Multiple Tick-Borne Pathogens in Ixodes ricinus Ticks Collected from Humans in Romania

Abstract

Ticks are medically important vectors of infectious diseases that are able to transmit pathogens to humans and animals. Tick-borne diseases represent a major health concern, posing an increasing risk to the public health during the last century and affecting millions of people. The aim of the current study was to provide epidemiological data regarding the presence of certain tick-borne pathogens in ticks feeding on humans in Romania. Overall, 522 Ixodes ricinus ticks collected from humans were screened for six pathogens: Borrelia spp., Neoehrlichia mikurensis, Babesia spp., Coxiella spp., Bartonella spp., and Francisella tularensis. Ticks attached to humans were collected between 2013–2015 in Cluj County, Romania. Conventional, nested and quantitative PCR were used to detect specific genetic sequences of each pathogen. For identifying the infectious agents, positive samples were sequenced. The infection prevalence was 21.07% from which 8.18% were mixed infections. The detected agents were Borrelia spp., N. mikurensis and Babesia spp. The present data reveal the endemic occurrence of potentially zoonotic pathogens in Romania. Revealing the current distribution of tick-borne pathogens in ticks collected from humans may provide new insights in understanding the complex ecology of tick-borne diseases and enlightens current knowledge about the infection prevalence at local, regional and national levels.

Long-Term Study of Borrelia and Babesia Species Distribution in Ixodes Ricinus and Dermacentor Recticulatus Ticks Removed From Humans in Poland, 2016-2019

“…For I. ricinus, we observed the peak of activity in June which is congruent with the results of our previous study on questing ticks [22] and other studies on seasonality of I. ricinus bites on humans [11,12]. The predominance of nymphs of up to 73% in dependence of month of study was similar to other European studies on ticks collected from humans [33][34][35][36][37][38]. The activity of larvae was the highest in August and September; however, only 54 specimens in total were removed from humans.…”

High Diversity, Prevalence, and Co-infection Rates of Tick-Borne Pathogens in Ticks and Wildlife Hosts in an Urban Area in Romania

“…In Romania, various molecular approaches have been used to detect the prevalence of infection with the Borrelia spp. (including the relapsing fever spirochete B. miyamotoi) ( Kalmár et al, 2016 ) in questing ticks ( Kalmár et al, 2013 ; Raileanu et al, 2017 ), ticks collected from animal hosts ( Gherman et al, 2012 ; Dumitrache et al, 2015 ; Kalmár et al, 2019 ), or humans ( Andersson et al, 2014 ; Briciu et al, 2014 ; Andersson et al, 2018 ; Kalmár et al, 2020 ). During 2018 a total of 532 human Lyme disease cases were confirmed by serology in Romania ( NCSCC, 2018 ), placing the country at the inferior position of the European incidence ( Rizzoli et al, 2011 ).…”

“…Despite the wide distribution of Anaplasma phagocytophilum across Romania ( Matei et al, 2015 ), and of the presence of this pathogen in I. ricinus ticks collected from humans ( Matei et al, 2017 ), no clinical human cases were reported so far in the country. Yet to be described from humans in Romania, nonetheless detected in questing ( Kalmár et al, 2016 ) and engorged I. ricinus ticks collected from humans ( Andersson et al, 2014 ; Kalmár et al, 2020 ), Neoehrlichia mikurensis is an emerging pathogen which can either lead to severe febrile illness in immunocompromised patients ( Grankvist et al, 2014 ) or fever in clinically healthy humans ( Li et al, 2012 ). The spotted fever group rickettsiae (SFG) cause rickettsioses in humans ( Parola et al, 2013 ).…”

“…This tick species is also a vector for zoonotic apicomplexans of the genus Babesia , such as B. divergens and B. microti ( Gray et al, 2010 ). To date, B. microti and B. venatorum are reported in ticks collected from humans in Romania ( Kalmár et al, 2020 ).…”

“…Co-infection prevalence in ticks in European countries ranges from 3.2% to 45% ( Reye et al, 2010 ; Reis et al, 2011 ; Lommano et al, 2012 ; Moutailler et al, 2016 ; Klitgaard et al, 2019 ; Nebbak et al, 2019 ; Kalmár et al, 2020 ). Little is known about the co-infection rates in questing ticks and wildlife hosts in urban and peri-urban Romania ( Raileanu et al, 2017 , 2018 ).…”