Distribution of Rickettsia spp. in Ticks from Northwestern and Southwestern Provinces, Republic of Korea

This study was done to characterize distribution of Rickettsia spp. in ticks in the northwestern and southwestern provinces in the Republic of Korea. A total of 2,814 ticks were collected between May and September 2009. After pooling, 284 tick DNA samples were screened for a gene of Rickettsia-specific 17-kDa protein using nested PCR (nPCR), and produced 88 nPCR positive samples. Of these positives, 75% contained 190-kDa outer membrane protein gene (ompA), 50% 120-kDa outer membrane protein gene (ompB), and 64.7% gene D (sca4). The nPCR products of ompA, ompB, and sca4 genes revealed close relatedness to Rickettsia japonica, R. heilongjiangensis, and R. monacensis. Most Rickettsia species were detected in Haemaphysalis longicornis. This tick was found a dominant vector of rickettsiae in the study regions in the Republic of Korea.

Survey on the Status of Biosafety Awareness Among Domestic Biology Researchers

In this study, a survey was conducted to investigate the current status of biosafety awareness by each region, targeting domestic biology researchers. A total of 4 surveys were conducted from September 24 to October 2, 2013 in Kangwon province, Seoul Metropolitan area, Chungchong Province, and Gyeongsang Province, and 189 respondents participated in the survey. Of the survey respondents, 135 (71.4%) answered that “It is likely for an infection to happen in the laboratory” and 23 (12.2%) answered “highly likely”. However, as to the Risk Group and Biosafety Facility Level, only 24 (12.7%) and 25 (13.2%) of the respondents, respectively, responded “know them very well”. These results indicate that researchers are aware of the need for the concept of biosafety in laboratories, but they lack systematic education and publicity. Therefore, it will be necessary to develop a system that can systematically educate the regulations and compliance of biosafety.

Emerging Infectious Diseases Require Biosafety Awareness and Procedures

In 2015, there was a Middle East respiratory syndrome (MERS) outbreak in Korea. Interestingly, most of the cases were nosocomial infection and significant numbers of healthcare workers (HCWs) were infected. There were various causes, but this study focused on HCWs and their ability to self-protect from infectious materials. HCWs did not receive sufficient instruction or training on biosafety, including how to use personal protection equipment and risk assessment at the beginning of the outbreak. Previous experience from an outbreak of severe acute respiratory syndrome or Ebola showed that HCWs must self-protect from infection sources, but HCW infection occurred again with this MERS outbreak. Therefore, the concept of biosafety self-protection must be emphasized so that HCWs can protect themselves from diseases and avoid spreading them.

Identification of Leptospira species of Korean Isolates using Phylogenetic Analysis of Polymerase Chain Reaction-amplified 16S rDNA and LipL32 Genes

In this study, we selected only serologically identified 15 Leptosira interrogans isolates in the past and analyzed and identified them by using molecular method. The partial 16S rDNA and LipL32 genes were amplified from the bacteria by polymerase chain reaction (PCR) and sequenced. Sizes of the PCR products were 529 bp and 819 bp respectively and analysis of the nucleotide sequence of 16S rDNA and LipL32 genes showed that 14 out the 15 Leptospira showed 99.4~100% and 99.2~99.9% similarity respectively to those of L. interrogans lai and one isolate named HS-7 showed 100% and 100% similarity to L. interrogans canicola. The phylogenetic tree based on the 16S rDNA and LipL32 genes obtained the study revealed that 14 of the Leptospira composed a cluster distinct to that of L. interrogans lai and HS-7 composed to L. interrogans canicola.

