1
|
Lamichhane P, Pokhrel KM, Alghalyini B, Zaidi ARZ, Alshehery MZ, Khanal K, Bhattarai M, Yadav A. Epidemiology, clinical characteristics, diagnosis, and complications of scrub typhus infection in Nepal: a systematic review. Ann Med Surg (Lond) 2023; 85:5022-5030. [PMID: 37811079 PMCID: PMC10553080 DOI: 10.1097/ms9.0000000000001259] [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: 07/22/2023] [Accepted: 08/23/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Scrub typhus (ST) is a neglected tropical disease of serious concern in Nepal. This systematic review aims to describe the burden of disease, clinical presentation, and complications of ST infection in Nepal. Methods A systematic search of PubMed, EMBASE, Google Scholar, and national databases was conducted for any literature published in English between January 2000 and January 2023. Any type of study design (observational studies, case series, and interventional studies) that reported laboratory-confirmed ST and was conducted in Nepal among patients of all age groups was included. The seroprevalence of ST among acute undifferentiated febrile illness (AUFI) cases, geographical distribution, monthly distribution, clinical presentations, complications, and treatment were assessed by the study. Result A total of 15 studies with 10, 977 participants were included in the review. The seroprevalence of ST among the AUFI cases in Nepal was 19.31%. Young people at or below 20 years of age were mostly affected. The maximum number of cases were reported from Bagmati province (59.46%) and in the month of August (26.33%). Fever, headache, cough, shortness of breath, nausea, and abdominal pain were the clinical characteristics in decreasing order of occurrence. The most common complication was acute kidney injury, followed by respiratory problems, cardiac issues, and neurological manifestations. The case fatality rate of ST in Nepal was 2.56%. Conclusion The authors findings showed a significant burden of ST among AUFI cases in Nepal. Improved surveillance, general public awareness, and early detection post-calamities could help reduce the disease burden and improve patient outcomes.
Collapse
Affiliation(s)
| | | | - Baraa Alghalyini
- Department of Family and Community Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Abdul Rehman Zia Zaidi
- Department of Family and Community Medicine, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Maied Z. Alshehery
- Department of Palliative Care, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Kapil Khanal
- Maharajgunj Medical Campus, Institute of Medicine, Kathmandu, Nepal
| | - Madhur Bhattarai
- Maharajgunj Medical Campus, Institute of Medicine, Kathmandu, Nepal
| | - Alisha Yadav
- Maharajgunj Medical Campus, Institute of Medicine, Kathmandu, Nepal
| |
Collapse
|
2
|
Brindle HE, Bastos LS, Christley R, Contamin L, Dang LH, Anh DD, French N, Griffiths M, Nadjm B, van Doorn HR, Thai PQ, Duong TN, Choisy M. The spatio-temporal distribution of acute encephalitis syndrome and its association with climate and landcover in Vietnam. BMC Infect Dis 2023; 23:403. [PMID: 37312047 PMCID: PMC10262680 DOI: 10.1186/s12879-023-08300-1] [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: 01/22/2023] [Accepted: 05/03/2023] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND Acute encephalitis syndrome (AES) differs in its spatio-temporal distribution in Vietnam with the highest incidence seen during the summer months in the northern provinces. AES has multiple aetiologies, and the cause remains unknown in many cases. While vector-borne disease such as Japanese encephalitis and dengue virus and non-vector-borne diseases such as influenza and enterovirus show evidence of seasonality, associations with climate variables and the spatio-temporal distribution in Vietnam differs between these. The aim of this study was therefore to understand the spatio-temporal distribution of, and risk factors for AES in Vietnam to help hypothesise the aetiology. METHODS The number of monthly cases per province for AES, meningitis and diseases including dengue fever; influenza-like-illness (ILI); hand, foot, and mouth disease (HFMD); and Streptococcus suis were obtained from the General Department for Preventive Medicine (GDPM) from 1998-2016. Covariates including climate, normalized difference vegetation index (NDVI), elevation, the number of pigs, socio-demographics, JEV vaccination coverage and the number of hospitals were also collected. Spatio-temporal multivariable mixed-effects negative binomial Bayesian models with an outcome of the number of cases of AES, a combination of the covariates and harmonic terms to determine the magnitude of seasonality were developed. RESULTS The national monthly incidence of AES declined by 63.3% over the study period. However, incidence increased in some provinces, particularly in the Northwest region. In northern Vietnam, the incidence peaked in the summer months in contrast to the southern provinces where incidence remained relatively constant throughout the year. The incidence of meningitis, ILI and S. suis infection; temperature, relative humidity with no lag, NDVI at a lag of one month, and the number of pigs per 100,000 population were positively associated with the number of cases of AES in all models in which these covariates were included. CONCLUSIONS The positive correlation of AES with temperature and humidity suggest that a number of cases may be due to vector-borne diseases, suggesting a need to focus on vaccination campaigns. However, further surveillance and research are recommended to investigate other possible aetiologies such as S. suis or Orientia tsutsugamushi.
