Biology session

Europe’s most studied and most common tick species, the sheep tick (Ixodes ricinus), has a well-known distribution, life cycle and vector role. However, in Hungary there are other, less studied tick species with a life cycle similar to I. ricinus. The forests of the Pilis Mountains give home to two of these less known ticks, Haemaphysalis concinna and Haemaphysalis inermis. The research group has been collecting monthly data at a sampling site in Pilis in the past 5 years. I joined to examine the seasonal activity of the tick species and the Borrelia miyamotoi infection rate of the area. Borrelia miyamotoi is a newly recognised human pathogenic spirochete bacterium. Unlike the Borrelia species that cause Lyme borreliosis, these spirochetes develop a relapsing fever in humans and vertebrates.

Flagging method was used to collect ticks from the undergrowth. The captured individuals were sorted by species and stage and preserved in alcohol. Quantification of the species and stages was based on time, not space. This is because the sampling site was too heterogeneous. It can be said that the Haemaphysalis species are generally uncommon in some months, however, they show higher abundance than that of I. ricinus. Although I. ricinus adults and nymphs were present in every sampling month.

The molecular analysis included ticks collected from 2012 and 2013. The individuals were selected so that they cover every species, stage and month. We used alkaline hydrolysis to extract DNA from the ticks, individually from adults and nymphs and in pools with up to 10 specimens for larvae. To demonstrate the presence of B. miyamotoi we used real-time polymerase chain reaction. From 752 samples (I. ricinus: 456 samples, 1002 individuals; H. inermis: 101 samples, 101 individuals; H. concinna: 195 sapmles, 770 individuals) 10 proved to be positive, from all stages of the I. ricinus. The pathogen was detected in 4.56% (minimum prevalence) of all I. ricinus samples. This value is especially high compared to similar European prevalence data. These findings will be confirmed by conventional polymerase chain reaction and sequencing. Individuals examined from the two Haemaphysalis species proved to be negative for B. miyamotoi.

The first Hungarian B. miyamotoi detection was in Gemenc. The finding that the pathogen also occurs in the Pilis Mountains with a relatively high prevalence could be pointing to an infection throughout the whole country making it a potential threat to humans.