High Prevalence and Low Diversity of Rickettsia in Dermacentor reticulatus Ticks, Central Europe

Abstract

T he ornate dog tick, Dermacentor reticulatus, is a proven vector of pathogens of public health and veterinary importance, including tick-borne encephalitis virus, Omsk hemorrhagic fever virus, rickettsiae, Babesia spp., and several others (1). D. reticulatus ticks are now expanding into new areas of northern and central Europe (1), where a higher prevalence of associated diseases can be expected.Although intensively studied during the past decade, bacteria of the genus Rickettsia have been overshadowed by other tickborne pathogens of primary medical importance. Rickettsiae of the typhus group and spotted fever group (SFG) present the greatest health risks. The D. reticulatus tick is a vector for SFG rickettsiae. Among Rickettsia species, R. raoultii and R. slovaca are recognized as causative agents of rickettsioses with typical lymphadenopathies, called tick-borne lymphadenopathy or Dermacentor-borne necrosis erythema and lymphadenopathy (2), which are widespread in Eurasia (1). R. helvetica, which causes milder symptoms, was also reported from D. reticulatus ticks (1,3).

Rickettsia species in Dermacentor reticulatus ticks feeding on human skin and clinical manifestations of tick-borne infections after tick bite

“…and N. mikurensis DNA were detected. Our results of Rickettsia prevalence correspond with our previous study 16 as well as with other data from Poland 41 , 42 , Germany 43 , Hungary 44 and Slovakia 11 . Not surprisingly, the majority of all Rickettsia isolates (14 out of 17) were identified as R. raoultii .…”

“…Dermacentor reticulatus ticks, mainly adults, can bite humans and are sporadically removed from human skin, therefore the medical consequences of their feeding are neglected compared to I. ricnus 3 , 4 , 6 – 9 . Distribution of the pathogen in European D. reticulatus tick populations seems to be very uneven 10 , 11 . Dermacentor reticulatus is the main vector of Babesia canis , the aetiological agent of canine babesiosis, as well as spotted fever group (SFG) rickettsiae with Rickettsia raoultii and R. slovaca , recognized as causative agents of rickettsioses with typical lymphadenopathies, called tick-borne lymphadenopathy (TIBOLA) or Dermacentor -borne necrosis erythema and lymphadenopathy (DEBONEL), which are widespread in Eurasia 11 , 12 .…”

“…Distribution of the pathogen in European D. reticulatus tick populations seems to be very uneven 10 , 11 . Dermacentor reticulatus is the main vector of Babesia canis , the aetiological agent of canine babesiosis, as well as spotted fever group (SFG) rickettsiae with Rickettsia raoultii and R. slovaca , recognized as causative agents of rickettsioses with typical lymphadenopathies, called tick-borne lymphadenopathy (TIBOLA) or Dermacentor -borne necrosis erythema and lymphadenopathy (DEBONEL), which are widespread in Eurasia 11 , 12 . Rickettsia helvetica , which causes milder symptoms, was also reported from D. reticulatus ticks 13 .…”

Novel Genetic Lineages of Rickettsia helvetica Associated with Ixodes apronophorus and Ixodes trianguliceps Ticks

“…R. tarasevichiae”, “ Ca. R. uralica” and R. raoultii are closely associated with I. persulcatus , I. trianguliceps and Dermacentor spp., respectively [ 11 , 14 , 16 , 32 , 33 , 34 ]. As for R. helvetica , this agent is associated with Ixodes spp.…”

High Prevalence of Rickettsia raoultii Found in Dermacentor Ticks Collected in Barnaul, Altai Krai, Western Siberia

“…Ticks of the genus Dermacentor are the main host and natural reservoir of R. raoultii not only in Europe [ 10 ] but also in some Asian countries [ 11 ]. All rickettsial DNA isolated from D. reticularis in Europe was found to belong to R. raoultii , with an average infection rate of 47.9% [ 12 ]. In a previous study, the percentage of R. raoultii in questing Dermacentor ticks in Altai Krai was relatively low (15.0%) [ 13 ].…”