Borrelia miyamotoi in host-seeking Ixodes ricinus ticks in England.

This paper reports the first detection of Borrelia miyamotoi in UK Ixodes ricinus ticks. It also reports on the presence and infection rates of I. ricinus for a number of other tick-borne pathogens of public health importance. Ticks from seven regions in southern England were screened for B. miyamotoi, Borrelia burgdorferi sensu lato (s.l.), Anaplasma phagocytophilum and Neoehrlichia mikurensis using qPCR. A total of 954 I. ricinus ticks were tested, 40 were positive for B. burgdorferi s.l., 22 positive for A. phagocytophilum and three positive for B. miyamotoi, with no N. mikurensis detected. The three positive B. miyamotoi ticks came from three geographically distinct areas, suggesting a widespread distribution, and from two separate years, suggesting some degree of endemicity. Understanding the prevalence of Borrelia and other tick-borne pathogens in ticks is crucial for locating high-risk areas of disease transmission.

First detection of spotted fever group rickettsiae in Ixodes ricinus and Dermacentor reticulatus ticks in the UK.

A preliminary study was conducted to determine the presence of spotted fever rickettsiae in two species of British tick (Ixodes ricinus and Dermacentor reticulatus). The 16S rRNA gene of Rickettsia spp. was detected in 39/401 (9·7%) of ticks tested, including 22/338 (6·5%) I. ricinus and 17/63 (27%) D. reticulatus. Some positive I. ricinus samples showed 100% homology with Rickettsia helvetica (10/22), and most positive D. reticulatus showed 100% homology with R. raoultii (13/17). Five other Rickettsia spp. were detected exhibiting 96-99% homology. Ticks positive for rickettsiae were collected from various hosts and from vegetation from eight counties across Great Britain. The distribution of R. helvetica in various engorged and unfed stages of I. ricinus suggests that R. helvetica is widespread. R. raoultii was found in questing adult D. reticulatus in Wales and England. This is the first evidence of potentially pathogenic spotted fever rickettsiae in British ticks.

A single dose of doxycycline after an ixodes ricinus tick bite to prevent Lyme borreliosis: An open-label randomized controlled trial.

OBJECTIVES: A single dose of doxycycline after a tick bite can prevent the development of Lyme borreliosis in North America, but extrapolation to Europe is hampered by differences in Borrelia burgdorferi sensu lato genospecies and tick species. We assessed the efficacy of prophylaxis after a tick bite in Europe. METHODS: We conducted an open-label randomized controlled trial, administering a single dose of 200 mg doxycycline within 72 h after removing an attached tick from the skin, compared to no treatment. Potential participants ≥ 8 years of age who reported a recent tick bite online were invited for the study. After informed consent, they were randomly assigned to either the prophylaxis or the no-treatment group. Participants in the prophylaxis group were asked to visit their general practitioner to administer the antibiotics. All participants were followed up by online questionnaires. Our primary outcome was the development of physician-confirmed Lyme borreliosis in a modified-intention-to-treat analysis. This study is registered in the Netherlands Trial Register (NTR3953) and is closed. RESULTS: Between April 11, 2013, and June 10, 2015, 3538 potential participants were randomized, of whom 1689 were included in the modified-intention-to-treat analysis. 10 cases of Lyme borreliosis were reported out of 1041 participants (0.96%) in the prophylaxis group, and 19 cases out of 648 no-treatment participants (2.9%), resulting in a relative risk reduction of 67% (95% CI 31 - 84%), and a number-needed-to-treat of 51 (95% CI 29 - 180). No serious adverse events were reported. CONCLUSIONS: This primary care-based trial provides evidence that a single dose of doxycycline can prevent the development of Lyme borreliosis after an Ixodes ricinus tick bite.

Ticks and tick-borne diseases in the city: Role of landscape connectivity and green space characteristics in a metropolitan area.

Green spaces in the city are important for human wellbeing, but are also zones in which humans can become infected with zoonotic diseases. Therefore, there is a need to understand how infection risk is related to green space characteristics, wildlife communities and connectivity with rural areas hosting reservoir populations of hosts. Our hypothesis is that wildlife hosts in urban green spaces, and thereby the prevalence of questing ticks and their Lyme disease causing pathogens (Borrelia burgdorferi s.l.), can be partly predicted based on green space characteristics as well as measures of connectivity to known source areas. We sampled ticks in twenty-two green spaces during Spring (2014 and 2016) and Autumn 2016, located along an urbanization gradient in Antwerp (Belgium). More than 18,000 m2 was sampled, with tick densities ranging from 0 to 386 individuals/100 m2. We estimated connectivity using the least-cost algorithm as either the cost distance to the nearest green space, or to a known population of roe deer (Capreolus capreolus), known to be an important tick propagation host. Both connectivity measures turned out to be correlated, reflecting a gradient in green space isolation from the periphery to the urban center. In 87% of plots where ticks were trapped, at least one Borrelia-infected tick was found. The overall Borrelia-prevalence in nymphs was 17.8%, in adults 32.6%. Density of infected ticks decreased with urbanization and increased with connectivity. Nymphs in larger green spaces were more likely to be infected. While density and infection prevalence for adults increased with the amount of neighboring agricultural land, the larval density and nymphal infection prevalence decreased. Interestingly, the proportion of Borrelia genospecies associated with birds or mammals was comparable in rural and (sub)urban areas (bird/mammal: 0.38), suggesting that even in small green spaces Borrelia infections can persist in local host populations.

