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Biomedica : Revista Del Instituto... Jun 2021This is the case of a 50-year-old male from the region of Urabá, Colombia, with a mixed infection by Rickettsia rickettsii and Leptospira interrogans serovar...
This is the case of a 50-year-old male from the region of Urabá, Colombia, with a mixed infection by Rickettsia rickettsii and Leptospira interrogans serovar Copenhageni ST78 and negative test for malaria and dengue fever. The patient presented with febrile syndrome and was unresponsive to systemic antibiotic treatment, who finally died in the intensive care unit. We established the postmortem diagnosis through molecular typification of the two etiological agents. In the inspection at the patient’s home, we found a Rattus rattus specimen infected with L. interrogans of the same serovar found in him. We found no ticks parasitizing the domestic animals cohabitating with the patient. This case of a mixed infection with progressive and fatal symptoms in a patient with occupational risk in a tropical disease endemic zone highlights the importance of considering the potential presentation of simultaneous etiologies in patients with multiple medical visits for unresolved febrile syndromes associated with risky exposure during agricultural activities.
Topics: Animals; Antibodies, Bacterial; Coinfection; Humans; Leptospirosis; Male; Middle Aged; Rats; Rickettsia Infections; Rickettsia rickettsii
PubMed: 34214261
DOI: 10.7705/biomedica.5598 -
International Journal of Molecular... Jun 2021Pathogenic intracellular bacteria, parasites and viruses have evolved sophisticated mechanisms to manipulate mammalian host cells to serve as niches for persistence and... (Review)
Review
Pathogenic intracellular bacteria, parasites and viruses have evolved sophisticated mechanisms to manipulate mammalian host cells to serve as niches for persistence and proliferation. The intracellular lifestyles of pathogens involve the manipulation of membrane-bound organellar compartments of host cells. In this review, we described how normal structural organization and cellular functions of endosomes, endoplasmic reticulum, Golgi apparatus, mitochondria, or lipid droplets are targeted by microbial virulence mechanisms. We focus on the specific interactions of , , , spp. and representing intracellular bacterial pathogens, and of spp. and representing intracellular parasites. The replication strategies of various viruses, i.e., Influenza A virus, Poliovirus, Brome mosaic virus, Epstein-Barr Virus, Hepatitis C virus, severe acute respiratory syndrome virus (SARS), Dengue virus, Zika virus, and others are presented with focus on the specific manipulation of the organelle compartments. We compare the specific features of intracellular lifestyle and replication cycles, and highlight the communalities in mechanisms of manipulation deployed.
Topics: Animals; Biological Transport; Biomarkers; Energy Metabolism; Host-Parasite Interactions; Host-Pathogen Interactions; Humans; Intracellular Space; Organelles; Phagocytosis
PubMed: 34204285
DOI: 10.3390/ijms22126484 -
Current Rheumatology Reports Jul 2021This article presents a comprehensive narrative review of reactive arthritis (ReA) with focus on articles published between 2018 and 2020. We discuss the entire spectrum... (Review)
Review
PURPOSE OF REVIEW
This article presents a comprehensive narrative review of reactive arthritis (ReA) with focus on articles published between 2018 and 2020. We discuss the entire spectrum of microbial agents known to be the main causative agents of ReA, those reported to be rare infective agents, and those reported to be new candidates causing the disease. The discussion is set within the context of changing disease terminology, definition, and classification over time. Further, we include reports that present at least a hint of effective antimicrobial therapy for ReA as documented in case reports or in double-blind controlled studies. Additional information is included on microbial products detected in the joint, as well as on the positivity of HLA-B27.
