scholarly journals Human ehrlichiosis

2006 ◽  
Vol 63 (4) ◽  
pp. 403-408 ◽  
Author(s):  
Milomir Djokic ◽  
Petar Curcic ◽  
Darko Nozic ◽  
Branislav Lako ◽  
Vesna Begovic ◽  
...  
Keyword(s):  
Bacterial Species ◽  
The United States ◽  
Amblyomma Americanum ◽  
Ehrlichia Chaffeensis ◽  
Granulocytic Ehrlichiosis ◽  
Human Granulocytic Ehrlichiosis ◽  
General Weakness ◽  
Infected Cells ◽  
Human Monocytic Ehrlichiosis ◽  
Human Ehrlichiosis

Background. Human ehrlichiosis is a newly recognized disease. It is a tick-borne disease caused by several bacterial species of the genhus Erlichia. These are small gram-negative pleomorphic cocci, that are obligatory intracellular bacteria. Tick Ixodes is the principle vector in Europe, and Amblyomma americanum in the United States. Bacterial organisms replicate in a tick, and are transmited from infected cells in a vector to the blood cells of animals or humans. Human ehrlichiosis is a name for a group of diseases caused by different species of Ehrlichia. One of them is the disease named human monocytic ehrlichiosis, caused by Ehrlichia chaffeensis, and the other is a human granulocytic ehrlichiosis caused by Anaplasma phagocytophilia. Case report. We reported a 23-year-old patient admitted for the clinical treatment with the symptoms of high febrility (above 40 ?C), headache, vomiting, general weakness and exhaustion, but without data on a tick bite. The patient was treated with trimetoprim-sulfamethoxazole for a week when Ehrlichia chaffeensis was confirmed by the immunofluoroscence test, and the therapy contimed with doxacyclin. Conclusion. Human ehrlichiosis is also present in our country, so this disease should be considered everyday, especially in infectology practice.

scholarly journals An Entry-Triggering Protein of Ehrlichia Is a New Vaccine Candidate against Tick-Borne Human Monocytic Ehrlichiosis

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Khemraj Budachetri ◽  
Omid Teymournejad ◽  
Mingqun Lin ◽  
Qi Yan ◽  
Mariella Mestres-Villanueva ◽  
...  
Keyword(s):  
The United States ◽  
Interferon Γ ◽  
Amblyomma Americanum ◽  
Human Cells ◽  
Ehrlichia Chaffeensis ◽  
Infected Tick ◽  
Content Type ◽  
Tick Attachment ◽  
Human Monocytic Ehrlichiosis

ABSTRACT Ehrlichia chaffeensis is an obligatory intracellular bacterium that causes human monocytic ehrlichiosis, an emerging disease transmitted by the Lone Star tick, Amblyomma americanum. E. chaffeensis outer membrane protein entry triggering protein of Ehrlichia (EtpE) is necessary for bacterial entry into human cells. We investigated the role of EtpE in transmission of the bacteria from tick to human cells and whether or not vaccination with EtpE can prevent transmission of ehrlichiae from ticks to mammals. An antiserum against the recombinant C terminus of EtpE (rEtpE-C), which binds a mammalian cell-surface receptor and triggers bacterial entry, significantly inhibited E. chaffeensis transmission from infected tick cells to human monocytes in culture. Each of five specific-pathogen-free dogs were vaccinated with rEtpE-C along with an immunostimulating complex or were sham vaccinated with the complex alone. Dogs vaccinated with rEtpE-C developed high antibody titers against rEtpE-C and produced interferon-γ-secreting cells, as assessed with the ELISpot assay. All 10 dogs were challenged with A. americanum adult ticks infected as nymphs by syringe inoculation with E. chaffeensis. Upon challenge, both the vaccinated and control dogs became infected by day 1 post-tick attachment, but the majority of rEtpE-C-vaccinated dogs rapidly cleared the infection from the bloodstream as soon as day 7, whereas most of sham-vaccinated dogs remained infected at day 35. Peripheral blood leukocytes from vaccinated dogs had significantly elevated interferon-γ mRNA levels and secreted significantly elevated interferon-γ soon after tick attachment. Thus, the EtpE-C vaccine represents the first ehrlichial protein vaccine demonstrated to reduce bacterial infection in mammals upon challenge with infected ticks. IMPORTANCE The incidence of tick-borne diseases has risen dramatically in the past two decades and continues to rise. Discovered in 1986 and designated a nationally notifiable disease in 1998 by the Centers for Disease Control and Prevention, human monocytic ehrlichiosis, which is caused by the bacterium Ehrlichia chaffeensis, is one of the most prevalent, life-threatening, emerging tick-borne zoonoses in the United States. We investigated the role of the E. chaffeensis protein EtpE in transmission of the bacterium from tick to human cells and in vaccinated dogs with EtpE to assess the efficacy of vaccination against E. chaffeensis-infected tick challenge. Our results help fill gaps in our understanding of E. chaffeensis-derived protective antigens that could be used in a candidate vaccine for immunization of humans to counter tick-transmitted ehrlichiosis.

