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Parasites & Vectors Aug 2023The Coronavirus disease 2019 (COVID-19) pandemic was marked by an increase in diagnosis and treatment delays for a range of medical conditions. Yet the impact of the...
BACKGROUND
The Coronavirus disease 2019 (COVID-19) pandemic was marked by an increase in diagnosis and treatment delays for a range of medical conditions. Yet the impact of the pandemic on the management of tick-borne diseases, which frequently manifest as an acute febrile illness similar to COVID-19, has not been well described.
METHODS
In this retrospective cohort study of patients with suspected tick-borne disease attending the University of North Carolina Health facilities, we compared the timeliness of diagnosis and treatment in a "pre-COVID" period (March 2019 to February 2020) and a "post-COVID" period (March 2020 to February 2021). Participants included patients with an ICD-10 diagnosis code of spotted fever group rickettsiosis or ehrlichiosis and a positive Rickettsia rickettsii or Ehrlichia indirect immunofluorescence assay immunoglobulin G antibody test result. Of the 897 patients who had an eligible diagnosis, 240 (26.8%) met the inclusion criteria. The main outcome was time from initial presentation to definitive diagnosis and treatment.
RESULTS
During the 2-year study period, 126 (52.5%) patients were grouped in the pre-COVID period and 114 (47.5%) were grouped in the post-COVID period; 120 (50.0%) were female; and 139 (57.9%) were aged > 50 years. Comparing the post-COVID to the pre-COVID period, the adjusted odds ratio (aOR) for delay in treatment > 0 days was 1.81 (95% confidence interval [CI] 1.07-3.07, P = 0.03), and for a treatment delay > 7 days, 1.65 (95% CI 0.94-2.90, P = 0.08). The odds of a delay in diagnosis were similar for patients in the post- and pre-COVID periods, with an aOR of 1.61 (95% CI 0.96-2.72, P = 0.07) for delays > 0 days, and aOR of 1.72 (95% CI 0.99-3.00, P = 0.05) for delays > 7 days.
CONCLUSIONS
The odds of a delay in treatment > 0 days were significantly higher in the post-COVID period than in the pre-COVID period. However, the odds of a delay in treatment > 7 days, or a delay in diagnosis, were similar between these two periods. Shifts in care-seeking, alternative care delivery models and prioritization of COVID-19 may contribute to diminished timeliness of treatment for patients with tick-borne diseases.
Topics: Humans; Female; Male; Pandemics; Retrospective Studies; COVID-19; Tick-Borne Diseases; Ehrlichiosis; COVID-19 Testing
PubMed: 37620979
DOI: 10.1186/s13071-023-05917-8 -
Cureus Jul 2023Rickettsial infection, known as Rocky Mountain spotted fever, is a challenging diagnosis as early clinical manifestations are difficult to distinguish from viral...
Rickettsial infection, known as Rocky Mountain spotted fever, is a challenging diagnosis as early clinical manifestations are difficult to distinguish from viral illnesses. Symptoms at presentation depend on the organs involved, ranging from a skin rash as evidence of vascular damage to prerenal azotemia, respiratory failure, hepatic injury, or encephalitis. We report an unusual case of an otherwise healthy 83-year-old female whose serologies tested positive for , which led to cardiac dysrhythmia, i.e., the new onset of atrial fibrillation associated with conversion pauses. The patient was treated with antibiotics and ultimately underwent permanent pacemaker placement with resolution. This case highlights cardiac dysrhythmia as a late and severe manifestation in patients diagnosed with rickettsial illness.
PubMed: 37609088
DOI: 10.7759/cureus.42288 -
PLoS Pathogens Jul 2023Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant....
Members of the spotted fever group rickettsia express four large, surface-exposed autotransporters, at least one of which is a known virulence determinant. Autotransporter translocation to the bacterial outer surface, also known as type V secretion, involves formation of a β-barrel autotransporter domain in the periplasm that inserts into the outer membrane to form a pore through which the N-terminal passenger domain is passed and exposed on the outer surface. Two major surface antigens of Rickettsia rickettsii, are known to be surface exposed and the passenger domain cleaved from the autotransporter domain. A highly passaged strain of R. rickettsii, Iowa, fails to cleave these autotransporters and is avirulent. We have identified a putative peptidase, truncated in the Iowa strain, that when reconstituted into Iowa restores appropriate processing of the autotransporters as well as restoring a modest degree of virulence.
Topics: Rickettsia rickettsii; Type V Secretion Systems; Peptide Hydrolases; Bacterial Outer Membrane Proteins; Virulence Factors
PubMed: 37523399
DOI: 10.1371/journal.ppat.1011527 -
Journal of the Pediatric Infectious... Aug 2023Tick-borne diseases have grown in incidence over recent decades. As a result, diagnostic testing has become more common, often performed as broad antibody-based panels...
BACKGROUND
Tick-borne diseases have grown in incidence over recent decades. As a result, diagnostic testing has become more common, often performed as broad antibody-based panels for multiple tick-transmitted pathogens. Rocky Mountain spotted fever (RMSF) is rare in our region yet may cause severe morbidity, leading to diagnostic screening in low-risk patients. We sought to describe trends in RMSF diagnostic testing, rate of IgG seropositivity, and clinical features of those tested.
METHODS
We performed a retrospective chart review of patients ≤21 years old undergoing testing for RMSF and/or with an ICD-9/10 code for RMSF. Patients were categorized by infection likelihood based on clinical and laboratory criteria adapted from Centers for Disease Control and Prevention's (CDC) case definition of spotted fever rickettsioses. Clinical data were collected and analyzed with descriptive statistics.
