Fauna and abundance of ixodids (Parasitiformes, Ixodidae) on Askold island (Primorsky krai): uniqueness, infection with pathogens

Abstract

Collecting of hard ticks by a flag from vegetation in Askold Island (Primorsky Territory) in May 17, 2023 has revealed the following 3 species: Haemaphysalis longicornis Neumann, 1901 (809 specimens), Haemaphysalis japonica douglasi Nuttall et Warburton, 1915 (223), Ixodes persulcatus Schulze, 1930 (4). A total of 1036 tick specimens were collected. The territory of the western part of the island was surveyed: a broad-leaved maple forest (925 ticks were collected) and a large-grass meadow (111). Identification of tick species was carried out according to morphological characters. The hard tick fauna of Askold Island is characterized by: 1) the dominance of H. longicornis, which is absent on neighboring islands; 2) a high proportion of nymphs in May among representatives of the genus Haemaphysalis (H. longicornis 96.0%, H. japonica 25.1%), the peak abundance of which is common in July–August; 3) a high abundance of ticks (more than 90.0 individuals per flag-hour; 4) absence of males in H. longicornis (32 females were collected). PCR did not detect infection of 160 nymphs (pools of 20 individuals) H. longicornis with markers of nucleic acids of tick-borne encephalitis virus, borrelia, anaplasma, ehrlichia and West Nile fever. However, since representatives of the genus Haemaphysalis are known as carriers of many other pathogens, the high abundance of hard ticks and the incompleteness of data on their infection rate do not allow us to classify the territory of Askold Island as an epidemiologically low-risk territory.