Collapse
Affiliation(s)
- Hannah E Brindle
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
- Oxford University Clinical Research Unit, Hanoi City, Vietnam.
| | - Leonardo S Bastos
- Scientific Computing Programme, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Robert Christley
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Lucie Contamin
- Institut de Recherche Pour Le Développement, Hanoi, Vietnam
| | - Le Hai Dang
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Dang Duc Anh
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Neil French
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Michael Griffiths
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Behzad Nadjm
- Oxford University Clinical Research Unit, Hanoi City, Vietnam
- MRC Unit The Gambia at the London, School of Hygiene & Tropical Medicine, Fajara, The Gambia
| | - H Rogier van Doorn
- Oxford University Clinical Research Unit, Hanoi City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Pham Quang Thai
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
- School Preventive Medicine and Public Health, Hanoi Medical University, Hanoi, Vietnam
| | - Tran Nhu Duong
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Marc Choisy
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| |
Collapse
|
3
|
Walker DH, Mendell NL. A scrub typhus vaccine presents a challenging unmet need. NPJ Vaccines 2023; 8:11. [PMID: 36759505 PMCID: PMC9910236 DOI: 10.1038/s41541-023-00605-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 01/17/2023] [Indexed: 02/11/2023] Open
Abstract
Scrub typhus caused by the obligately intracellular bacterium, Orientia tsutsugamushi, is a major cause of life-threatening acute undifferentiated febrile illness in eastern Asia and the islands of the Western Pacific and Indian oceans. Since the estimation of an incidence of 1 million cases annually two decades ago, the number of cases has increased substantially in endemic regions, reappeared where the disease was forgotten, and spread northward. Trombiculid mites are both reservoir and vector. Despite 80 years of efforts to develop a vaccine, there is none. Protective immunity is mediated by antibodies and CD8 and CD4 T cells. Previous efforts have failed because of gaps in understanding immunity to O. tsutsugamushi, particularly the requirements for vaccine-induced immunity, lack of knowledge regarding immune memory in scrub typhus, and lack of attention to addressing the issue of cross-protection between strains. There are numerous strains of O. tsutsugamushi, and modestly durable immunity is strain-specific. Antibodies to the strain that caused infection are protective against challenges with the homologous strain but, despite reactivity with other immunodominant antigens, the immune serum does not protect against heterologous strains. Among the antigens detected by western immunoblot in immune sera (22-, 47-, 56-, 58-, and 110 kDa proteins), only the 56 kDa protein stimulates strong protection. This protein contains four hypervariable regions which are likely, on the basis of limited data, to be the targets of neutralizing antibodies. However, a method that definitively detects neutralizing antibody has yet to be developed. Only one study has used genomic data to pursue the discovery of protective antigens. Three conserved autotransporters were identified, and only immunization with ScaA provided protection against the homologous strain, but only 40% of animals were protected against challenge with a heterologous strain. A multiplex vaccine containing conformational antigens of the hypervariable regions of the 56 kDa protein of the strains of the greatest clinical and epidemiological importance, as well as conserved regions of the 56 kDa protein, ScaA, and other protective antigens identified by future genomic and bioinformatics methods should be developed and tested.
