. Our results show for the first time how rapid and severe could the impact of sarcoptic mange be for one of its most important reservoir and vector species.

Home ranges of raccoon dogs in managed and natural areas.

Knowledge of space use is central to understand animals' role in ecosystems. The raccoon dog Nyctereutes procyonoides is considered as one of the most influential alien mesopredator species in Europe, having the potential to cause loss of local biodiversity and act as a vector for zoonotic diseases. We collared 12 animals to study their home range and habitat use in two areas with different management regimes in Estonia: in a protected natural area and in an intensively managed area. From May to October raccoon dogs inhabiting the natural area had considerably smaller home ranges compared to the managed area, 193.3ha±37.3SD and 391.9ha±292.9SD, respectively. This result contradicts somewhat earlier findings in other European raccoon dog populations, where the home range sizes in natural areas in summer and autumn period have usually been larger compared to managed areas. In both study areas raccoon dogs preferred watersides, where amphibians and other semi-aquatic prey are abundant, to other habitats available in their home ranges. We also studied movements of a raccoon dog pair in the managed study area in winter period. Due to mild weather conditions during the study period, raccoon dogs changed their resting sites quite often, covering a relatively large 599 ha area from November 2012 to January 2013, indicating the absence of usual winter lethargy during the mild winters.

Alien species and their zoonotic parasites in native and introduced ranges: The raccoon dog example.

The raccoon dog (Nyctereutes procyonoides) is a canid that is indigenous in East Asia and alien in Europe, where it was introduced more than half a century ago. The aim of this study was to compare the parasite faunas associated with raccoon dogs in their native and introduced ranges, and to identify zoonotic parasite species. We examined 255 carcasses of hunted raccoon dogs from Estonia and recorded a total of 17 helminth species: 4 trematodes, 4 cestodes and 9 nematodes. The most prevalent parasite species were Uncinaria stenocephala (97.6%) and Alaria alata (68.3%). Average parasite species richness was 2.86 (the highest was 9) and only two animals were not parasitized at all. Although the infection intensity was determined by weight and not by sex, all animals infected with more than five helminth species were males. We also found that animals infected with higher numbers of helminth species fed significantly more on natural plants. Intentional consumption of grass may represent a self-medicating behaviour among raccoon dogs. We included the Estonian data into a wider comparison of raccoon dog parasite faunas and found a total of 54 helminth taxa, including 28 of zoonotic potential. In Europe, raccoon dogs are infected with a minimum of 32 helminth species of which 19 are zoonotic; in the native range they are infected with 26 species of which 17 are zoonotic. Most species were nematodes or trematodes, with fewer cestodes described. The recent increase in the number and range of raccoon dogs in Europe and the relatively high number of zoonotic parasite taxa that it harbours suggests that this species should be considered an important source of environmental contamination with zoonotic agents in Europe.

First report of the zoonotic tapeworm Echinococcus multilocularis in raccoon dogs in Estonia, and comparisons with other countries in Europe.

The raccoon dog (Nyctereutes procyonoides) is an alien species in Europe and an important vector of zoonotic diseases. However, compared to the red fox (Vulpes vulpes), less attention has been paid to the raccoon dog as a potentially important host for Echinococcus multilocularis, the infective agent of alveolar echinococcosis, which is an emerging infectious disease with a high mortality rate. We examined the small intestines of 249 Estonian raccoon dogs and found 1.6% of individuals to be infected with E. multilocularis. The relatively large difference between this prevalence and that found in sympatric red foxes (31.5%) sampled during the same time period might be due to differences in diet: red foxes consume significantly more arvicolid rodents - the main intermediate hosts of the parasite - especially during the coldest period of the year when raccoon dogs hibernate. Nonetheless, given the relatively high density of raccoon dogs, our results suggest that the species also represents an important definitive host species for E. multilocularis in Estonia. Compared with other countries in Europe where E. multilocularis-infected raccoon dogs have been recorded (Latvia, Lithuania, Poland, Germany, and Slovakia), the prevalence in Estonia is low. The longer hibernation period of raccoon dogs at higher latitudes may explain this pattern. Both mitochondrial and nuclear loci were analysed for Estonian isolates: based on EmsB microsatellite genotyping the Estonian isolates shared an identical genotype with E. multilocularis in northern Poland, suggesting a common history with this region. The data from more than a quarter of the mitochondrial genome (3558 bp) revealed two novel haplotypes specific to Estonia and placed them into the same haplogroup with isolates from other European regions. Considering that the raccoon dog is becoming increasingly widespread and is already relatively abundant in several countries in Europe, the role of the species must be taken into account when assessing the E. multilocularis related risks to public health.

First report of highly pathogenic Echinococcus granulosus genotype G1 in dogs in a European urban environment.

BACKGROUND: Echinococcus granulosus and E. multilocularis are tapeworm parasites of major medical and veterinary importance, causing cystic and alveolar echinococcosis, respectively. Both diseases are listed among the most severe parasitic diseases in humans, representing 2 of the 17 neglected diseases prioritised by the World Health Organisation. However, little is known about the role of urban animals in transmission of both parasite species. FINDINGS: A sensitive non-invasive genetic method was used to monitor E. granulosus and E. multilocularis infection among dog faecal samples collected from an urban area in Estonia in 2012-13. Out of 181 dog faecal samples analysed, 2.2% tested positive for E. granulosus, determined by sequencing as genotype G1. None of the samples tested positive for E. multilocularis. CONCLUSIONS: We report contamination of an urban environment with highly pathogenic E. granulosus G1 disseminated by dogs, and a potential risk to human health.

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

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.