Rodents (Rodentia), due to their number and species diversity, are important elements of natural ecosystems. Some species of rodents are widely distributed. Glis glis (Linnaeus, 1766) (Rodentia, Gliridae) is one such species. An overview of the parasites, bacteria and viruses of G. glis inhabiting the Western Palearctic is given.
1. Introduction
Rodents (Rodentia), due to their number and species diversity, are important elements of natural ecosystems. Some species of rodents are widely distributed
[1][2][3][4][5][6][7]. The European edible dormouse,
Glis glis (Linnaeus, 1766) is one such species and is widespread across western Eurasia. This rodent species is found in most European countries and regions of western Asia: through northern Turkey to the Caucasus, northern Iran and Turkmenistan
[8][9][10][11].
Glis glis is the largest member of the family Gliridae, arboreal rodent with a nocturnal lifestyle. This rodent has the longest period of hibernation among the mammals of Europe, up to 9 months
[12].
It is known that small wild rodents play an important role in the life cycles of the helminths of carnivorous mammals and birds of prey in higher trophic levels. Small rodents are involved in maintaining natural foci of zoonoses—diseases dangerous to humans and animals
[4][13][14][15][16][17][18][19][20][21]. In this regard, the study of the parasite fauna of
G. glis is of great scientific (biodiversity monitoring) and practical importance (study of the dormouse’s role in the spread and preservation of zoonoses).
The literature on parasites, viruses and protozoans of
G. glis currently contains about 180 references, covering an approximately 200-year period. The first attempts to bring together data about the viruses, parasites and protozoans of
G. glis were undertaken in the reviews by Rossolimo
[22] and Kryštufek
[23][24], which contained data on 64 species of ecto- and endoparasites found in the dormouse. Unfortunately, these reviews did not include most papers not indexed in electronic databases, so they are still inaccessible to most researchers.
2. Parasites, Bacteria and Viruses of Glis glis in the Western Palaearctic
At the present stage of research, 104 species (with subspecies) of viruses, protozoans, ectoparasites and helminths were recorded in G. glis: 4 viruses, 8 Protozoa, 6 Cestoda, 6 Trematoda, 4 Nematoda, 1 Heteroptera, 2 Anoplura, 39 Siphonaptera and 34 Acari.
2.1. Viruses of Glis glis
The study of viruses in G. glis has a short history spanning only the last decades. Four viruses of three families were found in the edible dormouse (Table 1).
Table 1. Viruses of Glis glis in Western Palaearctic.
Note: E—Europe.
Encephalocarditis virus (EMCV) is found in many species of wild and domestic animals in various regions of the world
[30]. The host-specific
Polyomavirus found in
G. glis belongs to a group of DNA viruses that infect mammals, birds and fish
[31][32].
Hantaan orthohantavirus (formerly known as
Hantaan virus) is a negative-sense RNA virus species. The edible dormouse is a reservoir host for the
Hantaan orthohantavirus (HTNV).
Dobrava-Belgrade virus (also known as
Dobrava virus), found in the edible dormouse, is common in the former Yugoslavia, Germany, Estonia, Slovakia, European Russia and other Eastern European countries
[33]. All viruses have a European range (
Table 1).
2.2. Protozoa of Glis glis
Eight protozoan species from the five families are known in the edible dormouse (Table 2).
Table 2. Protozoa of Glis glis in Western Palaearctic.
Note: E—Europe, C—Cosmopolitan, H—Holarctic.
Among the protozoa found in
G. glis,
Borellia spp. (family Spirochaetaceae) are most represented (four species). They belong to the
Borrelia burgdorferi (Johnson et al., 1984) sensu lato species complex. The natural reservoir hosts of
Borrelia are wild animals (rodents, birds and deer).
Borrelia afzelii and
B. bavariensis are associated with rodents
[43][36][44].
Borrelia garinii is better adapted to birds
[45].
The obligate intracellular bacteria
Rickettsia typhi (Wolbach and Todd, 1920) is best known as the causative agent of an endemic human typhus that occurs worldwide
[46]. This protozoan species can be transmitted to a mammalian host by the bite of an infected flea or louse
[47].
2.3. Helminths of Glis glis
In total, 16 species of parasitic worms were recorded in G. glis: 6 Cestoda, 6 Trematoda and 4 Nematoda (Table 3). Most of the helminth species parasitise the edible dormouse at the mature stage (14 species). Only two species of helminths were noted at the larval stage: the trematode Alaria alata (Goeze, 1782) and the cestode Mesocestoides lineatus (Goeze, 1782), for which the dormice serve as paratenic hosts. The finding of a small number of larval stages of parasitic worms indicates an insignificant role of G. glis in the life cycles of helminths of vertebrates of high trophic levels.
Table 3. Helminths of Glis glis in Western Palaearctic.
Note: E—Europe, C—Cosmopolitan, H—Holarctic, P—Palaearctic, WP—Western Palaearctic.
2.4. Ectoparasites of Glis glis
In total, 76 species of ectoparasites were found on G. glis, belonging to Anoplura (2 species), Heteroptera (1), Siphonaptera (39) and Acari (34) (Table 4). Only eight species of ectoparasites are host-specific parasites of the edible dormouse: the lice Schizophthirus gliris (Blagoveshtchensky, 1965) and Schizophthirus pleurophaeus (Burmeister, 1839); the fleas Myoxopsylla jordani (Ioff and Argyropoulo, 1934) and Myoxopsylla laverani (Rothschild, 1911); and the mites Hirstionyssus gliricolus (Masan and Ambros, 2010), Hirstionyssus paulisimilis (Masan and Fenda, 2010), Gliricoptes glirinus (Canestrini, 1895) and Radfordia gliricola (Vesmanis and Lukoschus, 1978). Three species of ectopatasites are common parasites of arboreal rodents (squirrels and dormice): the fleas Ceratophyllus sciurorum (Schrank, 1803) and Leptopsylla sciurobia (Wagner, 1934) and the mite Hirstionyssus sciurinus (Hirst, 1921). The other 65 species of ectoparasites are accidental and facultative dormouse parasites, which parasitise many species of mammals and birds.
Table 4. Ectoparasites of Glis glis in the Western Palaearctic.
Note: E—Europe, C—Cosmopolitan, H—Holarctic, P—Palaearctic, WP—Western Palaearctic, G—Greenland, I—Iran, N—Nearctic.