Echinococcus across the north: Current knowledge, future challenges

Prevalence and geographic distribution of Echinococcus genus in wild canids in southern Québec, Canada

Echinococcus spp. is an emerging zoonotic parasite of high concern. In Canada, an increase in the number of human and animal cases diagnosed has been reported, but information regarding the parasite's distribution in wildlife reservoir remains limited. A cross-sectional study was conducted to estimate the prevalence of wild canids infected with Echinococcus spp. and Echinococcus multilocularis in areas surrounding populated zones in Québec (Canada); to investigate the presence of areas at higher risk of infection; to evaluate potential risk factors of the infection; and as a secondary objective, to compare coproscopy and RT-PCR diagnostic tests for Taenia spp. and Echinococcus identification. From October 2020 to March 2021, fecal samples were collected from 423 coyotes (Canis latrans) and 284 red foxes (Vulpes vulpes) trapped in 12 administrative regions. Real-time PCR for molecular detection of genus Echinococcus spp. and species-specific Echinococcus multilocularis were performed. A total of 38 positive cases of Echinococcus spp., of which 25 were identified as E. multilocularis, were detected. Two high-risk areas of infection were identified. The prevalence of Echinococcus spp. was 22.7% (95% CI 11.5-37.8%) in the Montérégie centered high-risk area, 26.5% (95% CI 12.9-44.4%) in the Bas-St-Laurent high-risk area, and 3.0% (95%CI 1.8-4.7%) outside those areas. For E. multilocularis, a prevalence of 20.5% (95% CI 9.8-35.3%) was estimated in the high-risk area centered in Montérégie compared to 2.4% (95% CI 1.4-3.9%) outside. Logistic regression did not show any association of infection status with species, sex, or geolocation of capture (p > 0.05). This study shows the circulation of Echinococcus in a wildlife cycle in 9/12 administrative regions of Québec.

Case report: Echinococcus multilocularis infection in a dog showing gastrointestinal signs in Hokkaido, Japan

Echinococcus multilocularis is a cestode that causes human alveolar echinococcosis, a lethal zoonotic disease distributed in the northern hemisphere. The life cycle of this parasite is maintained in nature by voles as intermediate hosts and foxes as definitive hosts in Hokkaido, Japan. Although dogs are also susceptible to the parasite, the infection has been considered typically asymptomatic. We report the detection of E. multilocularis eggs in the diarrheal feces of a dog with chronic gastrointestinal signs, which disappeared after anthelmintic treatment. The mitochondrial genome sequence constructed by sequencing of the overlapping PCRs using DNA from the eggs was identical to the most predominant haplotype previously reported in red foxes in Hokkaido. This case highlights that Echinococcus infection should be considered as a differential diagnosis for diarrheal dogs in the disease endemic areas. Further efforts are needed to accumulate parasite genotypes in domestic dogs as well as humans to assess the risk of human infection from dogs.

Echinococcus species in wildlife

Transmission of Echinococcus spp. in life cycles that involve mainly wildlife is well recognized for those species with small mammals as intermediate hosts (e. g. E. multilocularis), as well as for E. felidis and the 'northern' genotypes of E. canadensis (G8 and G10). In contrast, the remaining taxa of E. granulosus sensu lato are best known for their domestic life cycles, and the numerous wild mammal species (mainly ungulates) that have been recorded with cystic echinococcosis in the past were mainly considered a result of spill-over from the dog-livestock transmission system. This view was challenged with the advent of molecular characterization, allowing discrimination of the metacestodes, although the contribution of wild mammals to various Echinococcus life cycles has remained uncertain for scarcity of wildlife studies. Numerous records of cysts in wild ungulates date back to the 20th century, but cannot with certainty be allocated to the Echinococcus species and genotypes that are recognized today. This means that our current knowledge is largely restricted to studies of the past two decades that kept adding gradually to our concepts of transmission in various geographic regions. In particular, new insights were gathered in the past years on E. granulosus s.l. in wildlife of sub-Saharan Africa, but also on transmission patterns of E. multilocularis in previously neglected regions, e. g. North America. Here, an update is provided on the current state of knowledge on wild mammals as hosts for all Echinococcus species, listing >150 species of wild hosts with references, as well as estimates on their epidemiological impact and our current gaps of knowledge.

