1
|
Prasetyo DB, Fiorenzano JM, Nop D, Noch N, Huot B, Mom S, Prum S, Chhe V, Dul S, Heang V, Prom S, Jiang J, Richards AL, Farris CM, Hertz JC. Molecular detection of Rickettsia species in ectoparasites collected from two southern provinces of Cambodia. PLoS Negl Trop Dis 2024; 18:e0012544. [PMID: 39348408 DOI: 10.1371/journal.pntd.0012544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 10/10/2024] [Accepted: 09/17/2024] [Indexed: 10/02/2024] Open
Abstract
Arthropod-borne rickettsioses comprise a wide variety of subtypes that are endemic in Cambodia, but there remains very little data on the geographic distribution of the pathogens or their vectors. Surveys were conducted in Koh Kong and Preah Sihanouk Provinces between September 2017 and June 2018 to collect ectoparasites from peridomestic animals and the environment using dragging and flagging methods. Collected ectoparasites were sorted and identified morphologically, then pooled by species, host, and location for molecular detection using Rickettsia genus- and species-specific qPCR and/or multilocus sequence typing (MLST) assays. A total of 14,254 ectoparasites were collected including seven new locality records. Rickettsia species were detected in 35.5% (174/505) of the pools screened representing 3,149 randomly selected ectoparasites from the total collected. Rickettsia asembonensis was detected in 89.6% (147/164) of Rickettsia-positive flea pools and 3.6% (6/164) of the flea pools were positive for both R. asembonensis and Rickettsia felis. Candidatus Rickettsia senegalensis from Ctenocephalides orientis fleas and Rickettsia sp. close to Rickettsia japonica and Rickettsia heilongjiangensis from Haemaphysalis ticks were identified by MLST. This appears to be the first report of these new ectoparasite records and rickettsial species in southern Cambodia, suggesting a potential health risk to military and civilians in this region.
Collapse
Affiliation(s)
| | | | - Daliya Nop
- Vysnova Partners, LLC, Alexandria, Virginia, United States of America
| | - Nin Noch
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Boren Huot
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Sokly Mom
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Sitha Prum
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Visal Chhe
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Sokha Dul
- AC Investment Co., Ltd., Phnom Penh, Cambodia
| | - Vireak Heang
- U.S. Naval Medical Research Unit INDO PACIFIC, Phnom Penh, Cambodia
| | - Satharath Prom
- Department of Health, Ministry of National Defence, Phnom Penh, Cambodia
| | - Ju Jiang
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Allen L Richards
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Christina M Farris
- Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Jeffrey C Hertz
- U.S. Naval Medical Research Unit INDO PACIFIC, Sembawang, Singapore
| |
Collapse
|
2
|
Laukaitis-Yousey HJ, Macaluso KR. Cat Flea Coinfection with Rickettsia felis and Rickettsia typhi. Vector Borne Zoonotic Dis 2024; 24:201-213. [PMID: 38422214 PMCID: PMC11035851 DOI: 10.1089/vbz.2023.0122] [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] [Indexed: 03/02/2024] Open
Abstract
Purpose: Flea-borne rickettsioses, collectively referred to as a term for etiological agents Rickettsia felis, Rickettsia typhi, and RFLOs (R. felis-like organisms), has become a public health concern around the world, specifically in the United States. Due to a shared arthropod vector (the cat flea) and clinical signs, discriminating between Rickettsia species has proven difficult. While the effects of microbial coinfections in the vector can result in antagonistic or synergistic interrelationships, subsequently altering potential human exposure and disease, the impact of bacterial interactions within flea populations remains poorly defined. Methods: In this study, in vitro and in vivo systems were utilized to assess rickettsial interactions in arthropods. Results: Coinfection of both R. felis and R. typhi within a tick-derived cell line indicated that the two species could infect the same cell, but distinct growth kinetics led to reduced R. felis growth over time, regardless of infection order. Sequential flea coinfections revealed the vector could acquire both Rickettsia spp. and sustain coinfection for up to 2 weeks, but rickettsial loads in coinfected fleas and feces were altered during coinfection. Conclusion: Altered rickettsial loads during coinfection suggest R. felis and R. typhi interactions may enhance the transmission potential of either agent. Thus, this study provides a functional foundation to disentangle transmission events propelled by complex interspecies relationships during vector coinfections.
Collapse
Affiliation(s)
- Hanna J. Laukaitis-Yousey
- Department of Microbiology and Immunology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, Alabama, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kevin R. Macaluso
- Department of Microbiology and Immunology, Frederick P. Whiddon College of Medicine, University of South Alabama, Mobile, Alabama, USA
| |
Collapse
|
3
|
Corrigan J, Marion B, English J, Eneku W, Weng JL, Rugg M, Dotrang T, Dunford J, Byaruhanga AM, Byarugaba DK, Ramalho-Ortigao M, Wanja EW. Minimal Rickettsial Infection Rates and Distribution of Ticks in Uganda: An Assessment of the Seasonal Effects and Relevance to Tick-Borne Disease Risk in East Africa. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:185-192. [PMID: 36321534 DOI: 10.1093/jme/tjac166] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Indexed: 06/16/2023]
Abstract
Tick-borne diseases (TBDs) pose a significant risk to humans and represent one of the major factors influencing readiness within the United States' military worldwide. Additionally, ticks and TBDs constitute major animal health problems leading to economic losses at multiple levels affecting low- and middle-income countries the hardest. Tick control is frequently hampered by issues ranging from acaricide resistance to lack of data on tick distribution and infection rates. We conducted a cross-sectional study to assess tick species distribution, host use, and rickettsial pathogen infection rate of ticks in different areas of the Uganda Cattle Corridor. We identified 4,425 hard ticks (Ixodida: Ixodidae) comprised of seven species by morphological characters with 3,315 ticks collected from four locations during the dry season and 1,110 ticks from one location during the wet season. Rickettsial pathogen prevalence was assessed in ticks collected from two districts to determine the minimum infection rate compared across seasons, village location, and tick species. We found statistically significant differences in the abundance and distribution of tick species among districts in the dry season, host animal species, and the proportion of rickettsial positive pools between villages. Seasonality, village location, and tick species do not affect the minimum infection rate of rickettsial pathogens of ticks in Uganda, but village location affects the proportion of positive tick pools. These results indicate geographical and seasonal differences among pathogen-harboring ticks contributing to our understanding of the current distribution of ticks and TBDs in Uganda.
Collapse
Affiliation(s)
- James Corrigan
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
- MPH Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Brianna Marion
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
- MPH Program, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - James English
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | | | - Ju Lin Weng
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Molly Rugg
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Thoai Dotrang
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - James Dunford
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | | | | | - Marcelo Ramalho-Ortigao
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Elizabeth W Wanja
- Division of Global Public Health, Department of Preventive Medicine and Biostatistics, Uniformed Services University, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| |
Collapse
|
4
|
Rao AM, Popper SJ, Gupta S, Davong V, Vaidya K, Chanthongthip A, Dittrich S, Robinson MT, Vongsouvath M, Mayxay M, Nawtaisong P, Karmacharya B, Thair SA, Bogoch I, Sweeney TE, Newton PN, Andrews JR, Relman DA, Khatri P. A robust host-response-based signature distinguishes bacterial and viral infections across diverse global populations. Cell Rep Med 2022; 3:100842. [PMID: 36543117 PMCID: PMC9797950 DOI: 10.1016/j.xcrm.2022.100842] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/12/2022] [Accepted: 11/09/2022] [Indexed: 12/24/2022]
Abstract
Limited sensitivity and specificity of current diagnostics lead to the erroneous prescription of antibiotics. Host-response-based diagnostics could address these challenges. However, using 4,200 samples across 69 blood transcriptome datasets from 20 countries from patients with bacterial or viral infections representing a broad spectrum of biological, clinical, and technical heterogeneity, we show current host-response-based gene signatures have lower accuracy to distinguish intracellular bacterial infections from viral infections than extracellular bacterial infections. Using these 69 datasets, we identify an 8-gene signature to distinguish intracellular or extracellular bacterial infections from viral infections with an area under the receiver operating characteristic curve (AUROC) > 0.91 (85.9% specificity and 90.2% sensitivity). In prospective cohorts from Nepal and Laos, the 8-gene classifier distinguished bacterial infections from viral infections with an AUROC of 0.94 (87.9% specificity and 91% sensitivity). The 8-gene signature meets the target product profile proposed by the World Health Organization and others for distinguishing bacterial and viral infections.
Collapse
Affiliation(s)
- Aditya M. Rao
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, 240 Pasteur Dr., Biomedical Innovation Building, Room 1553, Stanford, CA, USA,Immunology Graduate Program, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Stephen J. Popper
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Sanjana Gupta
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, 240 Pasteur Dr., Biomedical Innovation Building, Room 1553, Stanford, CA, USA,Center for Biomedical Informatics Research, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Viengmon Davong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Krista Vaidya
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | - Anisone Chanthongthip
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Sabine Dittrich
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Matthew T. Robinson
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Manivanh Vongsouvath
- 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 and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK,Institute of Research and Education Development (IRED), University of Health Sciences, Ministry of Health, Vientiane, Lao PDR
| | - Pruksa Nawtaisong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Biraj Karmacharya
- Dhulikhel Hospital, Kathmandu University Hospital, Kavrepalanchok, Nepal
| | - Simone A. Thair
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, 240 Pasteur Dr., Biomedical Innovation Building, Room 1553, Stanford, CA, USA,Center for Biomedical Informatics Research, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Isaac Bogoch
- Department of Medicine, University of Toronto, Toronto, ON, Canada
| | | | - Paul N. Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Jason R. Andrews
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - David A. Relman
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, 240 Pasteur Dr., Biomedical Innovation Building, Room 1553, Stanford, CA, USA,Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, CA, USA,Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA,Infectious Diseases Section, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Purvesh Khatri
- Institute for Immunity, Transplantation, and Infection, Stanford University School of Medicine, 240 Pasteur Dr., Biomedical Innovation Building, Room 1553, Stanford, CA, USA,Center for Biomedical Informatics Research, Department of Medicine, Stanford University, Stanford, CA, USA,Corresponding author
| |
Collapse
|
5
|
Systematic Surveillance of Rickettsial Diseases in 27 Hospitals from 26 Provinces throughout Vietnam. Trop Med Infect Dis 2022; 7:tropicalmed7060088. [PMID: 35736967 PMCID: PMC9231031 DOI: 10.3390/tropicalmed7060088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/28/2022] [Accepted: 05/29/2022] [Indexed: 11/27/2022] Open
Abstract
In Vietnam, the public health burden of rickettsial infections continues to be underestimated due to knowledge gaps in the epidemiology of these diseases. We conducted a systematic study among 27 hospitals from 26 provinces in eight ecological regions throughout Vietnam to investigate the prevalence, distribution, and clinical characteristics of rickettsial diseases. We recruited 1834 patients in the study from April 2018 to October 2019. The findings showed that rickettsial diseases were common among undifferentiated febrile patients, with 564 (30.8%) patients positive by qPCR for scrub typhus, murine typhus or spotted fever. Scrub typhus (484, 85.8%) was the most common rickettsial disease, followed by murine typhus (67, 11.9%) and spotted fever (10, 1.8%). Rickettsial diseases were widely distributed in all regions of Vietnam and presented with nonspecific clinical manifestations.
Collapse
|
6
|
Kato CY, Chung IH, Robinson LK, Eremeeva ME, Dasch GA. Genetic typing of isolates of Rickettsia typhi. PLoS Negl Trop Dis 2022; 16:e0010354. [PMID: 35639778 PMCID: PMC9203007 DOI: 10.1371/journal.pntd.0010354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 06/16/2022] [Accepted: 03/24/2022] [Indexed: 11/18/2022] Open
Abstract
Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and interstitial pneumonia in severe cases. Comparisons of complete genome sequences of R. typhi isolates from North Carolina, USA (Wilmington), Myanmar (B9991PP), and Thailand (TH1527) identified only 26 single nucleotide polymorphism (SNP) and 7 insertion-deletion (INDEL) sites in these highly syntenic genomes. Assays were developed to further define the distribution of these variant sites among 15 additional isolates of R. typhi with different histories from Asia, the USA, and Africa. Mismatch amplification mutation assays (MAMA) were validated for 22 SNP sites, while the 7 INDEL sites were analyzed directly on agarose gels. Six SNP types, 9 INDEL types, 11 total types were identified among these 18 isolates. Replicate DNA samples as well as comparisons of isolates with different passage and source histories gave consistent genetic typing profiles. Comparison of the SNP and INDEL markers to R. typhi’s nearest neighbor Rickettsia prowazekii demonstrated that the majority of the SNPs represent intra-species variation that arose post divergence of these two species while several INDEL sites also exhibited intraspecies variability among the R. prowazekii genomes that have been completely sequenced. The assays for the presence of these SNP and INDEL sites, particularly the latter, comprise a low technology gel method for consistently distinguishing R. typhi and R. prowazekii as well as for differentiating genetic types of R. typhi. Rickettsia typhi is an obligately intracellular bacterium which is most commonly transmitted by rat fleas to humans and can cause the disease murine (endemic) typhus wherever both humans and infected rats are present. However, this agent is also present in a variety of other arthropod species associated with other vertebrate animals. Its closest relative is Rickettsia prowazekii, the etiologic agent of epidemic typhus (human louse-borne) and sylvatic typhus (associated with flying squirrels and its ectoparasites in the Eastern United States). Both classic louse-borne and flea-borne typhus rickettsiae can cause fatal infections and have the potential for use as biothreat agents as they can be grown in large quantities. We investigated the genetic differences that can be found in different stocks of R. typhi. Our work is important for two reasons. We have developed robust and sensitive methods for distinguishing isolates of R. typhi originating from different continents; these new assays require only simple instrumentation which is available in nearly all biology laboratories. Our results also provided new insights confirming the probable origin of R. typhi in Asia and its likely cosmopolitan spread by rats on ships around the world.