The Management of Laboratory Biological Safety in Korea

The Laboratories engaging with microorganisms have some potential risks, depending on handling of pathogens. The safety management system to extend recognition of biosafety and biosecurity needs to be established and practiced in order to prevent hazard possibility and secure safety of researchers who deal with pathogen. As the importance and regulation of global biosafety and biosecurity tended to be intensified, various laws and institutions for the security of biosafety were established when the Act on implementation of Living Modified Organisms, an implantation act of Cartagena was enforced in Korea in 2008. In particular, the system of permission report for Living Modified Organism (LMO), Highly Dangerous Pathogens (HDPs) and Biological Weapons Convention (BWC), in order to prevent intended or non-intended leakage and occurrence of biohazard derived from pathogen and infectious substance and safely use them. The bioterrorism can be controlled and autonomous management of biosafety by agencies that handle pathogens can be also secured by practicing the various laws and institutions.

Larval Chigger Mites Collected from Small Mammals in 3 Provinces, Korea

A total of 9,281 larval chigger mites were collected from small mammals captured at Hwaseong-gun, Gyeonggi-do (Province) (2,754 mites from 30 small mammals), Asan city, Chungcheongnam-do (3,358 mites from 48 mammals), and Jangseong-gun, Jeollanam-do (3,169 for 62 mammals) from April-November 2009 in the Republic of Korea (= Korea) and were identified to species. Leptotrombidium pallidum was the predominant species in Hwaseong (95.8%) and Asan (61.2%), while Leptotrombidium scutellare was the predominant species collected from Jangseong (80.1%). Overall, larval chigger mite indices decreased from April (27.3) to June (4.9), then increased in September (95.2) and to a high level in November (169.3). These data suggest that L. pallidum and L. scutellare are the primary vectors of scrub typhus throughout their range in Korea. While other species of larval chigger mites were also collected with some implications in the transmission of Orientia tsutsugamushi, they only accounted for 11.2% of all larval chigger mites collected from small mammals.

A case of scrub typhus requiring maintenance hemodialysis

Renal failure caused by scrub typhus is known to be reversible. In most cases, renal function is almost fully restored after appropriate antibiotic treatment. A 71-year-old man was diagnosed with scrub typhus complicated by renal failure. A renal biopsy revealed histopathologic findings consistent with acute tubulointerstitial nephritis. Renal function did not improve 18 months after discharge and the patient required continuous hemodialysis. Although severe renal failure requiring dialysis is a rare complication of scrub typhus, we describe a case of scrub typhus requiring maintenance hemodialysis. To the best of our knowledge, this is the first such report.

A Survey on Laboratory Biosafety Status of Public Healthcare Centers in Korea

The purpose of this study was to explore the laboratory biosafety status of Public Health Centers (PHCs) in Korea during Oct.7~26, 2012. We surveyed the environment of biosafety management, especially for the recognition level for biosafety of workers in the organizations. The questionnaires given out to 98 workers who are working for PHCs are to research the recognition level of workers for the knowledge of biosafety, related laws and regulations. The level was the highest in the Research Institute of the Public Health & Environment (RIPHE) followed by quarantine station, and the health center was assessed as the last. It was turned out that the biosafety educational program in the RIPHE was implemented on a regular basis (65.2%) with irregular cases (21.7%), and some outsourcing chances (8.7%). However, quarantine stations and health centers didn't practice actively biosafety training programs compared to RIPHE. In addition, there was a majority of opinions that the most important thing to improve biosafety level of PHCs is to strengthen current poor training and education system. In conclusion, it is necessary to develop more improved training system for biosafety on exposure risks including injuries, personal protective equipment, and chemical hazards.

Detection and Identification of the Spotted Fever Group Rickettsial Agents from Haemaphysalis Ticks in Jeju Island, Korea

