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Dasgupta S, Asish PR, Rachel G, Bagepally BS, Chethrapilly Purushothaman GK. Global seroprevalence of scrub typhus: a systematic review and meta-analysis. Sci Rep 2024; 14:10895. [PMID: 38740885 DOI: 10.1038/s41598-024-61555-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 05/07/2024] [Indexed: 05/16/2024] Open
Abstract
Scrub typhus, a neglected disease, is a significant health concern in the Tsutsugamushi triangle of the Asia-Pacific and has raised global concerns due to recent cases occurring outside this region. To estimate the global prevalence of scrub typhus, we conducted a systematic review and meta-analysis. We conducted a systematic search of PubMed, Scopus, and Embase databases for observational studies on scrub typhus. Using a random-effects model, we combined the prevalence estimates with inverse-variance weights while also evaluating heterogeneity and publication bias. Among 3551 reports screened, we identified 181 studies with 1,48,251 samples for inclusion in our synthesis. The overall pooled seroprevalence (95% confidence intervals) of scrub typhus infections was 24.93% (23.27-26.60). Gender-wise pooled prevalence was estimated to be 50.23% (47.05-53.40) for males and 48.84% (45.87-51.80) for females. Eschar prevalence was observed to be 30.34% (22.54-38.15) among the positive cases. One-fourth of all the samples tested positive for scrub typhus and eschar was present in one-third of these total positive cases, encompassing regions beyond the Tsutsugamushi triangle. This estimation underlines the importance of this neglected disease as a public health problem. Strengthening surveillance and implementing disease control measures are needed in the affected regions.
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Affiliation(s)
- Sauvik Dasgupta
- ICMR-National Institute of Epidemiology, Ayapakkam, Chennai, 600077, India
| | | | - Gladys Rachel
- ICMR-National Institute of Epidemiology, Ayapakkam, Chennai, 600077, India
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Liu L, Xiao Y, Wei X, Li X, Duan C, Jia X, Jia R, Guo J, Chen Y, Zhang X, Zhang W, Wang Y. Spatiotemporal epidemiology and risk factors of scrub typhus in Hainan Province, China, 2011-2020. One Health 2023; 17:100645. [PMID: 38024283 PMCID: PMC10665174 DOI: 10.1016/j.onehlt.2023.100645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Background The re-emergence of scrub typhus in the southern provinces of China in recent decades has been validated, thereby attracting the attention of public health authorities. There has been a spatial and temporal expansion of scrub typhus in Hainan Province, but the epidemiological characteristics, environmental drivers, and potential high-risk areas for scrub typhus have not yet been investigated. Objective The aims of this study were to characterize the spatiotemporal epidemiology of scrub typhus, identify dominant environmental risk factors, and map potential risk areas in Hainan Province from 2011 to 2020. Methods The spatiotemporal dynamics of scrub typhus in Hainan Province between 2011 and 2020 were analyzed using spatial analyses and seasonal-trend decomposition using regression (STR). The maximum entropy (MaxEnt) model was applied to determine the key environmental predictors and environmentally suitable areas for scrub typhus, and the demographic diversity of the predicted suitable zones was evaluated. Results During 2011-2020, 3260 scrub typhus cases were recorded in Hainan Province. The number of scrub typhus cases increased continuously each year, particularly among farmers (67.61%) and individuals aged 50-59 years (23.25%) who were identified as high-risk groups. A dual epidemic peak was detected, emerging annually from April to June and from July to October. The MaxEnt-based risk map illustrated that highly suitable areas, accounting for 25.36% of the total area, were mainly distributed in the northeastern part of Hainan Province, where 75.43% of the total population lived. Jackknife tests revealed that ground surface temperature, elevation, cumulative precipitation, evaporation, land cover, population density, and ratio of dependents were the most significant environmental factors. Conclusion In this study, we gained insights into the spatiotemporal epidemiological dynamics, pivotal environmental drivers, and potential risk map of scrub typhus in Hainan Province. These results have important implications for researchers and public health officials in guiding future prevention and control strategies for scrub typhus.