Collapse
Affiliation(s)
- Cecilia Y. Kato
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, Georgia, United States of America
| | - Ida H. Chung
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, Georgia, United States of America
| | - Lauren K. Robinson
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, Georgia, United States of America
| | - Marina E. Eremeeva
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, Georgia, United States of America
| | - Gregory A. Dasch
- Rickettsial Zoonoses Branch, Centers for Disease Control, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
7
|
Yuhana MY, Hanboonkunupakarn B, Tanganuchitcharnchai A, Sujariyakul P, Sonthayanon P, Chotivanich K, Pukrittayakamee S, Blacksell SD, Paris DH. Rickettsial Infections Are Neglected Causes of Acute Febrile Illness in Teluk Intan, Peninsular Malaysia. Trop Med Infect Dis 2022; 7:77. [PMID: 35622704 PMCID: PMC9143963 DOI: 10.3390/tropicalmed7050077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/13/2022] [Accepted: 05/15/2022] [Indexed: 02/01/2023] Open
Abstract
Rickettsial infections are among the leading etiologies of acute febrile illness in Southeast Asia. However, recent data from Malaysia are limited. This prospective study was conducted in Teluk Intan, Peninsular Malaysia, during January to December 2016. We recruited 309 hospitalized adult patients with acute febrile illness. Clinical and biochemistry data were obtained, and patients were stratified into mild and severe infections based on the sepsis-related organ failure (qSOFA) scoring system. Diagnostic assays including blood cultures, real-time PCR, and serology (IFA and MAT) were performed. In this study, pathogens were identified in 214 (69%) patients, of which 199 (93%) patients had a single etiology, and 15 (5%) patients had >1 etiologies. The top three causes of febrile illness requiring hospitalization in this Malaysian study were leptospirosis (68 (32%)), dengue (58 (27%)), and rickettsioses (42 (19%)). Fifty-five (18%) patients presented with severe disease with a qSOFA score of ≥2. Mortality was documented in 38 (12%) patients, with the highest seen in leptospirosis (16 (42%)) followed by rickettsiosis (4 (11%)). While the significance of leptospirosis and dengue are recognized, the impact of rickettsial infections in Peninsular Malaysia remains under appreciated. Management guidelines for in-patient care with acute febrile illness in Peninsular Malaysia are needed.
Collapse
Affiliation(s)
- Muhamad Yazli Yuhana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (M.Y.Y.); (K.C.); (S.P.)
- Department of Infectious Diseases and Tropical Medicine, School of Medicine, Universiti Teknologi MARA (UiTM), Sg Buloh Campus, Sungai Buloh 40600, Selangor, Malaysia
| | - Borimas Hanboonkunupakarn
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (M.Y.Y.); (K.C.); (S.P.)
| | - Ampai Tanganuchitcharnchai
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (A.T.); (P.S.); (S.D.B.)
| | - Pimpan Sujariyakul
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (A.T.); (P.S.); (S.D.B.)
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand;
| | - Kesinee Chotivanich
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (M.Y.Y.); (K.C.); (S.P.)
| | - Sasithon Pukrittayakamee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (M.Y.Y.); (K.C.); (S.P.)
| | - Stuart D. Blacksell
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (A.T.); (P.S.); (S.D.B.)
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Churchill Hospital, Oxford OX3 7FZ, UK
| | - Daniel H. Paris
- Faculty of Medicine, University of Basel, 4003 Basel, Switzerland;
- Department of Medicine, Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
| |
Collapse
|
8
|
Molecular Evidence for Flea-Borne Rickettsiosis in Febrile Patients from Madagascar. Pathogens 2021; 10:pathogens10111482. [PMID: 34832637 PMCID: PMC8621948 DOI: 10.3390/pathogens10111482] [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: 10/06/2021] [Revised: 11/02/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
Rickettsiae may cause febrile infections in humans in tropical and subtropical regions. From Madagascar, no molecular data on the role of rickettsioses in febrile patients are available. Blood samples from patients presenting with fever in the area of the capital Antananarivo were screened for the presence of rickettsial DNA. EDTA (ethylenediaminetetraacetic acid) blood from 1020 patients presenting with pyrexia > 38.5 °C was analyzed by gltA-specific qPCR. Positive samples were confirmed by ompB-specific qPCR. From confirmed samples, the gltA amplicons were sequenced and subjected to phylogenetic analysis. From five gltA-reactive samples, two were confirmed by ompB-specific qPCR. The gltA sequence in the sample taken from a 38-year-old female showed 100% homology with R. typhi. The other sample taken from a 1.5-year-old infant was 100% homologous to R. felis. Tick-borne rickettsiae were not identified. The overall rate of febrile patients with molecular evidence for a rickettsial infection from the Madagascan study site was 0.2% (2/1020 patients). Flea-borne rickettsiosis is a rare but neglected cause of infection in Madagascar. Accurate diagnosis may prompt adequate antimicrobial treatment.
Collapse
|
9
|
Current tools for the diagnosis and detection of spotted fever group Rickettsia. Acta Trop 2021; 218:105887. [PMID: 33713627 DOI: 10.1016/j.actatropica.2021.105887] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/28/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023]
Abstract
Spotted fever group (SFG) rickettsiae causes a number of diseases in humans worldwide, which can range from mild to highly lethal. Since the clinical presentations of rickettsioses caused by SFG rickettsiae are variable and may be similar to the diseases caused by other rickettsiae, such as Orientia tsutsugamushi (agent for scrub typhus), Coxiella burnetii (agent for Q fever) and the typhus group rickettsiae (agents for epidemic and murine typhus), the accurate diagnosis of infections caused by SFG Rickettsia remains challenging especially in resource-poor settings in developing countries. This review summarizes the various diagnostic and detection tools that are currently available for the confirmation of infections by SFG rickettsiae. The advantages and challenges pertaining to the different serological and molecular detections methods, as well as new assays in development, are discussed. The utility of the detection tools contributing to the surveillance of SFG rickettsiae in arthropods and animals are reviewed.
Collapse
|
10
|
Dhawan S, Althaus T, Lubell Y, Suwancharoen D, Blacksell SD. Evaluation of the Panbio Leptospira IgM ELISA among Outpatients Attending Primary Care in Southeast Asia. Am J Trop Med Hyg 2021; 104:1777-1781. [PMID: 33724923 PMCID: PMC8103482 DOI: 10.4269/ajtmh.20-0818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/12/2021] [Indexed: 01/12/2023] Open
Abstract
Despite estimates suggesting Leptospira spp. being endemic in Southeast Asia, evidence remains limited. Diagnostic accuracy evaluations based on Leptospira ELISA mainly rely on hospitalized and severe patients; therefore, studies measuring the pathogen burden may be inaccurate in the community. We evaluated the Panbio Leptospira ELISA IgM among 656 febrile outpatients attending primary care in Chiangrai, Thailand, and Hlaing Tha Yar, Yangon, Myanmar. ELISA demonstrated limited diagnostic accuracy for the detection of acute leptospiral infection using the manufacturer recommended cutoff, with a sensitivity of 71.4% and specificity of 36.4%, and an area under the receiver operator characteristic curve value of 0.65 (95% CI: 0.41-0.89), compared with our reference test, the PCR assay. ELISA also performed poorly as a screening tool for detecting recent exposure to Leptospira spp. compared with the "gold-standard" microscopic agglutination test, with a specificity of 42.7%. We conclude that the utility of the Leptospira IgM ELISA for both serodiagnosis and seroprevalence is limited in our setting.
Collapse
Affiliation(s)
- Sandhya Dhawan
- Mahidol-Oxford Tropical Research Medicine Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thomas Althaus
- Mahidol-Oxford Tropical Research Medicine Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;,Nuffield Department of Medicine, Nuffield Department of Medicine Research Building, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Yoel Lubell
- Mahidol-Oxford Tropical Research Medicine Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;,Nuffield Department of Medicine, Nuffield Department of Medicine Research Building, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Duangjai Suwancharoen
- Department of Livestock Development, National Institute of Animal Health, Ministry of Agriculture and Cooperatives, Bangkok, Thailand
| | - Stuart D. Blacksell
- Mahidol-Oxford Tropical Research Medicine Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand;,Nuffield Department of Medicine, Nuffield Department of Medicine Research Building, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom;,Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic,Address correspondence to Stuart D. Blacksell, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand. E-mail:
| |
Collapse
|
11
|
Danchenko M, Laukaitis HJ, Macaluso KR. Dynamic gene expression in salivary glands of the cat flea during Rickettsia felis infection. Pathog Dis 2021; 79:6189691. [PMID: 33770162 PMCID: PMC8062234 DOI: 10.1093/femspd/ftab020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/24/2021] [Indexed: 12/27/2022] Open
Abstract
The cat flea, Ctenocephalides felis, is an arthropod vector capable of transmitting several human pathogens including Rickettsia species. Earlier studies identified Rickettsia felis in the salivary glands of the cat flea and transmission of rickettsiae during arthropod feeding. The saliva of hematophagous insects contains multiple biomolecules with anticlotting, vasodilatory and immunomodulatory activities. Notably, the exact role of salivary factors in the molecular interaction between flea-borne rickettsiae and their insect host is still largely unknown. To determine if R. felis modulates gene expression in the cat flea salivary glands, cat fleas were infected with R. felis and transcription patterns of selected salivary gland-derived factors, including antimicrobial peptides and flea-specific antigens, were assessed. Salivary glands were microdissected from infected and control cat fleas at different time points after exposure and total RNA was extracted and subjected to reverse-transcriptase quantitative PCR for gene expression analysis. During the experimental 10-day feeding period, a dynamic change in gene expression of immunity-related transcripts and salivary antigens between the two experimental groups was detected. The data indicated that defensin-2 (Cf-726), glycine-rich antimicrobial peptide (Cf-83), salivary antigens (Cf-169 and Cf-65) and deorphanized peptide (Cf-75) are flea-derived factors responsive to rickettsial infection.
Collapse
Affiliation(s)
- Monika Danchenko
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, 610 Clinic Drive, Mobile, AL 36688, USA
| | - Hanna J Laukaitis
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, 610 Clinic Drive, Mobile, AL 36688, USA
| | - Kevin R Macaluso
- Department of Microbiology and Immunology, University of South Alabama College of Medicine, 610 Clinic Drive, Mobile, AL 36688, USA
| |
Collapse
|
12
|
Ter SK, Rattanavong S, Roberts T, Sengduangphachanh A, Sihalath S, Panapruksachat S, Vongsouvath M, Newton PN, Simpson AJH, Robinson MT. Molecular Detection of Pathogens in Negative Blood Cultures in the Lao People's Democratic Republic. Am J Trop Med Hyg 2021; 104:1582-1585. [PMID: 33646978 PMCID: PMC8045604 DOI: 10.4269/ajtmh.20-1348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/20/2020] [Indexed: 12/29/2022] Open
Abstract
Bloodstream infections cause substantial morbidity and mortality. However, despite clinical suspicion of such infections, blood cultures are often negative. We investigated blood cultures that were negative after 5 days of incubation for the presence of bacterial pathogens using specific (Rickettsia spp. and Leptospira spp.) and a broad-range 16S rRNA PCR. From 190 samples, 53 (27.9%) were positive for bacterial DNA. There was also a high background incidence of dengue (90/112 patient serum positive, 80.4%). Twelve samples (6.3%) were positive for Rickettsia spp., including two Rickettsia typhi. The 16S rRNA PCR gave 41 positives; Escherichia coli and Klebsiella pneumoniae were identified in 11 and eight samples, respectively, and one Leptospira species was detected. Molecular investigation of negative blood cultures can identify potential pathogens that will otherwise be missed by routine culture. Patient management would have been influenced in all 53 patients for whom a bacterial organism was identified, and 2.3-6.1% of patients would likely have had an altered final outcome. These findings warrant further study, particularly to determine the cost-benefit for routine use, ways of implementation, and timing of PCR for organisms such as Rickettsia and Leptospira, which are important pathogens in rural Asia.
Collapse
Affiliation(s)
- Soo Kai Ter
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Royal Veterinary College, London, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Sayaphet Rattanavong
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Tamalee Roberts
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Amphonesavanh Sengduangphachanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Somsavanh Sihalath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Siribun Panapruksachat
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Manivanh Vongsouvath
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
| | - Paul N. Newton
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Andrew J. H. Simpson
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Matthew T. Robinson
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao PDR
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
13
|
Otiang E, Chen D, Jiang J, Maina AN, Farris CM, Luce-Fedrow A, Richards AL. Pathogen Carriage by Peri-Domestic Fleas in Western Kenya. Vector Borne Zoonotic Dis 2021; 21:256-263. [PMID: 33481673 DOI: 10.1089/vbz.2020.2709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fleas are carriers for many largely understudied zoonotic, endemic, emerging, and re-emerging infectious disease agents, but little is known about their prevalence and role as a vector in Africa. The aim of this study was to determine the diversity of fleas and the prevalence of infectious agents in them collected from human dwellings in western Kenya. A total of 306 fleas were collected using light traps from 33 human dwellings; 170 (55.56%) were identified as Ctenocephalides spp., 121 (39.54%) as Echidnophaga gallinacea, 13 (4.25%) as Pulex irritans, and 2 (0.65%) as Xenopsylla cheopis. Of the 306 individual fleas tested, 168 (54.9%) tested positive for rickettsial DNA by a genus-specific quantitative real-time PCR (qPCR) assay based on the 17-kDa antigen gene. Species-specific qPCR assays and sequencing revealed presence of Rickettsia asembonensis in 166 (54.2%) and Rickettsia felis in 2 (0.7%) fleas. Borrelia burgdorferi, normally known to be carried by ticks, was detected in four (1.3%) flea DNA preparations. We found no evidence of Yersinia pestis, Bartonella spp., or Orientia spp. Not only were Ctenocephalides spp. the most predominant flea species in the human dwellings, but also almost all of them were harboring R. asembonensis.
Collapse
Affiliation(s)
- Elkanah Otiang
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Daniel Chen
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Alice N Maina
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Christina M Farris
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Alison Luce-Fedrow
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA.,Department of Biology, Shippensburg University, Shippensburg, Pennsylvania, USA
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, USA.,Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| |
Collapse
|
14
|
Beard D, Stannard HJ, Old JM. Parasites of wombats (family Vombatidae), with a focus on ticks and tick-borne pathogens. Parasitol Res 2021; 120:395-409. [PMID: 33409643 DOI: 10.1007/s00436-020-07036-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
Ticks (Arachnida: Acari) are vectors for pathogens and the biggest threat to animal health. Many Australian ticks are associated with pathogens that impact humans, domestic animals and livestock. However, little is known about the presence or impact of tick-borne pathogens in native Australian wildlife. Wombats are particularly susceptible to the effects of the ectoparasite Sarcoptes scabiei which causes sarcoptic mange, the reason for which is unknown. Factors such as other ectoparasites and their associated pathogens may play a role. A critical understanding of the species of ectoparasites that parasitise wombats and their pathogens, and particularly ticks, is therefore warranted. This review describes the ectoparasites of wombats, pathogens known to be associated with those ectoparasites, and related literature gaps. Pathogens have been isolated in most tick species that typically feed on wombats; however, there are minimal molecular studies to determine the presence of pathogens in any other wombat ectoparasites. The development of next-generation sequencing (NGS) technologies allows us to explore entire microbial communities in ectoparasite samples, allowing fast and accurate identification of potential pathogens in many samples at once. These new techniques have highlighted the diversity and uniqueness of native ticks and their microbiomes, including pathogens of potential medical and veterinary importance. An increased understanding of all ectoparasites that parasitise wombats, and their associated pathogens, requires further investigation.