Mitogenomic exploration supports the historical hypothesis of anthropogenic diffusion of a zoonotic parasite Echinococcus multilocularis

Animal movement across regions owing to human activity can lead to the introduction of pathogens, resulting in disease epidemics with medical and socioeconomic significance. Here, we validated the hypothesis that human activity, such as the transportation of infected animals, has played a significant role in introducing the zoonotic parasite Echinococcus multilocularis into Hokkaido, Japan, by synthesizing and evaluating parasite genetic data in light of historical records. Our analysis indicates that a major genetic group in Hokkaido originated from St. Lawrence Island, USA, which is in accordance with the route suggested by historical descriptions. Moreover, we identified a minor genetic group closely related to parasites found in Sichuan, China. This fact implies that parasite invasion in Japan may result from complex and inadvertent animal translocations. These findings emphasize the anthropogenic impacts on zoonotic parasite spread and provide a crucial perspective for preventing future potential epidemics.

Cystic echinococcosis in Iceland: a brief history and genetic analysis of a 46-year-old Echinococcus isolate collected prior to the eradication of this zoonotic disease

Cystic echinococcosis (CE) is considered the most severe parasitic disease that ever affected the human population in Iceland. Before the start of eradication campaign in the 1860s, Iceland was a country with very high prevalence of human CE, with approximately every fifth person infected. Eradication of CE from Iceland by 1979 was a huge success story and served as a leading example for other countries on how to combat such a severe One Health problem. However, there is no genetic information on Echinococcus parasites before eradication. Here, we reveal the genetic identity for one of the last Echinococcus isolates in Iceland, obtained from a sheep 46 years ago (1977). We sequenced a large portion of the mitochondrial genome (8141 bp) and identified the isolate as Echinococcus granulosus sensu stricto genotype G1. As G1 is known to be highly infective genotype to humans, it may partly explain why such a large proportion of human population in Iceland was infected at a time . The study demonstrates that decades-old samples hold significant potential to uncover genetic identities of parasites in the past.

It's a small world for parasites: evidence supporting the North American invasion of European Echinococcus multilocularis

Echinococcus multilocularis (Em), the causative agent of human alveolar echinococcosis (AE), is present in the Holarctic region, and several genetic variants deem to have differential infectivity and pathogenicity. An unprecedented outbreak of human AE cases in Western Canada infected with a European-like strain circulating in wild hosts warranted assessment of whether this strain was derived from a recent invasion or was endemic but undetected. Using nuclear and mitochondrial markers, we investigated the genetic diversity of Em in wild coyotes and red foxes from Western Canada, compared the genetic variants identified to global isolates and assessed their spatial distribution to infer possible invasion dynamics. Genetic variants from Western Canada were closely related to the original European clade, with lesser genetic diversity than that expected for a long-established strain and spatial genetic discontinuities within the study area, supporting the hypothesis of a relatively recent invasion with various founder events.

Evaluating noninvasive methods for estimating cestode prevalence in a wild carnivore population

Helminth infections are cryptic and can be difficult to study in wildlife species. Helminth research in wildlife hosts has historically required invasive animal handling and necropsy, while results from noninvasive parasite research, like scat analysis, may not be possible at the helminth species or individual host levels. To increase the utility of noninvasive sampling, individual hosts can be identified by applying molecular methods. This allows for longitudinal sampling of known hosts and can be paired with individual-level covariates. Here we evaluate a combination of methods and existing long-term monitoring data to identify patterns of cestode infections in gray wolves in Yellowstone National Park. Our goals were: (1) Identify the species and apparent prevalence of cestodes infecting Yellowstone wolves; (2) Assess the relationships between wolf biological and social characteristics and cestode infections; (3) Examine how wolf samples were affected by environmental conditions with respect to the success of individual genotyping. We collected over 200 wolf scats from 2018-2020 and conducted laboratory analyses including individual wolf genotyping, sex identification, cestode identification, and fecal glucocorticoid measurements. Wolf genotyping success rate was 45%, which was higher in the winter but decreased with higher precipitation and as more time elapsed between scat deposit and collection. One cestode species was detected in 28% of all fecal samples, and 38% of known individuals. The most common infection was Echinococcus granulosus sensu lato (primarily E. canadensis). Adult wolves had 4x greater odds of having a cestode infection than pups, as well as wolves sampled in the winter. Our methods provide an alternative approach to estimate cestode prevalence and to linking parasites to known individuals in a wild host system, but may be most useful when employed in existing study systems and when field collections are designed to minimize the time between fecal deposition and collection.