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Affiliation(s)
- Lisha Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Yang Xiao
- Chongqing University Cancer Hospital, School of Medicine, Chongqing University, Chongqing, China
| | - Xianyu Wei
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xuan Li
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Chunyuan Duan
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Xinjing Jia
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Ruizhong Jia
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Jinpeng Guo
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Yong Chen
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Xiushan Zhang
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Wenyi Zhang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Yong Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China
- Chinese PLA Center for Disease Control and Prevention, Beijing, China
- Department of Epidemiology and Biostatistics, School of Public Health, China Medical University, Shenyang, China
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Tasak N, Apidechkul T, Law ACK, Abdad MY, Srichan P, Perrone C, Tanganuchitcharnchai A, Wongsantichon J, Blacksell SD. Prevalence of and factors associated with scrub typhus exposure among the hill tribe population living in high incidence areas in Thailand: a cross-sectional study. BMC Public Health 2023; 23:2394. [PMID: 38041104 PMCID: PMC10693027 DOI: 10.1186/s12889-023-17313-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023] Open
Abstract
BACKGROUND Scrub typhus is a significant tropical disease, occurring in rural settings and therefore usually afflicting remote agricultural populations who have lower socioeconomic status and limited access to medical care. A large proportion of the hill tribe people in Thailand are financially poor, have limited education, and do not have adequate health care access. This study aimed to estimate the prevalence of and determine factors associated with scrub typhus exposure among the hill tribe population living in high-incidence areas in northern Thailand. METHODS A cross-sectional study design was used to gather information from hill tribe people aged 18 years and over living in ten hill tribe villages in Mae Fah Luang, Chiang Rai Province, Thailand. Participants who met the inclusion criteria were invited to participate in the study. A validated questionnaire was used as the research instrument, and 5 mL blood samples were taken. Orientia tsutsugamushi IgM and IgG antibodies were detected by enzyme-linked immunosorbent assay (ELISA) and then confirmed by immunofluorescence assay (IFA). Logistic regression was used to detect associations between variables at a significance level of α = 0.05. RESULTS A total of 485 hill tribe people participated in the study; 57.1% were female, 29.9% were over 60 years of age, 46.4% were from the Akha tribe, and 74.2% had never attended school. The overall prevalence of scrub typhus exposure was 48.0%. In the multivariate model, five variables were found to be associated with scrub typhus exposure. Participants aged over 60 years had a 4.31-fold increased risk (95% CI = 1.73-10.72) of scrub typhus exposure compared to those who were younger than 30 years. Those who were illiterate had a 3.46-fold increased risk (95% CI = 1.93-6.21) of scrub typhus exposure than those who had at least a primary education level. Participants from the Akha tribe had a 2.20-fold increased risk (95% CI = 1.31-3.72) of scrub typhus exposure than those from the Lahu tribe. Subjects who had a history of cutting grass had a 1.85-fold increased risk (95% CI = 1.20-2.84) of scrub typhus exposure. Those who never wore gloves for farming had a 2.12-fold increased risk (95% CI = 1.28-3.49) of scrub typhus exposure than those who wore gloves daily. CONCLUSIONS There is a high prevalence of scrub typhus exposure among the hill tribe in Thailand. Effective public health interventions to promote scrub typhus awareness and prevention are urgently needed in these populations.
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Affiliation(s)
- Nidanuch Tasak
- School of Health Science, Mae Fah Luang University, Chiang Rai, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand
| | - Tawatchai Apidechkul
- School of Health Science, Mae Fah Luang University, Chiang Rai, Thailand.
- Center of Excellence, The Hill Tribe Health Research, Mae Fah Luang University, Chiang Rai, Thailand.
| | - Andrew C K Law
- Department of Psychiatry, Royal College of Surgeons in Ireland & University College Dublin, (Malaysia Campus), Pulau Pinang, Malaysia
| | - Mohammad Yazid Abdad
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Peeradone Srichan
- School of Health Science, Mae Fah Luang University, Chiang Rai, Thailand
- Center of Excellence, The Hill Tribe Health Research, Mae Fah Luang University, Chiang Rai, Thailand
| | - Carlo Perrone
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | | | | | - Stuart D Blacksell
- Mahidol Oxford Tropical Medicine Research Unit, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
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Huang J, Deng K, Chen J, Zhang M. Epidemiological and clinical characteristics of scrub typhus in northern Fujian, China, from 2015 to 2019. BMC Infect Dis 2023; 23:479. [PMID: 37464324 PMCID: PMC10354924 DOI: 10.1186/s12879-023-08451-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/11/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND This study aimed to analyze the epidemiological and clinical characteristics of scrub typhus in northern Fujian Province on the southeast coast of China. METHODS A retrospective analysis was performed on 303 patients with scrub typhus admitted to the First Hospital of Nanping City, Fujian Province, from January 2015 to December 2019. The epidemic characteristics were analyzed, such as the annual number of cases, age distribution, sex distribution, and seasonal distribution in each region. The patient's clinical manifestations, signs, complications, auxiliary examinations, and prognosis were analyzed. RESULTS From 2015 to 2019, the age distribution of scrub typhus cases was mainly concentrated in 40-49 y (17.16%), 50-59 y (24.09%), and 60-69 y (26.73%). There were no sex differences among the patients. 68.98% of the cases were concentrated in rural areas, with farmers having the highest proportion. However, this study compared prognostic factors in the cured and uncured groups, and found significant differences in non-farmer occupation and diagnosis time ≥ 8 days. Scrub typhus showed two peaks north of Fujian; the prominent peak was from June to July, and the other slight rise was from October to November. The SDE plot showed that the cases were mainly concentrated in Yanping, Shunchang, Zhenghe, and Songxi counties. The number of cases in hilly and mountainous areas was higher than in plain areas. The main diagnostic methods in this area are based on specific eschar and epidemiology, while the positive rate of the Weil-Felix test is low. CONCLUSIONS The results of this study can guide primary care institutions to improve the level of diagnosis and treatment of scrub typhus and take effective public health intervention measures in endemic areas.