Collapse
Affiliation(s)
- Danielle Beard
- School of Science, Hawkesbury, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Hayley J Stannard
- School of Animal and Veterinary Science, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Julie M Old
- School of Science, Hawkesbury, Western Sydney University, Penrith, NSW, 2751, Australia.
| |
Collapse
|
15
|
Anstead GM. History, Rats, Fleas, and Opossums. II. The Decline and Resurgence of Flea-Borne Typhus in the United States, 1945-2019. Trop Med Infect Dis 2020; 6:2. [PMID: 33379251 PMCID: PMC7839051 DOI: 10.3390/tropicalmed6010002] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/14/2020] [Accepted: 12/18/2020] [Indexed: 11/17/2022] Open
Abstract
Flea-borne typhus, due to Rickettsia typhi and R. felis, is an infection causing fever, headache, rash, and diverse organ manifestations that can result in critical illness or death. This is the second part of a two-part series describing the rise, decline, and resurgence of flea-borne typhus (FBT) in the United States over the last century. These studies illustrate the influence of historical events, social conditions, technology, and public health interventions on the prevalence of a vector-borne disease. Flea-borne typhus was an emerging disease, primarily in the Southern USA and California, from 1910 to 1945. The primary reservoirs in this period were the rats Rattus norvegicus and Ra. rattus and the main vector was the Oriental rat flea (Xenopsylla cheopis). The period 1930 to 1945 saw a dramatic rise in the number of reported cases. This was due to conditions favorable to the proliferation of rodents and their fleas during the Depression and World War II years, including: dilapidated, overcrowded housing; poor environmental sanitation; and the difficulty of importing insecticides and rodenticides during wartime. About 42,000 cases were reported between 1931-1946, and the actual number of cases may have been three-fold higher. The number of annual cases of FBT peaked in 1944 at 5401 cases. American involvement in World War II, in the short term, further perpetuated the epidemic of FBT by the increased production of food crops in the American South and by promoting crowded and unsanitary conditions in the Southern cities. However, ultimately, World War II proved to be a powerful catalyst in the control of FBT by improving standards of living and providing the tools for typhus control, such as synthetic insecticides and novel rodenticides. A vigorous program for the control of FBT was conducted by the US Public Health Service from 1945 to 1952, using insecticides, rodenticides, and environmental sanitation and remediation. Government programs and relative economic prosperity in the South also resulted in slum clearance and improved housing, which reduced rodent harborage. By 1956, the number of cases of FBT in the United States had dropped dramatically to only 98. Federally funded projects for rat control continued until the mid-1980s. Effective antibiotics for FBT, such as the tetracyclines, came into clinical practice in the late 1940s. The first diagnostic test for FBT, the Weil-Felix test, was found to have inadequate sensitivity and specificity and was replaced by complement fixation in the 1940s and the indirect fluorescent antibody test in the 1980s. A second organism causing FBT, R. felis, was discovered in 1990. Flea-borne typhus persists in the United States, primarily in South and Central Texas, the Los Angeles area, and Hawaii. In the former two areas, the opossum (Didelphis virginiana) and cats have replaced rats as the primary reservoirs, with the cat flea (Ctenocephalides felis) now as the most important vector. In Hawaii, 73% of cases occur in Maui County because it has lower rainfall than other areas. Despite great successes against FBT in the post-World War II era, it has proved difficult to eliminate because it is now associated with our companion animals, stray pets, opossums, and the cat flea, an abundant and non-selective vector. In the new millennium, cases of FBT are increasing in Texas and California. In 2018-2019, Los Angeles County experienced a resurgence of FBT, with rats as the reservoir.
Collapse
Affiliation(s)
- Gregory M Anstead
- Medical Service, South Texas Veterans Health Care System and Department of Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| |
Collapse
|
16
|
Nguyen HM, Theppannga W, Vongphayloth K, Douangngeun B, Blacksell SD, Robinson MT. Screening of ectoparasites from domesticated dogs for bacterial pathogens in Vientiane, Lao PDR. Zoonoses Public Health 2020; 67:862-868. [PMID: 32649049 PMCID: PMC7983881 DOI: 10.1111/zph.12753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/01/2020] [Accepted: 06/17/2020] [Indexed: 01/16/2023]
Abstract
Arthropod-borne diseases are widespread worldwide and are a complex interaction between animals, humans and ectoparasites. The understanding of the diversity and epidemiology of organisms transmitted by arthropod vectors, and the role of hosts and vectors in transmission of infections remain limited in Lao PDR. What knowledge does exist is primarily focused on more rural regions of the country. This study screened ectoparasites from domestic dogs in Vientiane city for the presence of bacterial pathogens of zoonotic importance. A total of 3,511 arthropod vectors were collected from 112 dogs. Vectors collected were Rhipicephalus sanguineus ticks, Ctenocephalides felis felis and Ctenocephalides felis orientis fleas and Heterodoxus spiniger lice. A sub-sample of vectors from each dog was analysed by PCR to identify the potential bacteria. From 129 vector pools, Rickettsia spp. was detected in 6.7% (7/105) pools of ticks, 86.4% (19/22) pools of fleas and both pools of lice. Sequencing analysis confirmed Rickettsia felis in 13 flea pools and one louse pool and Rickettsia asembonensis in six flea pools. Anaplasmataceae was identified in 14.3% (15/105) tick pools and 100% (22/22) flea pools. Sequencing revealed the presence of Anaplasma platys in ticks and Wolbachia pipientis in fleas. Leptospira spp. was detected in one tick and one louse pool, and Brucella spp. was detected in 12.4% (13/105) tick pools. All samples were negative for Bartonella spp., Coxiella burnetii and Borrelia burgdorferi. This is the first study providing evidence of R. asembonensis in fleas in Laos. Results from this study show arthropods are potential vectors to transmit zoonotic infection in Vientiane city, suggesting humans are at risk of zoonotic infections in the city.
Collapse
Affiliation(s)
- Hung Manh Nguyen
- Lao Tropical and Public Health InstituteVientianeLaos
- Present address:
Faculty of MedicineFaculty of Nursing SciencesUniversité LavalQuébecQCCanada
| | | | | | | | - Stuart D. Blacksell
- Mahidol‐Oxford Tropical Medicine Research UnitBangkokThailand
- Centre for Tropical Medicine, Nuffield Department of MedicineUniversity of OxfordOxfordUK
| | - Matthew T. Robinson
- Centre for Tropical Medicine, Nuffield Department of MedicineUniversity of OxfordOxfordUK
- Lao‐Oxford‐Mahosot Hospital‐Wellcome Trust Research Unit (LOMWRU), Microbiology LaboratoryMahosot HospitalVientianeLaos
| |
Collapse
|
17
|
Eremeeva ME, Capps D, McBride CL, Williams-Newkirk AJ, Dasch GA, Salzer JS, Beati L, Durden LA. Detection of Rickettsia asembonensis in Fleas (Siphonaptera: Pulicidae, Ceratophyllidae) Collected in Five Counties in Georgia, United States. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1246-1253. [PMID: 32123904 DOI: 10.1093/jme/tjaa029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Indexed: 06/10/2023]
Abstract
We conducted a molecular survey of Rickettsia in fleas collected from opossums, road-killed and live-trapped in peridomestic and rural settings, state parks, and from pet cats and dogs in Georgia, United States during 1992-2014. The cat flea, Ctenocephalides felis (Bouché) was the predominant species collected from cats and among the archival specimens from opossums found in peridomestic settings. Polygenis gwyni (Fox) was more prevalent on opossums and a single cotton rat trapped in sylvatic settings. Trapped animals were infested infrequently with the squirrel flea, Orchopeas howardi (Baker) and C. felis. TaqMan assays targeting the BioB gene of Rickettsia felis and the OmpB gene of Rickettsia typhi were used to test 291 flea DNAs for Rickettsia. A subset of 53 C. felis collected from a cat in 2011 was tested in 18 pools which were all bioB TaqMan positive (34% minimum infection prevalence). Of 238 fleas tested individually, 140 (58.8%, 95% confidence interval [CI]: 52.5-64.9%) DNAs were bioB positive. Detection of bioB was more prevalent in individual C. felis (91%) compared to P. gwyni (13.4%). Twenty-one (7.2%) were ompB TaqMan positive, including 18 C. felis (9.5%) and 3 P. gwyni (3.2%). Most of these fleas were also positive with bioB TaqMan; however, sequencing of gltA amplicons detected only DNA of Rickettsia asembonensis. Furthermore, only the R. asembonensis genotype was identified based on NlaIV restriction analysis of a larger ompB fragment. These findings contribute to understanding the diversity of Rickettsia associated with fleas in Georgia and emphasize the need for development of more specific molecular tools for detection and field research on rickettsial pathogens.
Collapse
Affiliation(s)
- Marina E Eremeeva
- Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA
| | - Danielle Capps
- Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA
| | - Cynthia Logan McBride
- Jiann-Ping Hsu College of Public Health, Georgia Southern University, Statesboro, GA
| | - Amanda J Williams-Newkirk
- Environmental Sciences Department, Emory University, Atlanta, GA
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA
- Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, GA
| | - Gregory A Dasch
- Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA
| | - Johanna S Salzer
- Environmental Sciences Department, Emory University, Atlanta, GA
- Poxvirus and Rabies Branch, Centers for Disease Control and Prevention, Atlanta, GA
- Bacterial Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, GA
| | - Lorenza Beati
- U.S. National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA
| | - Lance A Durden
- College of Science and Mathematics, Georgia Southern University, Statesboro, GA
| |
Collapse
|
18
|
Lokida D, Hadi U, Lau CY, Kosasih H, Liang CJ, Rusli M, Sudarmono P, Lukman N, Laras K, Asdie RH, Murniati D, Utama IMS, Mubin RH, Karyana M, Gasem MH, Alisjahbana B. Underdiagnoses of Rickettsia in patients hospitalized with acute fever in Indonesia: observational study results. BMC Infect Dis 2020; 20:364. [PMID: 32448167 PMCID: PMC7245627 DOI: 10.1186/s12879-020-05057-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 04/28/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Reports of human rickettsial infection in Indonesia are limited. This study sought to characterize the epidemiology of human rickettsioses amongst patients hospitalized with fever at 8 tertiary hospitals in Indonesia. METHODS Acute and convalescent blood from 975 hospitalized non-dengue patients was tested for Rickettsia IgM and IgG by ELISA. Specimens from cases with seroconversion or increasing IgM and/or IgG titers were tested for Rickettsia IgM and IgG by IFA and Rickettsia genomes using primers for Rickettsia (R.) sp, R. typhi, and Orientia tsutsugamushi. Testing was performed retrospectively on stored specimens; results did not inform patient management. RESULTS R. typhi, R. rickettsii, and O. tsutsugamushi IgG antibodies were identified in 269/872 (30.8%), 36/634 (5.7%), and 19/504 (3.8%) of samples, respectively. For the 103/975 (10.6%) non-dengue patients diagnosed with acute rickettsial infection, presenting symptoms included nausea (72%), headache (69%), vomiting (43%), lethargy (33%), anorexia (32%), arthralgia (30%), myalgia (28%), chills (28%), epigastric pain (28%), and rash (17%). No acute rickettsioses cases were suspected during hospitalization. Discharge diagnoses included typhoid fever (44), dengue fever (20), respiratory infections (7), leptospirosis (6), unknown fever (6), sepsis (5), hepatobiliary infections (3), UTI (3), and others (9). Fatalities occurred in 7 (6.8%) patients, mostly with co-morbidities. CONCLUSIONS Rickettsial infections are consistently misdiagnosed, often as leptospirosis, dengue, or Salmonella typhi infection. Clinicians should include rickettsioses in their differential diagnosis of fever to guide empiric management; laboratories should support evaluation for rickettsial etiologies; and public policy should be implemented to reduce burden of disease.
Collapse
Affiliation(s)
- Dewi Lokida
- Tangerang District Hospital, Tangerang, Indonesia
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), Badan Litbangkes, Building 4, 5th floor, Jl Percetakan Negara no 29, Jakarta, 10560, Indonesia
| | - Usman Hadi
- Dr. Soetomo Academic General Hospital - Faculty of Medicine Universitas Airlangga, Surabaya, Indonesia
| | - Chuen-Yen Lau
- National Institute of Allergy and Infectious Disease (NIAID), National Institutes of Health, Bethesda, MD, USA
| | - Herman Kosasih
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), Badan Litbangkes, Building 4, 5th floor, Jl Percetakan Negara no 29, Jakarta, 10560, Indonesia.
| | - C Jason Liang
- National Institute of Allergy and Infectious Disease (NIAID), National Institutes of Health, Bethesda, MD, USA
| | - Musofa Rusli
- Dr. Soetomo Academic General Hospital - Faculty of Medicine Universitas Airlangga, Surabaya, Indonesia
| | | | - Nurhayati Lukman
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), Badan Litbangkes, Building 4, 5th floor, Jl Percetakan Negara no 29, Jakarta, 10560, Indonesia
| | - Kanti Laras
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), Badan Litbangkes, Building 4, 5th floor, Jl Percetakan Negara no 29, Jakarta, 10560, Indonesia
| | | | | | | | | | - Muhammad Karyana
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), Badan Litbangkes, Building 4, 5th floor, Jl Percetakan Negara no 29, Jakarta, 10560, Indonesia
- National Institute of Health Research and Development (NIHRD), Ministry of Health Republic of Indonesia, Jakarta, Indonesia
| | | | - Bachti Alisjahbana
- Hasan Sadikin Hospital - Faculty of Medicine Universitas Padjadjaran, Bandung, Indonesia
| |
Collapse
|
19
|
Phomjareet S, Chaveerach P, Suksawat F, Jiang J, Richards AL. Spotted Fever Group Rickettsia Infection of Cats and Cat Fleas in Northeast Thailand. Vector Borne Zoonotic Dis 2020; 20:566-571. [PMID: 32744925 DOI: 10.1089/vbz.2019.2564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rickettsia species cause rickettsioses, which are zoonotic diseases found worldwide, and are transmitted by arthropods such as lice, fleas, ticks, and mites. In Thailand, flea infestations are common among cats and dogs. This study aimed at determining the exposure to spotted fever group rickettsiae (SFGR) of cats in surrounding areas of Rajabhat Maha Sarakham University, Muang district, Maha Sarakham province and rickettsial infection among cat fleas, Ctenocephalides felis, collected from dogs of the surrounding area of Waeng Noi district, Khon Kaen province. Forty-two cat sera were assessed for IgG antibody titers against SFGR by a group-specific enzyme-linked immunosorbent assay. The prevalence of seroreactive cats was 4.76% (2/42). DNA preparations from 23 individual cat fleas from three dogs were assessed by Rickettsia genus-specific, group-specific, and species-specific quantitative real-time PCR (qPCR) assays. Positive results were confirmed by ompB gene fragment sequencing. Twenty-one of 23 cat fleas were positive for Rickettsia asembonensis, and the other two DNA preparations were negative for rickettsial DNA. This study's finding indicates that companion cats and dogs in Northeast Thailand are exposed to SFGR and that exposure may be due to infection with R. asembonensis, an organism known to infect humans, monkeys, and dogs. Clinicians for humans and animals in Northeast Thailand should be aware of rickettsial infections among their patients.
