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Ticks are becoming increasingly recognised as important vectors of pathogens in urban and peri-urban areas, including green space used for recreational activities. In the UK, the risk posed by ticks in such areas is largely unknown. In order to begin to assess the risk of ticks in urban/peri-urban areas in southern England, questing ticks were collected from five different habitat types (grassland, hedge, park, woodland and woodland edge) in a city during the spring, summer and autumn of 2013/2014 and screened for Borrelia burgdorferi sensu lato. In addition, seasonal differences in B. burgdorferi s.l. prevalence were also investigated at a single site during 2015. Ixodes ricinus presence and activity were significantly higher in woodland edge habitat and during spring surveys. DNA of Borrelia burgdorferi s.l. was detected in 18.1% of nymphs collected across the 25 sites during 2013 and 2014 and two nymphs also tested positive for the newly emerging tick-borne pathogen B. miyamotoi . Borrelia burgdorferi s.l. prevalence at a single site surveyed in 2015 were found to be significantly higher during spring and summer than in autumn, with B. garinii and B. valaisiana most commonly detected. These data indicate that a range of habitats within an urban area in southern England support ticks and that urban Borrelia transmission cycles may exist in some of the urban green spaces included in this study. Sites surveyed were frequently used by humans for recreational activities, providing opportunity for exposure to Borrelia infected ticks in an urban/peri-urban space that might not be typically associated with tick-borne disease transmission. [ABSTRACT FROM AUTHOR]

Human granulocytic anaplasmosis and tick-borne fever, affecting livestock, are diseases caused by an infection with the bacterium Anaplasma phagocytophilum. Its transmission dynamics between vertebrate hosts and ticks remain largely unknown and the potential impact on public health in the United Kingdom is unclear. This study aimed to assess the distribution and estimate the prevalence of A. phagocytophilum in questing Ixodes ricinus at recreational locations across England and Wales over six years. An additional objective was to investigate possible associations between prevalence, habitat and presence of ruminant hosts. Ixodes ricinus ticks were collected each spring at 20 recreational locations across England and Wales between 2014 and 2019. Nymphs were tested for infection with A. phagocytophilum by detection of bacterial genome in DNA extracts, targeting the msp2 gene locus. Positive samples were further investigated for the presence of different ecotypes based on the G roEL region. Of 3,919 nymphs tested, the mean infection prevalence was 3.6% [95%CI: 3.1-4.3] and ranged from 0 to 20.4%. Northern England had a higher overall prevalence (4.7% [95%CI: 3.4-6.4]) compared to Southern England (1.8% [95%CI: 1.3-2.5]) and the presence of sheep was associated with higher A. phagocytophilum prevalence (8.4% [95%CI: 6.9-10.1] vs 1.2% [95%CI: 0.8-1.7] when absent). There was also a negative correlation with the prevalence of Borrelia burgdorferi s.l. (causing Lyme borreliosis). When investigating the diversity of A. phagocytophilum , ecotype I accounted for 86.8% of samples and ecotype II for 13.2%. Our study presents an overview of A. phagocytophilum prevalence in questing I. ricinus in recreational areas across England and Wales and discusses the potential public and veterinary health relevance. [ABSTRACT FROM AUTHOR]

Highlights: [•] We evaluate the 5S–23S (rrf–rrl) intergenic spacer region (IGS) for its use in population genetics studies. [•] IGS is under neutral selection. [•] IGS can resolve subpopulations within Borrelia afzelii and Borrelia garinii. [•] IGS can detect genospecies-specific population dynamics of Borrelia burgdorferi s.l. [ABSTRACT FROM AUTHOR]

Abstract: Prevalences of parasitic infections in pigs from different housing systems may vary, due to their contact with the environment, and this might have consequences for food safety. In this study, 40 organic, 9 free-range and 24 intensive farms were selected and a total of 845 serum samples were tested for antibodies specific for Toxoplasma and Trichinella using ELISA assays. The overall seroprevalence of Toxoplasma in the total number of 845 serum samples tested is 2.6%, ranging from 0.38% in intensively raised pigs to 5.62% in free-range pigs. Of the housing systems tested, 4% (intensive farms) to 33% (free-range farms) is infected with Toxoplasma gondii. The risk of detecting Toxoplasma antibodies in a free-range farm are statistically higher (almost 16 times higher) than in an intensive farm. We observed that the risk of detecting specific antibodies is twice as high as in free-range compared with organic farms. Seropositivity of Trichinella spiralis antibodies was 0.12–0.35% (depending on the cut-off value at the 99.5% or 97.5% level). There was a tendency that Trichinella seropositivity was higher in organic pig farming (0.24%), but this was not significant. This serological study in pigs from different farming systems shows that the seroprevalence of antibodies specific for T. gondii is higher and for Trichinella equivalent in pigs raised in systems where there is contact with the environment than in pigs raised in intensive, indoor farming systems. This indicates that the prevalence of parasitic infections is higher in outdoor farming systems than in indoor farming systems. The possible consequences for food safety are discussed. [Copyright &y& Elsevier]

