Journal Article

Tick infestation on medium–large-sized mammalian hosts: are all equally suitable to Ixodes ricinus adults?

Mysterud, Atle, Hügli, Christian, Viljugrein, Hildegunn

2021

Overview

Background In Europe, the generalist tick, Ixodes ricinus , is the main vector of several tick-borne pathogens causing diseases in humans and livestock. Understanding how different species of hosts limit the tick population is crucial for management. In general, larger ectoparasites are expected to select hosts with larger body size. Consistent with this, larval and nymphal I. ricinus can feed on a wide range of different-sized vertebrates, while the adult female stage is expected to rely on a medium–large-sized host for reproduction. However, we still have a limited understanding of whether medium-sized hosts other than roe deer can serve as hosts to adult ticks, and other factors than size may also affect host selection. Methods To increase our understanding of the suitability of the different species of medium-sized hosts for adult ticks, we sampled mainly roadkill mammals from within the questing season of ticks. We counted life stages of ticks on roe deer ( Capreolus capreolus ) ( n  = 29), red fox ( Vulpes vulpes ) ( n  = 6), badger ( Meles meles ) ( n  = 14) and red squirrel ( Sciurus vulgaris ) ( n  = 17) from spatially overlapping populations in Norway, and analysed variation between species across different body parts with a mixed-effects negative binomial model (with and without zero-inflation). Results Red squirrel hosted a high density of larval and nymphal I. ricinus , but only one individual had adult female ticks. Roe deer hosted by far the largest number of adult ticks. Badgers had very few ticks, possibly due to their thick skin. Red foxes had intermediate numbers, but a high proportion of subcutaneous, dead ticks (69.3%), suggesting they are not very suitable hosts. Body mass predicted the presence of adult I. ricinus ticks. However, species was a better predictor than body mass for number of ticks, suggesting there was species variation in host suitability beyond body mass per se. Conclusions Our study provides evidence that roe deer are indeed the main suitable reproduction host to adult I. ricinus ticks, and are likely a key to host limitation of the tick population in this northern ecosystem. Graphical Abstract

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: adults / Animal behavior / Arachnids / badgers / Behavior / binomial distribution / Biomedical and Life Sciences / Biomedicine / Body mass / Body parts / Body size / body weight / Capreolus capreolus / Deer / Distribution / ecosystems / Ectoparasites / Entomology / Females / Foxes / Health aspects / Host competence / host preferences / Host selection / Host-parasite relationships / Hosts / Immune system / Infectious Diseases / Infestation / interspecific variation / Ixodes ricinus / Larvae / Livestock / Males / Mammals / Mass / Meles meles / Norway / Parasites / Parasitic diseases / Parasitological research / Parasitology / Pathogens / Reproduction / Risk factors / road kills / Rodents / Sciurus vulgaris / Short Report / Skin / Species / Squirrels / Tick abundance / tick infestations / Tick prevalence / Tick-borne diseases / Ticks / Ticks and tick-borne diseases / Tropical Medicine / Vertebrates / Veterinary Medicine/Veterinary Science / Virology / Vulpes vulpes