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We retrospectively evaluated the accuracy of conventional PCR targeting the 16S rRNA gene (16S C-PCR) using the Ot-16sRF1/Ot-16sRR1 primers for diagnosing scrub typhus. The diagnosis of Orientia tsutsugamushi infection by 16S C-PCR presented an increased sensitivity of 87.0% and specificity of 100% compared with those obtained with other targets and is thus a simple and clinically useful method with good diagnostic accuracy., (Copyright © 2015, American Society for Microbiology. All Rights Reserved.)

Background: Rickettsial diseases associated with the spotted fever group constitute a growing number of newly identified Rickettsia pathogens and their tick vectors in various parts of the world. At least 15 distinct tick species belonging to six genera have shown the presence of Rickettsia raoultii. Herein, we report the detection of R. raoultii in ticks from the Republic of Korea (ROK). Methods: Thirty-five ticks were collected from 29 patients with tick bites in Gwangju Metropolitan City, Jeollanam Province, ROK. The ticks were identified using molecular, morphological, and taxonomic characteristics. All samples were screened for presence of Rickettsia species using nested polymerase chain reactions of their outer membrane protein (ompA) and citrate synthase (gltA) genes. The amplified products were sequenced for subsequent phylogenetic analyses. Results: Sequencing data showed the DNA sequences of R. raoultii in three Haemaphysalis longicornis ticks. All three tick samples were 99.4–100% similar to previously reported partial sequences of ompA of R. raoultii strains CP019435 and MF002523, which formed a single clade with the reference strains. Conclusions: We provide the first description and molecular identification of R. raoultii detected in H. longicornis ticks in the ROK. This observation extends the geographical distribution of R. raoultii. Screening of human samples for this pathogen will provide information about the prevalence of rickettsial infections in this region. [ABSTRACT FROM AUTHOR]

In this study, we investigated the presence of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern provinces of the Republic of Korea (ROK). We identified 33 ticks from three tick species, namely Amblyomma testudinarium (60.6%), Haemaphysalis longicornis (27.3%), and Ixodes nipponensis (12.1%) in order of occurrence via morphology and 16S rDNA-targeting polymerase chain reaction (PCR). Tick-borne pathogens were detected in 16 ticks using pathogen-specific PCR. From the results, 12 ticks (36.4%) tested positive for spotted fever group (SFG) Rickettsia: Rickettsia monacensis (1/12), R. tamurae (8/12), and Candidatus Rickettsia jingxinensis (3/12). Three ticks (9.1%) were positive for Anaplasma phagocytophilum. In addition, three ticks (9.1%) tested positive for Babesia gibsoni (1/3) and B. microti (2/3). In conclusion, we identified three tick species; the most common species was A. testudinarium, followed by H. longicornis and I. nipponensis. SFG Rickettsia, A. phagocytophilum, and Babesia spp. were the most frequently detected pathogens in ticks removed from tick-bitten humans. To our knowledge, this is the first report of R. tamurae and Ca. R. jingxinensis detection in Korea. The present results will contribute to the understanding of tick-borne infections in animals and humans in the ROK. [ABSTRACT FROM AUTHOR]

This study investigated the prevalence of Orientia tsutsugamushi, Anaplasma phagocytophilum, and Leptospira interrogans in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). A total of 47 wild rodents, identified as Apodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in A. agrarius sera was analyzed; 17.4% (8/46) were identified as O. tsutsugamushi through indirect immunofluorescence assay and 2.2% (1/46) were identified as Leptospira species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of O. tsutsugamushi, A. phagocytophilum, and L. interrogans. Out of the 47 A. agrarius, 19.1% (9/47) were positive for A. phagocytophilum and 6.4% (3/47) were positive for L. interrogans, while none were positive for O. tsutsugamushi. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for A. phagocytophilum. Three out of 47 (6.4%) kidney samples were positive for L. interrogans. The sequencing results of PCR positive samples demonstrated > 99% similarity with A. phagocytophilum and L. interrogans sequences. A. phagocytophilum was mostly detected in the spleen, whereas L. interrogans was mostly detected in the kidneys. Notably, A. phagocytophilum and L. interrogans were detected in A. agrarius living in close proximity to humans in the metropolitan suburban areas. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK. [ABSTRACT FROM AUTHOR]