Collapse
Affiliation(s)
- David H. Walker
- grid.176731.50000 0001 1547 9964Department of Pathology, The University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555 USA
| | - Nicole L. Mendell
- grid.176731.50000 0001 1547 9964Department of Pathology, The University of Texas Medical Branch at Galveston, 301 University Blvd., Galveston, TX 77555 USA
| |
Collapse
|
4
|
Li X, Wei X, Yin W, Soares Magalhaes RJ, Xu Y, Wen L, Peng H, Qian Q, Sun H, Zhang W. Using ecological niche modeling to predict the potential distribution of scrub typhus in Fujian Province, China. Parasit Vectors 2023; 16:44. [PMID: 36721181 PMCID: PMC9887782 DOI: 10.1186/s13071-023-05668-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/13/2023] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Despite the increasing number of cases of scrub typhus and its expanding geographical distribution in China, its potential distribution in Fujian Province, which is endemic for the disease, has yet to be investigated. METHODS A negative binomial regression model for panel data mainly comprising meteorological, socioeconomic and land cover variables was used to determine the risk factors for the occurrence of scrub typhus. Maximum entropy modeling was used to identify the key predictive variables of scrub typhus and their ranges, map the suitability of different environments for the disease, and estimate the proportion of the population at different levels of infection risk. RESULTS The final multivariate negative binomial regression model for panel data showed that the annual mean normalized difference vegetation index had the strongest correlation with the number of scrub typhus cases. With each 0.1% rise in shrubland and 1% rise in barren land there was a 75.0% and 37.0% increase in monthly scrub typhus cases, respectively. In contrast, each unit rise in mean wind speed in the previous 2 months and each 1% increase in water bodies corresponded to a decrease of 40.0% and 4.0% in monthly scrub typhus cases, respectively. The predictions of the maximum entropy model were robust, and the average area under the curve value was as high as 0.864. The best predictive variables for scrub typhus occurrence were population density, annual mean normalized difference vegetation index, and land cover types. The projected potentially most suitable areas for scrub typhus were widely distributed across the eastern coastal area of Fujian Province, with highly suitable and moderately suitable areas accounting for 16.14% and 9.42%, respectively. Of the total human population of the province, 81.63% reside in highly suitable areas for scrub typhus. CONCLUSIONS These findings could help deepen our understanding of the risk factors of scrub typhus, and provide information for public health authorities in Fujian Province to develop more effective surveillance and control strategies in identified high risk areas in Fujian Province.
Collapse
Affiliation(s)
- Xuan Li
- grid.186775.a0000 0000 9490 772XDepartment of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China ,grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xianyu Wei
- grid.186775.a0000 0000 9490 772XDepartment of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China ,grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Wenwu Yin
- grid.198530.60000 0000 8803 2373Chinese Center for Disease Control and Prevention, Beijing, China
| | - Ricardo J. Soares Magalhaes
- grid.1003.20000 0000 9320 7537Spatial Epidemiology Laboratory, School of Veterinary Science, The University of Queensland, Brisbane, Australia ,grid.1003.20000 0000 9320 7537Child Health Research Center, The University of Queensland, Brisbane, Australia
| | - Yuanyong Xu
- grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Liang Wen
- grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Hong Peng
- grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Quan Qian
- grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Hailong Sun
- grid.186775.a0000 0000 9490 772XDepartment of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China ,grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Wenyi Zhang
