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Parasites & Vectors Feb 2015Canine ehrlichiosis and anaplasmosis are important tick-borne diseases with a worldwide distribution. Information has been continuously collected on these infections in... (Review)
Review
Canine ehrlichiosis and anaplasmosis are important tick-borne diseases with a worldwide distribution. Information has been continuously collected on these infections in Europe, and publications have increased in recent years. Prevalence rates are high for Ehrlichia and Anaplasma spp. infections in dogs from different European countries. The goal of this article was to provide a practical guideline for veterinary practitioners on the diagnosis, treatment, and prevention of ehrlichiosis and anaplasmosis in dogs from Europe. This guideline is intended to answer the most common questions on these diseases from a practical point of view.
Topics: Anaplasma; Anaplasmosis; Animals; Dog Diseases; Dogs; Ehrlichia; Ehrlichiosis; Europe; Practice Guidelines as Topic
PubMed: 25649069
DOI: 10.1186/s13071-015-0649-0 -
Journal of Veterinary Internal Medicine 2002Within the past several decades, the number of Ehrlichia spp. recognized to infect cats, dogs, and human beings has expanded substantially. The recent application of... (Review)
Review
Within the past several decades, the number of Ehrlichia spp. recognized to infect cats, dogs, and human beings has expanded substantially. The recent application of advanced techniques in molecular biology has changed how ehrlichiosis is diagnosed and has provided new tools for the assessment of treatment. As these techniques are applied, the numerous questions that relate to the management of dogs and cats with ehrlichiosis ultimately will be answered. We hope this consensus statement will assist veterinarians in the management of their patients.
Topics: Animals; Anti-Bacterial Agents; Cat Diseases; Cats; Diagnosis, Differential; Dog Diseases; Dogs; Ehrlichia; Ehrlichiosis; Geography; Prognosis; Serologic Tests; Ticks
PubMed: 12041661
DOI: 10.1892/0891-6640(2002)016<0309:csoedo>2.3.co;2 -
Pathogens and Disease May 2021Intracellular bacteria have evolved various strategies to evade host defense mechanisms. Remarkably, the obligately intracellular bacterium, Ehrlichia chaffeensis,... (Review)
Review
Intracellular bacteria have evolved various strategies to evade host defense mechanisms. Remarkably, the obligately intracellular bacterium, Ehrlichia chaffeensis, hijacks host cell processes of the mononuclear phagocyte to evade host defenses through mechanisms executed in part by tandem repeat protein (TRP) effectors secreted by the type 1 secretion system. In the past decade, TRP120 has emerged as a model moonlighting effector, acting as a ligand mimetic, nucleomodulin and ubiquitin ligase. These defined functions illuminate the diverse roles TRP120 plays in exploiting and manipulating host cell processes, including cytoskeletal organization, vesicle trafficking, cell signaling, transcriptional regulation, post-translational modifications, autophagy and apoptosis. This review will focus on TRP effectors and their expanding roles in infection and provide perspective on Ehrlichia chaffeensis as an invaluable model organism for understanding infection strategies of obligately intracellular bacteria.
Topics: Apoptosis; Bacterial Proteins; Ehrlichia chaffeensis; Ehrlichiosis; Host-Pathogen Interactions; Humans; Intracellular Space; Protein Processing, Post-Translational; Signal Transduction; Tandem Repeat Sequences; Type I Secretion Systems
PubMed: 33974702
DOI: 10.1093/femspd/ftab026 -
Frontiers in Bioscience (Landmark... Jan 2009Several tick-transmitted Anaplasmataceae family rickettsiales of the genera Ehrlichia and Anaplasma have been discovered in recent years. Some species are classified as... (Review)
Review
Several tick-transmitted Anaplasmataceae family rickettsiales of the genera Ehrlichia and Anaplasma have been discovered in recent years. Some species are classified as pathogens causing emerging diseases with growing health concern for people. They include human monocytic ehrlichiosis, human granulocytic ewingii ehrlichiosis and human granulocytic anaplasmosis which are caused by Ehrlichia chaffeensis, E. ewingii and Anaplasma phagocytophilum, respectively. Despite the complex cellular environments and defense systems of arthropod and vertebrate hosts, rickettsials have evolved strategies to evade host clearance and persist in both vertebrate and tick host environments. For example, E. chaffeensis growing in vertebrate macrophages has distinct patterns of global host cell-specific protein expression and differs considerably in morphology compared with its growth in tick cells. Immunological studies suggest that host cell-specific differences in Ehrlichia gene expression aid the pathogen, extending its survival. Bacteria from tick cells persist longer when injected into mice compared with mammalian macrophage-grown bacteria, and the host response is also significantly different. This review presents the current understanding of tick-Ehrlichia interactions and implications for future.