Background: This study investigated Borrelia species prevalence in ticks from vegetation, through a molecular method, in Gwangju Metropolitan City, South Korea. Methodology/Principal findings: A total of 484 ticks were collected through flagging and dragging in a suburban area of Gwangju Metropolitan City, South Korea, in 2014. These ticks were morphologically identified and subjected to nested PCR, targeting Borrelia–specific CTP synthase (pyrG), outer surface protein A (ospA) and flagellin (flaB) genes. Molecular biological species identification of Borrelia-positive ticks was conducted via 16S rRNA PCR assays. Of the 484 ticks collected, 417 (86.2%) were identified as Haemaphysalis longicornis, 42 (8.7%) as H. flava, and 25 (5.2%) as Ixodes nipponensis. All the ixodid ticks containing Borrelia species bacteria were confirmed to be I. nipponensis adults, by both morphological and molecular methods. Of the 25 I. nipponensis ticks collected, four (16%) were positive for Borrelia species, three of which were B. afzelii and one B. miyamotoi. Conclusions/Significance: Our study has shown the harboring of B. miyamotoi by I. nipponensis in South Korea. Morphological and molecular genetic analyses revealed that, in South Korea, I. nipponensis could potentially transmit B. miyamotoi to humans. [ABSTRACT FROM AUTHOR]

Candidatus Neoehrlichia mikurensis (Ca. N. mikurensis; family Anaplasmataceae) is an emerging tick-borne pathogen that causes a systemic inflammatory syndrome with thrombotic complications. We report here the first identification of Ca. N. mikurensis in organ samples from small mammals captured in southwest South Korea. Nested PCR of groEL and 16S rRNA genes was used to confirm the identity of the bacteria present, and successfully amplified fragments were sequenced. All captured animals were identified as striped field mice (Apodemus agrarius), approximately 28.6% (4/14) and 21.4% (3/14) of which were found to be PCR-positive for Ca. N. mikurensis and Anaplasma phagocytophilum, respectively. The detection of Ca. N. mikurensis in these animals represents the first evidence of this pathogen in South Korea. Carriage of this bacterium by rodents highlights the need for more detailed investigation of their role in its transmission to humans. [ABSTRACT FROM AUTHOR]

• Hantaan virus showing geographical clustering in the Republic of Korea. • Geographical variation presenting genetic divergence of Hantaan virus. • Genetic divergence indicates the emergence of new Hantavirus strains. • High hantavirus prevalence and seasonal variation in A. agrarius captured from Jeju. Several studies on hantavirus evolution have shown that genetic reassortment plays an important role in the evolution and epidemiology of this disease. To understand the genetic epidemiology of human hantaviruses, samples from rodent reservoirs were subjected to reverse-transcription nested polymerase chain reaction (RT-N-PCR) targeting the L - and S-segments of the hantavirus genome. Positive isolates from Gwangju, Boseong-gun (Jeollanam-do Province), and Jeju Island were confirmed as Hantaan virus using DNA sequencing. Phylogenetic analysis showed that all isolates grouped together as Hantaan virus but with each region forming a distinct cluster. In addition, these three clusters were distinct from other Hantaan isolates reported in previous studies from Korea and its neighboring countries China and Russia. This suggests Hantaan viruses exhibit a considerable degree of geographical clustering, and there may be a novel Hantaan genotype in southwestern ROK. This study helps expand our knowledge regarding the emergence of new hantavirus strains and their degree of geographical variation. Hantaan virus, a pathogenic prototype hantavirus carried by Apodemus agrarius , is found throughout China, Russia, and Korea. Here, we examined the genetic diversity of hantaviruses to expand our knowledge regarding the emergence of new hantavirus strains and their degree of geographical variation. We found that hantaan viruses show a considerable degree of geographical clustering, which may allude to the development of a new genotype variant in the southwestern region of the ROK. [ABSTRACT FROM AUTHOR]