RECENT FINDINGS
Recent reports of ReA cover several rare causative microorganism such as Neisseria meningitides, Clostridium difficile, Escherichia coli, Hafnia alvei, Blastocytosis, Giardia lamblia, Cryptosporidium, Cyclospora cayetanensis, Entamoeba histolytica/dispar, Strongyloides stercoralis, β-haemolytic Streptococci, Mycobacterium tuberculosis, Mycoplasma pneumoniae, Mycobacterium bovis bacillus Calmette-Guerin, and Rickettsia rickettsii. The most prominent new infectious agents implicated as causative in ReA are Staphylococcus lugdunensis, placenta- and umbilical cord-derived Wharton's jelly, Rothia mucilaginosa, and most importantly the SARS-CoV-2 virus. In view of the increasingly large spectrum of causative agents, diagnostic consideration for the disease must include the entire panel of post-infectious arthritides termed ReA. Diagnostic procedures cannot be restricted to the well-known HLA-B27-associated group of ReA, but must also cover the large number of rare forms of arthritis following infections and vaccinations, as well as those elicited by the newly identified members of the ReA group summarized herein. Inclusion of these newly identified etiologic agents must necessitate increased research into the pathogenic mechanisms variously involved, which will engender important insights for treatment and management of ReA.
Topics: Arthritis, Reactive; Blastocystis Infections; COVID-19; Clostridium Infections; Cryptosporidiosis; Cyclosporiasis; Entamoebiasis; Enterobacteriaceae Infections; Escherichia coli Infections; Giardiasis; HLA-B27 Antigen; Humans; Meningococcal Infections; Pneumonia, Mycoplasma; Prohibitins; Rocky Mountain Spotted Fever; SARS-CoV-2; Staphylococcal Infections; Streptococcal Infections; Strongyloidiasis; Tuberculosis
PubMed: 34196842
DOI: 10.1007/s11926-021-01018-6 -
Cureus Apr 2021Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by . The classic triad of fever, rash, and a recent tick bite is rarely present at diagnosis. Less...
Rocky Mountain spotted fever (RMSF) is a tick-borne illness caused by . The classic triad of fever, rash, and a recent tick bite is rarely present at diagnosis. Less known, but more common initial presentations include gastrointestinal symptoms such as anorexia, nausea, vomiting, and abdominal pain. In endemic areas, a persistent fever with gastrointestinal symptoms should prompt screening and early initiation of antibiotics to prevent the development of fulminant RMSF and its associated high mortality. This case aims to educate about the gastrointestinal and hepatic manifestations of this diagnostic enigma.
PubMed: 34079651
DOI: 10.7759/cureus.14438 -
Rocky Mountain Spotted Fever in a Large Metropolitan Center, Mexico-United States Border, 2009-2019.Emerging Infectious Diseases Jun 2021Epidemic levels of Rocky Mountain spotted fever (RMSF) have persisted in Mexicali, Mexico, since the initial outbreak was first reported in December 2008. We... (Review)
Review
Epidemic levels of Rocky Mountain spotted fever (RMSF) have persisted in Mexicali, Mexico, since the initial outbreak was first reported in December 2008. We compared clinical and epidemiologic data of cases in Mexicali during 2009–2019 between patients with an IgG titer reactive with bacteria by indirect immunofluorescence antibody (IFA) assay and those who demonstrated DNA of in a whole blood sample when tested by PCR. We identified 4,290 patients with clinical and epidemiologic features compatible with RMSF; of these, 9.74% tested positive by IFA and 8.41% by PCR. Overall, 140 patients died (11-year case-fatality rate 17.97%). Substantial differences in the frequency of commonly recognized clinical characteristics of RMSF were identified between PCR-positive and IFA-positive cases. The Mexicali epidemic is unique in its size and urban centralization. Cases confirmed by PCR most accurately reflect the clinical profile of RMSF.
