Clinical Features of Rickettsial Infection in Children in Tropical Australia—A Report of 15 Cases

Abstract Rickettsial infections are an under-recognized cause of acute, undifferentiated fever in the tropics. In Asia, intensive care unit (ICU) admission rates as high as 21% and case-fatality rates of up to 5% have been reported. This 20-year retrospective audit of children and adults with serologically confirmed scrub typhus or spotted fever group (SFG) infection was performed at a tertiary-referral hospital in tropical Australia. There were 15 paediatric cases during the study period (11 scrub typhus, 3 SFG and 1 undifferentiated). Hypotension [5/15 (33%)], tachycardia [6/15 (40%)] and tachypnoea [6/15 (40%)] were common at presentation. Children were more likely to be hypotensive at admission than adults [5/15 (33%) vs. 5/118 (4%), p = 0.002]. However, no child died or was admitted to ICU, compared with 18/120 (15%) adults who required ICU support during the study period, one of whom died. Paediatric rickettsial infections have a relatively benign clinical course in tropical Australia with serious complications appearing far less frequently than have been reported in the Asian literature.

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A study of the comparative clinical profiles of scrub typhus, spotted fever group, and typhus group rickettsial infections at a rural tertiary care hospital

APIK Journal of Internal Medicine ◽

10.4103/ajim.ajim_86_19 ◽

2020 ◽

Vol 8 (4) ◽

pp. 184

Author(s):

Shreyashi Ganguly ◽

Vasantha Kamath ◽

BHima Bindu

Keyword(s):

Scrub Typhus ◽

Tertiary Care Hospital ◽

Spotted Fever ◽

Tertiary Care ◽

Spotted Fever Group ◽

Care Hospital ◽

Rickettsial Infections ◽

Clinical Profiles

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Seroprevalence of Rickettsial Infections in Northeast India: A Population-Based Cross-Sectional Survey

Asia Pacific Journal of Public Health ◽

10.1177/10105395211015864 ◽

2021 ◽

pp. 101053952110158

Author(s):

Siraj A. Khan ◽

Manoj V. Murhekar ◽

Trishna Bora ◽

Santhosh Kumar ◽

Jahnabi Saikia ◽

...

Keyword(s):

Scrub Typhus ◽

Spotted Fever ◽

Age Groups ◽

Population Based ◽

Northeast India ◽

Spotted Fever Group ◽

Cross Sectional Survey ◽

Cross Sectional ◽

Spotted Fever Group Rickettsiae ◽

Rickettsial Infections

A cross-sectional survey was undertaken to estimate seroprevalence of immunoglobulin G antibodies against scrub typhus, spotted fever group rickettsiae, and typhus group rickettsiae in randomly selected 48 clusters in 12 districts of 3 Northeast states of India: Assam, Meghalaya, and Tripura. Individuals in 3 age groups (5-8, 9-17, and 18-45 years) were selected from each cluster. Sera (N = 2360) tested were collected as part of a national survey on dengue seroprevalence conducted between September 2017 and February 2018. Overall, seroprevalence of 2.5% was detected against rickettsioses, with highest positivity against spotted fever group rickettsiae, followed by scrub typhus and typhus group rickettsiae. Seroprevalence was highest in Tripura (3.7%), followed by Assam (2.6%) and Meghalaya (1.04%). Adults of 18 to 45 years of age were found to be most affected (3.8%). The study findings indicate the need for increasing testing facilities for active case detection at hospital levels. Efforts on implementing effective preventing strategies are suggested to be targeted in disease-specific endemic foci.

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Molecular and serological evidence of flea-associated typhus group and spotted fever group rickettsial infections in Madagascar

Parasites & Vectors ◽

10.1186/s13071-017-2061-4 ◽

2017 ◽

Vol 10 (1) ◽

Cited By ~ 10

Author(s):

Rado J. L. Rakotonanahary ◽

Alan Harrison ◽

Alice N. Maina ◽

Ju Jiang ◽

Allen L. Richards ◽

...

