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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 -
Mathematical Biosciences and... Oct 2023In some regions of the Americas, domestic dogs are the host for the tick vector , and spread the tick-borne pathogen , which causes Rocky Mountain Spotted Fever (RMSF)...
In some regions of the Americas, domestic dogs are the host for the tick vector , and spread the tick-borne pathogen , which causes Rocky Mountain Spotted Fever (RMSF) in humans. Interventions are carried out against the vector via dog collars and acaricidal wall treatments. This paper investigates the optimal control of acaricidal wall treatments, using a prior model for populations and disease transmission developed for this particular vector, host, and pathogen. It is modified with a death term during questing stages reflecting the cost of control and level of coverage. In the presence of the control, the percentage of dogs and ticks infected with decreases in a short period and remains suppressed for a longer period, including after treatment is discontinued. Risk of RMSF infection declines by 90% during this time. In the absence of re-application, infected tick and dog populations rebound, indicating the eventual need for repeated treatment.
Topics: Humans; Animals; Dogs; Rocky Mountain Spotted Fever; Arachnid Vectors; Rickettsia rickettsii; Rhipicephalus sanguineus
PubMed: 38052583
DOI: 10.3934/mbe.2023837 -
Pathogens (Basel, Switzerland) Oct 2023is a relevant tick species from a One Health perspective, playing an important role as a vector of , the main agent of spotted fever rickettsiosis in Brazil. In this...
is a relevant tick species from a One Health perspective, playing an important role as a vector of , the main agent of spotted fever rickettsiosis in Brazil. In this study, we evaluated the susceptibility of two populations from Goiás state (midwestern Brazil) to different acaricides. The first tick population (GYN strain) originated from an experimental farm, where the ticks are annually exposed to acaricides. The second (PNE strain) was collected in a national park (Emas National Park), where the ticks had not been exposed to acaricides. Immersion tests were conducted with 21-day-old laboratory-reared larvae and nymphs originating from adult ticks collected in the areas mentioned above. The chosen acaricides were two synthetic pyrethroids (cypermethrin and deltamethrin), one organophosphate (chlorfenvinphos), one formamidine (amitraz), and two combinations of pyrethroids and organophosphates (cypermethrin, chlorpyrifos and citronellal; cypermethrin, fenthion and chlorpyrifos). Mortality data were used to determine the lethal concentration (LC) values at which 50%, 90%, and 99% of the ticks died (LC, LC, and LC, respectively), and resistance ratios (RR) were calculated based on the LC values. The RR revealed differences between the acaricide-exposed (GYN) and unexposed (PNE) tick strains. The PNE strain larvae and nymphs were susceptible to all the tested acaricides. The GYN strain larvae were tolerant to cypermethrin, whereas the nymphs were tolerant to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal (2 < RR ≤ 10). The GYN strain nymphs were resistant to amitraz (RR > 10). This is the first report of nymphs with resistance to amitraz and tolerance to deltamethrin, chlorfenvinphos, and the combination of cypermethrin, chlorpyrifos, and citronellal.
PubMed: 38003769
DOI: 10.3390/pathogens12111304 -
Frontiers in Cellular and Infection... 2023Adult and ticks are partially refractory to when fed on infected hosts, hindering the functional characterization of potentially protective targets in the bacterial...
Adult and ticks are partially refractory to when fed on infected hosts, hindering the functional characterization of potentially protective targets in the bacterial acquisition. In the current study, we used the anal pore route to infect adult and ticks with and to assess the effects of the knockdown of microplusin in infection control. The anal pore route was efficient to infect both species, resulting in a prevalence of around 100% of infected ticks. Higher loads of were detected in microplusin-silenced in relation to the control, as previously obtained when microplusin-silenced ticks were fed on -infected rabbits. This is the first report showing . infection through the anal pore in ticks, highlighting this route as a powerful tool to assess the role played by additional targets in the control of pathogens.