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 granulosus sensu lato and Echinococcus multilocularis: A review

Echinococcus spp. have a global distribution and are found on every continent except Antarctica. Infections with these parasites are considered extremely serious, contributing to significant morbidity and mortality in addition to substantial economic losses to the livestock industry. Echinococcus granulosus sensu lato (s.l.) and Echinococcus multilocularis, causing cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively, are the two main species of interest from a human and veterinary perspective. This review collates the current state-of-the-art understanding of these two parasites within four key areas of relevance to human and veterinary professionals: transmission and epidemiology, clinical signs and pathogenesis, diagnosis, and treatment and prevention. This review should serve as a broad introduction to the most important Echinococcus spp. The reader is advised to seek out specific literature on individual diseases and their causative parasites for a deeper understanding.

First report of Echinococcus canadensis (G6/G7) by sequence analysis from the Khyber Pakhtunkhwa province of Pakistan

Cystic echinococcosis (CE) is a zoonotic parasitic disease that can result in human and animal health problems globally. Although the disease is known to be endemic in Asia and the Middle East, there are few epidemiological studies on CE in Pakistan. The purpose of the present study was to identify the Echinococcus granulosus sensu lato species and genotypes contributing to human CE cases in the Khyber Pakhtunkhwa (KPK) province of Pakistan. A total of fifty-six formalin fixed paraffin embedded (FFPE) CE cyst samples of human origin were collected from the Pathology Department, Rehman Medical Institute (RMI), KPK for the years 2012-2017. Cyst samples came from the liver (26/56; 46.4%), lungs (3/56; 5.3%), spleen (3/56; 5.3%), pelvis (1/56; 1.8%), breast (1/56; 1.8%), and thigh (1/56; 1.8%). The organ location for 21 of the cysts was not recorded. World Health Organization-Informal Working Group on Echinococcosis (WHO-IWGE) ultrasound-based cyst staging was available for 17 of the 26 (65.4%) hepatic cysts. Five of these cysts (29.4%) were CE3 (transitional), nine (52.9%) were CE4 (inactive), and three (17.6%) were CE5 (inactive). Most of the cysts were obtained from CE patients that were ethnically Afghan Pashtuns (44/56; 78.6%), while 12.5% (7/56) were from patients that were Pakistani Pashtuns. The majority (41/56; 73.2%) of patients reported having close interactions with dogs. Using 12SrRNA primers, 33 cyst samples were identified as being caused by E. granulosus sensu stricto (s.s.). Mitochondrially encoded cytochrome C oxidase 1 (mt-CO1) was evaluated for the remaining 23 samples. PCR product was obtained from six of these 23 samples. Of these six samples, one was identified as Echinococcus canadensis (G6/7). Haplotype analysis showed high haplotype and low nucleotide diversity for the mt-CO1 gene. There were 26 polymorphic sites for the mt-CO1 sequence, of which 65.3% (17/26) were parsimony informative. The E. canadensis mt-CO1 haplotype network consisted of 11 haplotypes, with a main central haplotype. In conclusion, it appears that E. granulosus s.s. and E. canadensis (G6/7) are circulating in the northwestern region of Pakistan. Further molecular epidemiological studies are needed to explore the local genetic diversity of the parasite.

Parasites in the changing world - Ten timely examples from the Nordic-Baltic region

The world is changing, and parasites adapt. The Nordic-Baltic region in northern Europe - including the Nordic countries Denmark, Finland, Iceland, Norway and Sweden, and the Baltic States Estonia, Latvia and Lithuania - is facing new parasitological challenges due to changes in populations of parasites and their hosts and the spread of new parasites to the region due to climate change. Some changes can also be ascribed to increased awareness and detection. In this paper, we review and discuss a convenience selection of ten timely examples of recent observations that exemplify trends and challenges from different fields of parasitology, with particular focus on climate change and potential changes in epidemiology of pathogens in northern Europe. The examples illustrate how addressing parasitological challenges often requires both intersectoral and international collaboration, and how using both historical baseline data and modern methodologies are needed.