- grid.186775.a0000 0000 9490 772XDepartment of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, China ,grid.488137.10000 0001 2267 2324Chinese PLA Center for Disease Control and Prevention, Beijing, China
| |
Collapse
|
5
|
Prajapati SM, Kaushal K, Tiwari S, Shewale A, Nale T, Dikid T. Evaluation of Scrub Typhus Surveillance, Alwar District, Rajasthan, India, July-August 2020. Indian J Community Med 2023; 48:177-182. [PMID: 37082391 PMCID: PMC10112742 DOI: 10.4103/ijcm.ijcm_385_22] [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: 05/07/2022] [Accepted: 12/07/2022] [Indexed: 02/11/2023] Open
Abstract
Introduction Scrub typhus is one of the most underreported and fatal illnesses accounting for 23% of all febrile illness. Rajasthan reported cases during 2018-2019 in state reporting system but did not report any case to central Integrated Disease Surveillance Programme (IDSP) unit. We evaluated the Scrub typhus surveillance system in Alwar district, Rajasthan, with the objective of describing and evaluating the system and providing evidence-based recommendations to identify gaps. Material and Methods In cross-sectional study, we reviewed records and conducted key informant interviews at district- and block-level health facilities. Using US Centers for Disease Control guidelines, we evaluated the system by framing indicators for selected attributes for a defined reference period. Overall performance was ranked as outstanding (90-100%), excellent (80-89%), very good (70-79%), good (60-69%), and poor (<60%). Results Line list of confirmed cases was sent from district to block level for additional active case search (ACS) to implement control measures. We conducted 26 key informant interviews and reviewed records and calculated simplicity as 79%, flexibility 100%, data quality 46%, acceptability 92%, representativeness 48%, timeliness 43%, and stability 79%. Conclusions Epidemiological surveillance (active and passive) is a core intervention under scrub typhus surveillance system. Lab reports were incompletely uploaded on IDSP portal. Surveillance reports should be updated after each ACS. Reporting format under IDSP should be uploaded timely, and lab reports from state should be sent within 48 hours of diagnosis so that case investigation is not delayed.
Collapse
Affiliation(s)
- Surendra M. Prajapati
- Deputy Chief Medical Officer, Integrated Disease Surveillance Programme, Agra, New Delhi, India
| | - Kanica Kaushal
- Department of Clinical Research and Epidemiology, Institute of Liver and Biliary Sciences, New Delhi, India
| | - Simmi Tiwari
- Joint Director, Division of Zoonotic Diseases Programme, NCDC, New Delhi, India
| | - Ajit Shewale
- Joint Director, Division of Zoonotic Diseases Programme, NCDC, New Delhi, India
| | - Tushar Nale
- Division of Zoonotic Diseases Programme, NCDC, New Delhi, India
| | - Tanzin Dikid
- Division of Epidemiology, NCDC, New Delhi, India
| |
Collapse
|
6
|
Bhandari M, Singh RK, Laishevtcev A, Mohapatra TM, Nigam M, Mori E, Vasconcelos de Lacerda BCG, Coutinho HDM, Mishra AP. Revisiting scrub typhus: A neglected tropical disease. Comp Immunol Microbiol Infect Dis 2022; 90-91:101888. [PMID: 36252451 DOI: 10.1016/j.cimid.2022.101888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/18/2022] [Accepted: 09/29/2022] [Indexed: 02/08/2023]
Abstract
Scrub typhus is an under diagnosed re-emerging vector borne disease caused by an intracellular gram negative bacteria, Orientia. The disease is commonly prevalent in rural and hilly areas of Tsutsugumashi triangle. The diagnosis of the disease is very challenging due to similarity of its early symptoms with other febrile illnesses, like dengue and COVID 19, as well as non-availability of rapid, reliable and cost-effective methods. Moreover, the diverse clinical presentation in severe cases make it significant health problem. The occupational and behavioral risks responsible for the transmission lead to urgent need of vaccine development against the disease. The complete knowledge about its pathogenesis and the interaction with host's immune cells may help the scientists in developing the appropriate diagnostic methods as well as the vaccines.