Topics: Animals; Rabbits; Rickettsia rickettsii; Ticks; Amblyomma; Rocky Mountain Spotted Fever; Ixodidae; Rickettsia; Brazil
PubMed: 37900319
DOI: 10.3389/fcimb.2023.1260390 -
Microbiology Spectrum Dec 2023spp. are intracellular bacterial parasites of a wide range of arthropod and vertebrate hosts. Some rickettsiae are responsible for several severe human diseases...
Autophagy facilitates intracellular survival of pathogenic rickettsiae in macrophages via evasion of autophagosomal maturation and reduction of microbicidal pro-inflammatory IL-1 cytokine responses.
spp. are intracellular bacterial parasites of a wide range of arthropod and vertebrate hosts. Some rickettsiae are responsible for several severe human diseases globally. One interesting feature of these pathogens is their ability to exploit host cytosolic defense responses to their benefits. However, the precise mechanism by which pathogenic spp. elude host defense responses remains unclear. Here, we observed that pathogenic and (Sheila Smith [SS]), but not non-pathogenic , become ubiquitinated and induce autophagy upon entry into macrophages. Moreover, unlike , and (SS) colocalized with LC3B but not with Lamp2 upon host cell entry. Finally, we observed that both and (SS), but not , reduce pro-inflammatory interleukin-1 (IL-1) responses, likely via an autophagy-mediated mechanism. In summary, we identified a previously unappreciated pathway by which both pathogenic and (SS) become ubiquitinated, induce autophagy, avoid autolysosomal destruction, and reduce microbicidal IL-1 cytokine responses to establish an intracytosolic niche in macrophages.
Topics: Humans; Interleukin-1; Cytokines; Rickettsia; Macrophages; Autophagy
PubMed: 37819111
DOI: 10.1128/spectrum.02791-23 -
Tropical Medicine and Health Sep 2023Body lice and head lice are the most common ectoparasites of humans. Head lice (Pediculus humanus capitis) occur worldwide in children and their caretakers, irrespective... (Review)
Review
Body lice and head lice are the most common ectoparasites of humans. Head lice (Pediculus humanus capitis) occur worldwide in children and their caretakers, irrespective of their social status. In contrast, body lice (Pediculus humanus corporis) are confined to marginalized population groups in countries of the Global South, homeless people, and refugees. Body lice are known to transmit an array of bacterial pathogens, such as R. prowazekii, R. rickettsii, C. burneti, B. quintana, B. recurrentis, and Y. pestis. The vector capacity of head lice is still a matter of debate. The objective of the review was to scrutinize the existing evidence on the vector capacity of head lice for the transmission of bacterial pathogens. The PUBMED database was searched using a combination of the terms "pediculus humanus" OR "body lice" OR "head lice" AND "pathogen" OR "Rickettsia prowazekii" OR "Bartonella quintana" OR "Borrelia recurrentis" OR "Coxiella burneti" without a time limit. Data from epidemiological studies as well as historical observations demonstrate that body lice and head lice can carry the same array of pathogens. Since the presence of a bacterial pathogen in an arthropod is not sufficient to state that it can be transmitted to humans, and since experimental models are lacking, as yet one cannot conclude with certainty that head lice serve as vectors, although this review presents circumstantial evidence that they do. Adequately designed experimental and epidemiological studies are needed to ascertain the exact transmission potential of head lice.
PubMed: 37730694
DOI: 10.1186/s41182-023-00545-5 -
Microbiology Resource Announcements Oct 2023Complete genomes of were sequenced with Illumina and PacBio technologies from low-passage isolates from ticks. These isolates were quality controlled for intact , a...
Complete genomes of were sequenced with Illumina and PacBio technologies from low-passage isolates from ticks. These isolates were quality controlled for intact , a regulator of actin-based motility that is negatively selected for in culture. The Sheila Smith strain was re-sequenced using the same methodology.
PubMed: 37655895
DOI: 10.1128/MRA.00362-23 -
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