Keyword(s):

Spotted Fever ◽

Spotted Fever Group ◽

Serological Evidence ◽

Rickettsial Infections

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Rickettsial Infections around the World, Part 1: Pathophysiology and the Spotted Fever Group

Journal of Cutaneous Medicine and Surgery ◽

10.1177/120347540500900203 ◽

2005 ◽

Vol 9 (2) ◽

pp. 54-62

Author(s):

Jashin J. Wu ◽

David B. Huang ◽

Katie R. Pang ◽

Stephen K. Tyring

Keyword(s):

Spotted Fever ◽

Clinical Manifestations ◽

Review Article ◽

Learning Activity ◽

Clinical Aspects ◽

Spotted Fever Group ◽

Infectious Agents ◽

Important Group ◽

Rickettsial Infections ◽

Rickettsial Diseases

Background: The rickettsial diseases are an important group of infectious agents that have dermatological manifestations. These diseases are important to consider in endemic areas, but in certain suspicious cases, possible acts of bioterrorism should warrant prompt notification of the appropriate authorities. Objective: In this two part review article, we review these diverse diseases by examining established and up-to-date information about the pathophysiology, epidemiology, clinical manifestations, and treatment of the ricksettsiae. Methods: Using PubMed to search for relevant articles, we browsed over 500 articles to compose a clinically based review article. Results: Part one focuses on pathophysiology of the rickettsial diseases and the clinical aspects of the spotted fever group. Conclusions: At the completion of part one of this learning activity, participants should be able to discuss all of the clinical manifestations and treatments of the sported fever group. Participants should also be familiar with the pathophysiology of the rickettsial diseases.

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Diagnosis of spotted fever group Rickettsia infections: the Asian perspective

Epidemiology and Infection ◽

10.1017/s0950268819001390 ◽

2019 ◽

Vol 147 ◽

Cited By ~ 7

Author(s):

Matthew T. Robinson ◽

Jaruwan Satjanadumrong ◽

Tom Hughes ◽

John Stenos ◽

Stuart D. Blacksell

Keyword(s):

Positive Result ◽

Diagnostic Tests ◽

Quantitative Polymerase Chain Reaction ◽

Spotted Fever ◽

Emerging Infectious Diseases ◽

Immunofluorescence Assay ◽

Diagnostic Methods ◽

Spotted Fever Group ◽

Sample Collection ◽

Rickettsial Infections

Abstract Spotted fever group rickettsiae (SFG) are a neglected group of bacteria, belonging to the genus Rickettsia, that represent a large number of new and emerging infectious diseases with a worldwide distribution. The diseases are zoonotic and are transmitted by arthropod vectors, mainly ticks, fleas and mites, to hosts such as wild animals. Domesticated animals and humans are accidental hosts. In Asia, local people in endemic areas as well as travellers to these regions are at high risk of infection. In this review we compare SFG molecular and serological diagnostic methods and discuss their limitations. While there is a large range of molecular diagnostics and serological assays, both approaches have limitations and a positive result is dependent on the timing of sample collection. There is an increasing need for less expensive and easy-to-use diagnostic tests. However, despite many tests being available, their lack of suitability for use in resource-limited regions is of concern, as many require technical expertise, expensive equipment and reagents. In addition, many existing diagnostic tests still require rigorous validation in the regions and populations where these tests may be used, in particular to establish coherent and worthwhile cut-offs. It is likely that the best strategy is to use a real-time quantitative polymerase chain reaction (qPCR) and immunofluorescence assay in tandem. If the specimen is collected early enough in the infection there will be no antibodies but there will be a greater chance of a PCR positive result. Conversely, when there are detectable antibodies it is less likely that there will be a positive PCR result. It is therefore extremely important that a complete medical history is provided especially the number of days of fever prior to sample collection. More effort is required to develop and validate SFG diagnostics and those of other rickettsial infections.

