ABSTRACT

Sciurus anomalus Güldenstädt, 1785, known as the Caucasian squirrel, is a rodent distributed in all geographical regions of Türkiye. The material of this study consists of ectoparasites collected from male S. anomalus found dead on the highway (Karasu, Sakarya, Türkiye). As a result of microscopic examination, the specimens were identified: ticks as Ixodes ricinus Linnaeus, 1758 (larvae and nymph), sucking louses as Neohaematopinus syriacus Ferris, 1923 (female), and fleas as Monopsyllus sciurorum sciurorum (Schrank, 1803) (female and male). In this study, the presence of Ixodes ricinus infestation on Sciurus anomalus is reported for the first time in Türkiye.

INTRODUCTION

Sciurus anomalus Güldenstädt, 1785, one of 21 species described within the genus Sciurus, is commonly known as the Caucasian squirrel (1). Sciurus anomalus is distributed in forests where the habitat is suitable in Iran, Armenia, Azerbaijan, Georgia, Greece, Iraq, Jordan, Lebanon, and Syria, as well as in Türkiye (2).

Apart from S. anomalus, Sciurus vulgaris, Spermophilus citellus, S. xanthophrymnus and S. torosensis species in the squirrel family (Sciuridae) are also distributed in Türkiye (2, 3).

Studies on ectoparasites of squirrels (Sciurus spp. and Spermophilus spp.) are unfortunately neglected in the field of veterinary parasitology in Türkiye. In the studies, four of the five squirrel species found in Türkiye have been examined as ectoparasitic, and only two ticks, 11 fleas and one lice species have been reported.

In the Turkish flea list published by Keskin and Hastriter (4), it has been reported of the presence of species that Chaetopsylla globiceps, Ctenocephalides canis, Ctenophthalmus turcicus, Monopsyllus sciurorum sciurorum, Nosopsyllus fasciatus on the Caucasian squirrel (Sciurus anomalus); Monopsyllus sciurorum sciurorum on the Eurasian red squirrel (Sciurus vulgaris); Citellophilus simplex simplex, Citellophilus transcaucasicus, Nosopsyllus fasciatus, Oropsylla ilovaiskii, Neopsylla setosa spinea, and Pulex irritans on the Asia minor ground squirrel (Spermophilus xanthoprymnus). In the Turkish mammal lice list published by Dik (5), Neohaematopinus syriacus infestation was reported only on the Caucasian squirrel (Sciurus anomalus). Among the tick species, it has been reported the presence of infestation of Ixodes ricinus on the Eurasian red squirrel (Sciurus vulgaris) (6), Ixodes laguri on Spermophilus citellus (as Citellus citellus in the study) (7), Haemaphysalis sp. and Ixodes sp. on the Asia minor ground squirrel Spermophilus xanthophrymnus (as Citellus citellus in the study) (8).

CASE REPORT

The specimen of the male Caucasian squirrel (Sciurus anomalus) (Rodentia: Sciuridae) (Figure 1), found dead on the highway (geographical coordinates: 41.087834, 30.647195) (Karasu, Sakarya, Türkiye) on April 12, 2024, was subjected to ectoparasitic examination.

Using a flea comb and blunt-ended forceps during ectoparasite examination, the ectoparasite (louse, flea, and tick) specimens were collected from the carcass. After that, all specimens were stored in Eppendorf tubes containing 70% ethanol. In the light of the relevant literature specific to each parasite group [flea (9), ticks (10), and louse (11)] under the light microscope (MIC-B30/B Binocular 45 Economic Microscope-Led-Achromat, SOIF Optical Instruments Factory, China), tick specimens were identified as Ixodes ricinus Linnaeus, 1758, louse specimens as Neohaematopinus syriacus (Mjöberg, 1910), and flea specimens as Monopsyllus sciurorum sciurorum (Schrank, 1803) (Figure 2) (n_louse: two females; n_ticks: two larvae and four nymphs; n_fleas: two males and one female). In addition, all permanent glass slides of louse, tick, and flea species identified are deposited in G. Eren’s personal collection.

DISCUSSION

It is noteworthy that studies on ectoparasites of wild mammals (ticks, lice, fleas, myiasis flies and keds) in Türkiye have increased compared to the past (5, 12). When the studies are carefully examined, it is seen that good results are obtained in terms of host-parasite relationships in studies carried out jointly, that is, multidisciplinary, by biologists, veterinarians or parasitologists (13, 14).

Although there are many reports in the world (1, 15) about the diversity of ticks infesting Sciurus anomalus and S. vulgaris, members of the Sciurus genus known as tree squirrels or bushy-tailed squirrels, information for Türkiye is limited or insufficient (4-8). It can be considered that the diversity of the ectoparasitic fauna of the Caucasian squirrel (S. anomalus) has been revealed to a great extent in studies conducted around the world. As a result of these studies, it is known that the Ixodes acuminatus and I. ricinus from the tick species; Chaetopsylla globiceps, Ctenocephalides canis, Ctenophthalmus turcicus, and Monopsyllus sciurorum sciurorum from the flea species; and Enderleinellus krochinae, E. nitzschi and Neohaematopinus sciurinus from the louse species cause infestation on Caucasian squirrels (1, 4). Similarly, in the study carried out in 4 biogeographic regions covering France and Italy, 356 red squirrels (S. vulgaris) carcasses specimens were collected from the highways; and many ectoparasite species including flea (Monopsyllus sciurorum sciurorum, Tarsopsylla octodecimdentata octodecimdentata, Dasypsyllus gallinulae gallinulae), louse (Enderleinellus nitzschi and Neohaematopinus sciurinus) and tick (Ixodes acuminatus and I. ricinus) have been reported on these carcasses (15). As mentioned in the introduction of the paper, only 3 of 5 the squirrel species found in Türkiye have been studied as ectoparasites. While flea (4) and lice (5) infestations were reported in previous studies on the Caucasian squirrel (S. anomalus) examined in the present study, there is no data on tick infestation. Ixodes ricinus, detected on the Sciurus anomalus in this study, is one of the most studied ticks in the Western Palearctic region due to its vectorial potential (tick-borne encephalitis, Borreliosis, and Babesiosis). While the larval and nymph stages prefer small mammals, birds and reptiles, the adult stages prefer large mammals (10).

CONCLUSION

As a result of the literature review, it was found that Ixodes ricinus had previously been reported on Sciurus vulgaris in Türkiye (7) but not on Sciurus anomalus. Such case reports, according to the author, Ixodes ricinus species ticks can contribute to future studies by revealing the host-parasite relationships and vectorial potential.

This study aims to report Ixodes ricinus infestation on the Sciurus anomalus for the first time in Türkiye.