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BMC Ophthalmology Mar 2024To report a case of unusual presentation of retinochoroiditis caused by Rickettsia typhi in a patient without prior uveitis.
BACKGROUND
To report a case of unusual presentation of retinochoroiditis caused by Rickettsia typhi in a patient without prior uveitis.
CASE PRESENTATION
In this case, we describe a 24-year-old male soldier with no previous eye disease, who was referred to our ophthalmology department due to bilateral retinochoroiditis and vitritis. The patient initially presented with a paracentral scotoma in his right eye persisting for 7 days and scattered dark spots in his left eye for 2 days in June 2023. Preceding these ocular symptoms, he experienced a two-week episode of fever, headaches, night sweats, and rapid weight loss of 10 kg. A transient rash covered his body briefly. His mother had a history of recurrent eye inflammation. Physical examination revealed bilateral keratic precipitates on the lower corneal periphery, 1 + anterior vitreous cells, small retinal lesions and mild optic discs elevation. Fluorescein angiography indicated mild discs hyperfluorescence, and the clinically visible round punctate lesions on OCT showed inner retinal hyper-reflective lesion with a depth till outer plexiform layer possibly suggestive of a retinitis lesion. Laboratory tests were normal except thrombocytosis, elevated ESR, liver enzymes and ACE levels, with positive Rickettsia typhi serology tests. Rheumatology and infectious disease consultations ruled out autoimmune diseases, confirming Rickettsia typhi infection. Treatment included systemic doxycycline and prednisone, with improvement of visual acuity, ocular symptoms, OCT abnormalities and resolution of inflammation. Prednisone was discontinued, and after two months, additional improvement was seen clinically, with preserved retinal structures on OCT.
CONCLUSION
This study explores retinochoroiditis as a rare ocular presentation of Rickettsia typhi, an unusual infection in the Middle East. Previously reported ocular manifestations include conjunctivitis, vitritis, post infectious optic neuropathy and a few cases of uveitis. Ocular symptoms followed systemic illness, highlighting the need for awareness among clinicians. Diagnosis relies on seroconversion, with fluorescein angiography and OCT aiding in assessment. Empiric doxycycline and systemic corticosteroid therapy is recommended. Ocular symptoms resolved in two months. Awareness of these ocular manifestations is essential for timely diagnosis and management. Further research is needed to fully understand this aspect of murine typhus.
Topics: Humans; Male; Young Adult; Chorioretinitis; Doxycycline; Inflammation; Prednisone; Typhus, Endemic Flea-Borne
PubMed: 38454387
DOI: 10.1186/s12886-024-03329-5 -
Vector Borne and Zoonotic Diseases... Apr 2024Flea-borne rickettsioses, collectively referred to as a term for etiological agents , , and RFLOs (-like organisms), has become a public health concern around the...
Flea-borne rickettsioses, collectively referred to as a term for etiological agents , , and RFLOs (-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 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. In this study, and systems were utilized to assess rickettsial interactions in arthropods. Coinfection of both and within a tick-derived cell line indicated that the two species could infect the same cell, but distinct growth kinetics led to reduced growth over time, regardless of infection order. Sequential flea coinfections revealed the vector could acquire both spp. and sustain coinfection for up to 2 weeks, but rickettsial loads in coinfected fleas and feces were altered during coinfection. Altered rickettsial loads during coinfection suggest and 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.
Topics: Animals; Humans; Cats; Rickettsia typhi; Rickettsia felis; Ctenocephalides; Coinfection; Rickettsia; Siphonaptera; Flea Infestations; Felis; Cat Diseases
PubMed: 38422214
DOI: 10.1089/vbz.2023.0122 -
Case Reports in Infectious Diseases 2024Flea-borne typhus (FBT), due to and , is an infection causing fever, headache, rash, hepatitis, thrombocytopenia, and diverse organ manifestations. Cough occurs in...
Flea-borne typhus (FBT), due to and , is an infection causing fever, headache, rash, hepatitis, thrombocytopenia, and diverse organ manifestations. Cough occurs in about 30% of patients with FBT, and chest X-ray abnormalities are seen in 17%. Severe pulmonary manifestations have also been reported in FBT, including adult respiratory distress syndrome and pulmonary embolism. Because of these pulmonary manifestations, FBT can mimic Coronavirus Illness 2019 (COVID-19), a febrile illness with prominent respiratory involvement. Flea-borne typhus and COVID-19 may also have similar laboratory abnormalities, including elevated ferritin, C-reactive protein, and D-dimer. However, elevated transaminase levels, rash, and thrombocytopenia are more common in FBT. Herein, we present four cases of patients with FBT who were initially suspected to have COVID-19. These cases illustrate the problem of availability bias, in which the clinician thinks a particular common condition (COVID-19 in this case) is more prevalent than it actually is.