Collapse
Affiliation(s)
- Sirirat Phomjareet
- Department of Veterinary Public Health and Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Prapansak Chaveerach
- Department of Veterinary Public Health and Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Fanan Suksawat
- Department of Veterinary Medicine, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Ju Jiang
- Rickettsial Diseases Research Program, Infectious Diseases Directorate, Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Allen L Richards
- Rickettsial Diseases Research Program, Infectious Diseases Directorate, Naval Medical Research Center, Silver Spring, Maryland, USA.,Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,International Visiting Scholar, Faculty of Veterinary Medicine, Khon Kaen University, Khon Kaen, Thailand
| |
Collapse
|
20
|
Lokida D, Sudarmono P, Kosasih H, Butar-butar DP, Salim G, Antonjaya U, Sari RA, Aman AT, Parwati I, Arif M, Lau CY, Karyana M. Comparison of Commercial Enzyme-Linked Immunosorbent Assay and Immunofluorescence Assay for Diagnosis of Acute Rickettsia typhi Infections. Vector Borne Zoonotic Dis 2020; 20:93-99. [PMID: 31448989 PMCID: PMC7041318 DOI: 10.1089/vbz.2019.2451] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Murine typhus is a tropical disease caused by Rickettsia typhi and is endemic in resource-limited settings such as Southeast Asian countries. Early diagnosis of R. typhi infection facilitates appropriate management and reduces the risk of severe disease. However, molecular detection of R. typhi in blood is insensitive due to low rickettsemia. Furthermore, the gold standard of sero-diagnosis by immunofluorescence assay (IFA) is cumbersome, subjective, impractical, and unavailable in many endemic areas. In an attempt to identify a practical diagnostic approach that can be applied in Indonesia, we evaluated the performance of commercial R. typhi IgM and IgG enzyme-linked immunosorbent assay (ELISA) and IFA using paired plasma from previously studied R. typhi PCR-positive cases and controls with other known infections. Sensitivity and specificity of combined ELISA IgM and IgG anti-R. typhi using paired specimens were excellent (95.0% and 98.3%, respectively), comparable to combined IFA IgM and IgG (97.5% and 100%, respectively); sensitivity of ELISA IgM from acute specimens only was poor (45.0%), but specificity was excellent (98.3%). IFA IgM was more sensitive (77.5%), but less specific (89.7%) for single specimens.
Collapse
Affiliation(s)
- Dewi Lokida
- Department of Clinical Pathology, Tangerang District Hospital, Tangerang, Indonesia
| | | | - Herman Kosasih
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Deni Pepy Butar-butar
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Gustiani Salim
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | | | - Rizky Amalia Sari
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| | - Abu Tholib Aman
- Faculty of Medicine, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Ida Parwati
- Department of Clinical Pathology, Universitas Padjadjaran/Hasan Sadikin Hospital, Bandung, Indonesia
| | - Mansyur Arif
- Faculty of Medicine, Universitas Hasanudin/Dr. Wahidin Sudirohusodo Hospital, Makassar, Indonesia
| | - Chuen-Yen Lau
- Collaborative Clinical Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland
| | - Muhammad Karyana
- Indonesia Research Partnership on Infectious Disease (INA-RESPOND), National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
- National Institute of Health Research and Development, Ministry of Health, Jakarta, Indonesia
| |
Collapse
|
21
|
Trung NV, Hoi LT, Dien VM, Huong DT, Hoa TM, Lien VN, Van Luan P, Lewycka SO, Choisy M, Bryant JE, Nadjm B, Rogier van Doorn H, Richards AL, Van Kinh N. Clinical Manifestations and Molecular Diagnosis of Scrub Typhus and Murine Typhus, Vietnam, 2015-2017. Emerg Infect Dis 2019; 25. [PMID: 30882318 PMCID: PMC6433017 DOI: 10.3201/eid2504.180691] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Scrub typhus was the predominant rickettsial disease diagnosed among hospitalized patients with acute undifferentiated fever in northern Vietnam. Rickettsioses are endemic to Vietnam; however, only a limited number of clinical studies have been performed on these vectorborne bacteria. We conducted a prospective hospital-based study at 2 national referral hospitals in Hanoi to describe the clinical characteristics of scrub typhus and murine typhus in northern Vietnam and to assess the diagnostic applicability of quantitative real-time PCR assays to diagnose rickettsial diseases. We enrolled 302 patients with acute undifferentiated fever and clinically suspected rickettsiosis during March 2015–March 2017. We used a standardized case report form to collect clinical information and laboratory results at the time of admission and during treatment. We confirmed scrub typhus in 103 (34.1%) patients and murine typhus in 12 (3.3%) patients. These results highlight the need for increased emphasis on training for healthcare providers for earlier recognition, prevention, and treatment of rickettsial diseases in Vietnam.
Collapse
|
22
|
Dubot-Pérès A, Mayxay M, Phetsouvanh R, Lee SJ, Rattanavong S, Vongsouvath M, Davong V, Chansamouth V, Phommasone K, Moore C, Dittrich S, Lattana O, Sirisouk J, Phoumin P, Panyanivong P, Sengduangphachanh A, Sibounheuang B, Chanthongthip A, Simmalavong M, Sengdatka D, Seubsanith A, Keoluangkot V, Phimmasone P, Sisout K, Detleuxay K, Luangxay K, Phouangsouvanh I, Craig SB, Tulsiani SM, Burns MA, Dance DAB, Blacksell SD, de Lamballerie X, Newton PN. Management of Central Nervous System Infections, Vientiane, Laos, 2003-2011. Emerg Infect Dis 2019; 25:898-910. [PMID: 31002063 PMCID: PMC6478220 DOI: 10.3201/eid2505.180914] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
During 2003–2011, we recruited 1,065 patients of all ages admitted to Mahosot Hospital (Vientiane, Laos) with suspected central nervous system (CNS) infection. Etiologies were laboratory confirmed for 42.3% of patients, who mostly had infections with emerging pathogens: viruses in 16.2% (mainly Japanese encephalitis virus [8.8%]); bacteria in 16.4% (including Orientia tsutsugamushi [2.9%], Leptospira spp. [2.3%], and Rickettsia spp. [2.3%]); and Cryptococcus spp. fungi in 6.6%. We observed no significant differences in distribution of clinical encephalitis and meningitis by bacterial or viral etiology. However, patients with bacterial CNS infection were more likely to have a history of diabetes than others. Death (26.3%) was associated with low Glasgow Coma Scale score, and the mortality rate was higher for patients with bacterial than viral infections. No clinical or laboratory variables could guide antibiotic selection. We conclude that high-dependency units and first-line treatment with ceftriaxone and doxycycline for suspected CNS infections could improve patient survival in Laos.
Collapse
|
23
|
Mullins KE, Maina AN, Krueger L, Jiang J, Cummings R, Drusys A, Williams G, Dhillon M, Richards AL. Rickettsial Infections among Cats and Cat Fleas in Riverside County, California. Am J Trop Med Hyg 2018; 99:291-296. [PMID: 29869607 DOI: 10.4269/ajtmh.17-0706] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Presently, few studies have investigated the role of domestic cats (Felis catus) in the recrudescence of flea-borne rickettsioses in California and the southern United States. In this study, we aimed to investigate the presence of Rickettsia typhi or Rickettisa felis in domestic cats (F. catus) and the fleas (primarily Ctenocephalides felis, the cat flea) associated with these cats in Riverside County, California. Thirty cats and 64 pools of fleas collected from these cats were investigated for rickettsial infections. Three cats and 17 flea pools (from 10 cats) tested positive for rickettsial infections. polymerase chain reaction and DNA sequencing indicated that one of the cats was positive for R. felis infections, whereas two were positive for Candidatus Rickettsia senegalensis infection. In addition, 12 of the flea pools were positive for R. felis, whereas five were positive for Ca. R. senegalensis. By contrast, no cats or their associated fleas tested positive for R. typhi. Finally, eight sera from these cats contained spotted fever group Rickettsia (SFGR) antibodies. The detection of R. felis and SFGR antibodies and the lack of R. typhi and TGR antibodies support R. felis as the main rickettsial species infecting cat fleas. The detection of Ca. R. senegalensis in both fleas and cats also provides additional evidence that cats and their associated fleas are infected with other R. felis-like organisms highlighting the potential risk for human infections with R. felis or R. felis-like organisms.
Collapse
Affiliation(s)
- Kristin E Mullins
- Naval Medical Research Center, Silver Spring, Maryland.,University of Maryland School of Medicine, Baltimore, Maryland
| | - Alice N Maina
- Naval Medical Research Center, Silver Spring, Maryland
| | - Laura Krueger
- Orange County Mosquito and Vector Control District, Garden Grove, California
| | - Ju Jiang
- Naval Medical Research Center, Silver Spring, Maryland
| | - Robert Cummings
- Orange County Mosquito and Vector Control District, Garden Grove, California
| | - Allan Drusys
- Riverside County Department of Animal Services, Riverside, California
| | - Greg Williams
- Northwest Mosquito and Vector Control District, Corona, California
| | - Major Dhillon
- Northwest Mosquito and Vector Control District, Corona, California
| | - Allen L Richards
- Uniformed Services University of the Health Sciences, Bethesda, Maryland.,Naval Medical Research Center, Silver Spring, Maryland
| |
Collapse
|
24
|
Nelson K, Maina AN, Brisco A, Foo C, Croker C, Ngo V, Civen R, Richards AL, Fujioka K, Wekesa JW. A 2015 outbreak of flea-borne rickettsiosis in San Gabriel Valley, Los Angeles County, California. PLoS Negl Trop Dis 2018; 12:e0006385. [PMID: 29677221 PMCID: PMC5931684 DOI: 10.1371/journal.pntd.0006385] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 05/02/2018] [Accepted: 03/12/2018] [Indexed: 11/23/2022] Open
Abstract
Although flea-borne rickettsiosis is endemic in Los Angeles County, outbreaks are rare. In the spring of 2015 three human cases of flea-borne rickettsiosis among residents of a mobile home community (MHC) prompted an investigation. Fleas were ubiquitous in common areas due to presence of flea-infested opossums and overabundant outdoor cats and dogs. The MHC was summarily abated in June 2015, and within five months, flea control and removal of animals significantly reduced the flea population. Two additional epidemiologically-linked human cases of flea-borne rickettsiosis detected at the MHC were suspected to have occurred before control efforts began. Molecular testing of 106 individual and 85 pooled cat fleas, blood and ear tissue samples from three opossums and thirteen feral cats using PCR amplification and DNA sequencing detected rickettsial DNA in 18.8% of the fleas. Seventeen percent of these cat fleas tested positive for R. felis-specific DNA compared to under two (<2) percent for Candidatus R. senegalensis-specific DNA. In addition, serological testing of 13 cats using a group-specific IgG-ELISA detected antibodies against typhus group rickettsiae and spotted fever group rickettsiae in six (46.2%) and one (7.7%) cat, respectively. These results indicate that cats and their fleas may have played an active role in the epidemiology of the typhus group and/or spotted fever group rickettsial disease(s) in this outbreak. Outbreaks of flea-borne rickettsiosis are rare despite the endemic status in Los Angeles County. In the spring of 2015 three human cases of flea-borne rickettsiosis among residents of a mobile home community (MHC) prompted an investigation. Fleas were found in all common areas at the MHC due to presence of flea-infested opossums and overabundant outdoor cats and dogs. The MHC was summarily abated in June 2015, and within five months, flea control and removal of animals significantly reduced the flea population. Two additional epidemiologically-linked human cases detected at the MHC were considered to have occurred before control efforts began. Molecular testing of cat fleas, immunological testing of opossums and feral cats collected at the site indicated active transmission of flea-borne rickettsiosis. This study represents the first flea-borne rickettsial outbreak that summary abatement approach was used to reduce its intensity.