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Optimization and Evaluation of a Multiplex Quantitative PCR Assay for Detection of Nucleic Acids in Human Blood Samples from Patients with Spotted Fever Rickettsiosis, Typhus Rickettsiosis, Scrub Typhus, Monocytic Ehrlichiosis, and Granulocytic Anaplasmosis

Journal of Clinical Microbiology ◽

10.1128/jcm.01802-19 ◽

2020 ◽

Vol 58 (9) ◽

Author(s):

Megan E. Reller ◽

J. Stephen Dumler

Keyword(s):

Quantitative Pcr ◽

Scrub Typhus ◽

Spotted Fever ◽

Febrile Illness ◽

Epidemiologic Studies ◽

Qpcr Assay ◽

Spotted Fever Group ◽

Analytical Sensitivity ◽

Content Type ◽

Real Time Quantitative Pcr

ABSTRACT Spotted fever group rickettsioses (SFGR), typhus group rickettsioses (TGR), scrub typhus (caused by Orientia tsutsugamushi), ehrlichiosis, and anaplasmosis often present as undifferentiated fever but are not treated by agents (penicillins and cephalosporins) typically used for acute febrile illness. Inability to diagnose these infections when the patient is acutely ill leads to excess morbidity and mortality. Failure to confirm these infections retrospectively if a convalescent blood sample is not obtained also impairs epidemiologic and clinical research. We designed a multiplex real-time quantitative PCR (qPCR) assay to detect SFGR, TGR, O. tsutsugamushi, and infections caused by Anaplasma phagocytophilum and Ehrlichia chaffeensis with the ompA, 17-kDa surface antigen gene, tsa56, msp2 (p44), and vlpt gene targets, respectively. Analytical sensitivity was ≥2 copies/μl (linear range, 2 to 2 × 105) and specificity was 100%. Clinical sensitivities for SFGR, TGR, and O. tsutsugamushi were 25%, 20%, and 27%, respectively, and specificities were 98%, 99%, and 100%, respectively. Clinical sensitivities for A. phagocytophilum and E. chaffeensis were 93% and 84%, respectively, and specificities were 99% and 98%, respectively. This multiplex qPCR assay could support early clinical diagnosis and treatment, confirm acute infections in the absence of a convalescent-phase serum sample, and provide the high-throughput testing required to support large clinical and epidemiologic studies. Because replication of SFGR and TGR in endothelial cells results in very low bacteremia, optimal sensitivity of qPCR for these rickettsioses will require use of larger volumes of input DNA, which could be achieved by improved extraction of DNA from blood and/or extraction of DNA from a larger initial volume of blood.

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Searching and Finding the Hidden Treasure: A Retrospective Analysis of Rickettsial Disease Among Dutch International Travelers

Clinical Infectious Diseases ◽

10.1093/cid/ciaa091 ◽

2020 ◽

Cited By ~ 1

Author(s):

Sophia G de Vries ◽

Louise E van Eekeren ◽

Hans van der Linden ◽

Benjamin J Visser ◽

Martin P Grobusch ◽

...

Keyword(s):

Retrospective Analysis ◽

Medical Records ◽

Scrub Typhus ◽

Spotted Fever ◽

Febrile Illness ◽

Empiric Antibiotic Therapy ◽

Spotted Fever Group ◽

Orientia Tsutsugamushi ◽

Rickettsial Disease ◽

Empiric Antibiotic

Abstract Background Rickettsial disease (RD) is a prevalent and underestimated cause of febrile illness worldwide, especially in the absence of an inoculation eschar. We attempted to quantify this underestimation at our clinic, by investigating past cases of febrile illness in travelers who had tested negative for leptospirosis, a disease that can initially present similarly to non-eschar RD, and which we routinely consider when other important causes of unspecified febrile illness have tested negative. Methods We performed a retrospective analysis in febrile returned travelers from Asia, Africa, or the Americas between 2010 and 2017, who had tested negative for leptospirosis. Serologic immunofluorescence assays were performed for Orientia tsutsugamushi (scrub typhus), typhus group, and spotted fever group RD. We performed a medical records review of all patients who tested positive. In case of a fitting medical history, cases were deemed either confirmed (based on convalescent serology) or suspected (based on single serology). Results Among 97 patients, convalescent serology was available in 16 (16.5%) patients, and a single serology in 81 (83.5%) patients. RD was the likely diagnosis in 8 of 16 (50.0%) patients with convalescent serology, and in 8 of 81 (9.9%) with single serology. Of the 16 confirmed/suspected cases, 11 (69%) had been missed and 7 (44%) had not received adequate empiric antibiotic therapy. Conclusions This study shows that non-eschar RD is an important and poorly recognized cause of illness in travelers, even in a specialized travel clinic. A lower threshold to test and treat for RD is warranted in returning travelers with febrile illness.

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