Topics: Animals; Mexico; Rhipicephalus sanguineus; Rickettsia rickettsii; Rocky Mountain Spotted Fever; United States
PubMed: 34014151
DOI: 10.3201/eid2706.191662 -
Dermatologic Therapy Jul 2021Cutaneous involvement can be an important sign of both COVID-19 and rickettsioses. Rickettsial infections may be first evident as an exanthem with eschars as a key... (Review)
Review
Cutaneous involvement can be an important sign of both COVID-19 and rickettsioses. Rickettsial infections may be first evident as an exanthem with eschars as a key finding. In contrast, eschars and necrotic lesions can be seen in critically ill COVID-19 patients. Both illnesses share a similar mechanism of infecting endothelial cells resulting in vasculopathy. Rickettsia parkeri and Rickettsia 364D are both characterized by eschars unlike Rickettsia rickettsii. Other eschar causing rickettsioses such as Rickettsia conorii, Rickettsia africae, and Orientia tsutsugamushi are commonly diagnosed in people from or having traveled through endemic areas. While there is no consensus on treatment for COVID-19, rickettsioses are treatable. Due to possibly serious consequences of delayed treatment, doxycycline should be administered given an eschar-presenting patient's travel history and sufficient suspicion of vector exposure. The proliferation of COVID-19 cases has rendered it critical to differentiate between the two, both of which may have overlapping vasculopathic cutaneous findings. We review these diseases, emphasizing the importance of cutaneous involvement, while also discussing possible therapeutic interventions.
Topics: COVID-19; Endothelial Cells; Humans; Rickettsia; Rickettsia Infections; SARS-CoV-2
PubMed: 34003557
DOI: 10.1111/dth.14984 -
MSphere May 2021Species of (: ) are obligate intracellular parasites of a wide range of eukaryotes, with recognized arthropod-borne human pathogens belonging to the transitional group...
Species of (: ) are obligate intracellular parasites of a wide range of eukaryotes, with recognized arthropod-borne human pathogens belonging to the transitional group (TRG), typhus group (TG), and spotted fever group (SFG) rickettsiae. Growing in the host cytosol, rickettsiae pilfer numerous metabolites to make a typical Gram-negative bacterial cell envelope. The O-antigen of rickettsial lipopolysaccharide (LPS) is immunogenic and has been shown to tether the S-layer to the rickettsial surface; however, little is known about the structure and immunogenicity of the lipid A moiety. The structure of lipid A, the membrane anchor of LPS, affects the ability of this molecule to interact with components of the host innate immune system, specifically the MD-2/TLR4 receptor complex. To dissect the host responses that can occur during and infection, structural analysis of lipid A is needed. Lipid A was extracted from four species and structurally analyzed. (TRG), (TG), and (SFG) produced a similar structure, whereas (SFG) altered the length of a secondary acyl group. While all structures have longer acyl chains than known highly inflammatory hexa-acylated lipid A structures, the modification should differentially alter interactions with the hydrophobic internal pocket in MD2. The significance of these characteristics toward inflammatory potential as well as membrane dynamics between arthropod and vertebrate cellular environments warrants further investigation. Our work adds lipid A to the secretome and O-antigen as variable factors possibly correlating with phenotypically diverse rickettsioses. Spikes in rickettsioses occur as deforestation, urbanization, and homelessness increase human exposure to blood-feeding arthropods. Still, effective vaccines remain elusive. Recent studies have determined that lipopolysaccharide anchors the protective S-layer to the bacterial surface and elicits bactericidal antibodies. Furthermore, growing immunological evidence suggests vertebrate sensors (MD-2/TLR4 and noncanonical inflammasome) typically triggered by the lipid A portion of lipopolysaccharide are activated during infection. However, the immunopotency of lipid A is unknown due to poor appreciation for its structure. We determined lipid A structures for four distinct rickettsiae, revealing longer acyl chains relative to highly inflammatory bacterial lipid A. Surprisingly, lipid A of the Rocky Mountain spotted fever agent deviates in structure from other rickettsiae. Thus, lipid A divergence may contribute to variable disease phenotypes, sounding an alarm for determining its immunopotency and possible utility (i.e., as an adjuvant or anti-inflammatory) for development of more prudent rickettsiacidal therapies.