Collapse
Affiliation(s)
- Kimberly Nelson
- San Gabriel Valley Mosquito and Vector Control District, West Covina, California, United States of America
| | - Alice N. Maina
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Angela Brisco
- San Gabriel Valley Mosquito and Vector Control District, West Covina, California, United States of America
| | - Chelsea Foo
- Acute Communicable Disease Control, Los Angeles County Department of Public Health, Los Angeles, California, United States of America
- CDC/CSTE Applied Epidemiology Fellowship Program, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Curtis Croker
- Acute Communicable Disease Control, Los Angeles County Department of Public Health, Los Angeles, California, United States of America
| | - Van Ngo
- Acute Communicable Disease Control, Los Angeles County Department of Public Health, Los Angeles, California, United States of America
| | - Rachel Civen
- Acute Communicable Disease Control, Los Angeles County Department of Public Health, Los Angeles, California, United States of America
- Community Health Services Program, Los Angeles County Department of Public Health, Los Angeles, California, United States of America
| | - Allen L. Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, Maryland, United States of America
| | - Kenn Fujioka
- San Gabriel Valley Mosquito and Vector Control District, West Covina, California, United States of America
| | - J. Wakoli Wekesa
- San Gabriel Valley Mosquito and Vector Control District, West Covina, California, United States of America
- * E-mail:
| |
Collapse
|
25
|
Afzal Z, Kallumadanda S, Wang F, Hemmige V, Musher D. Acute Febrile Illness and Complications Due to Murine Typhus, Texas, USA1,2. Emerg Infect Dis 2018; 23:1268-1273. [PMID: 28726607 PMCID: PMC5547806 DOI: 10.3201/eid2308.161861] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Murine typhus occurs relatively commonly in southern Texas, as well as in California. We reviewed records of 90 adults and children in whom murine typhus was diagnosed during a 3-year period in 2 hospitals in southern Texas, USA. Most patients lacked notable comorbidities; all were immunocompetent. Initial signs and symptoms included fever (99%), malaise (82%), headache (77%), fatigue (70%), myalgias (68%), and rash (39%). Complications, often severe, in 28% of patients included bronchiolitis, pneumonia, meningitis, septic shock, cholecystitis, pancreatitis, myositis, and rhabdomyolysis; the last 3 are previously unreported in murine typhus. Low serum albumin and elevated procalcitonin, consistent with bacterial sepsis, were observed in >70% of cases. Rash was more common in children; thrombocytopenia, hyponatremia, elevated hepatic transaminases, and complications were more frequent in adults. Murine typhus should be considered as a diagnostic possibility in cases of acute febrile illness in southern and even in more northern US states.
Collapse
|
26
|
|
27
|
Noden BH, Davidson S, Smith JL, Williams F. First Detection of Rickettsia typhi and Rickettsia felis in Fleas Collected From Client-Owned Companion Animals in the Southern Great Plains. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:1093-1097. [PMID: 28399210 DOI: 10.1093/jme/tjx069] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Indexed: 06/07/2023]
Abstract
Flea-borne rickettsiosis occurs worldwide and includes a number of pathogens, namely, Rickettsia typhi and Rickettsia felis. Most studies in the United States have occurred in southern Texas and California where flea-borne rickettsiosis is endemic, resulting in a lack of information from other regions of the country. Between March and August 2016, 222 fleas were collected from 52 client-owned dogs and cats in two urban areas in Oklahoma. Fleas were identified using morphological characteristics then pooled and tested by polymerase chain reaction (PCR) using published primers for gltA, ompB, and 17-kDa. The majority (98.6%) of fleas collected were Ctenocephalides felis (Bouché) followed by Pulex irritans (L) (1.4%). Overall, fleas collected from 30.0% (6/20) cats and 43.8% (14/32) dogs were infected with R. felis. Three C. felis-pools collected from three dogs, two in the Enid area (central Oklahoma) and one in the Elk City area (western Oklahoma), were infected with R. typhi as well as R. felis. 'Candidatus R. senegalensis' was detected in one pool of fleas taken from a cat in Oklahoma City. This is the first evidence that flea-borne Rickettsia species occur in fleas obtained from client-owned dogs and cats in the Great Plains region. The impact of these Rickettsia species on public health in the region needs further investigation.
Collapse
Affiliation(s)
- Bruce H Noden
- Department of Entomology and Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078
| | - Suzanna Davidson
- Department of Entomology and Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078
| | - Jessica Lynn Smith
- Department of Entomology and Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078
| | - Faithful Williams
- Department of Entomology and Plant Pathology, Oklahoma State University, 127 Noble Research Center, Stillwater, OK 74078
| |
Collapse
|
28
|
Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar. Parasit Vectors 2017; 10:125. [PMID: 28259176 PMCID: PMC5336680 DOI: 10.1186/s13071-017-2061-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/24/2017] [Indexed: 12/25/2022] Open
Abstract
Background Rickettsiae are obligate intracellular bacteria responsible for many febrile syndromes around the world, including in sub-Saharan Africa. Vectors of these pathogens include ticks, lice, mites and fleas. In order to assess exposure to flea-associated Rickettsia species in Madagascar, human and small mammal samples from an urban and a rural area, and their associated fleas were tested. Results Anti-typhus group (TGR)- and anti-spotted fever group rickettsiae (SFGR)-specific IgG were detected in 24 (39%) and 21 (34%) of 62 human serum samples, respectively, using indirect ELISAs, with six individuals seropositive for both. Only two (2%) Rattus rattus out of 86 small mammals presented antibodies against TGR. Out of 117 fleas collected from small mammals, Rickettsia typhi, a TGR, was detected in 26 Xenopsylla cheopis (24%) collected from rodents of an urban area (n = 107), while two of these urban X. cheopis (2%) were positive for Rickettsia felis, a SFGR. R. felis DNA was also detected in eight (31%) out of 26 Pulex irritans fleas. Conclusions The general population in Madagascar are exposed to rickettsiae, and two flea-associated Rickettsia pathogens, R. typhi and R. felis, are present near or in homes. Although our results are from a single district, they demonstrate that rickettsiae should be considered as potential agents of undifferentiated fever in Madagascar.
Collapse
|
29
|
Use of Multiplex Real-Time PCR To Diagnose Scrub Typhus. J Clin Microbiol 2017; 55:1377-1387. [PMID: 28202789 DOI: 10.1128/jcm.02181-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/06/2017] [Indexed: 12/15/2022] Open
Abstract
Scrub typhus, caused by Orientia tsutsugamushi, is a common cause of acute undifferentiated febrile illness in the Asia-Pacific region. However, its nonspecific clinical manifestation often prevents early diagnosis. We propose the use of PCR and serologic tests as diagnostic tools. Here, we developed a multiplex real-time PCR assay using hydrolysis (TaqMan) probes targeting O. tsutsugamushi 47-kDa, groEL, and human interferon beta (IFN-β gene) genes to improve early diagnosis of scrub typhus. The amplification efficiency was higher than 94%, and the lower detection limit was 10 copies per reaction. We used a human gene as an internal DNA quality and quantity control. To determine the sensitivity of this PCR assay, we selected patients with confirmed scrub typhus who exhibited a clear 4-fold increase in the level of IgG and/or IgM. The PCR assay result was positive in 45 of 52 patients, indicating a sensitivity of 86.5% (95% confidence interval [CI]: 74.2 to 94.4). The PCR assessment was negative for all 136 non-scrub typhus patients, indicating a specificity of 100% (95% CI: 97.3 to 100). In addition, this test helped diagnose patients with inconclusive immunofluorescence assay (IFA) results and using single blood samples. In conclusion, the real-time PCR assay proposed here is sensitive and specific in diagnosing scrub typhus. Combining PCR and serologic tests will improve the diagnosis of scrub typhus among patients presenting with acute febrile illness.
Collapse
|
30
|
Sothmann P, Keller C, Krumkamp R, Kreuels B, Aldrich C, Sarpong N, Steierberg S, Winter D, Boahen KG, Owusu-Dabo E, May J, Eibach D. Rickettsia felis Infection in Febrile Children, Ghana. Am J Trop Med Hyg 2017; 96:783-785. [PMID: 28115672 DOI: 10.4269/ajtmh.16-0754] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
AbstractRickettsial infections are an underrecognized cause of febrile illness in sub-Saharan Africa. To evaluate the epidemiology and clinical features of rickettsial disease in pediatric patients in Ghana, we screened blood samples from febrile children aged less than 15 years presenting to an outpatient department in Ghana's Ashanti Region for the presence of rickettsial DNA. We detected Rickettsia felis in 7/470 (1.5%) blood samples, using two independent real-time polymerase chain reactions. No other Rickettsia species were found. R. felis was detected repeatedly in one patient, and coinfection with Plasmodium falciparum was found in 3/7 samples. Symptoms apart from fever included cough (6/7) and vomiting (4/7). None of the R. felis-positive patients reported a rash. This study is the first report on R. felis in Ghana and adds to the growing evidence for its widespread occurrence with and without malaria coinfection in sub-Saharan Africa.
Collapse
Affiliation(s)
- Peter Sothmann
- Division of Tropical Medicine, 1st Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Christian Keller
- Institute of Virology, University Hospital Giessen and Marburg, Marburg, Germany
| | - Ralf Krumkamp
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany
| | - Benno Kreuels
- Division of Tropical Medicine, 1st Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany
| | - Cassandra Aldrich
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Nimako Sarpong
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Stefanie Steierberg
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Doris Winter
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Kennedy Gyau Boahen
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ellis Owusu-Dabo
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Jürgen May
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck, Hamburg, Germany
| | - Daniel Eibach
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| |
Collapse
|
31
|
Maude RR, Ghose A, Samad R, de Jong HK, Fukushima M, Wijedoru L, Hassan MU, Hossain MA, Karim MR, Sayeed AA, van den Ende S, Pal S, Zahed ASM, Rahman W, Karnain R, Islam R, Tran DTN, Ha TT, Pham AH, Campbell JI, van Doorn HR, Maude RJ, van der Poll T, Wiersinga WJ, Day NPJ, Baker S, Dondorp AM, Parry CM, Faiz MA. A prospective study of the importance of enteric fever as a cause of non-malarial febrile illness in patients admitted to Chittagong Medical College Hospital, Bangladesh. BMC Infect Dis 2016; 16:567. [PMID: 27737634 PMCID: PMC5064917 DOI: 10.1186/s12879-016-1886-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/01/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fever is a common cause of hospital admission in Bangladesh but causative agents, other than malaria, are not routinely investigated. Enteric fever is thought to be common. METHODS Adults and children admitted to Chittagong Medical College Hospital with a temperature of ≥38.0 °C were investigated using a blood smear for malaria, a blood culture, real-time PCR to detect Salmonella Typhi, S. Paratyphi A and other pathogens in blood and CSF and an NS1 antigen dengue ELISA. RESULTS We enrolled 300 febrile patients with a negative malaria smear between January and June 2012: 156 children (aged ≤15 years) and 144 adults with a median (interquartile range) age of 13 (5-31) years and median (IQR) illness duration before admission of five (2-8) days. Clinical enteric fever was diagnosed in 52 patients (17.3 %), lower respiratory tract infection in 48 (16.0 %), non-specific febrile illness in 48 (16.0 %), a CNS infection in 37 patients (12.3 %), urinary sepsis in 23 patients (7.7 %), an upper respiratory tract infection in 21 patients (7.0 %), and diarrhea or dysentery in 21 patients (7.0 %). Malaria was still suspected in seven patients despite a negative microscopy test. S. Typhi was detected in blood by culture or PCR in 34 (11.3 %) of patients. Of note Rickettsia typhi and Orientia tsutsugamushi were detected by PCR in two and one patient respectively. Twenty-nine (9 %) patients died during their hospital admission (15/160 (9.4 %) of children and 14/144 (9.7 %) adults). Two of 52 (3.8 %) patients with enteric fever, 5/48 (10.4 %) patients with lower respiratory tract infections, and 12/37 (32.4 %) patients with CNS infection died. CONCLUSION Enteric fever was confirmed in 11.3 % of patients admitted to this hospital in Bangladesh with non-malaria fever. Lower respiratory tract and CNS infections were also common. CNS infections in this location merit more detailed study due to the high mortality.
Collapse
Affiliation(s)
- Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), and Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | | | | | - Stannie van den Ende
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), and Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sujat Pal
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - A S M Zahed
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Wahid Rahman
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Rifat Karnain
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Rezina Islam
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | - Dung Thi Ngoc Tran
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Tuyen Thanh Ha
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Anh Hong Pham
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - James I Campbell
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK
| | - H Rogier van Doorn
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK
| | - Richard J Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK
| | - Tom van der Poll
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), and Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - W Joost Wiersinga
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), and Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK
| | - Stephen Baker
- Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit (OUCRU), Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK.,Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, Oxford University, Oxford, UK
| | - Christopher M Parry
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK. .,Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. .,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan.
| | - Md Abul Faiz
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Malaria Research Group and Dev Care Foundation, Chittagong, Bangladesh
| |
Collapse
|
32
|
Papp S, Rauch J, Kuehl S, Richardt U, Keller C, Osterloh A. Comparative evaluation of two Rickettsia typhi-specific quantitative real-time PCRs for research and diagnostic purposes. Med Microbiol Immunol 2016; 206:41-51. [PMID: 27696011 DOI: 10.1007/s00430-016-0480-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 09/21/2016] [Indexed: 01/03/2023]
Abstract
Rickettsioses are caused by intracellular bacteria of the family of Rickettsiaceae. Rickettsia (R.) typhi is the causative agent of endemic typhus. The disease occurs worldwide and is one of the most prevalent rickettsioses. Rickettsial diseases, however, are generally underdiagnosed which is mainly due to the lack of sensitive and specific methods. In addition, methods for quantitative detection of the bacteria for research purposes are rare. We established two qPCRs for the detection of R. typhi by amplification of the outer membrane protein B (ompB) and parvulin-type PPIase (prsA) genes. Both qPCRs are specific and exclusively recognize R. typhi but no other rickettsiae including the closest relative, R. prowazekii. The prsA-based qPCR revealed to be much more sensitive than the amplification of ompB and provided highly reproducible results in the detection of R. typhi in organs of infected mice. Furthermore, as a nested PCR the prsA qPCR was applicable for the detection of R. typhi in human blood samples. Collectively, the prsA-based qPCR represents a reliable method for the quantitative detection of R. typhi for research purposes and is a promising candidate for differential diagnosis.
Collapse
Affiliation(s)
- Stefanie Papp
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Jessica Rauch
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Svenja Kuehl
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Ulricke Richardt
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany
| | - Christian Keller
- Institute for Virology, University Medical Center Gießen and Marburg, 35032, Marburg, Germany
| | - Anke Osterloh
- Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, 20359, Hamburg, Germany.
| |
Collapse
|
33
|
Maina AN, Fogarty C, Krueger L, Macaluso KR, Odhiambo A, Nguyen K, Farris CM, Luce-Fedrow A, Bennett S, Jiang J, Sun S, Cummings RF, Richards AL. Rickettsial Infections among Ctenocephalides felis and Host Animals during a Flea-Borne Rickettsioses Outbreak in Orange County, California. PLoS One 2016; 11:e0160604. [PMID: 27537367 PMCID: PMC4990410 DOI: 10.1371/journal.pone.0160604] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 07/21/2016] [Indexed: 11/23/2022] Open
Abstract
Due to a resurgence of flea-borne rickettsioses in Orange County, California, we investigated the etiologies of rickettsial infections of Ctenocephalides felis, the predominant fleas species obtained from opossums (Didelphis virginiana) and domestic cats (Felis catus), collected from case exposure sites and other areas in Orange County. In addition, we assessed the prevalence of IgG antibodies against spotted fever group (SFGR) and typhus group (TGR) rickettsiae in opossum sera. Of the 597 flea specimens collected from opossums and cats, 37.2% tested positive for Rickettsia. PCR and sequencing of rickettsial genes obtained from C. felis flea DNA preparations revealed the presence of R. typhi (1.3%), R. felis (28.0%) and R. felis-like organisms (7.5%). Sera from opossums contained TGR-specific (40.84%), but not SFGR-specific antibodies. The detection of R. felis and R. typhi in the C. felis fleas in Orange County highlights the potential risk for human infection with either of these pathogens, and underscores the need for further investigations incorporating specimens from humans, animal hosts, and invertebrate vectors in endemic areas. Such studies will be essential for establishing a link in the ongoing flea-borne rickettsioses outbreaks.