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Affiliation(s)
- Jin Huang
- Department of Infectious Diseases, The Second Affiliated Hospital of Fujian University of Traditional Chinese Medicine, Wusi Road, Fuzhou, China.
| | - Kaixiang Deng
- Department of Traditional Chinese Medicine, First Hospital of Nanping City, Nanping, China
| | - Jiawei Chen
- Department of Infectious Diseases, The Second Affiliated Hospital of Fujian University of Traditional Chinese Medicine, Wusi Road, Fuzhou, China
| | - Meiquan Zhang
- Department of Pulmonary and Critical Care Medicine, Fujian Provincial Geriatric Hospital, Fuzhou, China
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Tran HTD, Hattendorf J, Do HM, Hoang TT, Hoang HTH, Lam HN, Huynh MK, Vu LTH, Zinsstag J, Paris DH, Schelling E. Ecological and behavioural risk factors of scrub typhus in central Vietnam: a case-control study. Infect Dis Poverty 2021; 10:110. [PMID: 34412700 PMCID: PMC8374119 DOI: 10.1186/s40249-021-00893-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/04/2021] [Indexed: 12/04/2022] Open
Abstract
Background The risk factors for scrub typhus in Vietnam remain unknown. Scrub typhus caused by Orientia tsutsugamushi often presents as an undifferentiated febrile illness and remains under appreciated due to the limited availability of diagnostic tests. This tropical rickettsial illness is increasingly recognized as an important cause of non-malaria acute undifferentiated fever in Asia. This study aimed to investigate behavioural and ecological related risk factors of scrub typhus to prevent this potentially life-threatening disease in Vietnam. Methods We conducted a clinical hospital-based active surveillance study, and a retrospective residence-enrolment date-age-matched case–control study in Khanh Hoa province, Vietnam, from August 2018 to March 2020. Clinical examinations, polymerase chain reaction and enzyme-linked immunosorbent assay IgM tests were applied to define cases and controls. All enrolled participants filled out a questionnaire including demographic socio-economic status, personal behaviors/protective equipment, habitat connections, land use, and possible exposure to the vector. Multivariable conditional logistic regression was used to define the scrub typhus associated risk factors. Results We identified 44 confirmed cases and matched them with 152 controls. Among cases and controls, the largest age group was the 41–50 years old and males accounted for 61.4% and 42.8%, respectively. There were similarities in demographic characteristics between the two groups, with the exception of occupation. Several factors were significantly associated with acquisition of scrub typhus, including sitting/laying directly on household floor [adjusted OR (aOR) = 4.9, 95% CI: 1.6–15.1, P = 0.006], household with poor sanitation/conditions (aOR = 7.9, 95% CI: 1.9–32.9, P = 0.005), workplace environment with risk (aOR = 3.0, 95% CI: 1.2–7.6, P = 0.020), always observing mice around home (aOR = 3.7, 95% CI: 1.4–9.9, P = 0.008), and use of personal protective equipment in the field (aOR = 0.4, 95% CI: 0.1–1.1, P = 0.076). Conclusions Ecological and household hygiene-related factors were more associated with scrub typhus infection, than individual-level exposure activities in the hyper-endemic area. These findings support local education and allow people to protect themselves from scrub typhus, especially in areas with limitations in diagnostic capacity. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-021-00893-6.
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Affiliation(s)
- Hanh Thi Duc Tran
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,Department of Epidemiology, Hanoi University of Public Health, Hanoi, Vietnam. .,University of Basel, Basel, Switzerland.