Alveolar echinococcosis in a dog in the eastern United States

An 8-y-old Labrador Retriever was presented to a small animal practice in northern Virginia with a history of recent lethargy. Physical examination findings were unremarkable. Ultrasound revealed several large hepatic masses and multiple smaller masses involving the pancreas. Cytologic findings on fine-needle aspirates of the hepatic masses included inflammation and necrosis with eosinophilic, membranous oval structures consistent with cestode infection. Histopathologic findings for biopsies of these masses included extensive necrosis, inflammation, and PAS-positive hyaline-like membranous material interpreted as metacestode cyst wall. A PCR product was generated from aspirate material using primers specific for Echinococcus multilocularis. Subsequent sequence data were 100% homologous to E. multilocularis NADH dehydrogenase subunit I gene sequences. The dog received daily oral albendazole (10 mg/kg) treatment, but its condition deteriorated, and the dog was euthanized. The dog, born in Mississippi, was brought as a puppy to Virginia with no other travel history. To our knowledge, alveolar echinococcosis has not been reported previously in a dog in the United States; E. multilocularis infection was apparently acquired in the mid-Atlantic region of the United States.

Isolated muscular cystic echinococcosis mimicking neoplasia

Musculoskeletal cystic echinococcosis can present as an isolated disease mimicking neoplasia. Along with albendazole therapy, complete excision avoiding cyst rupture is essential to prevent disease dissemination and hypersensitivity reactions. Conventional epidemiology and molecular typing can help differentiate between domestic and sylvatic strains of echinococcosis in the traveler and migrant population.

The fox tapeworm, Echinococcus multilocularis, in grey wolves and dogs in Slovakia: epidemiology and genetic analysis

Echinococcus multilocularis, the causative agent of human alveolar echinococcosis, is an important emerging parasite in the northern hemisphere. In epidemiological studies, the highest attention is being paid to foxes as the main reservoir hosts responsible for geographic expansion from multiple focal populations and the invasion of urban habitats, but little information is available on the parasite distribution in other carnivores. Hence, the study was designed to obtain updated information about the occurrence and genetic diversity of E. multilocularis in grey wolves and dogs in Slovakia. Faecal samples of wolves were collected from three locations under a certain level of environmental protection in the central and eastern parts of the country, and the presence of the parasite DNA was detected in 35.7% of 112 samples, with the highest rate (51.2%) recorded in the Poloniny National Park in north-eastern Slovakia. Among 110 faecal dog samples, E. multilocularis was detected in three faeces from segregated Roma settlements in the eastern part of the country, which accounted for an overall positivity of 2.7%. Sequence analysis of two mitochondrial genes, 12S rRNA and NADH dehydrogenase subunit 1, revealed four haplotypes in 13 isolates from wolves and dogs originating from four sites in eastern and central Slovakia, with all samples bearing a European-type pattern of E. multilocularis. The more than one-third positivity rate of E. multilocularis in wolf faecal samples dispersed over a large part of the country has corroborated the extensive circulation of the parasite in wildlife and confirmed the need to improve intervention control strategies.

Presence of eimerid oocysts in faeces of a quarantined dog in Iceland is explained by coprophagic behaviour prior to its importation. Case report

BACKGROUND

All dogs imported into Iceland must undergo mandatory quarantine in a special station before introduction into the country. A faecal sample is collected from the first stool passed by the dog in this station and subsequently examined for the presence of intestinal parasite stages.

CASE PRESENTATION

In May 2019 unsporulated oocysts were detected in faeces from a 7-year-old household dog that had been imported from Sweden. Most of the oocysts studied strongly resembled those of Eimeria canis Wenyon, 1923. As this species is not valid, the purpose of the present article was to identify the correct species and examine their possible origin. Studies confirmed the presence of two distinct unsporulated oocyst morphotypes in the faeces; measurements and photomicrographs confirmed their identification as Eimeria magna Pérard, 1925 and Eimeria stiedai (Lindemann, 1865) Kisskalt and Hartmann, 1907, both common parasites of European rabbits, Oryctolagus cuniculus (L., 1758). When the owner of the dog was questioned about the food administrated to the dog prior to its import to Iceland, it turned out that it had exclusively been fed dry dog food pellets. However, the owner also reported that on the morning prior to transportation to Iceland, the dog was allowed to move freely in a grassland area where rabbits are common and heaps of their faeces are present. Furthermore, the owner confirmed that the dog consumed rabbit faeces that morning.

CONCLUSION

It is believed that this coprophagic behaviour can explain the detection of rabbit eimerids in the dog's faeces, and that such behaviour must be taken into consideration by veterinarians and other diagnostic personnel when they detect atypical cysts or eggs during coprological examinations.

