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Liang Y, Aditi, Onyoni F, Wang H, Gonzales C, Sunyakumthorn P, Wu P, Samir P, Soong L. Brain transcriptomics reveal the activation of neuroinflammation pathways during acute Orientia tsutsugamushi infection in mice. Front Immunol 2023; 14:1194881. [PMID: 37426673 PMCID: PMC10326051 DOI: 10.3389/fimmu.2023.1194881] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 05/02/2023] [Indexed: 09/03/2023] Open
Abstract
Scrub typhus, an acute febrile illness caused by Orientia tsutsugamushi (Ot), is prevalent in endemic areas with one million new cases annually. Clinical observations suggest central nervous system (CNS) involvement in severe scrub typhus cases. Acute encephalitis syndrome (AES) associated with Ot infection is a major public health problem; however, the underlying mechanisms of neurological disorder remain poorly understood. By using a well-established murine model of severe scrub typhus and brain RNA-seq, we studied the brain transcriptome dynamics and identified the activated neuroinflammation pathways. Our data indicated a strong enrichment of several immune signaling and inflammation-related pathways at the onset of disease and prior to host death. The strongest upregulation of expression included genes involved in interferon (IFN) responses, defense response to bacteria, immunoglobulin-mediated immunity, IL-6/JAK-STAT signaling, and TNF signaling via NF-κB. We also found a significant increase in the expression of core genes related to blood-brain barrier (BBB) disruption and dysregulation in severe Ot infection. Brain tissue immunostaining and in vitro infection of microglia revealed microglial activation and proinflammatory cytokine production, suggesting a crucial role of microglia in neuroinflammation during scrub typhus. This study provides new insights into neuroinflammation in scrub typhus, highlighting the impact of excessive IFN responses, microglial activation, and BBB dysregulation on disease pathogenesis.
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Affiliation(s)
- Yuejin Liang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
| | - Aditi
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Florence Onyoni
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
| | - Hui Wang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Casey Gonzales
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Piyanate Sunyakumthorn
- Department of Veterinary Medicine, United States Army Medical Directorate, Armed Forces Research Institute of Medical Sciences (United States MD-AFRIMS), Bangkok, Thailand
| | - Ping Wu
- Department of Neuroscience, Cell Biology and Anatomy, University of Texas Medical Branch, Galveston, TX, United States
| | - Parimal Samir
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
| | - Lynn Soong
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, United States
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
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Zaman K. Scrub typhus, a salient threat: Needs attention. PLoS Negl Trop Dis 2023; 17:e0011427. [PMID: 37384603 DOI: 10.1371/journal.pntd.0011427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023] Open
Abstract
Scrub typhus (ST) infection is one of the most significant causes of acute undifferentiated febrile illness, and its prevalence has been increasing across the globe. Clinical suspicion and growing clinical understanding among healthcare professionals have resulted in the rapid diagnosis and effective management. Since ST has the potential to cause multiorgan failure and a higher mortality rate, it is critical to enhance surveillance, make rapid diagnosis, and administer antibiotics appropriately.