| | - Jan Hattendorf
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Hung Manh Do
- Department for Infectious Disease Control and Prevention, Nha Trang Pasteur Institute, Nha Trang, Khanh Hoa, Vietnam
| | - Thanh Tien Hoang
- Department for Infectious Disease Control and Prevention, Nha Trang Pasteur Institute, Nha Trang, Khanh Hoa, Vietnam
| | - Hang Thi Hai Hoang
- Department for Infectious Disease Control and Prevention, Nha Trang Pasteur Institute, Nha Trang, Khanh Hoa, Vietnam
| | - Hoa Ngoc Lam
- Institute of Gastroenterology and Hepatology, Hanoi, Vietnam
| | - Mai Kim Huynh
- Department of Microbiology and Immunology, Nha Trang Pasteur Institute, Nha Trang, Khanh Hoa, Vietnam
| | - Lan Thi Hoang Vu
- Department of Epidemiology, Hanoi University of Public Health, Hanoi, Vietnam
| | - Jakob Zinsstag
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Daniel Henry Paris
- Faculty of Medicine, University of Basel, Basel, Switzerland.,Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
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Roberts T, Parker DM, Bulterys PL, Rattanavong S, Elliott I, Phommasone K, Mayxay M, Chansamouth V, Robinson MT, Blacksell SD, Newton PN. A spatio-temporal analysis of scrub typhus and murine typhus in Laos; implications from changing landscapes and climate. PLoS Negl Trop Dis 2021; 15:e0009685. [PMID: 34432800 PMCID: PMC8386877 DOI: 10.1371/journal.pntd.0009685] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/22/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Scrub typhus (ST) and murine typhus (MT) are common but poorly understood causes of fever in Laos. We examined the spatial and temporal distribution of ST and MT, with the intent of informing interventions to prevent and control both diseases. METHODOLOGY AND PRINCIPLE FINDINGS This study included samples submitted from 2003 to 2017 to Mahosot Hospital, Vientiane, for ST and MT investigation. Serum samples were tested using IgM rapid diagnostic tests. Patient demographic data along with meteorological and environmental data from Laos were analysed. Approximately 17% of patients were positive for either ST (1,337/8,150 patients tested) or MT (1,283/7,552 patients tested). While both diseases occurred in inhabitants from Vientiane Capital, from the univariable analysis MT was positively and ST negatively associated with residence in Vientiane Capital. ST was highly seasonal, with cases two times more likely to occur during the wet season months of July-September compared to the dry season whilst MT peaked in the dry season. Multivariable regression analysis linked ST incidence to fluctuations in relative humidity whereas MT was linked to variation in temperature. Patients with ST infection were more likely to come from villages with higher levels of surface flooding and vegetation in the 16 days leading up to diagnosis. CONCLUSIONS The data suggest that as cities expand, high risk areas for MT will also expand. With global heating and risks of attendant higher precipitation, these data suggest that the incidence and spatial distribution of both MT and ST will increase.
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Affiliation(s)
- Tamalee Roberts
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Daniel M. Parker
- University of California, Irvine, California, United States of America
| | - Philip L. Bulterys
- Department of Pathology, Stanford University, California, United States of America
| | - Sayaphet Rattanavong
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Ivo Elliott
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Koukeo Phommasone
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Mayfong Mayxay
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Institute of Research and Education Development (IRED), University of Health Sciences, Ministry of Health, Vientiane, Lao PDR
| | - Vilada Chansamouth
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Matthew T. Robinson
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Stuart D. Blacksell
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Mahidol-Oxford-Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paul N. Newton
- Lao-Oxford-Mahosot-Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Centre for Tropical Medicine & Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Mahidol-Oxford-Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Musa TH, Ahmad T, Wana MN, Li W, Musa HH, Sharun K, Tiwari R, Dhama K, Chaicumpa W, Campbell MC, Wei P. The epidemiology, diagnosis and management of scrub typhus disease in China. Hum Vaccin Immunother 2021; 17:3795-3805. [PMID: 34124995 DOI: 10.1080/21645515.2021.1934355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Thirty-nine years ago, scrub typhus (ST), a disease, was not among the China's notifiable diseases. However, ST has reemerged to become a growing public health issue in the southwest part of China. The major factors contributing to an increased incidence and prevalence of this disease include rapid globalization, urbanization, expansion of humans into previously uninhabited areas, and climate change. The clinical manifestation of ST also consists of high fever, headache, weakness, myalgia, rash, and an eschar. In severe cases, complications (e.g. multi-organ failure, jaundice, acute renal failure, pneumonitis, myocarditis, and even death) can occur. The diagnosis of ST is mainly based on serological identification by indirect immunofluorescence assay and other molecular methods. Furthermore, several groups of antibiotics (e.g. tetracycline, chloramphenicol, macrolides, and rifampicin) are currently effective in treating this disease. This fact suggests the need for robust early diagnostic techniques, increased surveillance, and prompt treatment, and develop future vaccine.
