Molecular Evidence for Local Acquisition of Human Alveolar Echinococcosis in Saskatchewan, Canada

Urban Magpies Frequently Feed on Coyote Scats and May Spread an Emerging Zoonotic Tapeworm

Allocoprophagy, in which animals feed on the feces of other individuals or species, has been little studied in vertebrates, despite its relevance to parasite transmission. These relationships may be especially important in cities, where animal density, disease incidence, and spatial overlap of humans and wildlife increase. Our goal was to document the incidence and predictors of coprophagy by black-billed magpies (Pica hudsonia) at coyote (Canis latrans) scats in Edmonton, Canada. We detected scats by following coyote trails and recorded whether coprophagy had occurred. We used multiple logistic regression to determine the top contextual and environmental predictors of coprophagy. Of 668 coyote scats, 37.3% had apparently been fed on. Coprophagy was more likely in winter and when scats were not fresh and did not contain vegetation or garbage. Environmental predictors of coprophagy included proximity to other coyote scats and playgrounds, distance from water and maintained trails, abundant natural land cover, and proximity to encampments of people experiencing homelessness. Our results reveal that magpies frequently access coyote scat and often do so near human-use areas. In Edmonton, where > 50% of coyotes are infected with a zoonotic tapeworm, coprophagy likely causes magpies to transport parasites with implications for zoonotic disease risk.

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.

Canine Alveolar Echinococcosis: An Emerging and Costly Introduced Problem in North America

Alveolar echinococcosis (AE), caused by the metacestode of Echinococcus multilocularis, is emerging in both dogs and people in North America. Here, we review 27 cases of canine AE opportunistically reported since the index case was described in 2009 in Western Canada. We describe clinical presentation, diagnosis, treatment, outcome, and source of canine infection, based on genetics of the parasite isolated from some canine cases. Diagnosis of AE was by histopathology and/or PCR on DNA extracted from metacestodes. The median age of dogs at diagnosis was 4 years (range 1–12), which is low compared to neoplasia, the most common differential diagnosis. There was no sex predilection and different breeds were involved, but there were a disproportionate number of boxers and beagles relative to their representation in the general canine population. The most common potential risk factors included contact with wildlife and visits to off leash areas. Abdominal distension was the most common clinical sign at presentation, and medical imaging generally revealed an abdominal mass. On histopathology, protoscoleces were observed in 7 out of 14 dogs. In 7 cases, DNA sequences were most similar to European (versus North American) haplotypes, identical to those recently reported in coyotes as definitive hosts in North America, and different between eastern and western North America, implying multiple introduction events. Dogs that were not treated (n = 6) had 16% survival in the first 100 days in comparison with 82% survival of treated dogs (n = 11). Direct costs to the owner of treating canine AE ranged from 1,317 to 12,655 CAD depending on the situation at the onset of treatment. This study provides important clinical, epidemiological, and economic information for veterinary practitioners and regulators for importation of dogs, and for public health, as dogs with AE may serve as indicators of parasite range expansion and risk to humans.

A review on invasions by parasites with complex life cycles: the European strain of Echinococcus multilocularis in North America as a model

In a fast-changing and globalized world, parasites are moved across continents at an increasing pace. Co-invasion of parasites and their hosts is leading to the emergence of infectious diseases at a global scale, underlining the need for integration of biological invasions and disease ecology research. In this review, the ecological and evolutionary factors influencing the invasion process of parasites with complex life cycles were analysed, using the invasion of the European strain of Echinococcus multilocularis in North America as a model. The aim was to propose an ecological framework for investigating the invasion of parasites that are trophically transmitted through predator–prey interactions, showing how despite the complexity of the cycles and the interactions among multiple hosts, such parasites can overcome multiple barriers and become invasive. Identifying the key ecological processes affecting the success of parasite invasions is an important step for risk assessment and development of management strategies, particularly for parasites with the potential to infect people (i.e. zoonotic).