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Affiliation(s)
- Kamran Zaman
- Scientist E, Department of Microbiology and Molecular Biology, Indian Council of Medical Research - National Institute of Traditional Medicine Belagavi (ICMR-NITM Belagavi), Karnataka, India
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Alam AM, Gillespie CS, Goodall J, Damodar T, Turtle L, Vasanthapuram R, Solomon T, Michael BD. Neurological manifestations of scrub typhus infection: A systematic review and meta-analysis of clinical features and case fatality. PLoS Negl Trop Dis 2022; 16:e0010952. [PMID: 36441812 PMCID: PMC9731453 DOI: 10.1371/journal.pntd.0010952] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 12/08/2022] [Accepted: 11/07/2022] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Scrub typhus has become a leading cause of central nervous system (CNS) infection in endemic regions. As a treatable condition, prompt recognition is vital. However, few studies have focused on describing the symptomology and outcomes of neurological scrub typhus infection. We conducted a systematic review and meta-analysis to report the clinical features and case fatality ratio (CFR) in patients with CNS scrub typhus infection. METHODS A search and analysis plan was published in PROSPERO [ID 328732]. A systematic search of PubMed and Scopus was performed and studies describing patients with CNS manifestations of proven scrub typhus infection were included. The outcomes studied were weighted pooled prevalence (WPP) of clinical features during illness and weighted CFR. RESULTS Nineteen studies with 1,221 (656 adults and 565 paediatric) patients were included. The most common clinical features in CNS scrub typhus were those consistent with non-specific acute encephalitis syndromes (AES), such as fever (WPP 100.0% [99.5%-100.0%, I2 = 47.8%]), altered sensorium (67.4% [54.9-78.8%, I2 = 93.3%]), headache (65.0% [51.5-77.6%, I2 = 95.1%]) and neck stiffness 56.6% (29.4-80.4%, I2 = 96.3%). Classical features of scrub typhus were infrequently identified; an eschar was found in only 20.8% (9.8%-34.3%, I2 = 95.4%) and lymphadenopathy in 24.1% (95% CI 11.8% - 38.9%, I2 = 87.8%). The pooled CFR (95% CI) was 3.6% (1.5%- 6.4%, I2 = 67.3%). Paediatric cohorts had a CFR of 6.1% (1.9-12.1%, I2 = 77%) whilst adult cohorts reported 2.6% (0.7-5.3%, I2 = 43%). CONCLUSION Our meta-analyses illustrate that 3.6% of patients with CNS manifestations of scrub typhus die. Clinicians should have a high index of suspicion for scrub typhus in patients presenting with AES in endemic regions and consider starting empiric treatment whilst awaiting results of investigations, even in the absence of classical signs such as an eschar or lymphadenopathy.
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Affiliation(s)
- Ali M. Alam
- Department of Clinical Infection Microbiology and Immunology, Institute of Infection, Veterinary, and Ecological Science, University of Liverpool, Liverpool, United Kingdom
- Barts Health NHS Trust, London, United Kingdom
| | - Conor S. Gillespie
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Jack Goodall
- Tropical & Infectious Disease Unit, Liverpool University Hospitals NHS Foundation Trust, Liverpool, United Kingdom
| | - Tina Damodar
- Department of Neurovirology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Lance Turtle
- Tropical & Infectious Disease Unit, Liverpool University Hospitals NHS Foundation Trust, Liverpool, United Kingdom
- The Pandemic Institute, Liverpool, United Kingdom
- The NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
| | - Ravi Vasanthapuram
- Department of Neurovirology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Tom Solomon
- The Pandemic Institute, Liverpool, United Kingdom
- The NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
| | - Benedict D. Michael
- Department of Clinical Infection Microbiology and Immunology, Institute of Infection, Veterinary, and Ecological Science, University of Liverpool, Liverpool, United Kingdom
- The NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, United Kingdom
- Department of Neurology, The Walton Centre NHS Foundation Trust, Liverpool, United Kingdom
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Nanaware N, Desai D, Banerjee A, Zaman K, Mittal M, Mittal M, Kulkarni S. Genotypic Characterization of Orientia tsutsugamushi Isolated From Acute Encephalitis Syndrome and Acute Febrile Illness Cases in the Gorakhpur Area, Uttar Pradesh, India. Front Microbiol 2022; 13:910757. [PMID: 35865917 PMCID: PMC9294505 DOI: 10.3389/fmicb.2022.910757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/23/2022] [Indexed: 01/09/2023] Open
Abstract
Scrub typhus infections caused by Orientiatsutsugamushi (OT), continue to remain underdiagnosed globally, due to the lack of distinctive symptoms. The elusive nature of the Acute Encephalitis Syndrome (AES) outbreak in Gorakhpur, Uttar Pradesh that claimed numerous pediatric lives was the driving force of this study which involved serological diagnosis (IgM-ELISA), isolation of OT in cell culture, confirmation by PCR, and characterization by Sanger sequencing. In total, 12 out of 36 patients were seropositive, of which 4 were positive by PCR. Upon enrichment in cell culture, additional 3 patients (including two seronegative) were detected positive by PCR. In total, three of these 7 patients were found to be infected with two strains of OT. Taken together, this study for the first time reports the occurrence of dual infections in addition to three circulating OT genotypes (Gilliam, Kato, and Karp-like) and highlights the significance of enriching OT in cell culture systems for efficient molecular detection.