Collapse
Affiliation(s)
- Alice N. Maina
- Naval Medical Research Center, Silver Spring, MD, United States of America
- * E-mail:
| | - Carrie Fogarty
- Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America
| | - Laura Krueger
- Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America
| | - Kevin R. Macaluso
- Louisiana State University, Baton Rouge, LA, United States of America
| | - Antony Odhiambo
- Naval Medical Research Center, Silver Spring, MD, United States of America
| | - Kiet Nguyen
- Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America
| | | | - Alison Luce-Fedrow
- Naval Medical Research Center, Silver Spring, MD, United States of America
- Shippensburg University, Shippensburg, PA, United States of America
| | - Stephen Bennett
- Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America
| | - Ju Jiang
- Naval Medical Research Center, Silver Spring, MD, United States of America
| | - Sokanary Sun
- West Valley Mosquito and Vector Control District, Ontario, CA, United States of America
| | - Robert F. Cummings
- Orange County Mosquito and Vector Control District, Garden Grove, CA, United States of America
| | - Allen L. Richards
- Naval Medical Research Center, Silver Spring, MD, United States of America
| |
Collapse
|
34
|
Reference gene selection and RNA preservation protocol in the cat flea, Ctenocephalides felis, for gene expression studies. Parasitology 2016; 143:1532-42. [DOI: 10.1017/s0031182016001025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYThe cat flea, Ctenocephalides felis, is a major pest species on companion animals thus of significant importance to the animal health industry. The aim of this study was to develop sampling and storage protocols and identify stable reference genes for gene expression studies to fully utilize the growing body of molecular knowledge of C. felis. RNA integrity was assessed in adult and larvae samples, which were either pierced or not pierced and stored in RNAlater at ambient temperature. RNA quality was maintained best in pierced samples, with negligible degradation evident after 10 days. RNA quality from non-pierced samples was poor within 3 days. Ten candidate reference genes were evaluated for their stability across four group comparisons (developmental stages, genders, feeding statuses and insecticide-treatment statuses). Glyceraldehyde 3 phosphate dehydrogenase (GAPDH), 60S ribosomal protein L19 (RPL19) and elongation factor-1α (Ef) were ranked highly in all stability comparisons, thus are recommended as reference genes under similar conditions. Employing just two of these three stable reference genes was sufficient for accurate normalization. Our results make a significant contribution to the future of gene expression studies in C. felis, describing validated sample preparation procedures and reference genes for use in this common pest.
Collapse
|
35
|
Kolo AO, Sibeko-Matjila KP, Maina AN, Richards AL, Knobel DL, Matjila PT. Molecular Detection of Zoonotic Rickettsiae and Anaplasma spp. in Domestic Dogs and Their Ectoparasites in Bushbuckridge, South Africa. Vector Borne Zoonotic Dis 2016; 16:245-52. [PMID: 26974185 DOI: 10.1089/vbz.2015.1849] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Members of the order Rickettsiales are small, obligate intracellular bacteria that are vector-borne and can cause mild to fatal diseases in humans worldwide. There is little information on the zoonotic rickettsial pathogens that may be harbored by dogs from rural localities in South Africa. To characterize rickettsial pathogens infecting dogs, we screened 141 blood samples, 103 ticks, and 43 fleas collected from domestic dogs in Bushbuckridge Municipality, Mpumalanga Province of South Africa, between October 2011 and May 2012 using the reverse line blot (RLB) and Rickettsia genus and species-specific quantitative real-time PCR (qPCR) assays. Results from RLB showed that 49% of blood samples and 30% of tick pools were positive for the genus-specific probes for Ehrlichia/Anaplasma; 16% of the blood samples were positive for Ehrlichia canis. Hemoparasite DNA could not be detected in 36% of blood samples and 30% of tick pools screened. Seven (70%) tick pools and both flea pools were positive for Rickettsia spp; three (30%) tick pools were positive for Rickettsia africae; and both flea pools (100%) were positive for Rickettsia felis. Sequencing confirmed infection with R. africae and Candidatus Rickettsia asemboensis; an R. felis-like organism from one of the R. felis-positive flea pools. Anaplasma sp. South Africa dog strain (closely related to Anaplasma phagocytophilum), A. phagocytophilum, and an Orientia tsutsugamushi-like sequence were identified from blood samples. The detection of emerging zoonotic agents from domestic dogs and their ectoparasites in a rural community in South Africa highlights the potential risk of human infection that may occur with these pathogens.
Collapse
Affiliation(s)
- Agatha O Kolo
- 1 Department of Veterinary Tropical Diseases, University of Pretoria , Pretoria, South Africa
| | | | - Alice N Maina
- 2 Department of Viral and Rickettsial Disease, Naval Medical Research Center , Silver Spring, Maryland
| | - Allen L Richards
- 2 Department of Viral and Rickettsial Disease, Naval Medical Research Center , Silver Spring, Maryland
| | - Darryn L Knobel
- 3 Ross University School of Veterinary Medicine , Basseterre, Saint Kitts and Nevis
| | - Paul T Matjila
- 1 Department of Veterinary Tropical Diseases, University of Pretoria , Pretoria, South Africa
| |
Collapse
|
36
|
Luce-Fedrow A, Mullins K, Kostik AP, St John HK, Jiang J, Richards AL. Strategies for detecting rickettsiae and diagnosing rickettsial diseases. Future Microbiol 2016; 10:537-64. [PMID: 25865193 DOI: 10.2217/fmb.14.141] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rickettsial diseases and scrub typhus constitute a group of the oldest known vector-borne diseases. The cosmopolitan distribution of the vectors that transmit rickettsiae and orientiae leads to a worldwide prevalence of these diseases. Despite their significant historical status, detection and diagnosis of these diseases are still evolving today. Serological methods remain among the most prevalent techniques used for the detection/diagnosis of rickettsial diseases and scrub typhus. Molecular techniques have been instrumental in increasing the sensitivity/specificity of diagnosis, identifying new Rickettsia and Orientia species and have enhanced epidemiological capabilities when used in combination with serological methods. In this review, we discuss these techniques and their associated pros and cons.
Collapse
Affiliation(s)
- Alison Luce-Fedrow
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| | | | | | | | | | | |
Collapse
|
37
|
Blanton LS, Lea AS, Kelly BC, Walker DH. An Unusual Cutaneous Manifestation in a Patient with Murine Typhus. Am J Trop Med Hyg 2015; 93:1164-7. [PMID: 26416115 DOI: 10.4269/ajtmh.15-0380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 07/29/2015] [Indexed: 11/07/2022] Open
Abstract
Murine typhus is a flea-borne febrile illness caused by Rickettsia typhi. Although often accompanied by rash, an inoculation lesion has not been observed as it is with many tick- and mite-transmitted rickettsioses. We describe a patient with murine typhus and an unusual cutaneous manifestation at the site of rickettsial inoculation.
Collapse
Affiliation(s)
- Lucas S Blanton
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; Department of Dermatology, University of Texas Medical Branch, Galveston, Texas; Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Alfred S Lea
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; Department of Dermatology, University of Texas Medical Branch, Galveston, Texas; Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - Brent C Kelly
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; Department of Dermatology, University of Texas Medical Branch, Galveston, Texas; Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| | - David H Walker
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas; Department of Dermatology, University of Texas Medical Branch, Galveston, Texas; Department of Pathology, University of Texas Medical Branch, Galveston, Texas
| |
Collapse
|
38
|
Phetsouvanh R, Sonthayanon P, Pukrittayakamee S, Paris DH, Newton PN, Feil EJ, Day NPJ. The Diversity and Geographical Structure of Orientia tsutsugamushi Strains from Scrub Typhus Patients in Laos. PLoS Negl Trop Dis 2015; 9:e0004024. [PMID: 26317624 PMCID: PMC4552799 DOI: 10.1371/journal.pntd.0004024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 08/02/2015] [Indexed: 11/18/2022] Open
Abstract
Orientia tsutsugamushi is the causative agent of scrub typhus, a disease transmitted by Leptotrombidium mites which is responsible for a severe and under-reported public health burden throughout Southeast Asia. Here we use multilocus sequence typing (MLST) to characterize 74 clinical isolates from three geographic locations in the Lao PDR (Laos), and compare them with isolates described from Udon Thani, northeast Thailand. The data confirm high levels of diversity and recombination within the natural O. tsutsugamushi population, and a rate of mixed infection of ~8%. We compared the relationships and geographical structuring of the strains and populations using allele based approaches (eBURST), phylogenetic approaches, and by calculating F-statistics (FST). These analyses all point towards low levels of population differentiation between isolates from Vientiane and Udon Thani, cities which straddle the Mekong River which defines the Lao/Thai border, but with a very distinct population in Salavan, southern Laos. These data highlight how land use, as well as the movement of hosts and vectors, may impact on the epidemiology of zoonotic infections.
Collapse
Affiliation(s)
- Rattanaphone Phetsouvanh
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos PDR
| | - Piengchan Sonthayanon
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- * E-mail: ,
| | - Sasithon Pukrittayakamee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Daniel H. Paris
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine & Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Paul N. Newton
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos PDR
| | - Edward J. Feil
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Nicholas P. J. Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine & Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
39
|
Increased Nucleosomes and Neutrophil Activation Link to Disease Progression in Patients with Scrub Typhus but Not Murine Typhus in Laos. PLoS Negl Trop Dis 2015; 9:e0003990. [PMID: 26317419 PMCID: PMC4552835 DOI: 10.1371/journal.pntd.0003990] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 07/15/2015] [Indexed: 11/19/2022] Open
Abstract
Cell-mediated immunity is essential in protection against rickettsial illnesses, but the role of neutrophils in these intracellular vasculotropic infections remains unclear. This study analyzed the plasma levels of nucleosomes, FSAP-activation (nucleosome-releasing factor), and neutrophil activation, as evidenced by neutrophil-elastase (ELA) complexes, in sympatric Lao patients with scrub typhus and murine typhus. In acute scrub typhus elevated nucleosome levels correlated with lower GCS scores, raised respiratory rate, jaundice and impaired liver function, whereas neutrophil activation correlated with fibrinolysis and high IL-8 plasma levels, a recently identified predictor of severe disease and mortality. Nucleosome and ELA complex levels were associated with a 4.8-fold and 4-fold increased risk of developing severe scrub typhus, beyond cut off values of 1,040 U/ml for nucleosomes and 275 U/ml for ELA complexes respectively. In murine typhus, nucleosome levels associated with pro-inflammatory cytokines and the duration of illness, while ELA complexes correlated strongly with inflammation markers, jaundice and increased respiratory rates. This study found strong correlations between circulating nucleosomes and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that nucleosomes could originate from neutrophil extracellular trap (NET) degradation. High circulating plasma nucleosomes and ELA complexes represent independent risk factors for developing severe complications in scrub typhus. As nucleosomes and histones exposed on NETs are highly cytotoxic to endothelial cells and are strongly pro-coagulant, neutrophil-derived nucleosomes could contribute to vascular damage, the pro-coagulant state and exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and increased plasma levels of nucleosomes and ELA complexes represent independent risk factors for developing severe scrub typhus. Tropical rickettsial illnesses, especially scrub typhus and murine typhus, are increasingly recognized as a leading cause of treatable undifferentiated febrile illness in Asia, but remain severely neglected and under appreciated diseases in many areas. In this study we investigated the relationship of markers of neutrophil activation and cell death with disease severity in patients with acute scrub typhus and murine typhus in Laos. These easily measurable circulating markers were associated with a 4 to 5-fold increased risk of developing severe clinical disease manifestations in scrub typhus and represent independent predictors of severe disease, and possibly death. We also found strong correlations between circulating markers of cell death and neutrophil activation in patients with scrub typhus, but not murine typhus, providing indirect evidence that neutrophil extracellular traps could contribute to the vascular damage and pro-coagulant state leading to exacerbation of disease in scrub typhus, thus indicating a detrimental role of neutrophil activation. The data suggest that increased neutrophil activation relates to disease progression and severe complications, and increased plasma levels of nucleosomes and ELA complexes represent independent risk factors for developing severe scrub typhus.
Collapse
|
40
|
Segura F, Pons I, Pla J, Nogueras MM. Shell-vial culture and real-time PCR applied to Rickettsia typhi and Rickettsia felis detection. World J Microbiol Biotechnol 2015; 31:1747-54. [PMID: 26289162 DOI: 10.1007/s11274-015-1925-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/12/2015] [Indexed: 11/27/2022]
Abstract
Murine typhus is a zoonosis transmitted by fleas, whose etiological agent is Rickettsia typhi. Rickettsia felis infection can produces similar symptoms. Both are intracellular microorganisms. Therefore, their diagnosis is difficult and their infections can be misdiagnosed. Early diagnosis prevents severity and inappropriate treatment regimens. Serology can't be applied during the early stages of infection because it requires seroconversion. Shell-vial (SV) culture assay is a powerful tool to detect Rickettsia. The aim of the study was to optimize SV using a real-time PCR as monitoring method. Moreover, the study analyzes which antibiotics are useful to isolate these microorganisms from fleas avoiding contamination by other bacteria. For the first purpose, SVs were inoculated with each microorganism. They were incubated at different temperatures and monitored by real-time PCR and classical methods (Gimenez staining and indirect immunofluorescence assay). R. typhi grew at all temperatures. R. felis grew at 28 and 32 °C. Real-time PCR was more sensitive than classical methods and it detected microorganisms much earlier. Besides, the assay sensitivity was improved by increasing the number of SV. For the second purpose, microorganisms and fleas were incubated and monitored in different concentrations of antibiotics. Gentamicin, sufamethoxazole, trimethoprim were useful for R. typhi isolation. Gentamicin, streptomycin, penicillin, and amphotericin B were useful for R. felis isolation. Finally, the optimized conditions were used to isolate R. felis from fleas collected at a veterinary clinic. R. felis was isolated at 28 and 32 °C. However, successful establishment of cultures were not possible probably due to sub-optimal conditions of samples.