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Affiliation(s)
- Taha Hussein Musa
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China.,Biomedical Research Institute (BRI), Darfur College, Nyala, Sudan
| | - Tauseef Ahmad
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
| | - Mohammed Nasiru Wana
- Department of Biological Sciences, Faculty of Science, Abubakar Tafawa Balewa University, Bauchi, Nigeria
| | - Wei Li
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
| | - Hassan Hussein Musa
- Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan
| | - Khan Sharun
- Division of Surgery, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Ruchi Tiwari
- Department of Veterinary Microbiology and Immunology, College of Veterinary Sciences, UP Deen Dayal Upadhayaya Pashu Chikitsa Vigyan Vishwavidyalay Evum Go-Anusandhan Sansthan (DUVASU), Mathura, India
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Wanpen Chaicumpa
- Center of Research Excellence on Therapeutic Proteins and Antibody Engineering, Department of Parasitology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Pingmin Wei
- Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Department of Epidemiology and Health Statistics, School of Public Health, Southeast University, Nanjing, China
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Park JW, Yu DS, Lee GS, Seo JJ, Chung JK, Lee JI. Epidemiological Characteristics of Rodents and Chiggers with Orientia Tsutsugamushi in the Republic of Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2020; 58:559-564. [PMID: 33202508 PMCID: PMC7672239 DOI: 10.3347/kjp.2020.58.5.559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 09/26/2020] [Indexed: 01/31/2023]
Abstract
A survey of rodents and chiggers associated with Orientia tsutsugamushi was conducted in a rural region of the Republic of Korea (Korea) between 2014 and 2018. Overall Apodemus agrarius 15.2% had the highest seropisitive for O. tsutsugamushi, followed by Myodes regulus 11.4%. Monthly risk factors using logistic regression analysis were not associated with O. tsutsugamushi infections in rodents. The overall prevalence rate of O. tsutsugamushi among chiggers was 0.3%. The chigger (Leptotrombidium scutellare) and monthly (October) risk factors were associated with O. tsutsugamushi human infections (P<0.05). Orientia tsutsugamushi infections are endemic in rodents in Korea and people, for example, soldiers who are active outdoors, must employ preventive measures, especially during October (P<0.05). When there are many reports of O. tsutsugamushi infections in Korea. The Boryong strain 85.7% (2/14) was the most common strain detected in chiggers, followed by the Shimokoshi 7.1% (1/14) and Karp 7.1% strains.
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Affiliation(s)
- Jung Wook Park
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju, Gwangju 61986, Korea
| | - Dae Sung Yu
- Division of Animal Disease Control, Animal and Plant Quarantine Agency, Gyeongsangbuk-do 39660, Korea
| | - Gi Seong Lee
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju, Gwangju 61986, Korea
| | - Jin Jong Seo
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju, Gwangju 61986, Korea
| | - Jae Keun Chung
- Division of Infectious Disease Investigation, Health and Environment Research Institute of Gwangju, Gwangju 61986, Korea
| | - Jae Il Lee
- Department of Veterinary Public Health, College of Veterinary Medicine, Chonnam National University, Gwangju 62287, Korea
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Yao H, Wang Y, Mi X, Sun Y, Liu K, Li X, Ren X, Geng M, Yang Y, Wang L, Liu W, Fang L. The scrub typhus in mainland China: spatiotemporal expansion and risk prediction underpinned by complex factors. Emerg Microbes Infect 2019; 8:909-919. [PMID: 31233387 PMCID: PMC6598543 DOI: 10.1080/22221751.2019.1631719] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In mainland China, a geographic northward expansion of scrub typhus has been seen, highlighting the need to understand the factors and identify the risk for disease prevention. Incidence data from 1980 to 2013 were used. A Cox proportional hazard model was used to identify drivers for spatial spread, and a boosted regression tree (BRT) model was constructed to predict potential risk areas. Since the 1980s, an invasive expansion from South Natural Foci towards North Natural Foci was clearly identified, with the epidemiological heterogeneity observed between two regions, mainly in spatial distribution, seasonality, and demographic characteristics. Survival analysis disclosed significant factors contributing to the spatial expansion as following: being intersected by freeway (HR = 1.31, 95% CI: 1.11-1.54), coverage percentage of broadleaf forest (HR = 1.10, 95% CI: 1.06-1.15), and monthly average temperature (HR = 1.27, 95% CI: 1.25-1.30). The BRT models showed that precipitation, sunshine hour, temperature, crop field, and relative humidity contributed substantially to the spatial distribution of scrub typhus. A county-scale risk map was created to predict the regions with high probability of the disease. The current study enabled a comprehensive overview of epidemiological characteristics of scrub typhus in mainland China.