Collapse
Affiliation(s)
- Munni Bhandari
- Department of Microbiology, School of Life Sciences, Hemvati Nandan Bahuguna Garhwal University, Srinagar (Garhwal) 246174, India.
| | - Rahul Kunwar Singh
- Department of Microbiology, School of Life Sciences, Hemvati Nandan Bahuguna Garhwal University, Srinagar (Garhwal) 246174, India.
| | - Alexey Laishevtcev
- Federal Research Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Y.R. Kovalenko of the Russian Academy of Sciences, Moscow, Russia; Laboratory of Biocontrol and Antimicrobial Resistance, Orel State, University Named After I.S. Turgenev, Orel, Russia.
| | - Tribhuvan Mohan Mohapatra
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
| | - Manisha Nigam
- Department of Biochemistry, Hemvati Nandan Bahuguna Garhwal University, Srinagar Garhwal-246174, Uttarakhand, India.
| | - Edna Mori
- CECAPE - College of Dentistry, Av. Padre Cícero, 3917, Juazeiro do Norte, São José CE 63024-015, Brazil.
| | | | | | - Abhay Prakash Mishra
- Department of Pharmacology, Faculty of Health Science, University of Free State, Bloemfontein 9300, South Africa.
| |
Collapse
|
7
|
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.
Collapse
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
| | | |
Collapse
|
8
|
Seroprevalence and Clinical Features of Scrub Typhus among Febrile Patients Attending a Referral Hospital in Kathmandu, Nepal. Trop Med Infect Dis 2021; 6:tropicalmed6020078. [PMID: 34068402 PMCID: PMC8163188 DOI: 10.3390/tropicalmed6020078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/20/2021] [Accepted: 05/01/2021] [Indexed: 01/10/2023] Open
Abstract
(1) Background: Scrub typhus (ST) is endemic to Nepal. It is often underdiagnosed and misdiagnosed due to non-specific clinical presentation coupled with limited microbiological facilities, leading to adverse clinical outcomes. This study aimed to assess the seroprevalence of scrub typhus in febrile patients attending Sukraraj Tropical and Infectious Disease Hospital (STIDH), Nepal, from August 2018 to April 2019. (2) Materials and Method: Blood/serum samples and clinical and demographic data of adult febrile patients (≥19 years) who attended or were referred to the hospital were collected after obtaining written informed consent from the participants excluding immunocompromised individuals. Collected blood/serum samples were subjected to hematological, biochemical, and serological tests. A serological test for scrub typhus was performed using the ImmuneMed scrub typhus rapid diagnostic test kit. Data generated were analyzed using SPSS software version 24.0. (3) Results: Amongst the 2070 febrile patients, 462 (22.3%) were seropositive to at least one etiological agent of febrile illnesses (scrub typhus: 253 cases, dengue: 101 cases, leptospirosis: 9, brucellosis: 52, malaria: 9 and kala-azar: 20 cases). Scrub typhus accounted for 12.2% (n = 253) of total febrile illnesses followed by dengue (4.9%, n = 101). Mixed seropositivity of scrub typhus with dengue, brucellosis, and typhoid was found in 12 (0.6%), 9 (0.4%), and 5 (0.2%) cases, respectively. Among 253 scrub typhus patients, 53.4% were female. Among the 154 patients, the most common symptoms were fever (100%), headache (79.2%), sweating (70.1%), breathing difficulty (51.3%), redness of the eye (43.5%), and pathognomonic eschar was observed in 9.1% patients. Fifty percent of scrub typhus patients had low platelet count and >30% of patients had an elevated level of liver enzymes (such as serum glutamic oxaloacetic transaminase (SGPT) and serum glutamic pyruvic transaminase (SGOT). (4) Conclusion: Scrub typhus is a considerable cause of febrile illness in Nepal. Females apparently have a higher chance of acquiring scrub typhus. ST presents nonspecific clinical presentation. The diagnostic dilemma of typhus patients can be minimized by the early monitoring of ST-associated symptoms. The country's health system needs to be strengthened for early outbreak detection, and immediate response actions against scrub typhus to control the future outbreak of ST.
