1,526 results match your criteria Tick-Borne Diseases Rocky Mountain Spotted Fever


Fluazuron orally administered to guinea pigs: pharmacokinetic and efficacy against Amblyomma sculptum.

Parasit Vectors 2022 Jun 10;15(1):198. Epub 2022 Jun 10.

Animal Parasitology Department, Veterinary Institute, Federal Rural University of Rio de Janeiro, Seropédica, RJ, Brazil.

Background: Brazilian spotted fever (BSF), the most lethal tick-borne disease in the Western Hemisphere, is caused by the bacterium Rickettsia rickettsii and transmitted by the bite of Amblyomma sculptum. Capybaras are considered primary hosts of this tick and amplifier hosts of R. rickettsii, generating new infected lineages of A. Read More

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Seasonal dynamics of Amblyomma sculptum: a review.

Parasit Vectors 2022 Jun 6;15(1):193. Epub 2022 Jun 6.

Programa de Pós-Graduação em Ciência Animal, Universidade Federal de Goiás (UFG), Avenida Esperança, s/n, Campus Samambaia, Goiânia, Goiás, 74690-900, Brazil.

Background: Amblyomma sculptum is a hard tick that is associated with domestic animals and the transmission of Brazilian spotted fever. This association has motivated several field studies on this ixodid tick within its distribution area in South America. Thorough knowledge of the seasonal dynamics of A. Read More

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Brown Dog Tick ( Sensu Lato) Infection with Endosymbiont and Human Pathogenic spp., in Northeastern México.

Int J Environ Res Public Health 2022 05 20;19(10). Epub 2022 May 20.

Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843-2475, USA.

Of the documented tick-borne diseases infecting humans in México, Rocky Mountain spotted fever (RMSF), caused by the Gram-negative bacterium , is responsible for most fatalities. Given recent evidence of brown dog tick, s.l. Read More

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Current and Future Molecular Diagnostics of Tick-Borne Diseases in Cattle.

Vet Sci 2022 May 21;9(5). Epub 2022 May 21.

College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA 91766, USA.

Ticks and tick-borne diseases such as babesiosis, anaplasmosis, ehrlichiosis, Lyme disease, Crimean Congo hemorrhagic fever, and Rocky Mountain spotted fever pose a significant threat to animal and human health. Tick-borne diseases cause billions of dollars of losses to livestock farmers annually. These losses are partially attributed to the lack of sensitive, robust, cost effective and efficient diagnostic approaches that could detect the infectious pathogen at the early stages of illness. Read More

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Diagnostic Value of IgA Antibody Measurement in Tick-Borne Spotted Fever (Astrakhan Rickettsial Fever).

Microbiol Spectr 2022 Jun 25;10(3):e0168721. Epub 2022 Apr 25.

Laboratory of Gene Engineering of Pathogenic Microorganisms, N. F. Gamaleya National Research Center of Epidemiology and Microbiology, Moscow, Russia.

Tick-borne spotted fevers caused by occur worldwide. The symptoms of this bacterial infection are similar to those of viral infection, and thus, diagnostic accuracy has special clinical importance. One of the commonly used methods for the diagnosis of tick-borne spotted fever is enzyme-linked immunosorbent assay (ELISA), which is based on estimation of the presence of specific IgM antibodies in blood. Read More

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Regulator of Actin-Based Motility (RoaM) Downregulates Actin Tail Formation by Rickettsia rickettsii and Is Negatively Selected in Mammalian Cell Culture.

mBio 2022 04 14;13(2):e0035322. Epub 2022 Mar 14.

Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.

The etiological agent of Rocky Mountain spotted fever, Rickettsia rickettsii, is an obligately intracellular pathogen that induces the polymerization of actin filaments to propel the bacterium through the cytoplasm and spread to new host cells. Cell-to-cell spread via actin-based motility is considered a key virulence determinant for spotted fever group rickettsiae, as interruption of , the gene directly responsible for actin polymerization, has been shown to reduce fever in guinea pigs. However, little is known about how, or if, motility is regulated by the bacterium itself. Read More

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Rocky Mountain spotted fever, dengue and chikungunya, and other tropical vector borne infection.