Collapse
Affiliation(s)
- Ferran Segura
- Corporació Sanitària Parc Taulí, Institut Universitari Parc Taulí - Universitat Autonoma de Barcelona, 1st Parc Taulí, 08208, Sabadell, Spain
| | - Immaculada Pons
- Corporació Sanitària Parc Taulí, Institut Universitari Parc Taulí - Universitat Autonoma de Barcelona, 1st Parc Taulí, 08208, Sabadell, Spain
| | - Júlia Pla
- Veterinary Clinic "Centre", 53th Colom St., 08201, Sabadell, Spain
| | - María-Mercedes Nogueras
- Corporació Sanitària Parc Taulí, Institut Universitari Parc Taulí - Universitat Autonoma de Barcelona, 1st Parc Taulí, 08208, Sabadell, Spain.
| |
Collapse
|
41
|
Maude RR, de Jong HK, Wijedoru L, Fukushima M, Ghose A, Samad R, Hossain MA, Karim MR, Faiz MA, Parry CM. The diagnostic accuracy of three rapid diagnostic tests for typhoid fever at Chittagong Medical College Hospital, Chittagong, Bangladesh. Trop Med Int Health 2015; 20:1376-84. [PMID: 26094960 PMCID: PMC4832346 DOI: 10.1111/tmi.12559] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objective To determine the diagnostic accuracy of three rapid diagnostic tests (RDTs) for typhoid fever in febrile hospitalised patients in Bangladesh. Methods Febrile adults and children admitted to Chittagong Medical College Hospital, Bangladesh, were investigated with Bact/Alert® blood cultures and real‐time PCR to detect Salmonella enterica Typhi and Paratyphi A and assays for Rickettsia, leptospirosis and dengue fever. Acute serum samples were examined with the LifeAssay (LA) Test‐it™ Typhoid IgM lateral flow assay detecting IgM antibodies against S. Typhi O antigen, CTKBiotech Onsite Typhoid IgG/IgM Combo Rapid‐test cassette lateral flow assay detecting IgG and IgM antibodies against S. Typhi O and H antigens and SD Bioline line assay for IgG and IgM antibodies against S. Typhi proteins. Results In 300 malaria smear‐negative febrile patients [median (IQR) age of 13.5 (5–31) years], 34 (11.3%) had confirmed typhoid fever: 19 positive by blood culture for S. Typhi (three blood PCR positive) and 15 blood culture negative but PCR positive for S. Typhi in blood. The respective sensitivity and specificity of the three RDTs in patients using a composite reference standard of blood culture and/or PCR‐confirmed typhoid fever were 59% and 61% for LifeAssay, 59% and 74% for the CTK IgM and/or IgG, and 24% and 96% for the SD Bioline RDT IgM and/or IgG. The LifeAssay RDT had a sensitivity of 63% and a specificity of 91% when modified with a positive cut‐off of ≥2+ and analysed using a Bayesian latent class model. Conclusions These typhoid RDTs demonstrated moderate diagnostic accuracies, and better tests are needed.
Collapse
Affiliation(s)
- Rapeephan R Maude
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Hanna K de Jong
- Department of Internal Medicine, Division of Infectious Diseases and Center for Infection and Immunity Amsterdam (CINIMA), Amsterdam, The Netherlands.,Center for Experimental Molecular Medicine (CEMM), Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lalith Wijedoru
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Masako Fukushima
- Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | | | - Rasheda Samad
- Chittagong Medical College Hospital, Chittagong, Bangladesh
| | | | | | - Mohammed Abul Faiz
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Specialized Care and Research, Chittagong, Bangladesh
| | - Christopher M Parry
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK.,London School of Hygiene and Tropical Medicine, London, UK.,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | | |
Collapse
|
42
|
Development of Recombinase Polymerase Amplification Assays for Detection of Orientia tsutsugamushi or Rickettsia typhi. PLoS Negl Trop Dis 2015; 9:e0003884. [PMID: 26161793 PMCID: PMC4498641 DOI: 10.1371/journal.pntd.0003884] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 06/09/2015] [Indexed: 01/04/2023] Open
Abstract
Sensitive, specific and rapid diagnostic tests for the detection of Orientia tsutsugamushi (O. tsutsugamushi) and Rickettsia typhi (R. typhi), the causative agents of scrub typhus and murine typhus, respectively, are necessary to accurately and promptly diagnose patients and ensure that they receive proper treatment. Recombinase polymerase amplification (RPA) assays using a lateral flow test (RPA-nfo) and real-time fluorescent detection (RPA-exo) were developed targeting the 47-kDa gene of O. tsutsugamushi or 17 kDa gene of R. typhi. The RPA assay was capable of detecting O. tsutsugamushi or R. typhi at levels comparable to that of the quantitative PCR method. Both the RPA-nfo and RPA-exo methods performed similarly with regards to sensitivity when detecting the 17 kDa gene of R. typhi. On the contrary, RPA-exo performed better than RPA-nfo in detecting the 47 kDa gene of O. tsutsugamushi. The clinical performance of the O. tsutsugamushi RPA assay was evaluated using either human patient samples or infected mouse samples. Eight out of ten PCR confirmed positives were determined positive by RPA, and all PCR confirmed negative samples were negative by RPA. Similar results were obtained for R. typhi spiked patient sera. The assays were able to differentiate O. tsutsugamushi and R. typhi from other phylogenetically related bacteria as well as mouse and human DNA. Furthermore, the RPA-nfo reaction was completed in 20 minutes at 37oC followed by a 10 minute incubation at room temperature for development of an immunochromatographic strip. The RPA-exo reaction was completed in 20 minutes at 39oC. The implementation of a cross contamination proof cassette to detect the RPA-nfo fluorescent amplicons provided an alternative to regular lateral flow detection strips, which are more prone to cross contamination. The RPA assays provide a highly time-efficient, sensitive and specific alternative to other methods for diagnosing scrub typhus or murine typhus. Historically, rickettsial pathogens are among the leading causes of morbidity and mortality during military operations. Rickettsial diseases, lately, are reemerging in areas of known abundance or emerging in areas of unknown existence, posing a significant medical concern for local residents and travelers. The diseases are difficult to diagnose as they often share similar symptoms with many other diseases in the same geographical areas. Therefore, it is particularly challenging for clinicians to provide a timely and accurate diagnosis. A recombinase polymerase amplification (RPA)-based nucleic acid detection platform has been used to develop accurate, sensitive, specific, and easy-to-perform assays to detect O. tsutsugamushi or R. typhi, indicative of scrub typhus or murine typhus, respectively. These RPA assays provide similar limits of detection and specificity to that of qPCR. Unlike qPCR, they require no thermocycler and provide multiple end-point monitoring options amendable to different laboratory capabilities. This work presents an alternative assay platform for early detection of O. tsutsugamushi or R. typhi infection so that timely treatment can be prescribed in well-equipped laboratories as well as resource limited areas.
Collapse
|
43
|
Mayxay M, Castonguay-Vanier J, Chansamouth V, Dubot-Pérès A, Paris DH, Phetsouvanh R, Tangkhabuanbutra J, Douangdala P, Inthalath S, Souvannasing P, Slesak G, Tongyoo N, Chanthongthip A, Panyanouvong P, Sibounheuang B, Phommasone K, Dohnt M, Phonekeo D, Hongvanthong B, Xayadeth S, Ketmayoon P, Blacksell SD, Moore CE, Craig SB, Burns MA, von Sonnenburg F, Corwin A, de Lamballerie X, González IJ, Christophel EM, Cawthorne A, Bell D, Newton PN. Causes of non-malarial fever in Laos: a prospective study. LANCET GLOBAL HEALTH 2015; 1:e46-54. [PMID: 24748368 PMCID: PMC3986032 DOI: 10.1016/s2214-109x(13)70008-1] [Citation(s) in RCA: 182] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background Because of reductions in the incidence of Plasmodium falciparum malaria in Laos, identification of the causes of fever in people without malaria, and discussion of the best empirical treatment options, are urgently needed. We aimed to identify the causes of non-malarial acute fever in patients in rural Laos. Methods For this prospective study, we recruited 1938 febrile patients, between May, 2008, and December, 2010, at Luang Namtha provincial hospital in northwest Laos (n=1390), and between September, 2008, and December, 2010, at Salavan provincial hospital in southern Laos (n=548). Eligible participants were aged 5–49 years with fever (≥38°C) lasting 8 days or less and were eligible for malaria testing by national guidelines. Findings With conservative definitions of cause, we assigned 799 (41%) patients a diagnosis. With exclusion of influenza, the top five diagnoses when only one aetiological agent per patient was identified were dengue (156 [8%] of 1927 patients), scrub typhus (122 [7%] of 1871), Japanese encephalitis virus (112 [6%] of 1924), leptospirosis (109 [6%] of 1934), and bacteraemia (43 [2%] of 1938). 115 (32%) of 358 patients at Luang Namtha hospital tested influenza PCR-positive between June and December, 2010, of which influenza B was the most frequently detected strain (n=121 [87%]). Disease frequency differed significantly between the two sites: Japanese encephalitis virus infection (p=0·04), typhoid (p=0·006), and leptospirosis (p=0·001) were more common at Luang Namtha, whereas dengue and malaria were more common at Salavan (all p<0·0001). With use of evidence from southeast Asia when possible, we estimated that azithromycin, doxycycline, ceftriaxone, and ofloxacin would have had significant efficacy for 258 (13%), 240 (12%), 154 (8%), and 41 (2%) of patients, respectively. Interpretation Our findings suggest that a wide range of treatable or preventable pathogens are implicated in non-malarial febrile illness in Laos. Empirical treatment with doxycycline for patients with undifferentiated fever and negative rapid diagnostic tests for malaria and dengue could be an appropriate strategy for rural health workers in Laos. Funding Wellcome Trust, WHO–Western Pacific Region, Foundation for Innovative New Diagnostics, US Centers for Disease Control and Prevention.
Collapse
Affiliation(s)
- Mayfong Mayxay
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
- Faculty of Postgraduate Studies, University of Health Sciences, Vientiane, Laos
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Josée Castonguay-Vanier
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Vilada Chansamouth
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Audrey Dubot-Pérès
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- UMR_D 190 “Emergence des Pathologies Virales”, Aix-Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, Marseille, France
| | - Daniel H Paris
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Mahidol–Oxford Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Rattanaphone Phetsouvanh
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | | | | | - Saythong Inthalath
- Luang Namtha Provincial Hospital, Luang Namtha, Luang Namtha Province, Laos
| | | | - Günther Slesak
- Tropical Hospital Paul-Lechler-Krankenhaus, Tübingen, Germany
| | - Narongchai Tongyoo
- Mahidol–Oxford Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Anisone Chanthongthip
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Phonepasith Panyanouvong
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Bountoy Sibounheuang
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Koukeo Phommasone
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| | - Michael Dohnt
- WHO/FAO/OIE Collaborating Centre for Leptospirosis Reference and Research, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Queensland, Australia
| | - Darouny Phonekeo
- National Centre for Laboratory and Epidemiology, Vientiane, Laos
| | | | | | | | - Stuart D Blacksell
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Mahidol–Oxford Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok
| | - Catrin E Moore
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Scott B Craig
- WHO/FAO/OIE Collaborating Centre for Leptospirosis Reference and Research, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Queensland, Australia
| | - Mary-Anne Burns
- WHO/FAO/OIE Collaborating Centre for Leptospirosis Reference and Research, Queensland, Australia
- School of Biomedical Sciences, Queensland University of Technology, Queensland, Australia
| | - Frank von Sonnenburg
- Department of Infectious Diseases and Tropical Medicine, University of Munich, Munich, Germany
| | - Andrew Corwin
- Centers for Disease Control and Prevention, US Embassy, Vientiane, Laos
| | - Xavier de Lamballerie
- UMR_D 190 “Emergence des Pathologies Virales”, Aix-Marseille University, IRD French Institute of Research for Development, EHESP French School of Public Health, Marseille, France
| | - Iveth J González
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | | | - Amy Cawthorne
- WHO–Regional Office for the Western Pacific, Manila, Philippines
| | - David Bell
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Paul N Newton
- Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
- Correspondence to: Dr Paul Newton, Lao Oxford Mahosot Hospital Wellcome Trust Research Unit (LOMWRU), Microbiology Laboratory, Mahosot Hospital, Vientiane, Laos
| |
Collapse
|
44
|
Harrison GF, Scheirer JL, Melanson VR. Development and validation of an arthropod maceration protocol for zoonotic pathogen detection in mosquitoes and fleas. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2015; 40:83-89. [PMID: 26047188 DOI: 10.1111/jvec.12136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/15/2014] [Indexed: 06/04/2023]
Abstract
Arthropod-borne diseases remain a pressing international public health concern. While progress has been made in the rapid detection of arthropod-borne pathogens via quantitative real-time (qPCR), or even hand-held detection devices, a simple and robust maceration and nucleic acid extraction method is necessary to implement biosurveillance capabilities. In this study, a comparison of maceration techniques using five types of beads followed by nucleic acid extraction and detection were tested using two morphologically disparate arthropods, the Aedes aegypti mosquito and Xenopsylla spp. flea, to detect the zoonotic diseases dengue virus serotype-1 and Yersinia pestis. Post-maceration nucleic acid extraction was carried out using the 1-2-3 Platinum-Path-Sample-Purification (PPSP) kit followed by qPCR detection using the Joint Biological Agent Identification and Diagnostic System (JBAIDS). We found that the 5mm stainless steel beads added to the beads provided in the PPSP kit were successful in macerating the exoskeleton for both Ae. aegypti and Xenopsylla spp. Replicates in the maceration/extraction/detection protocol were increased in a stepwise fashion until a final 128 replicates were obtained. For dengue virus detection there was a 99% positivity rate and for Y. pestis detection there was a 95% positive detection rate. In the examination of both pathogens, there were no significant differences between qPCR instruments, days ran, time of day ran, or operators.
