Geographical Distribution of Borrelia burgdorferi sensu lato in Ticks Collected from Wild Rodents in the Republic of Korea

Abstract

: Lyme disease is a tick-borne zoonotic disease caused by Borrelia burgdorferi sensu lato (s. l.) via transmission cycles involving competent tick vectors and vertebrate reservoirs. Here, we determined the prevalence and distribution of Borrelia genospecies in 738 ticks of at least three species from wild rodents in nine regions of the Republic of Korea (ROK). Ticks were analyzed using nested PCR targeting partial flagellin B gene sequences, followed by sequence analysis. The prevalence of Borrelia infection was 33.6%, and the most common genospecies were B. afzelii (62.5%), B. valaisiana (31.9%), B. yangtzensis (2.4%), B. garinii (1.6%), and B. tanukii (1.6%). Borrelia afzelii was found in all regions except Jeju Island; this predominant genospecies was found in the northern and central sampling regions. Borrelia valaisiana, B. yangtzensis, and B. tanukii were found only in the southern regions with B. valaisiana being the most common, whereas B. yangtzensis and B. tanukii were only found on Jeju Island. Our study is the first to describe the nationwide prevalence of B. burgdorferi s. l. in ticks from wild rodents in the ROK. Continuous surveillance in ticks, animals, humans, and different regions is required to avoid disease distribution and possible transmission to humans in the ROK.

Molecular Identification of Borrelia spp. from Ticks in Pastures Nearby Livestock Farms in Korea

“…[4]. The main vectors of Lyme borreliosis are the ticks of the genus Ixodes and the main species in Asia are Ixodes persulcatus and I. nipponensis [7,8]. After B. burgdorferi s. l. was first identified in Korea in 1993, a human Lyme borreliosis case also occurred during the same year.…”

“…After B. burgdorferi s. l. was first identified in Korea in 1993, a human Lyme borreliosis case also occurred during the same year. The incidence has increased since then [4,7]. In Korea, on average, 15.4 cases per year have been reported in the past decade, with 23 cases reported in 2019 and 18 cases reported in 2020 [9,10].…”

“…In Korea, on average, 15.4 cases per year have been reported in the past decade, with 23 cases reported in 2019 and 18 cases reported in 2020 [9,10]. In Korea, research on Borrelia is currently being carried out on the pathogenicity of various wild animals, including ticks, rodents, and companion animals [3,7,[11][12][13].…”

“…In Korea, B. afzelii and B. garinii were first identified in Ixodes ticks and wild rodents. Then, B. bavariensis, B. tanukii, B. turdi, B. valaisiana, and B. yangtzensis were identified in ticks and wild animals [7], whereas B. afzelii and B. garinii were also detected in domestic and wild animals [4,7,13]. B. afzelii (6/329, 1.8%) was detected in ticks collected from mammals such as horses, wild boars, native goats, and Korean water deer [4].…”

“…were observed; B. afzelii was found in all regions except Jeju Island, and some species were found only in the southern regions (Borrelia valaisiana, B. yangtzensis, and B. tanukii). Furthermore, some were found only in Jeju Island (B. yangtzensis and B. tanukii) [7]. Recently, B. burgdorferi sensu stricto, known to cause Lyme borreliosis in northern America, has been identified for the first time in Korea [10].…”