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Am J Ophthalmol Case Rep 2022 Jun 29;26:101566. Epub 2022 Apr 29.

Department of Ophthalmology & Vision Science, College of Medicine, University of Arizona, 655 N Alvernon Way, Tucson, AZ, 85711, USA.

Purpose: To report a case of infectious pediatric retinitis attributed to Rocky Mountain spotted fever which is rarely reported in the United States.

Observations: A previously healthy 14-year-old male return traveler from Mexico was admitted to the pediatric ICU with septic shock and a diffuse rash. He subsequently complained of blurry vision and was found to have evidence of retinitis on exam. Read More

PeerJ 2022 3;10:e13279. Epub 2022 May 3.

Biodiversity Institute, University of Kansas, Lawrence, KS, United States of America.

(Gulf Coast tick), and (Rocky Mountain wood tick) are two North American ticks that transmit spotted fevers associated . transmits and , while transmits , , (Colorado tick fever virus), and . Increases in temperature causes mild winters and more extreme dry periods during summers, which will affect tick populations in unknown ways. Read More

Microbiol Spectr 2022 Apr 25: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

Int J Environ Res Public Health 2022 04 1;19(7). Epub 2022 Apr 1.

Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.

s.l. (Latreille, 1806), the brown dog tick, is the most widely distributed tick species in the world. Read More

Infect Chemother 2022 Mar;54(1):165-172

Infectious & Tropical Diseases Unit, Annunziata Hub Hospital, Cosenza, Italy.

This brief report documents the safety and efficacy of high-dose tigecycline as a salvage-therapy in in a case series of five patients with serious central nervous system (CNS) rocky mountain spotted fever (RMSF). These severily ill patients were unable to take any oral drug therapy, parenteral doxycycline was unavailable and absorption of oral doxycycline was a concern in these critically ill patients. As far as we know, we report the successfull use of tigecycline for the treatment of rickettsial meningitis for the first time in Italy. Read More

Insects 2022 Mar 7;13(3). Epub 2022 Mar 7.

Department of Mathematics, Dartmouth College, Hanover, NH 03755, USA.

Rocky Mountain spotted fever (RMSF) is a significant health problem in Sonora, Mexico. The tick vector, , feeds almost exclusively on domestic dogs that, in this region, also serve as the reservoir for the tick-borne pathogen, . A process-based mathematical model of the life cycle of was developed to predict combinations of insecticidal dog collars and long-lasting insecticidal wall treatments resulting in suppression of indoor tick populations. Read More

Am J Trop Med Hyg 2022 Mar 14. Epub 2022 Mar 14.

Clinical and laboratory diagnosis of rickettsial diseases is challenging because of the undifferentiated symptoms (commonly fever, headache, and malaise) and low bacteremia (< 100 genomic copies [gc]/mL) during the early acute stage of illness. Early treatment with doxycycline is critical for a positive outcome, especially in Rickettsia rickettsii (Rocky Mountain spotted fever) infections where cases may be fatal within 5 to 10 days from symptom onset, emphasizing the need for more sensitive diagnostics. A real-time reverse transcriptase polymerase chain reaction (PCR) assay, RCKr, was developed and validated for Rickettsia spp. Read More

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

Insects 2022 Jan 22;13(2). Epub 2022 Jan 22.

Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA.

A wide range of pathogens, such as bacteria, viruses, and parasites can be transmitted by ticks and can cause diseases, such as Lyme disease, anaplasmosis, or Rocky Mountain spotted fever. Landscape and climate changes are driving the geographic range expansion of important tick species. The morphological identification of ticks is critical for the assessment of disease risk; however, this process is time-consuming, costly, and requires qualified taxonomic specialists. Read More

Trop Med Infect Dis 2022 Feb 19;7(2). Epub 2022 Feb 19.

CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.

The order Rickettsiales includes species that cause a range of human diseases such as human granulocytic anaplasmosis (), human monocytic ehrlichiosis (), scrub typhus (), epidemic typhus (), murine typhus (), Mediterranean spotted fever (), or Rocky Mountain spotted fever (). These diseases are gaining a new momentum given their resurgence patterns and geographical expansion due to the overall rise in temperature and other human-induced pressure, thereby remaining a major public health concern. As obligate intracellular bacteria, Rickettsiales are characterized by their small genome sizes due to reductive evolution. Read More

mBio 2022 Feb 8:e0291821. Epub 2022 Feb 8.

Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA.

species (spp.) are strict obligate intracellular bacteria, some of which are pathogenic in their mammalian host, including humans. One critical feature of these stealthy group of pathogens is their ability to manipulate hostile cytosolic environments to their benefits. Read More

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

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

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

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

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

JAAD Case Rep 2021 Nov 5;17:87-91. Epub 2021 Oct 5.

Department of Dermatology, University of Florida College of Medicine, Gainesville, Florida.

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

Dela J Public Health 2021 Jan 21;7(1):66-71. Epub 2021 Jan 21.

Enteric Disease Epidemiologist, Division of Public Health, Delaware Department of Health and Social Services.

Public health messaging in the eastern United States has historically underemphasized the risks posed by lone star ticks (), focusing instead on blacklegged ticks (). This gap persists despite mounting evidence that lone star ticks also play an important role in disease ecology as confirmed vectors for a wide variety of tick-borne pathogens. These pathogens include several distinct bacterial agents that cause ehrlichiosis and tularensis in humans and dogs, a protozoal agent that causes cytauxzoonosis in cats, and emerging viruses such as Heartland, Bourbon, and Tacaribe. Read More

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

Pediatr Infect Dis J 2021 09;40(9):845

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

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

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

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

Kans J Med 2021 9;14:186-187. Epub 2021 Jul 9.

Epiphany Dermatology, Dallas, TX.

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

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

Cureus 2021 Apr 12;13(4):e14438. Epub 2021 Apr 12.

Hepatology, Methodist Dallas Medical Center, Dallas, USA.

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. Read More

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

Antimicrob Agents Chemother 2021 07 16;65(8):e0066521. Epub 2021 Jul 16.

Department of Internal Medicine-Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, USA.

Emerg Infect Dis 2021 06;27(6)