Topics: Humans; Lipid A; Rickettsia; Rickettsia Infections
PubMed: 33952661
DOI: 10.1128/mSphere.00184-21 -
Revista Brasileira de Parasitologia... 2021Brazilian spotted fever (BSF) is a common tick-borne disease caused by Rickettsia rickettsii. Horses are the primary hosts of the main vector, Amblyomma sculptum, and...
Brazilian spotted fever (BSF) is a common tick-borne disease caused by Rickettsia rickettsii. Horses are the primary hosts of the main vector, Amblyomma sculptum, and are considered efficient sentinels for circulation of Rickettsia. Therefore, the aim of this study was to detect antibodies reactive to R. rickettsii antigens in horses from a non-endemic area in the north-central region of Bahia state, Brazil. Blood samples and ticks were collected from 70 horses from the municipalities of Senhor do Bonfim, Antônio Gonçalves, Pindobaçu, and Campo Formoso. The sera obtained were tested by an indirect immunofluorescence assay to detect anti-Rickettsia antibodies. Overall, 5.7% (4/70) of the horses reacted to R. rickettsii antigens. Ticks were collected from 18.6% (13/70) of the horses and were identified as A. sculptum and Dermacentor nitens. Despite being a non-endemic area, seropositive animals were identified in our study, suggesting circulation of rickettsial agents in the region. This is the first serological survey of this agent in horses from the north-central region of Bahia, and further studies are needed to understand the epidemiology of BSF in these locations.
Topics: Animals; Brazil; Fluorescent Antibody Technique; Horse Diseases; Horses; Rickettsia rickettsii; Rocky Mountain Spotted Fever; Ticks
PubMed: 33825800
DOI: 10.1590/S1984-29612021011 -
The American Journal of Tropical... Apr 2021Rhipicephalus sanguineus is a species complex of ticks that vector disease worldwide. Feeding primarily on dogs, members of the complex also feed incidentally on humans,...
Rhipicephalus sanguineus is a species complex of ticks that vector disease worldwide. Feeding primarily on dogs, members of the complex also feed incidentally on humans, potentially transmitting disease agents such as Rickettsia rickettsii, Rickettsia conorii, and Ehrlichia species. There are two genetic Rh. sanguineus lineages in North America, designated as the temperate and tropical lineages, which had occurred in discrete locations, although there is now range overlap in parts of California and Arizona. Rh. sanguineus in Europe are reportedly more aggressive toward humans during hot weather, increasing the risk of pathogen transmission to humans. The aim of this study was to assess the impact of hot weather on choice between humans and dog hosts among tropical and temperate lineage Rh. sanguineus individuals. Ticks in a two-choice olfactometer migrated toward a dog or human in trials at room (23.5°C) or high temperature (38°C). At 38°C, 2.5 times more tropical lineage adults chose humans compared with room temperature, whereas temperate lineage adults demonstrated a 66% reduction in preference for dogs and a slight increase in preference for humans. Fewer nymphs chose either host at 38°C than at room temperature in both lineages. These results demonstrate that risk of disease transmission to humans may be increased during periods of hot weather, where either lineage is present, and that hot weather events associated with climatic change may result in more frequent rickettsial disease outbreaks.
Topics: Animals; Disease Vectors; Dog Diseases; Dogs; Female; Host Specificity; Male; Nymph; Phylogeny; Rhipicephalus sanguineus; Rickettsia rickettsii; Temperature; Tropical Climate; Zoonoses
PubMed: 33819179
DOI: 10.4269/ajtmh.20-1376 -
Revista Da Sociedade Brasileira de... 2021
Topics: Antibodies, Bacterial; Brazil; Humans; Rickettsia rickettsii; Rocky Mountain Spotted Fever
PubMed: 33759917
DOI: 10.1590/0037-8682-0391-2020