This study investigated the presence of nucleic acids of various Rickettsial agents in ticks collected in Jeju Island, Korea from June 2007 to August 2008, through the nested polymerase chain reaction (PCR) and sequencing analysis of partial citrate synthase (gltA), Rickettsial outer membrane protein B (ompB), and 17-kDa genes. Examination of the 1,584 ticks showed that the subspecies distribution of Haemaphysalis longicornis was 99.81% (n=1,581) and H. flava was 0.19% (n=3). A total 224 out of 250 pools from one to 15 ticks were found to be positive in ompB-PCR assay (minimal infection rate 141 ticks/1,000 tested). From the positive samples, 26 were analyzed by gltA- and 17-kDa-PCR assays. The nucleotide sequences of the ompB- and gltA-PCR products showed a high degree of similarity with those of the Rickettsia japonica (98.7~99.2% and 98.7~99.3%, n=25) and R. monacensis (99% and 99.7%, n=1). However, analysis of the nucleotide sequences of the 17-kDa-PCR amplicons showed that the sequences of the 25 PCR amplicons were more close to R. marmionii (99.4~100%) than R. japonica (98.6~99.1%). These findings suggest that various rickettsial diseases could be transmitted via the bite of tick vectors in Jeju Island, Korea.

A Case of Tsutsugamushi Disease after Traveling to the Philippines

Infectious diseases imported from other countries have increased as more and more Koreans are going abroad for various purposes. Tsutsugamushi disease from other endemic area such as Southeast Asia is important, because it can occur in any season and eschar may be absent. We report a case of imported tsutsugamushi disease acquired in the Philippines. A patient presented with fever, headache, and maculopapular skin rash. However, eschar was absent. Polymerase chain reaction (PCR) for 56-kDa gene of Orientia tsutsugamushi using buffy coat was positive. Serum indirect immunofluorescent antibody assay was initially negative but became positive with a titer of 1:320 at follow-up. Sequencing analysis revealed the strain to be 100% identical to the TW73R strain identified in Taiwan. After the patient received doxycycline, body temperature normalized in 12 hours. Tsutsugamushi disease is one of the differential diagnoses that should be included for patients with fever who have recently returned from Southeast Asian countries. PCR for O. tsutsugamushi using patient's buffy coat was useful for early diagnosis.

A Case of Tsutsugamushi Disease after Traveling to the Philippines

Infectious diseases imported from other countries have increased as more and more Koreans are going abroad for various purposes. Tsutsugamushi disease from other endemic area such as Southeast Asia is important, because it can occur in any season and eschar may be absent. We report a case of imported tsutsugamushi disease acquired in the Philippines. A patient presented with fever, headache, and maculopapular skin rash. However, eschar was absent. Polymerase chain reaction (PCR) for 56-kDa gene of Orientia tsutsugamushi using buffy coat was positive. Serum indirect immunofluorescent antibody assay was initially negative but became positive with a titer of 1:320 at follow-up. Sequencing analysis revealed the strain to be 100% identical to the TW73R strain identified in Taiwan. After the patient received doxycycline, body temperature normalized in 12 hours. Tsutsugamushi disease is one of the differential diagnoses that should be included for patients with fever who have recently returned from Southeast Asian countries. PCR for O. tsutsugamushi using patient's buffy coat was useful for early diagnosis.

Rapid Identification of Rickettsiae using the Real-Time PCR

In this study, new real-time PCR method based on the groEL gene was developed and investigated. Four spotted fever group (SFG) strains, four typhus group (TG) strains, and four scrub typhus group (STG) strains were easily differentiated as a distinct entity. This PCR assay was applied to detect Rickettsia DNA from 100 ticks. Twelve Haemaphysalis longicornis ticks were found positive and identified as spotted fever group Rickettsia. This real-time PCR method could simultaneously perform the rapid identification of rickettsiae and the differential diagnosis of SFG, TG, and STG in a single reaction.

Prevalence of Spotted Fever Group Rickettsia from Haemaphysalis Ticks in Chungju Province

A total of 190 ticks collected from the Chungju area of Korea was examined for the presence of Spotted Fever Group(SFG) Rickettsia using a PCR assay. Twenty-five (13.2%) Haemaphysalis ticks were found positive of the groEL gene of SFG Rickettsia. The prevalence rate of R. japonica in these 25 Haemaphysalis ticks was 72% (18 out of 25 SFG Rickettsia). The prevalence rate of R. conorii and new SFG rickettsia in these 25 Haemaphysalis ticks was 4% (1 out of 25 SFG Rickettsia) and 24% (6 out of 25 SFG Rickettsia), respectively. These results suggest that R. japonica was the highest infection frequency among in Haemaphysalis ticks SFG Rickettsia, and that R. conorii and new SFG Rickettsia are also present in the Chungju area.

