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Wild rodents are important hosts for tick larvae but co-infestations with other mites and insects are largely neglected. Small rodents were trapped at four study sites in Berlin, Germany, to quantify their ectoparasite diversity. Host-specific, spatial and temporal occurrence of ectoparasites was determined to assess their influence on direct and indirect zoonotic risk due to mice and voles in an urban agglomeration. Rodent-associated arthropods were diverse, including 63 species observed on six host species with an overall prevalence of 99%. The tick Ixodes ricinus was the most prevalent species, found on 56% of the rodents. The trapping location clearly affected the presence of different rodent species and, therefore, the occurrence of particular host-specific parasites. In Berlin, fewer temporary and periodic parasite species as well as non-parasitic species (fleas, chiggers and nidicolous Gamasina) were detected than reported from rural areas. In addition, abundance of parasites with low host-specificity (ticks, fleas and chiggers) apparently decreased with increasing landscape fragmentation associated with a gradient of urbanisation. In contrast, stationary ectoparasites, closely adapted to the rodent host, such as the fur mites Myobiidae and Listrophoridae, were most abundant at the two urban sites. A direct zoonotic risk of infection for people may only be posed by Nosopsyllus fasciatus fleas, which were prevalent even in the city centre. More importantly, peridomestic rodents clearly supported the life cycle of ticks in the city as hosts for their subadult stages. In addition to trapping location, season, host species, body condition and host sex, infestation with fleas, gamasid Laelapidae mites and prostigmatic Myobiidae mites were associated with significantly altered abundance of I. ricinus larvae on mice and voles. Whether this is caused by predation, grooming behaviour or interaction with the host immune system is unclear. The present study constitutes a basis to identify interactions and vector function of rodent-associated arthropods and their potential impact on zoonotic diseases.

Background: In three randomized, controlled laboratory efficacy studies, the efficacy in the prevention of patent infections of a topical combination of imidacloprid 10%/moxidectin 1% (Advocate ® spot-on formulation for cats, Bayer Animal Health GmbH) against larval stages and immature adults of Aelurostrongylus abstrusus, as well as the treatment efficacy of a single or three monthly treatments against adult A. abstrusus, were evaluated. Methods: Cats were experimentally inoculated with 300-800 third-stage larvae (L3). Each group comprised 8 animals and the treatment dose was 10 mg/kg bodyweight (bw) imidacloprid and 1 mg/kg bw moxidectin in each study. Prevention of the establishment of patent infections was evaluated by two treatments at a monthly interval at three different time points before and after challenge infection. Curative efficacy was tested by one or three treatments after the onset of patency. Worm counts at necropsy were used for efficacy calculations. Results: In Study 1, the control group had a geometric mean (GM) of 28.8 adult nematodes and the single treatment group had a GM of 3.4 (efficacy 88.3%). In Study 2, the control group had a GM of 14.3, the prevention group had a GM of 0 (efficacy 100%), while the treatment group had a GM of 0.1 (efficacy 99.4%). In Study 3, the GM worm burden in the control group was 32.6 compared to 0 in all three prevention groups (efficacy 100% for all of those groups). Conclusions: The monthly administration of Advocate ® reliably eliminated early larval stages and thereby prevented lung damage from and patent infections with A. abstrusus in cats. Regarding treatment, a single application of Advocate ® reduced the worm burden, but it did not sufficiently clear the infection. In contrast, three monthly treatments were safe and highly efficacious against A. abstrusus.

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Anthelmintic resistant parasitic nematodes present a significant threat to sustainable livestock production worldwide. The ability to detect the emergence of anthelmintic resistance at an early stage, and therefore determine which drugs remain most effective, is crucial for minimising production losses. Despite many years of research into the molecular basis of anthelmintic resistance, no molecular-based tools are commercially available for the diagnosis of resistance as it emerges in field settings. We described a mixed deep amplicon sequencing approach to determine the frequency of the levamisole (LEV) resistant single nucleotide polymorphism (SNP) within arc-8 exon 4 (S168T) in Haemonchus spp., coupled with benzimidazole (BZ) resistance SNPs within β-tubulin isotype-1 and ITS-2 nemabiome. This constitutes the first multi-drug and multi-species molecular diagnostic developed for helminths of veterinary importance. Of the ovine, bovine, caprine and camelid Australian field isolates we tested, S168T was detected in the majority of Haemonchus spp. populations from sheep and goats, but rarely at a frequency greater than 16%; an arbitrary threshold we set based on whole genome sequencing of LEV resistant H. contortus GWBII. Overall, BZ resistance was far more prevalent in Haemonchus spp. than LEV resistance, confirming that LEV is still an important anthelmintic class for small ruminants in New South Wales. The mixed amplicon metabarcoding approach described herein, paves the way towards the use of large scale sequencing as a surveillance technology in the field, the results of which can be translated into evidence-based recommendations for the livestock sector.