Collapse
Affiliation(s)
- Genelle F Harrison
- McGill University, 1205 Avenue Docteur Penfield, Montreal, Quebec, H3A 1B1, Canada
| | - Jessica L Scheirer
- Diagnostics and Laboratory Services Department, Entomology Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD 20910, U.S.A
| | - Vanessa R Melanson
- Diagnostics and Laboratory Services Department, Entomology Branch, Walter Reed Army Institute of Research, 503 Robert Grant Ave, Silver Spring, MD 20910, U.S.A..
| |
Collapse
|
45
|
Thompson CN, Blacksell SD, Paris DH, Arjyal A, Karkey A, Dongol S, Giri A, Dolecek C, Day N, Baker S, Thwaites G, Farrar J, Basnyat B. Undifferentiated febrile illness in Kathmandu, Nepal. Am J Trop Med Hyg 2015; 92:875-878. [PMID: 25667056 PMCID: PMC4385789 DOI: 10.4269/ajtmh.14-0709] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 12/16/2014] [Indexed: 01/07/2023] Open
Abstract
Undifferentiated febrile illnesses (UFIs) are common in low- and middle-income countries. We prospectively investigated the causes of UFIs in 627 patients presenting to a tertiary referral hospital in Kathmandu, Nepal. Patients with microbiologically confirmed enteric fever (218 of 627; 34.8%) randomized to gatifloxacin or ofloxacin treatment were previously reported. We randomly selected 125 of 627 (20%) of these UFI patients, consisting of 96 of 409 (23%) cases with sterile blood cultures and 29 of 218 (13%) cases with enteric fever, for additional diagnostic investigations. We found serological evidence of acute murine typhus in 21 of 125 (17%) patients, with 12 of 21 (57%) patients polymerase chain reaction (PCR)-positive for Rickettsia typhi. Three UFI cases were quantitative PCR-positive for Rickettsia spp., two UFI cases were seropositive for Hantavirus, and one UFI case was seropositive for Q fever. Fever clearance time (FCT) for rickettsial infection was 44.5 hours (interquartile range = 26–66 hours), and there was no difference in FCT between ofloxacin or gatifloxacin. Murine typhus represents an important cause of predominantly urban UFIs in Nepal, and fluoroquinolones seem to be an effective empirical treatment.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Buddha Basnyat
- *Address correspondence to Buddha Basnyat, Oxford University Clinical Research Unit–Nepal, Patan Academy of Health Sciences, Patan Hospital, Lagankhel Rodd, 44700, Lalitpur, Nepal. E-mail:
| |
Collapse
|
46
|
McGready R, Prakash JAJ, Benjamin SJ, Watthanaworawit W, Anantatat T, Tanganuchitcharnchai A, Ling CL, Tan SO, Ashley EA, Pimanpanarak M, Blacksell SD, Day NP, Singhasivanon P, White NJ, Nosten F, Paris DH. Pregnancy outcome in relation to treatment of murine typhus and scrub typhus infection: a fever cohort and a case series analysis. PLoS Negl Trop Dis 2014; 8:e3327. [PMID: 25412503 PMCID: PMC4238995 DOI: 10.1371/journal.pntd.0003327] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/08/2014] [Indexed: 11/18/2022] Open
Abstract
Background There is a paucity of published reports on pregnancy outcome following scrub and murine typhus despite these infections being leading causes of undifferentiated fever in Asia. This study aimed to relate pregnancy outcome with treatment of typhus. Methodology/Principal Findings Data were analyzed from: i) pregnant women with a diagnosis of scrub and/or murine typhus from a fever cohort studies; ii) case series of published studies in PubMed using the search terms “scrub typhus” (ST), “murine typhus” (MT), “Orientia tsutsugamushi”, “Rickettsia tsutsugamushi”, “Rickettsia typhi”, “rickettsiae”, “typhus”, or “rickettsiosis”; and “pregnancy”, until February 2014 and iii) an unpublished case series. Fever clearance time (FCT) and pregnancy outcome (miscarriage and delivery) were compared to treatment. Poor neonatal outcome was a composite measure for pregnancies sustained to 28 weeks or more of gestation ending in stillbirth, preterm birth, or delivery of a growth restricted or low birth weight newborn. Results There were 26 women in the fever cohort. MT and ST were clinically indistinguishable apart from two ST patients with eschars. FCTs (median [range] hours) were 25 [16–42] for azithromycin (n = 5), 34 [20–53] for antimalarials (n = 5) and 92 [6–260] for other antibiotics/supportive therapy (n = 16). There were 36.4% (8/22) with a poor neonatal outcome. In 18 years, 97 pregnancies were collated, 82 with known outcomes, including two maternal deaths. Proportions of miscarriage 17.3% (14/81) and poor neonatal outcomes 41.8% (28/67) were high, increasing with longer FCTs (p = 0.050, linear trend). Use of azithromycin was not significantly associated with improved neonatal outcomes (p = 0.610) Conclusion The published ST and MT world literature amounts to less than 100 pregnancies due to under recognition and under diagnosis. Evidence supporting the most commonly used treatment, azithromycin, is weak. Collaborative, prospective clinical trials in pregnant women are urgently required to reduce the burden of adverse maternal and newborn outcomes and to determine the safety and efficacy of antimicrobial treatment. Typhus is an under-recognised and under-studied public health problem in Asia. In rural areas of Southeast Asia murine and scrub typhus are probably the most common treatable cause of fever. The estimated number of scrub typhus cases in Southeast Asia, more than 1 million yearly, results in approximately 50–80,000 deaths per year. Treatment delays due to lack of appropriate diagnostics and lack of awareness lead to a substantial health and economic impact in the one of the world's most densely populated regions. Only 97 cases in pregnancy are available from the published world literature over the past 18 years. Only 82 of these had known outcomes, including two maternal deaths. The proportion of poor neonatal outcome including stillbirth, prematurity and low birth weight was high occurring in more than 40% of pregnancies, and higher when the fever clearance time was longer. While poor neonatal outcomes were observed with all antibiotics prescribed, azithromycin appeared to be associated with shorter fever clearance times but this was not statistically significant. Evidence to support the use of azithromycin is weak. The correct antimicrobial or combination for undifferentiated fever in pregnant women in Southeast Asia is unknown.
Collapse
Affiliation(s)
- Rose McGready
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - John Antony Jude Prakash
- Immunology Laboratories, Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Santosh Joseph Benjamin
- Immunology Laboratories, Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Wanitda Watthanaworawit
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
| | - Tippawan Anantatat
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Ampai Tanganuchitcharnchai
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Clare L. Ling
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Saw Oo Tan
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
| | - Elizabeth A. Ashley
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mupawjay Pimanpanarak
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
| | - Stuart D. Blacksell
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas P. Day
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Pratap Singhasivanon
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nicholas J. White
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - François Nosten
- Shoklo Malaria Research Unit (SMRU), Mahidol-Oxford Tropical Medicine Research Unit, Mae Sot, Tak, Thailand
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Daniel H. Paris
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| |
Collapse
|
47
|
Segura F, Pons I, Miret J, Pla J, Ortuño A, Nogueras MM. The role of cats in the eco-epidemiology of spotted fever group diseases. Parasit Vectors 2014; 7:353. [PMID: 25084969 PMCID: PMC4141105 DOI: 10.1186/1756-3305-7-353] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/15/2014] [Indexed: 11/12/2022] Open
Abstract
Background Mediterranean Spotted Fever (MSF), whose etiological agent is R. conorii, is one of the oldest described vector-borne infectious diseases. Although it is endemic in the Mediterranean area, clinical cases have also been reported in other regions. R. massiliae-Bar29 is related to MSF cases. This strain is distributed worldwide. R. conorii and R. massiliae-Bar29 are transmitted by ticks. Dogs are considered the sentinel of R. conorii infection. Cats could also be involved in their transmission. Rickettsia felis, etiological agent of Flea-borne spotted fever, is mainly transmitted by the cat flea, Ctenocephalides felis. Up to now, the role of cats in its transmission is not entirely elucidated. The aim of the study is to analyze the infection in cats by these microorganisms. Methods The study was undertaken in Northeastern Spain. Twenty municipalities of seven regions participated in the study. 212 cats (pets and stray cats) were analyzed. Variables surveyed were: date of collection, age, sex, municipality, source, living place, outdoor activities, health status, type of disease, contact with other animals, and ectoparasite infestation. Sera were evaluated by indirect immunofluorescence antibody assay (IFA). Molecular detection (real-time PCR and sequencing) and cultures were performed on blood samples. Results There were 59 (27.8%) cats seroreactive to one or more microorganisms. Considering cross-reactions, the seroprevalences were 15.6%-19.5% (R. massiliae-Bar29), 1.9%-6.2% (R. conorii), and 5.2%-7.5% (R. felis). A weak association was observed between SFG seropositivity and tick infestation. Ticks found on seropositive cats were Rhipicephalus pusillus, R. sanguineus and R. turanicus. DNA of Rickettsia was detected in 23 cats. 21 of them could be sequenced. Sequences obtained were identical to those sequences of SFG rickettsiae similar to R. conorii and R. massiliae. No amplification of R. felis was obtained. Conclusions Cats can be infected by SFG rickettsiae and produce antibodies against them. Cats may play a role in the transmission cycle of R. conorii and R. massiliae-Bar29, although the role in the R. felis cycle needs further analysis.
Collapse
Affiliation(s)
| | | | | | | | | | - María-Mercedes Nogueras
- Department of Infectious Diseases, Corporació Sanitària Parc Taulí - Institut Universitari Parc Taulí - Universitat Autonoma de Barcelona, Sabadell, Spain.
| |
Collapse
|
48
|
Odhiambo AM, Maina AN, Taylor ML, Jiang J, Richards AL. Development and validation of a quantitative real-time polymerase chain reaction assay specific for the detection of Rickettsia felis and not Rickettsia felis-like organisms. Vector Borne Zoonotic Dis 2014; 14:476-81. [PMID: 24918658 DOI: 10.1089/vbz.2013.1518] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Human infections with Rickettsia felis have been reported worldwide. Recent studies have revealed the presence of many closely related but unique rickettsiae, referred to as Rickettsia felis-like organisms (RFLO), identified in various arthropods. Due to the recent discovery of the lack of specificity of earlier R. felis-specific assays, there has become a need to develop a new generation of R. felis-specific molecular assays that will differentiate R. felis not only from other rickettsiae but more importantly from other members of the R. felis genogroup that may not be pathogenic to humans. This new generation of assays is essential for determining the true risk for flea-borne spotted fever (FBSF) by surveying arthropod vectors/hosts. Because of the lack of specificity of previous assays developed to detect R. felis infections, prior surveys may have overestimated the prevalence of R. felis in arthropod vectors and thus the perceived risk of FBSF. We have developed a specific quantitative real-time polymerase chain reaction (qPCR) assay to detect R. felis (RfelB). Specificity of the assay was determined by testing it with a panel of 17 related Rickettsia species and 12 nonrickettsial bacterial DNA preparations. The RfelB qPCR assay was positive for R. felis DNA and negative for all of the 17 related Rickettsia species and 12 nonrickettsia bacterial DNA preparations. The limit of detection of the RfelB qPCR assay was determined to be two copies (two genoequivalents) per microliter of R. felis target ompB fragment-containing plasmid. Validation of the RfelB qPCR assay was accomplished by testing 83 previously sequence-confirmed R. felis and RFLOs containing DNA preparations from human and flea samples collected from different geographical locations around the world. This assay will be useful for rapid detection, identification, and enumeration of R. felis, an emerging human pathogen of worldwide importance, from both clinical and environmental samples.
Collapse
Affiliation(s)
- Antony M Odhiambo
- Viral and Rickettsial Diseases Department, Naval Medical Research Center , Silver Spring, Maryland
| | | | | | | | | |
Collapse
|
49
|
Luce-Fedrow A, Macaluso KR, Richards AL. Growth ofRickettsia felisinDrosophila melanogasterS2 Cells. Vector Borne Zoonotic Dis 2014; 14:101-10. [DOI: 10.1089/vbz.2013.1370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Alison Luce-Fedrow
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, Maryland
| | - Kevin R. Macaluso
- Louisiana State University, School of Veterinary Medicine, Skip Bertman Drive, Baton Rouge, Louisiana
| | - Allen L. Richards
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, Maryland
| |
Collapse
|
50
|
Loop-mediated isothermal amplification for Rickettsia typhi (the causal agent of murine typhus): problems with diagnosis at the limit of detection. J Clin Microbiol 2013; 52:832-8. [PMID: 24371248 PMCID: PMC3957756 DOI: 10.1128/jcm.02786-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Murine typhus is a flea-borne disease of worldwide distribution caused by Rickettsia typhi. Although treatment with tetracycline antibiotics is effective, treatment is often misguided or delayed due to diagnostic difficulties. As the gold standard immunofluorescence assay is imperfect, we aimed to develop and evaluate a loop-mediated isothermal amplification (LAMP) assay. LAMP assays have the potential to fulfill the WHO ASSURED criteria (affordable, sensitive, specific, user friendly, robust and rapid, equipment free, deliverable to those who need them) for diagnostic methodologies, as they can detect pathogen-derived nucleic acid with low technical expenditure. The LAMP assay was developed using samples of bacterial isolates (n = 41), buffy coat specimens from R. typhi PCR-positive Lao patients (n = 42), and diverse negative controls (n = 47). The method was then evaluated prospectively using consecutive patients with suspected scrub typhus or murine typhus (n = 266). The limit of detection was ∼40 DNA copies/LAMP reaction, with an analytical sensitivity of <10 DNA copies/reaction based on isolate dilutions. Despite these low cutoffs, the clinical sensitivity was disappointing, with 48% (95% confidence interval [95% CI], 32.5 to 62.7%) (specificity, 100% [95% CI, 100 to 100%]) in the developmental phase and 33% (95% CI, 9.2 to 56.8%) (specificity, 98.5% [95% CI, 97.0% to 100%]) in the prospective study. This low diagnostic accuracy was attributed to low patient R. typhi bacterial loads (median, 210 DNA copies/ml blood; interquartile range, 130 to 500). PCR-positive but LAMP-negative samples demonstrated significantly lower bacterial loads than LAMP-positive samples. Our findings highlight the diagnostic challenges for diseases with low pathogen burdens and emphasize the need to integrate pathogen biology with improved template production for assay development strategies.
Collapse
|