The Effects of Intravenous Anesthetics on Human Cytomegalovirus Infection / 대한마취과학회지

BACKGROUND: Reactivation of human cytomegalovirus (HCMV) from latency is a frequent complication of organ transplantation, and the molecular mechanism by which this occurs is unknown. Previous studies have shown that allogenaic transplantation combined with immunosuppression may be required to achieve complete reactivation in vivo and many anesthetics have wide range immunomodulatory properties. HCMV infection of endothelial cells plays an important role in the establishment of latency and persistence, which appears critical for the maintenance of HCMV within the host. METHODS: We compared the effects of intravenous anaesthetics (propofol, thiopental, and ketamine) on the susceptability of endothelial cells to HCMV infection by indirect immunofluorescent assay at 48 hour postinfection and we also have investigated the time course of luciferase gene expression in human umbilical vein endothelial cell (HUVEC) infected with recombinant HCMV. RESULTS: Treatment with anesthetics after HCMV strain Towne inoculation did not increase HUVEC susceptibility to HCMV infection by indirect immunofluorescent assay. Treatment of HUVEC with propofol, thiopental, and ketamine after the recombinant virus inoculation had no significant effects on the level of the late genes expression. CONCLUSIONS: Intravenous anesthetics (propofol, thiopental, and ketamine) did not increase the susceptability of endothelial cells to HCMV infection at plasma concentrations. Further studies are required to evaluate higher anesthetic concentration which may increases the susceptability of HUVEC to HCMV infection without cell destruction.

groEL Gene Analysis of Borrelia afzelii Isolated in Korea

Eleven Borrelia afzelii strains, isolated from Ixodes nipponensis and Apodemus agrarius in Korea, were characterized by groEL gene analysis. Results from previous studies suggested that the groEL gene, which encodes the 60-kDa heat shock protein GroEL, was useful for the differentiation of B. burgdorferi sensu lato. The B. afzelii isolates could be divided into two groups by the phylogenetic tree constructed by UPGMA method and Tsp509 I PCR-RFLP analysis. The result suggested that the groEL gene is useful for identification and characterization of B. burgdorferi sensu lato though a short DNA fragment (310 bp) of the gene was sequenced and compared each other, and that Korean B. afzelii strains are heterogeneous genotypically.

groEL Gene Analysis of Borrelia afzelii Isolated in Korea

Eleven Borrelia afzelii strains, isolated from Ixodes nipponensis and Apodemus agrarius in Korea, were characterized by groEL gene analysis. Results from previous studies suggested that the groEL gene, which encodes the 60-kDa heat shock protein GroEL, was useful for the differentiation of B. burgdorferi sensu lato. The B. afzelii isolates could be divided into two groups by the phylogenetic tree constructed by UPGMA method and Tsp509 I PCR-RFLP analysis. The result suggested that the groEL gene is useful for identification and characterization of B. burgdorferi sensu lato though a short DNA fragment (310 bp) of the gene was sequenced and compared each other, and that Korean B. afzelii strains are heterogeneous genotypically.

Development of Rickettsia Specific Nested PCR Method Based on groEL Gene Sequences

To detect Rickettsia, we have developed a nested PCR method amplifying the groEL gene. Rickettsia strains were successfully amplified by this PCR method but the microorganisms causing other febrile diseases, such as Orientia tsutsugamushi, Coxiella burnetii, Ehrlichia sennetsu, Borrelia burgdorferi sensu lato, Borrelia hermsii, and Leptospira interrogans were not amplified. This PCR assay was applied to detect Rickettsia DNA from 100 ticks. Sixteen Haemaphysalis longicornis ticks were positive by this PCR assay. These results suggest that the new nested PCR method might be sensitive and useful for discrimination between Rickettsia and other febrile disease-causing microorganisms.