Zusammenfassung Gegenstand und Ziel: Ein wichtiger Bestandteil für eine gute Tiergesundheit in Pferdebetrieben ist das Entwurmungsmanagement. Ziel der Studie war, Unterschiede im Management zwischen Betrieben mit strategischer und selektiver Entwurmung darzustellen. Material und Methoden: Mithilfe eines Online-Fragebogens wurden von Pferdehaltern Informationen zu den Entwurmungsgewohnheiten sowie zu Haltung und Hygienemaßnahmen erhoben. Ergebnisse: Zur Auswertung standen 283 Fragebögen zur Verfügung. Insgesamt 155 Betriebe führten eine strategische, regelmäßige und 77 Betriebe eine selektive Entwurmung durch. Bei Betrieben mit selektiver Entwurmung handelte es sich eher um kleinere, privat organisierte Pferdehaltungen. In diesen Betrieben wurden Neuzugänge stärker kontrolliert und die Weiden häufiger entmistet. In Betrieben mit selektiver Entwurmung erfolgte die anthelminthische Behandlung signifikant häufiger entweder gar nicht oder nur einmal pro Jahr (55%), während 97% der Betriebe mit strategischer Entwurmung häufiger als einmal pro Jahr entwurmten (p ≤ 0,001). Die jährlichen Kosten für Entwurmung und Kotprobenuntersuchungen pro Pferd lagen in Betrieben mit selektiver Entwurmung durchschnittlich 37,50 € höher als in Betrieben mit strategischer Entwurmung. In 69% der Betriebe mit strategischer Entwurmung waren die Befragten bereit, das bestehende Entwurmungsmanagement zu ändern, und 43% hatten Interesse, die selektive Entwurmung einzuführen. Schlussfolgerung und klinische Relevanz: Bei selektiver Entwurmung erfolgen deutlich weniger anthelminthische Behandlungen. Die resultierenden Einsparungen heben allerdings nicht die höheren Kosten für Kotprobenuntersuchungen auf. Insgesamt bestand eine geringe Bereitschaft, das Weidemanagement zu verbessern. Die Kombination aus gutem Weideund Entwurmungsmanagement hat große Bedeutung für eine erfolgreiche Durchführung der selektiven Entwurmung.

A recent publication by Levecke et al. (Int. J. Parasitol, 2018, 8, 67–69) provides important insights into the kinetics of worm expulsion from humans following treatment with albendazole. This is an important aspect of determining the optimal time-point for post treatment sampling to examine anthelmintic drug efficacy. The authors conclude that for the determination of drug efficacy against Ascaris, samples should be taken not before day 14 and recommend a period between days 14 and 21. Using this recommendation, they conclude that previous data (Krücken et al., 2017; Int. J. Parasitol, 7, 262–271) showing a reduction of egg shedding by 75.4% in schoolchildren in Rwanda and our conclusions from these data should be interpreted with caution. In reply to this, we would like to indicate that the very low efficacy of 0% in one school and 52–56% in three other schools, while the drug was fully efficient in other schools, cannot simply be explained by the time point of sampling. Moreover, there was no correlation between the sampling day and albendazole efficacy. We would also like to indicate that we very carefully interpreted our data and, for example, nowhere claimed that we found anthelmintic resistance. Rather, we stated that our data indicated that benzimidazole resistance may be suspected in the study population. We strongly agree that the data presented by Levecke et al. suggests that recommendations for efficacy testing of anthelmintic drugs should be revised.