Gac Med Mex 2021 Sep 1;157(5). Epub 2021 Sep 1.

Department of Community Medicine, Dr. DY Patil University, Pune, India.

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September 2021

Case Report: Rocky Mountain Spotted Fever with Adrenalectomy and a Hard-to-Find Tick.

Am J Case Rep 2022 Jan 31;23:e934505. Epub 2022 Jan 31.

Department of Internal Medicine, Virginia Commonwealth University School of Medicine, Richmond, VA, USA.

BACKGROUND Rocky Mountain spotted fever (RMSF) is a potentially fatal infectious disease caused by the gram-negative intracellular bacterium Rickettsia rickettsii. The classic triad includes fever, rash, and history of tick exposure; however, the triad presents in only 3% to 18% of cases at the initial visit, and the tick bite is often painless and overlooked. RMSF can present with other manifestations, including hyponatremia, lymphopenia, thrombocytopenia, and coagulopathy. Read More

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January 2022

Identification of spp. and in spp. Collected from Dogs and Cats Across the United States.

Vector Borne Zoonotic Dis 2021 12;21(12):911-920

Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA.

In the United States, and are considered key vectors for , the causative agent of Rocky Mountain spotted fever. Through regional surveillance, a wide diversity of spp. have been documented in , and spp. Read More

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December 2021

The Retropepsin-Type Protease APRc as a Novel Ig-Binding Protein and Moonlighting Immune Evasion Factor of .

mBio 2021 12 7;12(6):e0305921. Epub 2021 Dec 7.

CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.

Rickettsiae are obligate intracellular Gram-negative bacteria transmitted by arthropod vectors. Despite their reduced genomes, the function(s) of the majority of rickettsial proteins remains to be uncovered. APRc is a highly conserved retropepsin-type protease, suggested to act as a modulator of other rickettsial surface proteins with a role in adhesion/invasion. Read More

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December 2021

Nitric Oxide Inhibition of Rickettsia rickettsii.

Infect Immun 2021 11 7;89(12):e0037121. Epub 2021 Sep 7.

Host-Parasite Interactions Section, Laboratory of Bacteriology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.

Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is an enzootic, obligate, intracellular bacterial pathogen. Nitric oxide (NO) synthesized by the inducible NO synthase (iNOS) is a potent antimicrobial component of innate immunity and has been implicated in the control of virulent spp. in diverse cell types. Read More

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November 2021

Small mammals, ticks and rickettsiae in natural and human-modified landscapes: Diversity and occurrence of Brazilian spotted fever in Brazil.

Ticks Tick Borne Dis 2021 11 13;12(6):101805. Epub 2021 Aug 13.

Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, SP, Brazil; Laboratório de Ixodologia, Faculdade de Medicina Veterinária, Universidade Federal de Uberlândia, Uberlândia, MG, Brazil. Electronic address:

We studied communities of small mammals and their ticks in endemic (E) and non-endemic (NE) areas for Brazilian spotted fever (BSF), aiming to infer if diversity parameters of parasites and hosts could be related to occurrence and prevalence of rickettsial infection, especially Rickettsia rickettsii. We compared E and NE areas in human-modified landscapes (HMLs) and natural areas (BIO) with no report of BSF cases. Composition and equitability were important components of diversity explaining differences among areas. Read More

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November 2021

Impact of a Severe Rocky Mountain Spotted Fever Case on Treatment Practices at an Academic Institution Within a Nonendemic Area.

Wilderness Environ Med 2021 12 12;32(4):427-432. Epub 2021 Aug 12.

Pediatric Critical Care Medicine, Department of Pediatrics, Penn State Health Children's Hospital, Hershey, Pennsylvania; Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, Pennsylvania.

Introduction: Rocky Mountain spotted fever (RMSF) is a bacterial disease associated with morbidity and mortality when untreated. The primary study objectives are to describe clinician diagnostic and treatment practices in a nonendemic area after the occurrence of an unrecognized severe pediatric presumed RMSF case (index case). We hypothesized that inpatient diagnostic testing frequency and initiation of empiric treatment will increase after the index case. Read More

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December 2021

The first reported outbreak of an undetermined species of human infection with spotted fever group Rickettsia in Lu'an, China.