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Affiliation(s)
- Nikita Nanaware
- Indian Council of Medical Research (ICMR)–National AIDS Research Institute, Pune, India
| | - Dipen Desai
- Indian Council of Medical Research (ICMR)–National AIDS Research Institute, Pune, India
| | - Anwesha Banerjee
- Indian Council of Medical Research (ICMR)–National AIDS Research Institute, Pune, India
| | - Kamran Zaman
- Indian Council of Medical Research (ICMR)–Regional Medical Research Centre, Gorakhpur, India
| | - Mahim Mittal
- Baba Raghav Das (B.R.D.) Medical College, Gorakhpur, India
| | - Mahima Mittal
- Baba Raghav Das (B.R.D.) Medical College, Gorakhpur, India
| | - Smita Kulkarni
- Indian Council of Medical Research (ICMR)–National AIDS Research Institute, Pune, India,*Correspondence: Smita Kulkarni, ;
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Murhekar MV, Vivian Thangaraj JW, Sadanandane C, Mittal M, Gupta N, Rose W, Sahay S, Kant R, Gupte MD. Investigations of seasonal outbreaks of acute encephalitis syndrome due to Orientia tsutsugamushi in Gorakhpur region, India: A One Health case study. Indian J Med Res 2021; 153:375-381. [PMID: 33907001 PMCID: PMC8204837 DOI: 10.4103/ijmr.ijmr_625_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Indexed: 11/05/2022] Open
Abstract
Gorakhpur division consisting of Gorakhpur and neighboring districts Deoria, Kushinagar and Maharajganj in Uttar Pradesh, India, have been witnessing seasonal outbreaks of acute encephalitis syndrome (AES) among children for the last three decades. Investigations conducted during 2005 identified Japanese encephalitis (JE) virus as an aetiology of AES. With the introduction of JE vaccination and other control strategies, the incidence of JE in the region declined, however, outbreaks of acute febrile illness with neurological manifestations continued to occur. Subsequent investigations identified Orientia tsutsugamushi, as the major aetiology of AES outbreaks in the region. This review details clinical, epidemiological, animal and entomological investigations conducted for AES due to O. tsutsugamushi during 2015 and 2017 in Gorakhpur region. Surveillance of acute febrile illness among children attending peripheral health facilities identified scrub typhus as an important aetiology of febrile illness during monsoon and post-monsoon months. Population-based serosurveys indicated high endemicity of scrub typhus. Entomological studies demonstrated natural infection of O. tsutsugamushi in small animal hosts and vector mites. Children acquired this infection through recent exposure to outdoor environment, while playing, or visiting fields or defecating in open fields. A few of the children with scrub typhus progress to develop CNS manifestations. Hence, early administration of appropriate antibiotics is crucial in preventing progression of AFI due to scrub typhus to AES. The investigations conducted by the multi-disciplinary team helped understand the transmission dynamics of scrub typhus in Gorakhpur division and recommend strategies for its control.
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Affiliation(s)
| | | | | | - Mahima Mittal
- All India Institute of Medical Sciences, Gorakhpur, Uttar Pradesh, India
| | - Nivedita Gupta
- Division of Epidemiology and Communicable Diseases Division, Indian Council of Medical Research, New Delhi, India
| | - Winsley Rose
- Christian Medical College, Vellore, Tamil Nadu, India
| | - Seema Sahay
- ICMR-National AIDS Research Institute, Pune, Maharashtra, India
| | - Rajni Kant
- ICMR-Regional Medical Research Centre, Gorakhpur, Uttar Pradesh, India
| | - Mohan D. Gupte
- ICMR-National Institute of Epidemiology, Chennai, India
- Division of Epidemiology and Communicable Diseases Division, Indian Council of Medical Research, New Delhi, India
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