Echinococcus canadensis G8 Tapeworm Infection in a Sheep, China, 2018

We report a sheep infected with Echinococcus canadensis G8 tapeworm in China in 2018. This pathogen was previously detected in moose, elk, muskox, and mule deer in Europe and North America; our findings suggest a wider host range and geographic distribution. Surveillance for the G8 tapeworm should be conducted in China.

Worldwide literature on epidemiology of human alveolar echinococcosis: a systematic review of research published in the twenty-first century

PURPOSE

Human alveolar echinococcosis (AE) is a potentially lethal zoonosis caused by the cestode Echinococcus multilocularis. The aim of this systematic review is to establish a comprehensive global AE literature overview taking into account the epidemiologically relevant AE research of the twenty-first century.

METHODS

We systematically searched the global literature published from 2001 through 2018 via MEDLINE, EMBASE, the Russian databases eLIBRARY.RU, CyberLeninka, the Chinese databases CNKI, VIP, Journals.

RESEARCH

ac.ir (Farsi language-based), Jordan E-Library (Arab language-based) and supplementary Google Scholar, in accordance with the PRISMA guidelines. QGIS software was used for the mapping of the affected countries.

RESULTS

We have listed 154 relevant publications in the final literature synopsis in consideration of our quality assessment. Including non-autochthonous cases, human AE was reported in 36 countries within the northern hemisphere from 2001 to 2018. The first publication of AE in Tajikistan, Pakistan, South Korea, Belgium, the Netherlands, Slovakia, Hungary, Lithuania, Latvia, Slovenia and Morocco occurred in this century; further first cases in Taiwan, Thailand, and Denmark were considered to be non-autochthonous by the authors. The highest total case numbers (n ≥ 100 in a single article) were reported in France, Germany, Switzerland, Poland, and Lithuania, including China and Kyrgyzstan with by far the highest prevalence figures.

CONCLUSIONS

Our paper emphasises the increasing spread of reported cases and the rise in its numbers in the literature of the twenty-first century, especially in western, northern and eastern Europe, as well as in central Asia. Epidemiological studies on human infections are lacking in many parts of the world.

A One Health systematic review of diagnostic tools for Echinococcus multilocularis surveillance: Towards equity in global detection

Echinococcus multilocularis is a zoonotic cestode of canid definitive hosts that is emerging as a parasite of medical and veterinary concern in regions of North America, Europe and Asia. Infection with the metacestode stage (alveolar echinococcosis - AE) is life-threatening, especially for patients who reside in low resource countries and lack access to modern diagnostic tests and treatments. The overall objectives of this One Health review were to systematically describe the diagnostic tests currently employed in endemic countries to detect E. multilocularis in people, canids and the environment, and to report the test characteristics of new diagnostic techniques for population surveillance. In this systematic review of English and Chinese language databases, we identified 92 primary records of E. multilocularis surveillance in canids (N = 75), humans (N = 20) and/or the environment (food, soil; N = 3) and 12 grey literature records that reported E. multilocularis surveillance or health systems protocols between 2008 and 2018. Surveillance for E. multilocularis was conducted using a broad range of combined morphological, molecular, immunological and imaging techniques. Nine studies reporting diagnostic evaluations for cestode or metacestode detection were identified, including studies on copro-antigen ELISA, copro-PCR, intestinal examination, Western Blot, magnetic capture RT-PCR and immunochromatography. Our dataset includes prevalence estimates for E. multilocularis in canids, people, or environment in 27 of the 43 endemic countries and reports data gaps in surveillance, laboratory methods, and diagnostic sensitivity. International consensus on gold standard diagnostic techniques and harmonization of human, canid and environmental surveillance data across political boundaries are needed to comprehensively assess the global burden and distribution of this parasite.

Echinococcus in wild canids in Québec (Canada) and Maine (USA)

Zoonotic Echinococcus spp. cestodes (E. canadensis and E. multilocularis) infect domestic animals, wildlife, and people in regions of Canada and the USA. We recovered and quantified Echinococcus spp. cestodes from 22 of 307 intestinal tracts of wild canids (23 wolves, 100 coyotes, 184 red and arctic foxes) in the state of Maine and the province of Québec. We identified the species and genotypes of three Echinococcus spp. cestodes per infected animal by sequencing mitochondrial DNA at two loci. We further confirmed the absence of E. multilocularis by extracting DNA from pools of all cestodes from each animal and running a duplex PCR capable of distinguishing the two species. We detected E. canadensis (G8 and G10), but not E. multilocularis, which is emerging as an important human and animal health concern in adjacent regions. Prevalence and median intensity of E. canadensis was higher in wolves (35%, 460) than coyotes (14%, 358). This parasite has historically been absent in Atlantic regions of North America, where suitable intermediate hosts, but not wolves, are present. Our study suggests that coyotes are serving as sylvatic definitive hosts for E. canadensis in Atlantic regions, and this may facilitate eastward range expansion of E. canadensis in the USA and Canada. As well, compared to wolves, coyotes are more likely to contaminate urban green spaces and peri-urban environments with zoonotic parasites.

