Imported Hyalomma ticks in the Netherlands 2018\u20132020

Mathilde Uiterwijk,Bart Van De Vossenberg,Paul Overgaauw,Arjan Stroo,Rolf Nijsse,Frans Jacobs,Adolfo Ibáñez-Justicia,Hein Sprong,Charlotte Dabekaussen

doi:10.1186/s13071-021-04738-x

Abstract

BackgroundTicks of the genus Hyalomma, which are vectors for several tick-borne diseases, are occasionally found in areas outside their endemic range including northern parts of Europe. The objective of this study was to analyse adult Hyalomma ticks that were recently found in the Netherlands.MethodsHyalomma ticks were morphologically identified. Cluster analysis, based upon sequence data (cox1 barcoding) for molecular identification, and pathogen detection were performed. Additionally, a cross-sectional survey of horses was conducted to actively search for Hyalomma ticks in summer 2019. Analysis of temperature was done to assess the possibility of (i) introduced engorged nymphs moulting to adults and (ii) establishment of populations in the Netherlands.ResultsSeventeen adult Hyalomma ticks (one in 2018, eleven in 2019, five in 2020) were found by citizens and reported. Fifteen ticks were detected on horses and two on humans. Twelve were identified as H. marginatum, one as H. rufipes and four, of which only photographic images were available, as Hyalomma sp. No Crimean-Congo haemorrhagic fever virus or Babesia/Theileria parasites were detected. One adult tick tested positive for Rickettsia aeschlimannii. In the cross-sectional horse survey, no Hyalomma ticks were found. Analysis of temperatures showed that engorged nymphs arriving on migratory birds in spring were able to moult to adults in 2019 and 2020, and that cumulative daily temperatures in the Netherlands were lower than in areas with established H. marginatum populations.ConclusionsOur results show that Hyalomma ticks are regularly introduced in the Netherlands as nymphs. Under the Dutch weather conditions, these nymphs are able to develop to the adult stage, which can be sighted by vigilant citizens. Only one human pathogen, Rickettsia aeschlimannii, was found in one of the ticks. The risk of introduction of tick-borne diseases via Hyalomma ticks on migratory birds is considered to be low. Establishment of permanent Hyalomma populations is considered unlikely under the current Dutch climatic conditions.Graphical

Highlights

Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are occasionally found in areas outside their endemic range including northern parts of Europe
Citizens could send photographic images of Hyalomma ticks to the Centre for Monitoring of Vectors (CMV, Netherlands Food and Consumer Product Safety Authority (NVWA), National Reference Centre, the Netherlands) via email or using the specific Hyalomma tick report system included on the NVWA website
We evaluated the possibility of Hyalomma wintering and establishment using the temperature-related limiting factor described by Gray et al (2009), where temperatures between September and December are critical for wintering of H. marginatum ticks

Summary

Introduction

Ticks of the genus Hyalomma, which are vectors for several tick-borne diseases, are occasionally found in areas outside their endemic range including northern parts of Europe. The objective of this study was to analyse adult Hyalomma ticks that were recently found in the Netherlands. Uiterwijk et al Parasites Vectors (2021) 14:244 of Europe for which thousands of migratory birds were checked for ticks, several hundreds of larvae and nymphs of Hyalomma spp. were collected [5,6,7,8,9,10,11,12,13,14]. In northern and western parts of Europe such as in the United Kingdom [11], Sweden [12], Norway [13] and the Netherlands [15], immature stages of Hyalomma spp. were found on migrating birds, but to a lesser extent. In the Netherlands, three adult Hyalomma sp. ticks were reported on horses between 2005 and 2009 [24, 25], and one adult Hyalomma sp. tick was found attached to a person in 2012 [26]

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