A comparative test of ixodid tick identification by a network of European researchers.

This study reports the results of a comparative test of identification of ticks occurring in Western Europe and Northern Africa. A total of 14 laboratories were voluntarily enrolled in the test. Each participant received between 22 and 25 specimens of adult and nymphal ticks of 11 species: Dermacentor marginatus, D. reticulatus, Haemaphysalis punctata, Hyalomma lusitanicum, Hy. marginatum, Ixodes ricinus, I. hexagonus, Rhipicephalus annulatus, R. bursa, R. rossicus, and/or R. sanguineus s.l. Ticks were morphologically identified by three of the co-authors and the identification confirmed by a fourth co-author who used molecular methods based on several genes. Then ticks were randomly selected and blindly distributed among participants, together with a questionnaire. Only specimens collected while questing and, if possible, in the same survey, were circulated. Because of the random nature of the test, a participant could receive several specimens of the same species. Species in the different genera had variable misidentification rates (MR) of 7% (Dermacentor), 14% (Ixodes), 19% (Haemaphysalis), 36% (Hyalomma), and 54% (Rhipicephalus). Within genera, the MR was also variable ranging from 5.4% for I. ricinus or 7.4% for D. marginatus or D. reticulatus to 100% for R. rossicus. The test provided a total misidentification rate of 29.6% of the species of ticks. There are no significant differences in MR according to the sex of the tick. Participants were requested to perform a second round of identifications on the same set of ticks, using only purposely prepared keys (without illustrations), circulated to the enrolled participants, including 2 species of the genus Dermacentor, 8 of Haemaphysalis, 10 of Hyalomma, 23 of Ixodes, and 6 of Rhipicephalus. The average MR in the second round was 28%: 0% (Dermacentor), 33% (Haemaphysalis), 30% (Hyalomma) 18% (Ixodes), and 50% (Rhipicephalus). Species which are not reported in the countries of a participating laboratory had always highest MR, i.e. purely Mediterranean species had highest MR by laboratories in Central and Northern Europe. Participants expressed their concerns about a correct identification for almost 50% of the ticks of the genera Hyalomma and Rhipicephalus. The results revealed less than total confidence in identifying the most prominent species of ticks in the Western Palearctic, and underpin the need for reference libraries for specialists involved in this task. Results also showed that a combination of certain genes may adequately identify the target species of ticks.

Phylogenetic analysis of encapsulated and non-encapsulated Trichinella species by studying the 5S rDNA tandemly repeated intergenic region.

The identification of sequence regions in the genomes of pathogens which can be useful to distinguish among species and genotypes, is of great importance for epidemiological, molecular, and phylogenetic studies. The 5S ribosomal DNA intergenic spacer region has been identified as a good target to distinguish among eight Trichinella species and genotypes. The recent discovery of two non-encapsulated species in this genus, Trichinella papuae and Trichinella zimbabwensis, which can infect both mammals and reptiles, has suggested analyzing their 5S rDNA. Amplification of the tandem repeats of the 5S rDNA intergenic region of encapsulated species of Trichinella shows a 751bp fragment, whereas the three non-encapsulated species show a fragment of 800bp with T. pseudospiralis showing an additional fragment of 522bp. Although the size of the 800bp PCR fragments of T. papuae and T. zimbabwensis are similar to that of T. pseudospiralis, there are differences in the 5S rDNA intergenic regions among the three non-encapsulated species. Phylogenetic analysis of the 5S rDNA intergenic regions shows a clustering together of the three non-encapsulated Trichinella species that is well separated from the encapsulated ones. In addition, a single PCR-based method allows distinguishing non-encapsulated and encapsulated species.

The Presence of Borrelia miyamotoi, A Relapsing Fever Spirochaete, in Questing Ixodes ricinus in Belgium and in The Netherlands.

Borrelia miyamotoi is a tick-borne bacterium that may cause relapsing fever in humans. As this pathogen has been discovered in Europe only recently, only little is known about its local impact on human health and its spatial distribution. In this study, we show the results of PCR screenings for B. miyamotoi in flagged Ixodes ricinus from Belgium and the Netherlands. B. miyamotoi was detected in nine of thirteen, and three of five locations from the Netherlands and Belgium, respectively. These outcomes indicate that B. miyamotoi is more spread than previously thought. The mean infection rate B. miyamotoi was 1.14% for Belgium and 3.84% for the Netherlands.