Background Scrub typhus, anaplasmosis, and leptospirosis are well-known diseases that are considered common, widespread rodent-borne infectious diseases Methods This study investigated the prevalence of Orientia tsutsugamushi , Anaplasma phagocytophilum , and Leptospira interrogans in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). Results A total of 47 wild rodents, identified as Apodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in A. agrarius sera was analyzed; 17.4% (8/46) were identified as O. tsutsugamushi through indirect immunofluorescence assay and 2.2% (1/46) were identified as Leptospira species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of O. tsutsugamushi, A. phagocytophilum , and L. interrogans. Out of the 47 A. agrarius , 19.1% (9/47) were positive for A. phagocytophilum and 6.4% (3/47) were positive for L. interrogans , while none were positive for O. tsutsugamushi. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for A. phagocytophilum. Three out of 47 (6.4%) kidney samples were positive for L. interrogans. The sequencing results of PCR positive samples demonstrated >99% similarity with A. phagocytophilum and L. interrogans sequences Conclusion A. phagocytophilum was mostly detected in the spleen, whereas L. interrogans was mostly detected in the kidneys. Notably, A. phagocytophilum and L. interrogans were detected in A. agrarius living in close proximity to humans in the metropolitan suburbans. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Background: Human granulocytic anaplasmosis (HGA) is a tick-borne infectious disease caused by Anaplasma phagocytophilum. To date, there have been no reported cases of A. phagocytophilum infection found in both the biting tick and the patient following a tick bite.Case Presentation: An 81-year-old woman presented with fever following a tick bite, with the tick still intact on her body. The patient was diagnosed with HGA. The tick was identified as Ixodes nipponensis by morphological and molecular biological detection methods targeting the 16S rRNA gene. The patient's blood was cultured after inoculation into the human promyelocytic leukemia cell line HL-60. A. phagocytophilum growth was confirmed via culture and isolation. A. phagocytophilum was identified in both the tick and the patient's blood by Anaplasma-specific groEL- and ankA-based nested polymerase chain reaction followed by sequencing. Moreover, a four-fold elevation in antibodies was observed in the patient's blood.Conclusion: We report a case of a patient diagnosed with HGA following admission for fever due to a tick bite. A. phagocytophilum was identified in both the tick and the patient, and A. phagocytophilum was successfully cultured. The present study suggests the need to investigate the possible incrimination of I. nipponensis as a vector for HGA in Korea. [ABSTRACT FROM AUTHOR]

Background: Scrub typhus is an acute disease, characterized by symptoms of fever, which occurs due to infection by Orientia tsutsugamushi. In most cases, patients recover from the disease with appropriate treatment, but serious and fatal complications may occur. The present study examined laboratory findings and tumor necrosis factor-alpha (TNF-α) levels of scrub typhus patients to identify the prognostic predictors of disease severity.Method: Patients whose scrub typhus diagnosis was confirmed by elevated indirect fluorescent antibody (IFA) levels and positive polymerase chain reaction (PCR) results were classified according to disease severity into one of three groups; i.e., deceased (n = 7), severe (n = 15), and mild (n = 15) retrospectively registered. Additionally, the usefulness of modified Acute Physiology and Chronic Health Evaluation II (APACHE II) score, C-reactive protein (CRP) level, white blood cell (WBC) count, and TNF-α level as prognostic predictors were examined.Result: The mean TNF-α levels of the deceased, severe, and mild groups were 53.5 (range: 7.8-147.8), 26.0 (1.7-64.4), and 8.8 pg/mL (4.6-16.0), respectively. The results of Kruskal-Wallis tests showed statistically significant differences between the deceased and severe groups versus the mild group (p = 0.005). CRP level and Modified APACHE II score also differed significantly among the groups (p = 0.046 and 0.007, respectively); however, WBC count did not (p = 0.196).Conclusion: An elevated serum TNF-α level in patients with scrub typhus could predict a severe condition or death and may be useful in predicting patient prognosis. [ABSTRACT FROM AUTHOR]