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Ticks
Published in Jerome Goddard, Public Health Entomology, 2022
Ehrlichiosis and anaplasmosis. Ehrlichia and Anaplasma organisms may be transmitted by ticks as well. They are rickettsia-like bacteria that primarily infect circulating leukocytes. The most common of them, Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (HME), occurs mostly in the central and southern United States, and infects mononuclear phagocytes in blood and tissues.12 There were 1,799 cases of HME in the United States in 2018.4 A new species of Ehrlichia causing human illness in Minnesota and Wisconsin has recently been recognized.13 Another, Anaplasma (formerly Ehrlichia) phagocytophilum, infects granulocytes and causes human granulocytic anaplasmosis (HGA); it is mostly reported from the upper Midwest and northeastern United States. There were 4,008 cases of HGA in the United States in 2018.4
Severe Tick-Borne Infections and Their Mimics in the Critical Care Unit
Published in Cheston B. Cunha, Burke A. Cunha, Infectious Diseases and Antimicrobial Stewardship in Critical Care Medicine, 2020
Praveen Sudhindra, Gary P. Wormser
Ehrlichia chaffeensis, a gram-negative intracellular bacterium, is the etiologic agent of HME. Infection occurs from the bite of an infected lone star tick (Amblyomma americanum). The highest incidence is in South Central and southeastern United States; however, the disease can potentially occur in any state in which this tick species is endemic [3,14].
Rifampicin (Rifampin)
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
C. Alan, C. Street, Tony M. Korman
Ehrlichiae are rickettsia-like organisms transmitted by ticks. Recognized human pathogens are Ehrlichia chaffeensis, Anaplasma phagocytophilum (formerly E. phagocytophilia), and E. ewingii (Amsden et al., 2005; Dumler et al., 2007). These organisms are very sensitive to rifampicin in vitro (Brouqui and Raoult, 1990; Dumler and Bakken, 1995; Klein et al., 1997; Horowitz et al., 2001; Maurin et al., 2003; Branger et al., 2004), although rifampicin was inconsistently effective in eradicating organisms in experimental E. canis infection (Theodorou et al., 2013).
Multiple coinfections and Guillain Barré syndrome following outdoor travel to the American Northeast
Published in Baylor University Medical Center Proceedings, 2023
William Farrington, Farzam Farahani, Kevin Garrett Tayon, Jaclyn Rudzinski, Mark Feldman, Kartavya Sharma
A thick blood smear (Figure 1) demonstrated intraerythrocytic parasites with ringed, wisped, appliqué, and dual-organism morphology. Positive microbiology studies included Babesia microti polymerase chain reaction (PCR), IgM and IgG antibodies for Ehrlichia chaffeensis, IgM, IgG viral capsid antigen antibodies to Epstein Barr virus (EBV) and qualitative EBV PCR, and stool culture detecting Arcobacter butzleri. Stool culture was negative for Salmonella, Shigella, and Campylobacter species as well as Escherichia coli O157:H7. Cytomegalovirus serology was positive only for IgG antibodies. Testing for Borrelia burgdorferi, human immunodeficiency virus, and West Nile virus was negative. Given the lack of central nervous system involvement, meningismus, or cerebrospinal fluid pleocytosis, further testing for meningoencephalitis with an arbovirus panel or Ehrlichia chaffeensis PCR of the cerebrospinal fluid was not pursued. He did not have a past medical history of frequent infections or use of immunosuppressive medications. Tick paralysis was considered clinically but the patient’s timeline of symptomatic onset was too gradual, and sensory involvement was inconsistent with this diagnosis.
How relevant are in vitro culture models for study of tick-pathogen interactions?
Published in Pathogens and Global Health, 2021
Cristiano Salata, Sara Moutailler, Houssam Attoui, Erich Zweygarth, Lygia Decker, Lesley Bell-Sakyi
The immunodominant surface proteins of the human pathogen Ehrlichia chaffeensis, and the closely related canine pathogen Ehrlichia canis, are encoded by multigene families. Protein expression studies of E. chaffeensis and E. canis grown in tick cell lines [44,139] confirmed previous observations on differential transcription of genes encoding their immunodominant outer membrane proteins in tick and mammalian hosts [140,141]. Two of the proteins encoded by members of the E. chaffeensis p28-Omp multigene family were predominantly expressed in infected canine macrophage (DH82) cultures, whereas a single, different p28-Omp protein was expressed in infected vector (AAE2) and non-vector (ISE6) tick cell lines [44,139]. Similarly, three of the proteins encoded by the E. canis p30-Omp multigene family were expressed in infected DH82 cultures, while the protein encoded by a single, different p30-Omp member was expressed in infected, non-vector (ISE6) tick cells.
Advances in multiplex nucleic acid diagnostics for blood-borne pathogens: promises and pitfalls - an update
Published in Expert Review of Molecular Diagnostics, 2019
Robert Duncan, Elena Grigorenko, Carolyn Fisher, Donna Hockman, Bryan Lanning
Tick-borne pathogenic agents continue to emerge as blood safety threats. Babesia microti is well characterized and an FDA approved assay is available, however other recently emerged agents transmitted by the deer tick (Ixodes scapularis), increasingly demonstrate expanded geographic ranges, clinical case reports and more evidence of transmission by blood transfusion. During the last five years, several newly described tick-borne viral agents have also emerged and potentially may be transmitted by blood transfusion [2]. Examples of emerging tick-borne agents include the obligate intracellular Gram-negative bacterium, Anaplasma phagocytophilum, causing infections that range from asymptomatic to more severe disease and death in less than 1% of cases [3]; Ehrlichia chaffeensis, which causes human monocytic ehrlichiosis (HME), is primarily found in the southeastern US and is transmitted by the Lone Star tick, Amblyomma americanum [4]; of widespread concern the spirochete, Borrelia burgdorferi (Lyme Disease), is not typically a blood-borne agent due to its unique biology, however Borrelia miyamotoi, the agent of relapsing fever in the Northeast US, has been transfusion transmitted in a murine model [5].