PubMed: 38384261
DOI: 10.1155/2024/9914306 -
Travel Medicine and Infectious Disease 2024Rickettsia is a zoonotic bacterial pathogen transmitted by vectors and has extensive reservoirs in animal and human populations. Rickettsiosis is a public health problem... (Review)
Review
SUBJECT
Rickettsia is a zoonotic bacterial pathogen transmitted by vectors and has extensive reservoirs in animal and human populations. Rickettsiosis is a public health problem all over the world. However, comprehensive information on the geographical distribution of different Rickettsia species, infection status of reservoirs, vectors, and human cases is lacking in most parts of the world. Therefore, this study aimed to investigate the geographical distribution of different Rickettsia species and their vectors in countries of the WHO-EMRO region.
METHODS
In this review study, a search was conducted for reports and published studies on Rickettsia species from WHO-EMRO region countries in various databases from 1995 to 2022. Finally, the reported status of human cases, reservoirs, and vectors associated with each species in different countries was documented.
RESULTS
Reports of infections related to the detection of Rickettsia species were only available for 15 out of 22 WHO-EMRO member countries. A total of twenty-four Rickettsia species, including R. sibrica, R. lusitaniae, R. africae, R. prowazekii, R. felis, R. typhi, R. rickettsii, R. aeschlimannii, R. conorii, R. massiliae, R. helvetica, R. monacensis, R. rhipicephali, R. bellii, R. asembonensis, R. hoogstraalii, R. andeanae, R. raoultii, R. asiatica, R. slovaca, R. australis, R. barbariae, Candidatus R. amblyommii, and Candidatus R. goldwasserii, were reported from WHO-EMRO member countries. Furthermore, human cases infected with six different Rickettsia species, including R. sibrica, R. prowazekii, R. felis, R. typhi, R. rickettsii, R. aeschlimannii, R. conorii, R. massiliae, and R. helvetica, were reported from these countries.
CONCLUSION
The vast diversity of Rickettsia vectors has contributed to the ongoing discovery of new Rickettsia species. Therefore, further research on the reservoir hosts of Rickettsia infections in the understudied WHO-EMRO region is crucial. This research sheds light on Rickettsia disease's epidemiology and transmission dynamics in this region.
Topics: Animals; Humans; Rickettsia; Rickettsia Infections; World Health Organization
PubMed: 38360158
DOI: 10.1016/j.tmaid.2024.102695 -
Emerging Infectious Diseases Feb 2024
Topics: Mice; Animals; Japan; Typhus, Endemic Flea-Borne; Seroepidemiologic Studies
PubMed: 38270544
DOI: 10.3201/eid3002.230827 -
Emerging Infectious Diseases Feb 2024
Topics: Mice; Animals; Japan; Typhus, Endemic Flea-Borne; Seroepidemiologic Studies
PubMed: 38270143
DOI: 10.3201/eid3002.231465 -
MSphere Feb 2024Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the transitional group (TRG), typhus group (TG), and spotted...
Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae infect blood-feeding arthropods, have dissimilar clinical manifestations, and possess unique genomic and morphological attributes. Lacking glycolysis, rickettsiae pilfer numerous metabolites from the host cytosol to synthesize peptidoglycan and lipopolysaccharide (LPS). For LPS, O-antigen immunogenicity varies between SFG and TG pathogens; however, lipid A proinflammatory potential is unknown. We previously demonstrated that (TRG), (TG), and (SFG) produce lipid A with long 2' secondary acyl chains (C16 or C18) compared to short 2' secondary acyl chains (C12) in (SFG) lipid A. To further probe this structural heterogeneity and estimate a time point when shorter 2' secondary acyl chains originated, we generated lipid A structures for two additional SFG rickettsiae ( and ) utilizing fast lipid analysis technique adopted for use with tandem mass spectrometry (FLAT). FLAT allowed analysis of lipid A structure directly from host cell-purified bacteria, providing a substantial improvement over lipid A chemical extraction. FLAT-derived structures indicate SFG rickettsiae diverging after evolved shorter 2' secondary acyl chains. While 2' secondary acyl chain lengths do not distinguish pathogens from non-pathogens, analyses of LpxL late acyltransferases revealed discrete active sites and hydrocarbon rulers for long versus short 2' secondary acyl chain addition. Our collective data warrant determining lipid A inflammatory potential and how structural heterogeneity impacts lipid A-host receptor interactions.IMPORTANCEDeforestation, urbanization, and homelessness lead to spikes in Rickettsioses. Vector-borne human pathogens of transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae differ by clinical manifestations, immunopathology, genome composition, and morphology. We previously showed that lipid A (or endotoxin), the membrane anchor of Gram-negative bacterial lipopolysaccharide (LPS), structurally differs in (later-evolving SFG) relative to (basal SFG), (TG), and (TRG). As lipid A structure influences recognition potential in vertebrate LPS sensors, further assessment of lipid A structural heterogeneity is needed. Here, we sidestepped the difficulty of lipid A chemical extraction by utilizing fast lipid analysis technique adopted for use with tandem mass spectrometry, a new procedure for generating lipid A structures directly from host cell-purified bacteria. These data confirm that later-evolving SFG pathogens synthesize structurally distinct lipid A. Our findings impact interpreting immune responses to different pathogens and utilizing lipid A adjuvant or anti-inflammatory properties in vaccinology.
Topics: Humans; Lipid A; Lipopolysaccharides; Typhus, Epidemic Louse-Borne; Rickettsia; Spotted Fever Group Rickettsiosis
PubMed: 38259062
DOI: 10.1128/msphere.00609-23 -
The American Journal of Tropical... Jan 2024
Topics: Animals; Humans; Siphonaptera; Rickettsia typhi; Typhus, Endemic Flea-Borne; Rickettsia Infections; California; Rickettsia; Rickettsia felis
PubMed: 38109770
DOI: 10.4269/ajtmh.23-0742 -
The American Journal of Tropical... Jan 2024Flea-borne typhus (FBT), also referred to as murine typhus, is an acute febrile disease in humans caused by the bacteria Rickettsia typhi. Currently, cases of FBT are...
Flea-borne typhus (FBT), also referred to as murine typhus, is an acute febrile disease in humans caused by the bacteria Rickettsia typhi. Currently, cases of FBT are reported for public health surveillance purposes (i.e., to detect incidence and outbreaks) in a few U.S. states. In California, healthcare providers and testing laboratories are mandated to report to their respective local public health jurisdictions whenever R. typhi or antibodies reactive to R. typhi are detected in a patient, who then report cases to state health department. In this study, we characterize the epidemiology of flea-borne typhus cases in California from 2011 to 2019. A total of 881 cases were reported during this period, with most cases reported among residents of Los Angeles and Orange Counties (97%). Demographics, animal exposures, and clinical courses for case patients were summarized. Additionally, spatiotemporal cluster analyses pointed to five areas in southern California with persistent FBT transmission.
Topics: Animals; Mice; Humans; Typhus, Endemic Flea-Borne; Typhus, Epidemic Louse-Borne; Rickettsia typhi; California; Siphonaptera
PubMed: 38109767
DOI: 10.4269/ajtmh.23-0272 -
The Brazilian Journal of Infectious... 2024Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to...
Multisystem Inflammatory Syndrome in Children (MIS-C) presents with fever, fatigue, elevated inflammatory markers (acute phase reactants), and a history of exposure to SARS-CoV-2 or positive antibodies to SARS-CoV-2. As the COVID-19 pandemic unfolded, the risk of MIS-C in the pediatric population increased. However, exposure to other viruses and the presence of SARS-CoV-2 positive antibodies in children hospitalized for various pathogen-associated illnesses will also remain common and may complicate differential diagnoses with diseases endemic to the region such as rickettsial diseases. The objective was to highlight the desirability of medical personnel systematically incorporating rickettsiosis as a differential diagnosis for MIS-C when studying a child with fever, non-specific symptoms, and elevated inflammatory markers. In conclusion MIS-C should be considered in children with elevated inflammatory markers when there is a history of COVID-19 and they also meet criteria that have already been established by international agencies, such as CDC and WHO.
Topics: Child; Humans; Rickettsia rickettsii; Rickettsia typhi; Child, Hospitalized; Mexico; Pandemics; Fever; COVID-19; Systemic Inflammatory Response Syndrome
PubMed: 38070540
DOI: 10.1016/j.bjid.2023.103707