[Display omitted] • Low haplotype diversity in Eurasian Dermacentor reticulatus populations forms a bipolar pattern along an east–west cline. • Microsatellite analysis differentiates the dataset into three clusters. • The northern cluster arose only ca. 200–800 years ago. • The spread of clusters reflects the current range expansion, leading to increased admixture. The ornate dog tick (Dermacentor reticulatus) shows a recently expanding geographic distribution. Knowledge on its intraspecific variability, population structure, rate of genetic diversity and divergence, including its evolution and geographic distribution, is crucial to understand its dispersal capacity. All such information would help to evaluate the potential risk of future spread of associated pathogens of medical and veterinary concern. A set of 865 D. reticulatus ticks was collected from 65 localities across 21 countries, from Portugal in the west to Kazakhstan and southern Russia in the east. Cluster analyses of 16 microsatellite loci were combined with nuclear (ITS2, 18S) and mitochondrial (12S, 16S, COI) sequence data to uncover the ticks' population structures and geographical patterns. Approximate Bayesian computation was applied to model evolutionary relationships among the found clusters. Low variability and a weak phylogenetic signal showing an east–west cline were detected both for mitochondrial and nuclear sequence markers. Microsatellite analyses revealed three genetic clusters, where the eastern and western cluster gradient was supplemented by a third, northern cluster. Alternative scenarios could explain such a tripartite population structure by independent formation of clusters in separate refugia, limited gene flow connected with isolation by distance causing a "bipolar pattern", and the northern cluster deriving from admixture between the eastern and western populations. The best supported demographic scenario of this tick species indicates that the northern cluster derived from admixture between the eastern and western populations 441 (median) to 224 (mode) generations ago, suggesting a possible link with the end of the Little Ice Age in Europe. [ABSTRACT FROM AUTHOR]

In this study we used typing based on the eight multilocus sequence typing scheme housekeeping genes (MLST) and 5S-23S rDNA intergenic spacer (IGS) to explore the population structure of Borrelia burgdorferi sensu lato isolates from patients with Lyme borreliosis (LB) and to test the association between the B. burgdorferi s.l. sequence types (ST) and the clinical manifestations they cause in humans. Isolates of B. burgdorferi from 183 LB cases across Europe, with distinct clinical manifestations, and 257 Ixodes ricinus lysates from The Netherlands, were analyzed for this study alone. For completeness, we incorporated in our analysis also 335 European B. burgdorferi s.l. MLST profiles retrieved from literature. Borrelia afzelii and Borrelia bavariensis were associated with human cases of LB while Borrelia garinii , Borrelia lusitaniae and Borrelia valaisiana were associated with questing I. ricinus ticks. B. afzelii was associated with acrodermatitis chronica atrophicans , while B. garinii and B. bavariensis were associated with neuroborreliosis. The samples in our study belonged to 251 different STs, of which 94 are newly described, adding to the overall picture of the genetic diversity of Borrelia genospecies. The fraction of STs that were isolated from human samples was significantly higher for the genospecies that are known to be maintained in enzootic cycles by mammals ( B. afzelii , B. bavariensis , and Borrelia spielmanii ) than for genospecies that are maintained by birds ( B. garinii and B. valaisiana ) or lizards ( B. lusitaniae ). We found six multilocus sequence types that were significantly associated to clinical manifestations in humans and five IGS haplotypes that were associated with the human LB cases. While IGS could perform just as well as the housekeeping genes in the MLST scheme for predicting the infectivity of B. burgdorferi s.l., the advantage of MLST is that it can also capture the differential invasiveness of the various STs. [ABSTRACT FROM AUTHOR]