Prevalence of Coxiella burnetii in ticks after a large outbreak of Q fever.

Q fever has emerged as an important human and veterinary public health problem in the Netherlands with major outbreaks in three consecutive years. Goat farms are probably the prime source from which Coxiella burnetii have spread throughout the environment, infecting people living in the vicinity. Coxiella burnetii infection not only spilled over from animal husbandry to humans but could also have spread to neighbouring wildlife and pets forming novel reservoirs and consequently posing another and lingering threat to humans, companion animals and livestock. In these cases, transmission routes other than airborne spread of contaminated aerosols may become significant. Therefore, the role of ticks in the transmission of Coxiella burnetii in the current situation was investigated. A total of 1891 questing Ixodes ricinus ticks and 1086 ticks feeding on pets, wildlife and livestock were tested by a recently developed multiplex Q-PCR. All ticks were negative, except for a few ticks feeding on a herd of recently vaccinated sheep. Coxiella-positive ticks were not detected after resampling this particular herd three months later. Based on these data we conclude that the current risk of acquiring Q fever from questing ticks in the Netherlands is negligible. However, for future risk assessments, it might be relevant to sample more ticks in the vicinity of previously C. burnetii infected goat farms and to assess whether C. burnetii can be transmitted transovarially and transstadially in I. ricinus ticks.

Usefulness of sero-surveillance for Trichinella infections in animal populations.

In this paper we evaluate serology as a tool to monitor Trichinella-free pig herds. Indoor, industrial-raised fattening pigs in the Netherlands are practically Trichinella-free, and were used as a negative reference cohort. A positive cohort was not available but we used sera from an endemic region in Argentina to model a plausible distribution of serological responses (as OD levels) in positive sera, employing the difference between the endemic sera and the negative Dutch sera. We describe a method for correcting for variation among ELISA plates using on-plate reference sera, and demonstrate how to apply these corrections to a collection of test sera from pig farms. The positive and negative reference distributions can be used to estimate fractions true and false positives, necessary for defining appropriate cutoffs to be used for classifying positive and negative animals. Based on this analysis, the serological test was shown to lack the predictive power required for its large scale deployment. The properties of the serological test were also compared to the conventional digestion assay, which is highly specific but considerably less sensitive.

Persistent airway hyper-responsiveness and inflammation in Toxocara canis-infected BALB/c mice.

BACKGROUND: Infection with Toxocara canis, the roundworm of dogs, has been associated with asthmatic manifestations. Clinical symptoms such as wheezing, coughing and episodic airflow obstruction have been described for patients infected with this helminth. OBJECTIVE: In order to characterize the effect of T. canis infection on the lungs, we monitored immune responses, pulmonary pathology and lung function over a period of 60 days in BALB/c mice. METHODS: Infection was performed by a single oral administration of 1000 T. canis embryonated eggs. Airway responsiveness was measured in conscious, unrestrained mice at 7, 14, 30 and 60 days post-infection (p.i.). RESULTS: Infection of mice resulted in airway hyper-responsiveness (AHR) that persisted up to 30 days p.i. Pulmonary inflammation as well as increased levels of IgE and eosinophils in bronchoalveolar lavage (BAL) persisted up to 60 days p.i. Cytokine analysis in BAL indicated increased levels of IL-5 at day 7 and 14 p.i., whereas the levels of IL-2, IFN-gamma, IL-4 and IL-10 did not differ from those of uninfected controls. Toxocara-specific stimulation of spleen cells using recombinant TES-70 protein resulted in the induction of IL-5 at day 7 and 14 p.i. and IL-10 at day 14 p.i. Production of all other cytokines did not differ from that of uninfected controls. Evaluation of larval burden revealed that T. canis was still present in the lungs of infected mice at 60 days p.i. CONCLUSION: The presence of Toxocara larva in the lungs at 60 days p.i. following a single infection could explain the persistent pulmonary inflammation, airway hyper-reactivity, eosinophilia and increased IgE production observed in T. canis-infected BALB/c mice.

A comparative study of toxocariasis and allergic asthma in murine models.

Histopathology of the lung and total IgE in serum were compared in toxocariasis and allergic asthma murine models using BALB/c and C57BL/6 mice. Infection with Toxocara canis resulted in both strains of mice in marked histological changes and increased levels of total serum IgE. The ovalbumin (OVA) sensitization/challenge treatment for the induction of allergic asthma resulted in similar histological changes in BALB/c and, to a less extent, in C57BL/6 mice. Serum IgE levels of OVA-treated C57BL/6 mice were low. Histological changes observed included perivascular infiltration with eosinophils and mononuclear cells, peribronchiolitis, alveolitis and mucus production. Although these changes in addition to increased IgE production did occur in T. canis-infected C57BL/6 mice they were more pronounced in BALB/c mice. Thus, BALB/c mice appear to be the most appropriate strain of mice to perform studies on the possible connection between infection with T. canis and allergic asthma.