Collapse
|
9
|
Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal. Pathogens 2021; 10:pathogens10040422. [PMID: 33916224 PMCID: PMC8066985 DOI: 10.3390/pathogens10040422] [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: 03/15/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 11/17/2022] Open
Abstract
Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that homologous recombination may influence the genetic diversity of strains in this region. Knowledge on the circulating strains in Nepal is important to the development of diagnostic tests and vaccines to support public health measures to control scrub typhus in this country.
Collapse
|
10
|
Paris DH, Kelly DJ, Fuerst PA, Day NPJ, Richards AL. A Brief History of the Major Rickettsioses in the Asia-Australia-Pacific Region: A Capstone Review for the Special Issue of TMID. Trop Med Infect Dis 2020; 5:tropicalmed5040165. [PMID: 33121158 PMCID: PMC7709643 DOI: 10.3390/tropicalmed5040165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
The rickettsioses of the "Far East" or Asia-Australia-Pacific region include but are not limited to endemic typhus, scrub typhus, and more recently, tick typhus or spotted fever. These diseases embody the diversity of rickettsial disease worldwide and allow us to interconnect the various contributions to this special issue of Tropical Medicine and Infectious Disease. The impact of rickettsial diseases-particularly of scrub typhus-was substantial during the wars and "police actions" of the last 80 years. However, the post-World War II arrival of effective antibiotics reduced their impact, when recognized and adequately treated (chloramphenicol and tetracyclines). Presently, however, scrub typhus appears to be emerging and spreading into regions not previously reported. Better diagnostics, or higher population mobility, change in antimicrobial policies, even global warming, have been proposed as possible culprits of this phenomenon. Further, sporadic reports of possible antibiotic resistance have received the attention of clinicians and epidemiologists, raising interest in developing and testing novel diagnostics to facilitate medical diagnosis. We present a brief history of rickettsial diseases, their relative importance within the region, focusing on the so-called "tsutsugamushi triangle", the past and present impact of these diseases within the region, and indicate how historically, these often-confused diseases were ingeniously distinguished from each another. Moreover, we will discuss the importance of DNA-sequencing efforts for Orientia tsutsugamushi, obtained from patient blood, vector chiggers, and rodent reservoirs, particularly for the dominant 56-kD type-specific antigen gene (tsa56), and whole-genome sequences, which are increasing our knowledge of the diversity of this unique agent. We explore and discuss the potential of sequencing and other effective tools to geographically trace rickettsial disease agents, and develop control strategies to better mitigate the rickettsioses.
Collapse
Affiliation(s)
- Daniel H. Paris
- Department of Medicine, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
- Department of Clinical Research, University of Basel, 4051 Basel, Switzerland
- Correspondence: ; Tel.: +41-61-284-8111
| | - Daryl J. Kelly
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA; (D.J.K.); (P.A.F.)
| | - Paul A. Fuerst
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA; (D.J.K.); (P.A.F.)
| | - Nicholas P. J. Day
- Mahidol-Oxford Tropical Medicine Research Programme, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithee Road, Bangkok 10400, Thailand;
- Center for Tropical Medicine, Nuffield Department of Clinical Medicine, Churchill Hospital, Old Road, Headington, Oxford OX3 7LJ, UK
| | - Allen L. Richards
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA;
| |
Collapse
|
11
|
Mapping Environmental Suitability of Scrub Typhus in Nepal Using MaxEnt and Random Forest Models. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16234845. [PMID: 31810239 PMCID: PMC6926588 DOI: 10.3390/ijerph16234845] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 11/17/2022]
Abstract
Being a globally emerging mite-borne zoonotic disease, scrub typhus is a serious public health concern in Nepal. Mapping environmental suitability and quantifying the human population under risk of the disease is important for prevention and control efforts. In this study, we model and map the environmental suitability of scrub typhus using the ecological niche approach, machine learning modeling techniques, and report locations of scrub typhus along with several climatic, topographic, Normalized Difference Vegetation Index (NDVI), and proximity explanatory variables and estimated population under the risk of disease at a national level. Both MaxEnt and RF technique results reveal robust predictive power with test The area under curve (AUC) and true skill statistics (TSS) of above 0.8 and 0.6, respectively. Spatial prediction reveals that environmentally suitable areas of scrub typhus are widely distributed across the country particularly in the low-land Tarai and less elevated river valleys. We found that areas close to agricultural land with gentle slopes have higher suitability of scrub typhus occurrence. Despite several speculations on the association between scrub typhus and proximity to earthquake epicenters, we did not find a significant role of proximity to earthquake epicenters in the distribution of scrub typhus in Nepal. About 43% of the population living in highly suitable areas for scrub typhus are at higher risk of infection, followed by 29% living in suitable areas of moderate-risk, and about 22% living in moderately suitable areas of lower risk. These findings could be useful in selecting priority areas for surveillance and control strategies effectively.