Acta Trop 2021 Nov 3;223:106072. Epub 2021 Aug 3.

Lu'an Municipal Center for Disease Control and Prevention, Lu'an, China. Electronic address:

Objective: On May 2, 2017, an outbreak of unexplained fever with rashes was reported in Lu'an, China. In this study, we aimed to identify the possible pathogens, epidemiological characteristics, and risk factors of this outbreak.

Methods: We conducted descriptive field epidemiological studies. Read More

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November 2021

Sulfonamide Contraindication in Rocky Mountain Spotted Fever.

Skinmed 2021;19(3):223-224. Epub 2021 Jun 1.

Department of Dermatology, Temple University Lewis Katz School of Medicine, Philadelphia, PA.

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February 2022

Reactive Arthritis Update: Spotlight on New and Rare Infectious Agents Implicated as Pathogens.

Curr Rheumatol Rep 2021 07 1;23(7):53. Epub 2021 Jul 1.

Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, USA.

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. Read More

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Clinical features of patients with Rocky Mountain spotted fever, dengue and chikungunya infection.

Gac Med Mex 2021 ;157(1):58-63

Department of Medicine and Health Sciences, Universidad de Sonora, Sonora. Mexico.

Introduction: Clinical distinction between arbovirus infections and those caused by rickettsia is crucial to initiate appropriate medical treatment.

Objective: To compare the differences between Rocky Mountain spotted fever (RMSF) and other vector-borne diseases (dengue and chikungunya) with similar clinical presentation, and to identify data that could aid rapid diagnosis of these diseases.

Methods: We evaluated sociodemographic, clinical and laboratory data of 399 patients from five hospitals and clinics of Sonora, Mexico, between 2004 and 2016, with laboratory-confirmed diagnosis of RMSF, dengue, or chikungunya. Read More

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November 2021

Capybara (Hydrochoerus hydrochaeris) exposure to Rickettsia in the Federal District of Brazil, a non-endemic area for Brazilian spotted fever.

Rev Bras Parasitol Vet 2021 28;30(2):e028720. Epub 2021 May 28.

Laboratório de Patologia Clínica Veterinária, Faculdade de Agronomia e Veterinária - FAV, Universidade de Brasília - UnB, Brasília, DF, Brasil.

In this study, whole blood samples and ticks were collected from 57 capybaras in recreational areas in the Federal District, Brazil, aiming to investigate the presence of Rickettsia spp. using polymerase chain reaction (PCR) and indirect immunofluorescence (IFAT) assays. None of the capybara blood samples yielded rickettsial DNA by PCR. Read More

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Prevalence of in Ticks: Systematic Review and Meta-Analysis.

Vector Borne Zoonotic Dis 2021 08 19;21(8):557-565. Epub 2021 May 19.

Ministério da Saúde, Distrito Federal, Brazil.

is a pathogen that is known to cause spotted fever, a zoonosis that is endemic in several regions of the Americas. However, no systematic review and meta-analysis has been conducted to estimate the prevalence of this rickettsial disease in the Americas. Therefore, the objective of this study was to estimate the prevalence of in ticks in the Americas. Read More

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Acute disseminated encephalomyelitis due to Rickettsia conorii infection.

S Afr Med J 2021 Mar 31;111(4):307-308. Epub 2021 Mar 31.

Department of Medicine, Faculty of Health Sciences, University of Cape Town, South Africa.

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated acute inflammatory demyelinating disorder, which typically occurs after viral infections or immunisation. We present a case of a man with acute Rickettsia conorii infection whose diagnosis was delayed. He presented with fever, headache, an eschar and an acute paraplegia. Read More

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Serological evidence of Rickettsia in horses from a semi-arid Brazilian region.

Rev Bras Parasitol Vet 2021 2;30(1):e026220. Epub 2021 Apr 2.

Laboratório de Doenças Parasitárias, Universidade Federal do Vale do São Francisco - UNIVASF, Petrolina, PE, Brasil.

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. Read More

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Likely Geographic Distributional Shifts among Medically Important Tick Species and Tick-Associated Diseases under Climate Change in North America: A Review.

Insects 2021 Mar 5;12(3). Epub 2021 Mar 5.

Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA.