RESULTS
One hundred and seventy patients were included. 5.8% met CDC criteria for rickettsial infection, 6.5% had an elevated IgG titer but lacked suggestive symptoms, and 87.6% had a negative IgG titer. Many patients tested were unlikely to have RMSF, including 50% lacking fever, 20% lacking any RMSF "classic triad" symptoms, 13% without acute illness, and 22% tested during months with low tick activity. Convalescent serology was performed in 7.6% of patients and none underwent Rickettsia rickettsii polymerase chain reaction (PCR) testing.
CONCLUSIONS
Diagnostic testing was frequently performed in patients unlikely to have RMSF. We identified many opportunities for improving test utilization. Reserving testing for those with higher pretest probability, performing convalescent serology, and utilizing PCR may improve the accuracy of RMSF diagnosis and reduce clinical challenges stemming from inappropriate testing.
Topics: Humans; Young Adult; Adult; Rocky Mountain Spotted Fever; Incidence; Retrospective Studies; Likelihood Functions; Immunoglobulin G
PubMed: 37467350
DOI: 10.1093/jpids/piad051 -
BioRxiv : the Preprint Server For... Jul 2023Rickettsiae are Gram-negative obligate intracellular parasites of numerous eukaryotes. Human pathogens of the Transitional Group (TRG), Typhus Group (TG), and Spotted...
UNLABELLED
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 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 substantial improvement over lipid A chemical extraction. FLAT -derived structures indicate SFG rickettsiae diverging after evolved shorter 2' secondary acyl chains. Bioinformatics analysis of LpxL late acyltransferases revealed discrete active sites and hydrocarbon rulers for long versus short 2' secondary acyl chain addition. While the significance of different lipid A structures for diverse pathogens is unknown, our success using FLAT will facilitate determining how structural heterogeneity impacts interactions with host lipid A receptors and overall inflammatory potential.
IMPORTANCE
Deforestation, 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 FLAT , a new procedure for generating lipid A structures directly from host cell-purified bacteria. These data confirm 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.
PubMed: 37461656
DOI: 10.1101/2023.07.06.547954 -
Travel Medicine and Infectious Disease 2023
Topics: Animals; Humans; Rickettsia rickettsii; Rickettsia; Ticks; Panama
PubMed: 37271199
DOI: 10.1016/j.tmaid.2023.102595 -
Travel Medicine and Infectious Disease 2023
Topics: Animals; Humans; Rickettsia rickettsii; Rickettsia; Ticks; Panama
PubMed: 37268084
DOI: 10.1016/j.tmaid.2023.102596 -
Journal of Parasitic Diseases :... Jun 2023In the present study, epidemiological analysis on 839 ticks collected from 50 cattle in Gadag district, Karnataka state, tick identification and detection of tick-borne...
In the present study, epidemiological analysis on 839 ticks collected from 50 cattle in Gadag district, Karnataka state, tick identification and detection of tick-borne pathogens was conducted by PCR, sequencing, and phylogeny. The morphological identification revealed that spp. [48.6%], spp. [48.4%], and spp. [3.0%] tick genera in Gadag district. Further, a higher infestation of spp. [69.0%] and spp. [62.3%] in Shirahatti and Gadag taluk, respectively was observed. Based on the taluk-wise and tick genus-wise analysis, a higher number of ticks was present in the dewlap region of cattle body sites, except for spp., the majority of which was present in the neck. Tick genus prevalence was 45.1, 42.7%, and 12.2 for spp., spp., and spp., respectively. The mean tick per cattle was 11.6, 11.0, and 2.5 for spp., spp., and spp., respectively. The prevalence of , spp., and was 8.0, 6.4, and 6.4%, respectively in the tick DNA samples and was negative for and spp. The sequencing of the cytochrome oxidase subunit 1 gene revealed the presence of , , and tick species in the Gadag district. The phylogenetic analysis revealed the tick species have similarities and identity with the isolates from India and neighboring countries. Thus, the study provides knowledge on tick genus distribution and tick-borne pathogens in Gadag district, Karnataka which will help in developing the control and prevention strategies by the policymakers and for profitable dairy farming by farmers.
PubMed: 37193487
DOI: 10.1007/s12639-023-01584-9 -
Animals : An Open Access Journal From... Apr 2023Brazilian spotted fever (BSF) is the most important tick-borne diseases affecting humans in Brazil. Cases of BSF have recently been reported in the Goiás state,...
Brazilian spotted fever (BSF) is the most important tick-borne diseases affecting humans in Brazil. Cases of BSF have recently been reported in the Goiás state, midwestern Brazil. All cases have been confirmed by reference laboratories by seroconversion to antigens. Because serological cross-reactions among different rickettsial species that belong to the spotted fever group (SFG) are common, the agent responsible for BSF cases in Goiás remains unknown. From March 2020 to April 2022, ticks and plasma were collected from dogs, horses and capybaras (), and from the vegetation in an area where BSF cases have been reported and two areas under epidemiological surveillance in Goiás. Horses were infested by , and ; dogs by sensu lato (s.l.), and , and capybaras by and . Adults of , , and immature stages of and , and spp. were collected from the vegetation. DNA of that did not belong to the SFG was detected in , which was identified by DNA sequencing as . Seroreactivity to SFG and antigens was detected in 25.4% (42/165) of dogs, 22.7% (10/44) of horses and 41.2% (7/17) of capybaras, with higher titers for in dogs and capybaras. The seropositivity of animals to SFG spp. antigens demonstrates the circulation of SFG rickettsiae in the region. Further research is needed to fully determine the agent responsible for rickettsiosis cases in this area.
PubMed: 37106851
DOI: 10.3390/ani13081288