Adeleorid apicomplexan parasites of the genus Hepatozoon Miller, 1908 are broadly distributed among the rodents. Broader molecular data on Hepatozoon from Palaearctic squirrels are necessary for evaluation of diversity and origin of Hepatozoon in Eurasian red squirrel Sciurus vulgaris populations, considering ongoing invasion by Gray squirrel S. carolinensis. Our report brings a set of molecular data from a population of S. vulgaris in the Czech Republic, non-invaded by any invasive squirrel species. Cadavers of 41 Eurasian red squirrels were examined using nested PCR targeting 18S rRNA gene; 30 animals tested positive for the presence of Hepatozoon spp. DNA in at least one tissue. Phylogenetic analysis of obtained sequence types revealed relatedness to sequences of Hepatozoon sp. from S. vulgaris from Spain and the Netherlands, forming a sister clade to Hepatozoon isolates from other European rodents. The fact that all available 18S rRNA gene sequences form a monophyletic clade is interpreted as a presence of a single Hepatozoon species in S. vulgaris in continental Europe, most probably Hepatozoon sciuri. The presented molecular data on the Hepatozoon from European squirrels provides a basis for future studies on possible exchange of Hepatozoon species between Eurasian red and gray squirrels.

CEITEC University of Veterinary Sciences Brno Czech Republic

Department of Botany and Zoology Faculty of Science Masaryk University Brno Czech Republic

Department of Parasitology Faculty of Science Charles University Prague Czech Republic

Department of Pathology and Parasitology Faculty of Veterinary Medicine University of Veterinary Sciences Brno Czech Republic

Department of Veterinary Sciences Faculty of Agrobiology Food and Natural Resources CINeZ Czech University of Life Sciences Prague Czech Republic

Faculty of Medicine in Pilsen Biomedical Center Charles University Plzeň Czech Republic

Institute of Parasitology Biology Centre Czech Academy of Sciences Branišovská 31 Ceske Budejovice Czech Republic

Veterinary Research Institute Brno Hudcova 70 62100 Brno Czech Republic

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Bertolino S, Lurz PWW, Sanderson R, Rushton SP (2008) Predicting the spread of the American grey squirrel (Sciurus carolinensis) in Europe: a call for a co-ordinated European approach. Biol Conserv 141:2564–2575. https://doi.org/10.1016/j.biocon.2008.07.017 DOI

Clark GM (1958) Hepatozoon griseisciuri n. sp.; a new species of Hepatozoon from the grey squirrel (Sciurus carolinensis Gmelin, 1788), with studies on the life cycle. J Parasitol 44:52–63. https://doi.org/10.2307/3274829 PubMed DOI

Coles AC (1914) Blood parasites found in mammals, birds and fishes in England. Parasitology 7:17–61. https://doi.org/10.1017/S0031182000006284 DOI

Criado A, Martinez J, Buling A et al (2006) New data on epizootiology and genetics of piroplasms based on sequences of small ribosomal subunit and cytochrome b genes. Vet Parasitol 142:238–247. https://doi.org/10.1016/j.vetpar.2006.07.004 PubMed DOI

Franchini G (1932) Su di una leucocito-gregarina dello scoiattolo (Sciurus vulgaris). Arch Ital Sci Med Colon 13:385–389

Guindon S, Gascuel O (2003) A simple, fast, and accurate algorithm to estimate large phylogenies by maximum likelihood. Syst Biol 52:696–704. https://doi.org/10.1080/10635150390235520 PubMed DOI

Kalyaanamoorthy S, Minh BQ, Wong TKF et al (2017) ModelFinder: fast model selection for accurate phylogenetic estimates. Nat Methods 14:587–589. https://doi.org/10.1038/nmeth.4285 PubMed DOI PMC

Karadjian G, Chavatte JM, Landau I (2015) Systematic revision of the adeleid haemogregarines, with creation of Bartazoon n. g., reassignment of Hepatozoon argantis Garnham, 1954 to Hemolivia, and molecular data on Hemolivia stellata. Parasite 22. https://doi.org/10.1051/parasite/2015031

Katoh K, Rozewicki J, Yamada KD (2019) MAFFT online service: multiple sequence alignment, interactive sequence choice and visualization. Brief Bioinform 20:1160–1166. https://doi.org/10.1093/bib/bbx108 PubMed DOI

Kearse M, Moir R, Wilson A et al (2012) Geneious basic: an integrated and extendable desktop software platform for the organization and analysis of sequence data. Bioinformatics 28:1647–1649 DOI

Kvičerová J, Pakandl M, Hypša V (2008) Phylogenetic relationships among Eimeria spp. (Apicomplexa, Eimeriidae) infecting rabbits: evolutionary significance of biological and morphological features. Parasitology 135:443–452. https://doi.org/10.1017/S0031182007004106 PubMed DOI

Lawton C, Cowan P, Bertolino S, et al (2010) The consequences of introducing non-indigenous species: two case studies, the grey squirrel in Europe and the brushtail possum in New Zealand. OIE Rev Sci Tech 29:287–298. https://doi.org/10.20506/rst.29.2.1983

Léveillé AN, El Skhawy N, Barta JR (2020) Multilocus sequencing of Hepatozoon cf. griseisciuri infections in Ontario eastern gray squirrels (Sciurus carolinensis) uncovers two genotypically distinct sympatric parasite species. Parasitol Res 119:713–724. https://doi.org/10.1007/s00436-019-06583-5 PubMed DOI

Maia JP, Carranza S, Harris DJ (2016) Comments on the systematic revision of adeleid haemogregarines: are more data needed? J Parasitol 102:549–552. https://doi.org/10.1645/15-930 PubMed DOI

Minh BQ, Nguyen MAT, Von Haeseler A (2013) Ultrafast approximation for phylogenetic bootstrap. Mol Biol Evol 30:1188–1195. https://doi.org/10.1093/molbev/mst024 PubMed DOI PMC

Nguyen LT, Schmidt HA, Von Haeseler A, Minh BQ (2015) IQ-TREE: a fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Mol Biol Evol 32:268–274. https://doi.org/10.1093/molbev/msu300 PubMed DOI

Sainsbury AW, Nettleton P, Gilray J, Gurnell J (2000) Grey squirrels have high seroprevalence to a parapoxvirus associated with deaths in red squirrels. Anim Conserv 3:229–233. https://doi.org/10.1111/j.1469-1795.2000.tb00107.x DOI

Simpson VR, Birtles RJ, Bown KJ et al (2006) Hepatozoon species infection in wild red squirrels (Sciurus vulgaris) on the Isle of Wight. Vet Rec 159:202–205. https://doi.org/10.1136/vr.159.7.202 PubMed DOI

Simpson VR, Hargreaves J, Butler HM et al (2013) Causes of mortality and pathological lesions observed post-mortem in red squirrels (Sciurus vulgaris) in Great Britain. BMC Vet Res 9:229 DOI

Smith TG (1996) The genus Hepatozoon (Apicomplexa: Adeleina). J Parasitol 82:565–585. https://doi.org/10.2307/3283781 PubMed DOI

Strauss A, White A, Boots M (2012) Invading with biological weapons: the importance of disease-mediated invasions. Funct Ecol 26:1249–1261. https://doi.org/10.1111/1365-2435.12011 DOI

Talavera G, Castresana J (2007) Improvement of phylogenies after removing divergent and ambiguously aligned blocks from protein sequence alignments. Syst Biol 56:564–577. https://doi.org/10.1080/10635150701472164 PubMed DOI PMC