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Solving the Puzzle of Global Health Inequity: Completing the Picture Piece by Piece by Piece

Achieving health equity is an ongoing priority for the global community. Understanding, supporting, and addressing the challenges that face health workers is a critical component of the solution to this problem. The University of Global Health Equity (UGHE) in Rwanda has established the Institute of Global Health Equity Research (IGHER) to contribute to the generation of new knowledge through high-quality research and research training that seeks to improve our understanding of the important issues that influence the distribution of health and healthcare globally. With an unrelenting emphasis on increased impact by prioritizing implementation research, IGHER is particularly interested in amassing a compendium of important research lessons to increase the likelihood that effective implementation strategies will be employed to enhance healthcare service provision. IGHER organizes research according to five foundational research questions, which address different elements that are pivotal to a comprehensive approach to appreciating the nuanced realities of effective healthcare service provision. UGHE outputs for 2020 indicate that: appropriate resourcing of healthcare services is critical for the eradication of global health inequities; policy reform is required for many healthcare innovations and initiatives to be implemented adequately; and high-quality research that is applicable to different contexts is essential for eradicating global health inequities. Furthermore, reimagining healthcare delivery will benefit from an intentional, ongoing, bidirectional influence between evidence-based pedagogy (methods and practices of teaching, education, and instruction) and supporting research activity such that education and instruction inform the research conducted and research findings are fed back to the classroom to help improve education and instruction. As IGHER continues to grow, the valuable insights afforded by high-impact implementation research will increase. These insights will help to inform the development and use of evidence-based implementation strategies for the adoption, scaling, and sustainability of equitable, effective, and efficient health services globally.

Asian Admixture in European Echinococcus multilocularis Populations: New Data From Poland Comparing EmsB Microsatellite Analyses and Mitochondrial Sequencing

The cestode Echinococcus multilocularis is the causative agent of a severe zoonotic disease: alveolar echinococcosis (AE). The parasite is distributed over a vast area in northern Eurasia and North America, but the impact of AE on human health is highly uneven between different regions. One hypothetical reason for this difference in virulence may be the genetic structure of E. multilocularis which—based on mitochondrial sequences and EmsB microsatellite profiles—forms four distinct clades. These clades correspond approximately to their continents of origin: Asia, Europe, and North America, with a fourth clade apparently restricted to Mongolia and neighboring regions, even though this clade has not yet been described by EmsB genotyping. However, there are various records of genetic variants from the “wrong” region, e.g., “European” haplotypes in Western Canada, which may be the result of introduction or natural migration of host animals. One such example, prompting this study, is the recent record of an “Asian” mitochondrial haplotype in worms from foxes in Poland. At the time, this could not be confirmed by EmsB microsatellite analysis, a method that has proven to possess greater discriminatory power with the E. multilocularis nuclear genome than sequencing of mitochondrial markers. Therefore, worms collected from foxes in Poland were examined both by EmsB analysis and sequencing of the full mitochondrial cox1 gene in order to allocate the samples to the European or Asian cluster. Based on EmsB analyses of 349 worms from 97 Polish red foxes, 92% of the worms clearly showed “European-type” EmsB profiles, but 27 worms (8%) from seven foxes showed profiles that clustered with samples of Asian origin. According to cox1 sequences, a total of 18 worms from 8 foxes belonged to the Asian cluster of haplotypes. The two methods did not fully agree: only 13 worms from three foxes belonged to Asian clusters by both EmsB and cox1, whereas 18 worms from nine foxes belonged to different clusters, according to each marker. Cross-fertilization between worms of Asian origin and those from the European Polish population may explain these conflicting results. The presence of clearly Asian elements in the Polish E. multilocularis population could be the result of introduction of E. multilocularis with host animals (e.g., domestic dogs), or the migration of foxes. In the absence of genetic data from eastern European countries, especially those bordering Poland, it cannot be concluded whether this Asian admixture is typical for a larger area toward central/eastern Europe, or the Polish parasite population is the western extreme of a gradient where both European and Asian elements mingle. Further studies are needed on this subject, preferably using both mitochondrial sequencing and EmsB microsatellite analysis.