Ornithological and molecular evidence of a reproducing Hyalomma rufipes population under continental climate in Europe

Abstract

Reports on adult Hyalomma ticks in certain regions of the Carpathian Basin date back to the 19th century. These ticks were thought to emerge from nymphs dropping from birds, then molting to adults. Although the role of migratory birds in carrying ticks of this genus is known from all parts of Europe, in most countries no contemporaneous multiregional surveillance of bird-associated ticks was reported which could allow the recognition of hotspots in this context. From 38 passeriform bird species 956 ixodid ticks were collected at seven locations in Hungary. Tick species were identified as Ixodes ricinus (n = 598), Ixodes frontalis (n = 18), Ixodes lividus (n = 6), Haemaphysalis concinna (n = 321), and D. reticulatus (n = 1). All 12 Hyalomma sp. ticks (11 engorged nymphs and 1 unengorged larva) were identified as H. rufipes based on three mitochondrial markers. This species was only found in the Transdanubian region and along its southeastern border. The Common Blackbird and the European Robin were the two main hosts of I. ricinus and I. frontalis, whereas H. concinna was almost exclusively collected form long-distance migrants. The predominant hosts of H. rufipes were reed-associated bird species, the Sedge Warbler and the Bearded Reedling, both in their nesting period. This study provides ornithological explanation for the regional, century-long presence of adult Hyalomma ticks under continental climate in the Transdanubian Region of the Carpathian Basin. More importantly, the autochthonous occurrence of a H. rufipes population was revealed for the first time in Europe, based on the following observations: (1) the bird species infested with H. rufipes are not known to migrate during their nesting period; (2) one larva was not yet engorged; (3) the larva and the nymphs must have belonged to different local generations; and (4) all H. rufipes found in the relevant location were identical in their haplotypes based on three maternally inherited mitochondrial markers, probably reflecting founder effect. This study also demonstrated regional and temporal differences in tick species carried by birds.

Investigations of the tick burden on passeriform, water-associated and predatory birds reveal new tick–host associations and habitat-related factors of tick infestation

“…Tick species were identified according to standard keys [ 17 ]. In addition, the species identity of Dermacentor reticulatus nymph was confirmed molecularly based on the 16S rRNA gene (data not shown), as reported [ 10 ].

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“…Prevalence data were compared with Fisher's exact test ( https://www.langsrud.com/fisher.htm ), and differences were considered significant if P < 0.05. Bird species were assigned into categories according to their typical habitat (Table 2 ; Additional file 1 ) as previously reported [ 10 ].…”

“…Most of these studies in the past were either based on random, sporadic tick collections [ 7 ] or annual removal of ticks from birds at one stop-over site [ 8 , 9 ]. In 2022, however, a country-wide survey on ticks associated with avian hosts was also conducted [ 10 ]. Nevertheless, all these bird tick studies focused on just one order of birds, the Passeriformes (songbirds).…”

Contributions to our knowledge on avian louse flies (Hippoboscidae: Ornithomyinae) with the first European record of the African species Ornithoctona laticornis

“…The role of birds in the “transportation” of arthropods with vector potential is long-known [ 1 ]. This aspect of bird life as parasite hosts is suspected to become more and more important due to the changes in ecological conditions and which may become a consequence of the currently ongoing climate change [ 2 ].…”

“…Although studies on louse flies originating from Central [ 3 ] Northern [ 14 ], Southern [ 10 ], Western [ 15 ] and Eastern Europe [ 16 ] have also been conducted, only a few of these report long-term evaluations with continuous sample collection. The number of studies conducted on avian ectoparasites steadily increased in Hungary and in other Central European countries during the previous decade [ 2 , 3 , 12 , 17 , 18 ], but studies on ornithophilic hippoboscids appear to have been neglected compared to other arthropod vectors that are generally considered epidemiologically more important (i.e. ticks and mosquitoes) [ 19 , 20 ].…”