Echinococcosis is a zoonosis caused by ingestion of tapeworm eggs in feces of wild or domestic canids (e.g. foxes, wolves, coyotes, and dogs). In North America, the number of new human echinococcosis cases reported annually is low; however, recent reports of these parasites in unusual presentations, in new locations, and in wildlife near urban areas have caused renewed interest by veterinary and human health professionals. In a cross-border collaboration, we examined the intestines of wolves (Canis lupus), coyotes (C. latrans) and foxes (Vulpes vulpes, V. lagopus) trapped in Québec (Canada) and neighboring Maine (USA), using genetic tools to identify Echinococcus tapeworms. We did not detect E. multilocularis, a serious threat to human health that has recently emerged in southern Ontario. We did identify E. canadensis in wolves and coyotes, in both Quebec and Maine. The presence of this parasite in coyotes is especially concerning because coyotes are more likely to come into close proximity with human communities. This information is relevant to veterinarians who should promote regular fecal examination and/or deworming of high risk dogs (dogs that scavenge or hunt cervids, such as moose), to physicians who might encounter this relatively rare disease, and to public health agencies who should promote surveillance and develop precautions for high risk people.

A Comparative Study on the Faecal Bacterial Community and Potential Zoonotic Bacteria of Muskoxen (Ovibos moschatus) in Northeast Greenland, Northwest Greenland and Norway

Muskoxen (Ovibos moschatus) are ruminants adapted to a high-fibre diet. There is increasing interest in the role that gut microbes play in the digestion and utilization of these specialized diets but only limited data available on the gut microbiome of high-Arctic animals. In this study, we metabarcoded the 16S rRNA region of faecal samples from muskoxen of Northeast Greenland, Northwest Greenland and Norway, and quantified the effects of physiological and temporal factors on bacterial composition. We found significant effects of body mass, year of sampling and location on the gut bacterial communities of North East Greenland muskoxen. These effects were however dwarfed by the effects of location, emphasizing the importance of the local ecology on the gut bacterial community. Habitat alterations and rising temperatures may therefore have a considerable impact on muskoxen health and reproductive success. Moreover, muskoxen are hunted and consumed in Greenland, Canada and Alaska; therefore, this study also screened for potential zoonoses of food safety interest. A total of 13 potentially zoonotic genera were identified, including the genera Erysipelothrix and Yersinia implicated in recent mass die-offs of the muskoxen themselves.

Detecting co-infections of Echinococcus multilocularis and Echinococcus canadensis in coyotes and red foxes in Alberta, Canada using real-time PCR

The continued monitoring of Echinococcus species in intermediate and definitive hosts is essential to understand the eco-epidemiology of these parasites, as well to assess their potential impact on public health. In Canada, co-infections of Echinococcus canadensis and Echinococcus multilocularis based on genetic characterization have been recently reported in wolves, but not yet in other possible hosts such as coyotes and foxes. In this study, we aimed to develop a quantitative real-time PCR assay to detect E. multilocularis and E. canadensis and estimate the occurrence of co-infections while inferring about the relative abundance of the two parasites within hosts. We tested DNA extracted from aliquots of Echinococcus spp. specimens collected from intestinal tracts of 24 coyote and 16 fox carcasses from Alberta, Canada. We found evidence of co-infections of E. multilocularis and E. canadensis in 11 out of 40 (27%) samples, with 8 out of 24 (33%) in coyote samples and 3 out of 16 (19%) in red fox samples. DNA concentrations were estimated in three samples with Cq values within the range of the standard curve for both parasites; two of them presented higher DNA concentrations of E. multilocularis than E. canadensis. The use of qPCR aided detection of co-infections when morphological discrimination was difficult and quantification of DNA for samples within the standard curve. This is the first molecularly confirmed record of E. canadensis in coyotes and the first evidence of co-infections of E. multilocularis and E. canadensis in coyotes and red foxes.

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

Ecology and Life Cycle Patterns of Echinococcus Species

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.