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Affiliation(s)
- Hongwu Yao
- a Department of Infection Management and Disease Control , Chinese PLA General Hospital , Beijing , People's Republic of China
| | - Yixing Wang
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China
| | - Xianmiao Mi
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China
| | - Ye Sun
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China.,c Center for Disease Control and Prevention of the North Military region , Jinan , People's Republic of China
| | - Kun Liu
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China.,d Department of Epidemiology and Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment , School of Public Health, Fourth Military Medical University , Xi'an , People's Republic of China
| | - Xinlou Li
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China.,e PLA Strategic Support Force Characteristic Medical Center , Beijing , People's Republic of China
| | - Xiang Ren
- f Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease , Chinese Centre for Disease Control and Prevention , Beijing , People's Republic of China
| | - Mengjie Geng
- f Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease , Chinese Centre for Disease Control and Prevention , Beijing , People's Republic of China
| | - Yang Yang
- g Department of Biostatistics , College of Public Health and Health Professions, and Emerging Pathogens Institute, University of Florida , Gainesville , FL , USA
| | - Liping Wang
- f Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease , Chinese Centre for Disease Control and Prevention , Beijing , People's Republic of China
| | - Wei Liu
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China.,h Beijing Key Laboratory of Vector Borne and Natural Focus Infectious Diseases , Beijing , People's Republic of China
| | - Liqun Fang
- b The State Key Laboratory of Pathogen and Biosecurity , Beijing Institute of Microbiology and Epidemiology , Beijing , People's Republic of China
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10
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Evans SM, Adcox HE, VieBrock L, Green RS, Luce-Fedrow A, Chattopadhyay S, Jiang J, Marconi RT, Paris D, Richards AL, Carlyon JA. Outer Membrane Protein A Conservation among Orientia tsutsugamushi Isolates Suggests Its Potential as a Protective Antigen and Diagnostic Target. Trop Med Infect Dis 2018; 3:E63. [PMID: 30274459 PMCID: PMC6073748 DOI: 10.3390/tropicalmed3020063] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/31/2018] [Accepted: 06/04/2018] [Indexed: 01/28/2023] Open
Abstract
Scrub typhus threatens one billion people in the Asia-Pacific area and cases have emerged outside this region. It is caused by infection with any of the multitude of strains of the bacterium Orientia tsutsugamushi. A vaccine that affords heterologous protection and a commercially-available molecular diagnostic assay are lacking. Herein, we determined that the nucleotide and translated amino acid sequences of outer membrane protein A (OmpA) are highly conserved among 51 O. tsutsugamushi isolates. Molecular modeling revealed the predicted tertiary structure of O. tsutsugamushi OmpA to be very similar to that of the phylogenetically-related pathogen, Anaplasma phagocytophilum, including the location of a helix that contains residues functionally essential for A. phagocytophilum infection. PCR primers were developed that amplified ompA DNA from all O. tsutsugamushi strains, but not from negative control bacteria. Using these primers in quantitative PCR enabled sensitive detection and quantitation of O. tsutsugamushi ompA DNA from organs and blood of mice that had been experimentally infected with the Karp or Gilliam strains. The high degree of OmpA conservation among O. tsutsugamushi strains evidences its potential to serve as a molecular diagnostic target and justifies its consideration as a candidate for developing a broadly-protective scrub typhus vaccine.
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Affiliation(s)
- Sean M Evans
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
| | - Haley E Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
| | - Lauren VieBrock
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
| | - Ryan S Green
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
| | - Alison Luce-Fedrow
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Biology, Shippensburg University, Shippensburg, PA 17257, USA.
| | - Suschsmita Chattopadhyay
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Richard T Marconi
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
| | - Daniel Paris
- Department of Medicine, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
| | - Jason A Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, VA 23298, USA.
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11
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Luce-Fedrow A, Lehman ML, Kelly DJ, Mullins K, Maina AN, Stewart RL, Ge H, John HS, Jiang J, Richards AL. A Review of Scrub Typhus (Orientia tsutsugamushi and Related Organisms): Then, Now, and Tomorrow. Trop Med Infect Dis 2018; 3:E8. [PMID: 30274407 PMCID: PMC6136631 DOI: 10.3390/tropicalmed3010008] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/26/2022] Open
Abstract
Scrub typhus and the rickettsial diseases represent some of the oldest recognized vector-transmitted diseases, fraught with a rich historical aspect, particularly as applied to military/wartime situations. The vectors of Orientia tsutsugamushi were once thought to be confined to an area designated as the Tsutsugamushi Triangle. However, recent reports of scrub typhus caused by Orientia species other than O. tsutsugamushi well beyond the limits of the Tsutsugamushi Triangle have triggered concerns about the worldwide presence of scrub typhus. It is not known whether the vectors of O. tsutsugamushi will be the same for the new Orientia species, and this should be a consideration during outbreak/surveillance investigations. Additionally, concerns surrounding the antibiotic resistance of O. tsutsugamushi have led to considerations for the amendment of treatment protocols, and the need for enhanced public health awareness in both the civilian and medical professional communities. In this review, we discuss the history, outbreaks, antibiotic resistance, and burgeoning genomic advances associated with one of the world's oldest recognized vector-borne pathogens, O. tsutsugamushi.