Collapse
|
12
|
Wangdi K, Kasturiaratchi K, Nery SV, Lau CL, Gray DJ, Clements ACA. Diversity of infectious aetiologies of acute undifferentiated febrile illnesses in south and Southeast Asia: a systematic review. BMC Infect Dis 2019; 19:577. [PMID: 31272417 PMCID: PMC6610835 DOI: 10.1186/s12879-019-4185-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 06/12/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Acute undifferentiated febrile illness (AUFI) is caused by a multitude of diverse pathogens, with significant morbidity and mortality in the developing world. The objective of this review was to characterise the diversity and relative importance of common infectious aetiologies of AUFI in South and Southeast Asia. METHODS We conducted a comprehensive literature review to identify common aetiologies of AUFI in Asian countries. Four medical and life sciences databases including PubMed, Medline, Embase and Cochrane Central, and Google Scholar were searched for articles published from January 1998 to March 2019. RESULTS Forty-three studies met the inclusion criteria. Among AUFI cases, viral aetiologies at 18.5% (14888) were more common than bacterial aetiologies (12.9% [10384]). From 80,554 cases, dengue fever was the most common aetiology (11.8%, 9511), followed by leptospirosis (4.4%, 3549), typhoid (4.0%, 3258), scrub typhus (4.0%, 3243) and influenza other than H1N1 (3.1%, 2514). In both adults and children: dengue fever was the leading cause of AUFI with 16.6% (1928) and 18.7% (1281) of the total cases. In admitted patients, dengue fever was the main cause of AUFI at 16.4% (2377), however leptospirosis at 13.9% (2090) was the main cause of AUFI for outpatients. In South Asia, dengue fever was the main cause of AUFI, causing 12.0% (6821) of cases, whereas in Southeast Asia, leptospirosis was the main diagnosis, causing 12.1% (2861) of cases. CONCLUSIONS In this study the most common causes of AUFI were viral, followed by bacterial and protozoal (malaria) infections. Dengue was the commonest virus that caused AUFI while leptospirosis and typhoid were important bacterial infectious causes. Therefore, it is imperative to maintain a sound epidemiological knowledge of AUFI so that evidence-based diagnostic criteria and treatment guidelines can be developed.
Collapse
Affiliation(s)
- Kinley Wangdi
- Department of Global Health, Research School of Population Health, Australian National University, Action, ACT, Canberra, Australia.
| | | | - Susana Vaz Nery
- Department of Global Health, Research School of Population Health, Australian National University, Action, ACT, Canberra, Australia.,Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Colleen L Lau
- Department of Global Health, Research School of Population Health, Australian National University, Action, ACT, Canberra, Australia.,Children's Health and Environment Program, Child Health Research Centre, The University of Queensland, QLD, South Brisbane, Australia
| | - Darren J Gray
- Department of Global Health, Research School of Population Health, Australian National University, Action, ACT, Canberra, Australia
| | - Archie C A Clements
- Department of Global Health, Research School of Population Health, Australian National University, Action, ACT, Canberra, Australia.,Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| |
Collapse
|