Bacterial Pathogens and Symbionts Harboured by Ixodes ricinus Ticks Parasitising Red Squirrels in the United Kingdom

Abstract

Red squirrels (Sciurus vulgaris) are native to most of Eurasia; in much of the United Kingdom, they have been supplanted by the non-native grey squirrel, and are considered an endangered species. Very little is known about the range of tick-borne pathogens to which UK red squirrels are exposed. As part of trap-and-release surveys examining prevalence of Mycobacterium spp. in red squirrel populations on two UK islands, Ixodes ricinus ticks were removed from squirrels and PCR screened for Borrelia spp., intracellular arthropod-borne bacteria and the parasitic wasp Ixodiphagus hookeri. At both sites, the most commonly encountered tick-transmitted bacterium was Borrelia burgdorferi sensu lato (overall minimum prevalence 12.7%), followed by Anaplasma phagocytophilum (overall minimum prevalence 1.6%). Single ticks infected with Spiroplasma were found at both sites, and single ticks infected with Borrelia miyamotoi or an Ehrlichia sp. at one site. Ticks harbouring Wolbachia (overall minimum prevalence 15.2%) were all positive for I. hookeri. Our study shows that UK red squirrels are potentially exposed to a variety of bacterial pathogens via feeding ticks. The effects on the health and survival of this already vulnerable wildlife species are unknown, and further studies are needed to evaluate the threat posed to red squirrels by Borrelia and other tick-borne pathogens.

Isolation in Natural Host Cell Lines of Wolbachia Strains wPip from the Mosquito Culex pipiens and wPap from the Sand Fly Phlebotomus papatasi

“…Although ticks are not currently considered to be natural hosts of Wolbachia [85][86][87], our study confirmed the susceptibility of tick cells in vitro for multiple Wolbachia strains of differing insect origins [24]. As well as growing vigorously in all the tick cell lines tested, wPip grew in insect cell lines derived from the lepidopteran S. frugiperda, the mosquito Ae.…”

First detection of Ixodiphagus hookeri (Hymenoptera: Encyrtidae) in Ixodes ricinus ticks (Acari: Ixodidae) from multiple locations in Hungary

“…Other European countries where the presence of I. hookeri has been reported include the Czech Republic (detected in former Czechoslovakia) 45 , Finland 46 , France 47 , 48 , the Georgia 49 , Germany 24 , 26 , 50 , Italy 51 , the Netherlands 27 , 52 , the United Kingdom 53 , Russia (detected in the Ussuri forest, in the Asian part of the former Soviet Union) 54 and Ukraine (detected in the former Soviet Union) 55 . To our knowledge, sampling point d (Sáska) in Hungary represents the southernmost detection point of I. hookeri within Central Europe.…”

First detection ofIxodiphagus hookeri(Hymenoptera: Encyrtidae) inIxodes ricinusticks (Acari: Ixodidae) from multiple locations of Hungary

“…The basis of receiving false negative results will be described further on. Other European countries where the presence of I. hookeri have been reported include the Czech Republic (detected in the former Czechoslovakia), 44 Finland, 45 France, 46,47 the Georgia, 48 Germany, 25,27,49 Italy, 50 the Netherlands, 28,51 the United Kingdom, 52 Russia (detected in the Ussuri forest, in the Asian part of the former Soviet Union) 53 and Ukraine (detected in the former Soviet Union). 54 To our knowledge, sampling point d (Sáska) in Hungary represents the southernmost detection point of I. hookeri within Central Europe.…”