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Affiliation(s)
- Alison Luce-Fedrow
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Marcie L Lehman
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Daryl J Kelly
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA.
| | - Kristin Mullins
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Alice N Maina
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Richard L Stewart
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Hong Ge
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Heidi St John
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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12
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Xu G, Walker DH, Jupiter D, Melby PC, Arcari CM. A review of the global epidemiology of scrub typhus. PLoS Negl Trop Dis 2017; 11:e0006062. [PMID: 29099844 PMCID: PMC5687757 DOI: 10.1371/journal.pntd.0006062] [Citation(s) in RCA: 251] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/15/2017] [Accepted: 10/21/2017] [Indexed: 12/18/2022] Open
Abstract
Scrub typhus is a serious public health problem in the Asia-Pacific area. It threatens one billion people globally, and causes illness in one million people each year. Caused by Orientia tsutsugamushi, scrub typhus can result in severe multiorgan failure with a case fatality rate up to 70% without appropriate treatment. The antigenic heterogeneity of O. tsutsugamushi precludes generic immunity and allows reinfection. As a neglected disease, there is still a large gap in our knowledge of the disease, as evidenced by the sporadic epidemiologic data and other related public health information regarding scrub typhus in its endemic areas. Our objective is to provide a systematic analysis of current epidemiology, prevention and control of scrub typhus in its long-standing endemic areas and recently recognized foci of infection.
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Affiliation(s)
- Guang Xu
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David H. Walker
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Daniel Jupiter
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Peter C. Melby
- Department of Internal Medicine, Division of Infectious Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Christine M. Arcari
- Department of Preventive Medicine and Community Health, The University of Texas Medical Branch, Galveston, Texas, United States of America
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13
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Sun Y, Wei YH, Yang Y, Ma Y, de Vlas SJ, Yao HW, Huang Y, Ma MJ, Liu K, Li XN, Li XL, Zhang WH, Fang LQ, Yang ZC, Cao WC. Rapid increase of scrub typhus incidence in Guangzhou, southern China, 2006-2014. BMC Infect Dis 2017; 17:13. [PMID: 28056840 PMCID: PMC5216553 DOI: 10.1186/s12879-016-2153-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/22/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In the last decade, scrub typhus (ST) has been emerging or re-emerging in some areas of Asia, including Guangzhou, one of the most affected endemic areas of ST in China. METHODS Based on the data on all cases reported in Guangzhou from 2006 to 2014, we characterized the epidemiological features, and identified environmental determinants for the spatial distribution of ST using a panel negative binomial model. RESULTS A total of 4821 scrub typhus cases were reported in Guangzhou during 2006-2014. The annual incidence increased noticeably and the increase was relatively high and rapid in rural townships and among elderly females. The majority of cases (86.8%) occurred during May-October, and farmers constituted the majority of the cases, accounting for 33.9% in urban and 61.6% in rural areas. The number of housekeeper patients had a rapid increment in both rural and urban areas during the study period. Atmospheric pressure and relative humidity with lags of 1 or 2 months, distributions of broadleaved forest and rural township were identified as determinants for the spatiotemporal distribution of scrub typhus. CONCLUSION Our results indicate that surveillance and public education need to be focused on the elderly farmers in rural areas covered with broadleaf forest in southern China.
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Affiliation(s)
- Ye Sun
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China.,Center for Disease Control and Prevention of Jinan Military Region, Shandong Province, Jinan, 250014, People's Republic of China
| | - Yue-Hong Wei
- Guangzhou Center for Disease Control and Prevention, Guangdong Province, Guangzhou, 510440, People's Republic of China
| | - Yang Yang
- Department of Biostatistics, College of Public Health and Health Professions, and Emerging Pathogens Institute, University of Florida, 32311, Florida, USA
| | - Yu Ma
- Guangzhou Center for Disease Control and Prevention, Guangdong Province, Guangzhou, 510440, People's Republic of China
| | - Sake J de Vlas
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, 999025, Rotterdam, The Netherlands
| | - Hong-Wu Yao
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China
| | - Yong Huang
- Guangzhou Center for Disease Control and Prevention, Guangdong Province, Guangzhou, 510440, People's Republic of China
| | - Mai-Juan Ma
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China
| | - Kun Liu
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China
| | - Xiao-Ning Li
- Guangzhou Center for Disease Control and Prevention, Guangdong Province, Guangzhou, 510440, People's Republic of China
| | - Xin-Lou Li
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China
| | - Wen-Hui Zhang
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China
| | - Li-Qun Fang
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China.
| | - Zhi-Cong Yang
- Guangzhou Center for Disease Control and Prevention, Guangdong Province, Guangzhou, 510440, People's Republic of China.
| | - Wu-Chun Cao
- The State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dong-Da Street, Fengtai District, Beijing, 100071, People's Republic of China.