Genetic Heterogeneity of Borrelia burgdorferi Sensu Lato Isolated in Chungju, Korea, by ospC Gene Sequence Analysis

Eight Borrelia burgdorferi strains, which had been isolated from Ixodes nipponensis and Apodemus agrarius captured in the Chungju area of Korea, were characterized by ospC gene sequence analysis. Nucleotide sequence similarity among the Chungju strains ranged from 83.6 to 100%. Deduced amino acid sequence similarity of the Chungju strains ranged from 75.4 to 100%. In a molecular phylogenetic analysis, the Chungju strains were separated from B. burgdorferi and B. garinii reference strains, and formed a cluster with B. afzelii reference strains. Three (KK2, KM4, and KK5), two (CJ2 and CJ21), and one (CJ3) Chungju strains formed clusters with OspC serotype 5, OspC serotype 8, and OspC serotype 7 reference strains, respectively. However, two Chungju strains (KK1 and KM10) formed a distinctive cluster that was separated from other strains of B. afzelii reference strains. These results suggest that Chungju strains are very heterogeneous in clonality.

Seroprevalence to Coxiella burnetii in Patients with Acute Febrile Episodes during 1993

Coxiella burnetii is the etiological agent of Q fever, that may occur either acutely or the chronically. To understand the seroepidemiological patterns of C. burnetii infection in Korea, we examined a total of 3,178 sera from patients with acute febrile episodes by using indirect immunofluorescence assay (IFA) for detectable antibodies to C. burnetii and other eight rickettsial antigens. The IFA seropositivity>or=1:20 for C. burnetii phase II was 11.5% (368 out of 3,178 sera). The co-existence of antibodies to other rickettsial antigens was found in 216 out of the 368 positive sera. Thirty-seven point five percent (n=138) had antibodies to R. tsutsugamushi (cutoff>or=1:20), 16% (n=59) to Ehrlichia sennetsu, 14.9% (n=55) to Rickettsia typhi, 13.5% (n=50) to R. akari, 11.4% (n=42) to R. japonica, 8.9% (n=33) to R. prowazekii, 7.6% (n=28) to R. sibirica, and 6.7% (n=25) to R. conorii by IFA, respectively. These results are consistent with previous reports documenting diverse serum cross-reactivity in chronic Q fever. Therefore we excluded the samples that reacted to other rickettsial antigens at same or higher titers than to C. burnetii, resulting in the seropositive rate of 4.1%. The serological prevalence was 2% (n=64) when the conventional cut-off titer of 1:80 was used. Our results suggest that infections with C. burnetii are more prevalent than expected previously and should be differentially diagnosised for febrile illness occurring after exposure to ticks or other vectors.

Serological Analysis of Ehrlichiosis in Korean from 1990 to 1992

Ehrlichia sennetsu is the causative agent of human Sennetsu ehrlichiosis. Ehrlichiosis is an acute and occasionally chronic infectious disease caused by obligate intracellular bacteria in the family Rickettsiaceae. To understand the seroepidemiological patterns of ehrlichiosis in Korea, a total of 2,625 patients with acute febrile episode reported from 1990 to 1992 were surveyed using an indirect fluorescent antibody assay (IFA). The result was as follows. Seropositivity for ehrlichiosis was 3.23% by excluding highly cross-reacted sera with other rickettsial antigens. Sera reacted to E. sennetsu showed the cross reaction with other rickettsia as in the order of R. typhi 49.6%, R. conorii 31.6%, R. japonica 28.1%, C. burnetii 26.4%, R. sibirica 25.8%, O. tsutsugamushi 25.8%, R. akari 25.4%, and R. prowazekii 25.4%. Sexual difference in the seropositivity was not noted. The age groups of fifties and under the tenth showed higher prevalence than others. Seropositivity was most prevalent in July and August. As for regional distribution, Chonbuk (10.5%) showed the highest seropositive rate. Geographical distribution of the seropositivity covered most area except Cheju province in Korea.