Topics: Animals; Ehrlichia; Host-Pathogen Interactions; Macrophages; Ticks
PubMed: 19273271
DOI: 10.2741/3449 -
Clinics in Laboratory Medicine Mar 2010Human ehrlichiosis and anaplasmosis are acute febrile tick-borne diseases caused by various members of the genera Ehrlichia and Anaplasma (Anaplasmataceae). Human... (Review)
Review
Human ehrlichiosis and anaplasmosis are acute febrile tick-borne diseases caused by various members of the genera Ehrlichia and Anaplasma (Anaplasmataceae). Human monocytotropic ehrlichiosis has become one of the most prevalent life-threatening tick-borne disease in the United States. Ehrlichiosis and anaplasmosis are becoming more frequently diagnosed as the cause of human infections, as animal reservoirs and tick vectors have increased in number and humans have inhabited areas where reservoir and tick populations are high. Ehrlichia chaffeensis, the etiologic agent of human monocytotropic ehrlichiosis (HME), is an emerging zoonosis that causes clinical manifestations ranging from a mild febrile illness to a fulminant disease characterized by multiorgan system failure. Anaplasma phagocytophilum causes human granulocytotropic anaplasmosis (HGA), previously known as human granulocytotropic ehrlichiosis. This article reviews recent advances in the understanding of ehrlichial diseases related to microbiology, epidemiology, diagnosis, pathogenesis, immunity, and treatment of the 2 prevalent tick-borne diseases found in the United States, HME and HGA.
Topics: Anaplasma; Anaplasmosis; Animals; Ehrlichia; Ehrlichiosis; Humans; Ixodes
PubMed: 20513551
DOI: 10.1016/j.cll.2009.10.004 -
Nature Communications May 2024Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for...
Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for Ehrlichia and Anaplasma infections in the rainforests of the Amazon biome of French Guiana. Through molecular genetics and metagenomics reconstruction, we observe a high indigenous biodiversity of infections circulating among humans, wildlife, and ticks inhabiting these ecosystems. Molecular typing identifies these infections as highly endemic, with a majority of new strains and putative species specific to French Guiana. They are detected in unusual rainforest wild animals, suggesting they have distinctive sylvatic transmission cycles. They also present potential health hazards, as revealed by the detection of Candidatus Anaplasma sparouinense in human red blood cells and that of a new close relative of the human pathogen Ehrlichia ewingii, Candidatus Ehrlichia cajennense, in the tick species that most frequently bite humans in South America. The genome assembly of three new putative species obtained from human, sloth, and tick metagenomes further reveals the presence of major homologs of Ehrlichia and Anaplasma virulence factors. These observations converge to classify health hazards associated with Ehrlichia and Anaplasma infections in the Amazon biome as distinct from those in the Northern Hemisphere.
Topics: Anaplasma; Ehrlichia; Humans; Animals; Rainforest; Ticks; Animals, Wild; Phylogeny; Anaplasmosis; French Guiana; Ehrlichiosis; Metagenomics; Genome, Bacterial; RNA, Ribosomal, 16S
PubMed: 38734682
DOI: 10.1038/s41467-024-48459-y -
Frontiers in Cellular and Infection... 2023Obligate intracellular bacteria in the order Rickettsiales are transmitted by arthropod vectors and cause life-threatening infections in humans and animals. While both... (Review)
Review
Obligate intracellular bacteria in the order Rickettsiales are transmitted by arthropod vectors and cause life-threatening infections in humans and animals. While both type 1 and type 4 secretion systems (T1SS and T4SS) have been identified in this group, the most extensive studies of Rickettsiales T1SS and associated effectors have been performed in . These studies have uncovered important roles for the T1SS effectors in pathobiology and immunity. To evade innate immune responses and promote intracellular survival, and other related obligate pathogens secrete multiple T1SS effectors which interact with a diverse network of host targets associated with essential cellular processes. T1SS effectors have multiple functional activities during infection including acting as nucleomodulins and ligand mimetics that activate evolutionarily conserved cellular signaling pathways. In , an array of newly defined major immunoreactive proteins have been identified that are predicted as T1SS substrates and have conformation-dependent antibody epitopes. These findings highlight the underappreciated and largely uncharacterized roles of T1SS effector proteins in pathobiology and immunity. This review summarizes current knowledge regarding roles of T1SS effectors in Rickettsiales members during infection and explores newly identified immunoreactive proteins as potential T1SS substrates and targets of a protective host immune response.