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14
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Abstract
The obligate intracellular bacterium Orientia tsutsugamushi is responsible for more than one million cases of scrub typhus annually throughout the Asia-Pacific region. Human infection occurs via the bite of the larval form (chigger) of several species of trombiculid mites. While in some patients the result of infection is a mild, febrile illness, others experience severe complications, which may even be fatal. This review discusses the genome and biology of the causative agent, the changing epidemiology of scrub typhus, the challenges of its diagnosis, and current treatment recommendations.
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Affiliation(s)
- Sunil Thomas
- Lankenau Institute for Medical Research, Wynnewood, Pennsylvania USA
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15
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Park SW, Ha NY, Ryu B, Bang JH, Song H, Kim Y, Kim G, Oh MD, Cho NH, Lee JK. Urbanization of scrub typhus disease in South Korea. PLoS Negl Trop Dis 2015; 9:e0003814. [PMID: 26000454 PMCID: PMC4441427 DOI: 10.1371/journal.pntd.0003814] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 05/05/2015] [Indexed: 01/19/2023] Open
Abstract
Background Scrub typhus is an endemic disease in Asia. It has been a rural disease, but indigenous urban cases have been observed in Seoul, South Korea. Urban scrub typhus may have a significant impact because of the large population. Methods Indigenous urban scrub typhus was epidemiologically identified in Seoul, the largest metropolitan city in South Korea, using national notifiable disease data from 2010 to 2013. For detailed analysis of clinical features, patients from one hospital that reported the majority of cases were selected and compared to a historic control group. Chigger mites were prospectively collected in the city using a direct chigger mite-collecting trap, and identified using both phenotypic and 18S rDNA sequencing analyses. Their infection with Orientia tsutsugamushi was confirmed by sequencing the 56-kDa antigen gene. Results Eighty-eight cases of urban scrub typhus were determined in Seoul. The possible sites of infection were mountainous areas (56.8%), city parks (20.5%), the vicinity of one’s own residence (17.0%), and riversides (5.7%). Eighty-seven chigger mites were collected in Gwanak mountain, one of the suspected infection sites in southern Seoul, and seventy-six (87.4%) of them were identified as Helenicula miyagawai and eight (9.2%) as Leptotrombidium scutellare. Pooled DNA extracted from H. miyagawai mites yielded O. tsutsugamushi Boryong strain. Twenty-six patients from one hospital showed low APACHE II score (3.4 ± 2.7), low complication rate (3.8%), and no hypokalemia. Conclusions We identified the presence of indigenous urban scrub typhus in Seoul, and a subgroup of them had mild clinical features. The chigger mite H. miyagawai infected with O. tsutsugamushi within the city was found. In endemic area, urban scrub typhus needs to be considered as one of the differential febrile diseases and a target for prevention. Scrub typhus is one of the high burdened infectious diseases in endemic rural areas. Our study showed that the disease could be endemic in urban areas. Indigenous urban scrub typhus may also have significant impact in terms of a disease burden and differential diagnosis. A low rate of characteristic eschar and skin rash may make the clinical suspicion more troublesome. Scrub typhus is the 3rd most frequent notifiable infectious disease in South Korea. Seoul is a densely populated capital city located in northwestern South Korea. We epidemiologically identified indigenous urban cases. A subgroup of them showed mild clinical characteristics. Direct mite collection from a suspected infection site, Mt. Gwanak in Seoul, showed that Helenicula miyagawai (87.4%) and Leptotrombidium scutellare (9.2%) were the dominant species. In addition, O. tsutsugamushi-specific gene, tsa56, was identified in a fraction of the collected H. miyagawai. The 18S rDNA sequencing of the chigger mites was complementarily helpful for the differentiation of species. Our data are from one region, but urban scrub typhus is likely a scenario in endemic areas. Urban areas should be included as possible locations for scrub typhus.
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Affiliation(s)
- Sang-Won Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Internal Medicine, Boramae Medical Center, Seoul, Republic of Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine and Bundang Hospital, Seoul, Republic of Korea
| | - Boyeong Ryu
- Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
- Seoul Center for Infectious Disease Control, Seoul, Republic of Korea
| | - Ji Hwan Bang
- Department of Internal Medicine, Boramae Medical Center, Seoul, Republic of Korea
- Seoul Center for Infectious Disease Control, Seoul, Republic of Korea
| | - Hoyeon Song
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine and Bundang Hospital, Seoul, Republic of Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine and Bundang Hospital, Seoul, Republic of Korea
| | - Gwanghun Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine and Bundang Hospital, Seoul, Republic of Korea
| | - Myoung-don Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- Seoul Center for Infectious Disease Control, Seoul, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine and Bundang Hospital, Seoul, Republic of Korea
- * E-mail: (NHC); (JkL)
| | - Jong-koo Lee
- Seoul Center for Infectious Disease Control, Seoul, Republic of Korea
- Department of Family Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- * E-mail: (NHC); (JkL)
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