BackgroundRickettsiae constitute a group of arthropod-borne, Gram-negative, obligate intracellular bacteria that are the causative agents of diseases ranging from mild to life threatening that impact on medical and veterinary health worldwide.MethodsA total of 6,484 ticks were collected by tick drag from June-October 2013 in the southwestern provinces of the Republic of Korea (ROK) (Jeollanam, n = 3,995; Jeollabuk, n = 680; Chungcheongnam, n = 1,478; and Chungcheongbuk, n = 331). Ticks were sorted into 311 pools according to species, collection site, and stage of development. DNA preparations of tick pools were assayed for rickettsiae by 17 kDa antigen gene and ompA nested PCR (nPCR) assays and the resulting amplicons sequenced to determine the identity and prevalence of spotted fever group rickettsiae (SFGR).Results Haemaphysalis longicornis (4,471; 52 adults, 123 nymphs and 4,296 larvae) were the most commonly collected ticks, followed by Haemaphysalis flava (1,582; 28 adults, 263 nymphs and 1,291 larvae), and Ixodes nipponensis (431; 25 adults, 5 nymphs and 401 larvae). The minimum field infection rate/100 ticks (assuming 1 positive tick/pool) was 0.93% for the 17 kDa antigen gene and 0.82% for the ompA nPCR assays. The partial 17 kDa antigen and ompA gene sequences from positive pools of H. longicornis were similar to: Rickettsia sp. HI550 (99.4–100%), Rickettsia sp. FUJ98 (99.3–100%), Rickettsia sp. HIR/D91 (99.3–100%), and R. japonica (99.7%). One sequence of the partial 17 kDa antigen gene for H. flava was similar to Rickettsia sp. 17kd-005 (99.7%), while seven sequences of the 17 kDa antigen gene obtained from I. nipponensis ticks were similar to R. monacensis IrR/Munich (98.7–100%) and Rickettsia sp. IRS3 (98.9%).ConclusionsSFG rickettsiae were detected in three species of ixodid ticks collected in the southwestern provinces of the ROK during 2013. A number of rickettsiae have been recently reported from ticks in Korea, some of which were identified as medically important. Results from this study and previous reports demonstrate the need to conduct longitudinal investigations to identify tick-borne rickettsiae and better understand their geographical distributions and potential impact on medical and veterinary health, in addition to risk communication and development of rickettsial disease prevention strategies.
Objective:This study aimed at finding epidemiological and clinical features of autochthonous Lyme borreliosis in humans through epidemiological investigations and identifying its vectors and pathogens through analysis of ticks.Method:Epidemiological investigations, including review of the retrospective medical records and patient interviews, were conducted in two cases that occurred in 2012. To identify the vectors and pathogens, ticks were collected between September 23 and October 6, 2012 from the area where the tick bite in the first patient occurred. The ticks were classified, and polymerase chain reaction (PCR) tests and cultures were performed.Results:The first patient, a 46-year-old female, visited a forest in Gangwon province, which was 900 m above sea level, where the tick bite occurred. Two weeks after the tick bite, erythema migrans (12 × 6 cm2 in size) appeared on the site of tick bite, along with fever, chill, fatigue, myalgia, and arthralgia on shoulders, knees, and hips. The second patient, a 44-year-old male, visited a mountain in Gangwon province, which was 1200 m above sea level, where a tick bite occurred. One month after the tick bite, erythema migrans appeared at the site of the tick bite, along with fatigue, myalgia, and arthralgia on the right shoulder and temporomandibular joint. Indirect fluorescent antibody testing and Western blotting were carried out in these two cases for diagnosis, and positive findings were obtained. As a result, Lyme borreliosis could be confirmed. To estimate the pathogens and vectors, the ticks were collected. A total of 122 ticks were collected and only two species, Haemaphysalis japonica and Haemaphysalis flava, were identified. PCR and culture were performed on ticks. However, Borrelia burgdo rferi sensu lato was not isolated from any collected ticks.Conclusions:This study is significant to confirm Lyme borreliosis officially at first by the national surveillance system, although identification of the mites and pathogens failed.
We report here the genome sequence of Borrelia garinii strain 935T isolated from Ixodes persulcatus in South Korea. The 1,176,739 bp (G+C content, 27.73%) genome consists of 1,194 coding regions, 4 rRNA genes, and 33 aminoacyl-tRNA synthetase genes. This is the first whole-genome report of a Korean Borrelia species isolate.
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