Topics: Humans; Animals; Type I Secretion Systems; Rickettsiales; Bacterial Proteins; Type IV Secretion Systems; Ehrlichia; Host-Pathogen Interactions
PubMed: 37256108
DOI: 10.3389/fcimb.2023.1175688 -
Frontiers in Cellular and Infection... 2023Obligate intracellular pathogens occupy one of two niches - free in the host cell cytoplasm or confined in a membrane-bound vacuole. Pathogens occupying membrane-bound... (Review)
Review
Obligate intracellular pathogens occupy one of two niches - free in the host cell cytoplasm or confined in a membrane-bound vacuole. Pathogens occupying membrane-bound vacuoles are sequestered from the innate immune system and have an extra layer of protection from antimicrobial drugs. However, this lifestyle presents several challenges. First, the bacteria must obtain membrane or membrane components to support vacuole expansion and provide space for the increasing bacteria numbers during the log phase of replication. Second, the vacuole microenvironment must be suitable for the unique metabolic needs of the pathogen. Third, as most obligate intracellular bacterial pathogens have undergone genomic reduction and are not capable of full metabolic independence, the bacteria must have mechanisms to obtain essential nutrients and resources from the host cell. Finally, because they are separated from the host cell by the vacuole membrane, the bacteria must possess mechanisms to manipulate the host cell, typically through a specialized secretion system which crosses the vacuole membrane. While there are common themes, each bacterial pathogen utilizes unique approach to establishing and maintaining their intracellular niches. In this review, we focus on the vacuole-bound intracellular niches of , and .
Topics: Vacuoles; Coxiella burnetii; Anaplasma phagocytophilum; Chlamydia trachomatis; Ehrlichia chaffeensis
PubMed: 37645379
DOI: 10.3389/fcimb.2023.1206037 -
Microbes and Infection Mar 2016Ehrlichia is a large genus of obligate intracellular Gram-negative bacteria transmitted by ticks that cause several emerging infectious diseases in humans and are... (Review)
Review
Ehrlichia is a large genus of obligate intracellular Gram-negative bacteria transmitted by ticks that cause several emerging infectious diseases in humans and are pathogenic on rodents, ruminants, and dogs. Ehrlichia spp. invade and replicate either in endothelial cells, white blood cells, or within midgut cells and salivary glands of their vector ticks. In this review, we discuss the insights that functional studies are providing on how this group of bacteria exploits their host by subverting host innate immunity and hijacking cellular processes.
Topics: Animals; Dogs; Ehrlichia; Host-Pathogen Interactions; Humans; Immune Evasion; Rodentia; Ticks
PubMed: 26617397
DOI: 10.1016/j.micinf.2015.11.001 -
Ticks and Tick-borne Diseases Jul 2023The Anaplasmataceae family includes obligate, arthropod-transmitted intracellular bacteria that can be zoonotic and potentially fatal. Studies focusing on the...
The Anaplasmataceae family includes obligate, arthropod-transmitted intracellular bacteria that can be zoonotic and potentially fatal. Studies focusing on the interaction between neotropical primates and the agents of this family are scarce. The present study aimed to identify agents of the Anaplasmataceae family in the whole blood of free-living and captive neotropical primates in the State of Mato Grosso, Central-West Brazil. Thirty-eight samples of six nonhuman primate (NHP) species were collected in seven municipalities and analysed through polymerase chain reaction (PCR), nucleotide sequencing, and phylogenetic analysis of the dsb, groEL, 16S rRNA, and gltA genes. DNA fragments similar to those of Ehrlichia canis were detected in Sapajus apella and Ehrlichia chaffeensis from Mico melanurus. The sequences generated in this study and homologous sequences retrieved from GenBank® were used for phylogenetic analyses to characterize the Ehrlichial agents detected in NHPs. The agents were then grouped into clades corresponding to different isolates from the NHP species. In addition, an Anaplasma sp. closely related to Anaplasma marginale was identified in two S. apella individuals. These findings shed light on the susceptibility of neotropical NHPs to Anaplasmataceae agents. These bacteria are known to be transmitted by ticks, which can also serve as possible sources of infection for other animals, including humans.
Topics: Humans; Animals; Ehrlichia; Ehrlichia canis; RNA, Ribosomal, 16S; Brazil; Phylogeny; Anaplasmataceae; Anaplasma; Ehrlichia chaffeensis; Primates
PubMed: 36989601
DOI: 10.1016/j.ttbdis.2023.102179