Unravelling the genetic diversity and relatedness of Echinococcus multilocularis isolates in Eurasia using the EmsB microsatellite nuclear marker.

The cestode Echinococcus multilocularis is the causative agent of alveolar echinococcosis, a severe helminthic zoonotic disease distributed in the Northern Hemisphere. The lifecycle of the parasite is mainly sylvatic, involving canid and rodent hosts. The absence of genetic data from most eastern European countries is a major knowledge gap, affecting the study of associations with parasite populations in Western Europe. In this study, EmsB microsatellite genotyping of E. multilocularis was performed to describe the genetic diversity and relatedness of 785 E. multilocularis isolates from four western and nine eastern European countries, as well as from Armenia and the Asian parts of Russia and Turkey. The presence of the same E. multilocularis populations in the Benelux resulting from expansion from the historical Alpine focus can be deduced from the main profiles shared between these countries. All 33 EmsB profiles obtained from 528 samples from the nine eastern European countries belonged to the European clade, except one Asian profile form Ryazan Oblast, Russia. The expansion of E. multilocularis seems to have progressed from the historical Alpine focus through Hungary, Slovakia, the Czech Republic and southern Poland towards Latvia and Estonia. Most of the samples from Asia belong to the Asian clade, with one EmsB profile shared between Armenia and Turkey, and two between Turkey and Russia. However, two European profiles were described from two foxes in Turkey, including one harboring worms from both European and Asian clades. Three EmsB profiles from three Russian samples were associated with the Arctic clade. Two E. multilocularis profiles from rodents from Lake Baikal belonged to the Mongolian clade, described for the first time here using EmsB. Further worldwide studies on the genetic diversity of E. multilocularis using both mitochondrial sequencing and EmsB genotyping are needed to understand the distribution and expansion of the various clades.

Echinococcus multilocularis and other zoonotic parasites in red foxes in Estonia.

Red fox (Vulpes vulpes) is the most widely distributed canid in the world and an important source of multiple zoonotic pathogens capable of causing life-threatening diseases, such as rabies and alveolar echinococcosis. Informing general public of potential risks related to foxes is becoming more important since the fox densities have increased in many countries and the species is colonizing urban areas in Europe and around the world with increasing pace, bringing zoonotic pathogens to the immediate neighbourhood of humans and their companion animals. The aim of this study was to examine the parasite fauna of red foxes in Estonia. We found in Estonian foxes a total of 17 endoparasite taxa, including ten zoonotic species. All the analysed individuals were infected and the average parasite species richness was 6·37. However, the infection rates varied to a very large extent for different parasite species, ranging from 0·9 to 91·5%. Of zoonotic species, the highest infection rate was observed for Alaria alata (90·7%), Eucoleus aerophilus (87·6%) and Uncinaria stenocephala (84·3%). The prevalence of tapeworm Echinococcus multilocularis, a causative agent for alveolar echinococcosis, was also relatively high (31·5%), presenting a potential risk to human health.

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.