Abstract: Trichinella spiralis is transmitted and maintained in both a domestic and sylvatic cycle, whereby rats contribute to the spread of T. spiralis from domestic to sylvatic animals and vice versa. As a model for T. spiralis transmission in wildlife, we studied the potential of rats to act as a reservoir species for T. spiralis, by assessing experimentally its within-host infection dynamics, and simulating the between-host dynamics by a Monte Carlo approach. The distribution of parasite burden in individual rats is mathematically defined by roots of the dose response equation intersecting with the diagonal. In simulated between-host dynamics, up to 104 events of uninterrupted parasite transmission were observed. Histograms of parasite burdens per individual rat matched closely with the mixture of two gamma distributions, which were derived from the within-host infection dynamics. In conclusion, T. spiralis transmission persists in a population of rats when they cannibalize their own species. Rats should be included in the minimal set of wildlife species that maintain the life cycle of T. spiralis. [Copyright &y& Elsevier]

Abstract: Trichinella is a food-borne parasitic zoonoses and human cases are still reported in Europe mainly due to the consumption of pig meat originating from small backyard farms. Infections originating from industrialized pig farming have not been reported for decades in Europe, due to control measures to prevent the transmission of Trichinella from wildlife by indoor housing and good management practices. Therefore, risk-based monitoring programs might replace individual carcass control in industrialized pig farming as described in EU legislation SANCO 2075/2005. Transmission of Trichinella species between wildlife and the risk that may pose to humans via consumption of contaminated pork meat has not been studied quantitatively. One pathway by which human trichinellosis can occur is the rat–pig–human route. To evaluate the transmission risk though this pathway the dose responses of rat, pig, and human were studied. Experimental T. spiralis infection was performed in rats with doses of as few as 10 parasites and the data set was analysed using a newly developed dose response model that describes larvae per gram (LPG). Experimental T. spiralis infection in pig was analysed in a similar way. Furthermore nine published outbreaks of human trichinellosis were analysed to determine the dose response in humans. The risk of human trichinellosis via the rat–pig–human transmission was simulated by the Monte Carlo method. A pair of female and male parasites representing the lowest infection pressure from the environment, led to the probability of human trichinellosis by consumption of 100g of raw pork meat equal to 5% via the studied rat–pig–human pathway. In the absence of rodent control near the farm, a low infection pressure from wildlife presents a relatively high risk of human trichinellosis via consumption of uncooked pork meat. [Copyright &y& Elsevier]

Both early localized and late disseminated forms of Lyme borreliosis are caused by Borrelia burgdorferi senso lato. Differentiating between the spirochetes that only cause localized skin infection from those that cause disseminated infection, and tracing the group of medically-important spirochetes to a specific vertebrate host species, are two critical issues in disease risk assessment and management. Borrelia burgdorferi senso lato isolates from Lyme borreliosis cases with distinct clinical manifestations (erythema migrans, neuroborreliosis, acrodermatitis chronica atrophicans, and Lyme arthritis) and isolates from Ixodes ricinus ticks feeding on rodents, birds and hedgehogs were typed to the genospecies level by sequencing part of the intergenic spacer region. In-depth molecular typing was performed by sequencing eight additional loci with different characteristics (plasmid-bound, regulatory, and housekeeping genes). The most abundant genospecies and genotypes in the clinical isolates were identified by using odds ratio as a measure of dominance. Borrelia afzelii was the most common genospecies in acrodermatitis patients and engorged ticks from rodents. Borrelia burgdorferi senso stricto was widespread in erythema migrans patients. Borrelia bavariensis was widespread in neuroborreliosis patients and in ticks from hedgehogs, but rare in erythema migrans patients. Borrelia garinii was the dominant genospecies in ticks feeding on birds. Spirochetes in ticks feeding on hedgehogs were overrepresented in genotypes of the plasmid gene ospC from spirochetes in erythema migrans patients. Spirochetes in ticks feeding on hedgehogs were overrepresented in genotypes of ospA from spirochetes in acrodermatitis patients. Spirochetes from ticks feeding on birds were overrepresented in genotypes of the plasmid and regulatory genes dbpA , rpoN and rpoS from spirochetes in neuroborreliosis patients. Overall, the analyses of our datasets support the existence of at least three transmission pathways from an enzootic cycle to a clinical manifestation of Lyme borreliosis. Based on the observations with these nine loci, it seems to be justified to consider the population structure of B . burgdorferi senso lato as being predominantly clonal. [ABSTRACT FROM AUTHOR]