Ticks rank high among arthropod vectors in terms of numbers of infectious agents that they transmit to humans, including Lyme disease, Rocky Mountain spotted fever, Colorado tick fever, human monocytic ehrlichiosis, tularemia, and human granulocytic anaplasmosis. Increasing temperature is suspected to affect tick biting rates and pathogen developmental rates, thereby potentially increasing risk for disease incidence. Tick distributions respond to climate change, but how their geographic ranges will shift in future decades and how those shifts may translate into changes in disease incidence remain unclear. Read More

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A new focus of Brazilian spotted fever in the central-west region of São Paulo state, Brazil.

Rev Soc Bras Med Trop 2021 22;54:e0391-2020. Epub 2021 Mar 22.

Universidade Estadual Paulista Júlio de Mesquita Filho, Faculdade de Medicina Veterinária e Zootecnia, Centro de Medicina e Pesquisa em Animais Selvagens, Departamento de Produção Animal e Medicina Veterinária Preventiva, Botucatu, SP, Brasil.

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Isolation of Rickettsia rickettsii in Rocky Mountain Spotted Fever Outbreak, Panama.

Emerg Infect Dis 2021 04;27(4):1245-1247

We report new cases of Rocky Mountain spotted fever in patients from Kinkantu, Ngäbe-Bugle indigenous comarca, Panama. We isolated Rickettsia rickettsii in cell culture after intraperitoneal inoculation of guinea pigs with tissues from a deceased patient. Our results indicate that Rocky Mountain spotted fever is emerging in this region. Read More

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Recent advances in understanding tick and rickettsiae interactions.

Parasite Immunol 2021 05 15;43(5):e12830. Epub 2021 Apr 15.

Center for Molecular and Cellular Biosciences, School of Biological. Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, USA.

Ticks are haematophagous arthropods with unique molecular mechanisms for digesting host blood meal while acting as vectors for various pathogens of public health significance. The tick's pharmacologically active saliva plays a fundamental role in modulating the host's immune system for several days to weeks, depending on the tick species. The vector tick has also developed sophisticated molecular mechanisms to serve as a competent vector for pathogens, including the spotted fever group (SFG) rickettsiae. Read More

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Report of in a House in a Circulation Area.

Vector Borne Zoonotic Dis 2021 05 10;21(5):388-390. Epub 2021 Mar 10.

Department of Parasitology, Biological Science Institute, Federal University of Minas Gerais, Belo Horizonte, Brazil.

is a tick that has medical and veterinary importance as, in Brazil, it is the main vector of , a disease affecting humans. The presence of ticks was observed outside a residence in a peri-urban area of the Atlantic Forest region in Brazil, as well as on two dogs that lived there. Eighteen adults were seen walking on a cemented pillar at the porch of the house and sheltering inside the pillar's crevices; meanwhile on the dogs, only lato ticks were found. Read More

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Significant Growth by Species within Human Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals.

Pathogens 2021 Feb 19;10(2). Epub 2021 Feb 19.

Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA.

are significant sources of tick-borne diseases in humans worldwide. In North America, two species in the spotted fever group of have been conclusively associated with disease of humans: , the causative agent of Rocky Mountain spotted fever, and , the cause of rickettsiosis. Previous work in our lab demonstrated non-endothelial parasitism by another pathogenic SFG species, , within THP-1-derived macrophages, and we have hypothesized that this growth characteristic may be an underappreciated aspect of rickettsial pathogenesis in mammalian hosts. Read More

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February 2021

Diversity of rickettsiae in domestic, synanthropic, and sylvatic mammals and their ectoparasites in a spotted fever-epidemic region at the western US-Mexico border.

Transbound Emerg Dis 2022 Mar 5;69(2):609-622. Epub 2021 Mar 5.

Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA.

Over one hundred cases of human rickettsiosis, many fatal, are reported annually across the US-Mexico transboundary region, representing a likely undercount. Although cases are often attributed to Rickettsia rickettsii, the agent of Rocky Mountain spotted fever, multiple other Rickettsia pathogens are present in North America. We conducted multiple-host surveillance of domestic, synanthropic, and sylvatic mammals and their ectoparasites to investigate the ecology of Rickettsia species in this region. Read More

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