Detection of a Rickettsia sp. and an Ehrlichia chaffeensis-like organism in ticks parasitizing the endangered Florida Grasshopper Sparrow (Ammodramus savannarum floridanus)

2020 ◽  
Vol 25 (12) ◽  
pp. 2165-2171
Author(s):  
Erin L. Hewett Ragheb ◽  
Karl E. Miller ◽  
Katherine A. Sayler ◽  
Richard G. Robbins
Keyword(s):  
Causative Agent ◽  
Pathogenic Bacteria ◽  
Spotted Fever ◽  
The United States ◽  
Mediterranean Spotted Fever ◽  
Spotted Fever Group ◽  
Ehrlichia Chaffeensis ◽  
Grasshopper Sparrow ◽  
Ammodramus Savannarum ◽  
Human Monocytic Ehrlichiosis

Between 2013 and 2015, 163 resident endangered Florida Grasshopper Sparrows (Ammodramus savannarum floridanus) and four migratory Eastern Grasshopper Sparrows (A. savannarum pratensis) were examined for the presence of ticks in peninsular Florida. Thirteen Amblyomma maculatum and seven Haemaphysalis chordeilis ticks were removed from 13 Florida Grasshopper Sparrows. Two A. maculatum were discovered on two Eastern Grasshopper Sparrows. Polymerase chain reaction (PCR) and sequencing of resultant amplicons of some of the tick specimens were performed to determine if ticks were infected with pathogenic bacteria. Salivary gland and midgut contents of five of six (83%) of the H. chordeilis tested positive for a novel Rickettsia closely related to, but distinct from, Rickettsia aeschlimannii (causative agent of Mediterranean spotted fever-like illness), an infectious zoonotic bacterium that has not been previously reported in the United States. Four of 14 (29%) of the A. maculatum tested positive for an agent most closely related to an uncultured Ehrlichia previously isolated from Oriental house rats (Rattus tanezumi; 97.5% identity to GenBank KM817187), which is genetically similar to Ehrlichia chaffeensis (causative agent of human monocytic ehrlichiosis), another infectious zoonotic bacterium. Blood from 16 Florida Grasshopper Sparrows and one Eastern Grasshopper Sparrow tested negative for spotted fever group rickettsiae, Anaplasma spp. and Ehrlichia spp. We recommend that additional collections and screening of ticks and blood from Florida Grasshopper Sparrows be undertaken to determine the rates of infection with rickettsiae and ehrlichiae in these imperiled songbirds.

scholarly journals Antibiotic Susceptibilities of Anaplasma (Ehrlichia) phagocytophilum Strains from Various Geographic Areas in the United States

2003 ◽  
Vol 47 (1) ◽  
pp. 413-415 ◽  
Author(s):  
Max Maurin ◽  
Johan S. Bakken ◽  
J. Stephen Dumler
Keyword(s):  
United States ◽  
New York ◽  
Anaplasma Phagocytophilum ◽  
The United States ◽  
Granulocytic Ehrlichiosis ◽  
Antibiotic Susceptibilities ◽  
Human Granulocytic Ehrlichiosis

ABSTRACT We tested the antibiotic susceptibilities of eight strains of Anaplasma phagocytophilum (the agent of human granulocytic ehrlichiosis) collected in various geographic areas of the United States, including Minnesota, Wisconsin, California, and New York. The results are homogeneous and show that doxycycline, rifampin, and levofloxacin are the most active antibiotics against these strains in vitro.

scholarly journals Multi-Locus Sequence Typing of Ehrlichia chaffeensis Reveals Extensive Genotypic Variation across the United States

2021 ◽  
Vol 104 (4) ◽  
pp. 1297-1304
Author(s):  
Maria L. Zambrano ◽  
Christopher D. Paddock ◽  
Sandor E. Karpathy
Keyword(s):  
United States ◽  
Genetic Differentiation ◽  
Genotypic Variation ◽  
The United States ◽  
Amblyomma Americanum ◽  
Ehrlichia Chaffeensis ◽  
South Central ◽  
Typing System ◽  
Intergenic Regions ◽  
Multiple Strains

ABSTRACTEhrlichia chaffeensis causes human monocytic ehrlichiosis, and its principal vector is the Amblyomma americanum tick. The most frequently identified cases of ehrlichiosis come from the southeastern and south central states of the United States. In this study, a molecular typing system was developed that allows for the genetic differentiation of E. chaffeensis isolates. This multi-locus typing system included sequencing and analyzing intergenic regions ECH0033–ECH0035 and ECH0217–ECH0218, plus, variable genes variable length PCR target, 28-kDa, 120-kDa, and hemE. We examined a total of 31 unique isolates from humans and white-tailed deer, and eight DNA samples extracted from infected A. americanum collected from multiple states. This is the largest evaluation of E. chaffeensis isolates and their genotypes. Our findings show that when sequences of all six loci were concatenated and compared, the 39 samples could be separated into 23 genotypes and further grouped into six phylogenetic clades. The data in this study show no clear pattern between the geographic alignment with the genetic differentiation between the strains. As a result, this poses a challenge to understanding the spread of E. chaffeensis in the United States. Interestingly, our findings indicate that multiple strains from distant geographic origins share the same mutations, which suggests that the strains are being moved from one site to another by their hosts or vectors. In addition, we are seeing a northward shift in the lone star tick distribution in the United States. Last, some data also suggest minimal genetic mutations have occurred over time among strains that are within geographical proximity.

scholarly journals Serologic Evidence of Infection with Ehrlichia spp. in Wild Rodents (Muridae: Sigmodontinae) in the United States

1998 ◽  
Vol 36 (3) ◽  
pp. 695-700 ◽  
Author(s):  
William L. Nicholson ◽  
Susie Muir ◽  
John W. Sumner ◽  
James E. Childs
Keyword(s):  
New York ◽  
Geometric Mean ◽  
The United States ◽  
Immunofluorescence Assay ◽  
Wild Rodents ◽  
Public Health Importance ◽  
Granulocytic Ehrlichiosis ◽  
Human Granulocytic Ehrlichiosis ◽  
Serologic Evidence ◽  
Endpoint Titer

Rodent (Muridae: Sigmodontinae) blood and sera collected from 14 states were tested for seroreactivity to a cultured isolate of the human granulocytic ehrlichiosis (HGE) agent by using an indirect immunofluorescence assay. Of the 1,240 samples tested, 136 (11%) were found to be reactive at titers of ≥32. Rodents with HGE agent-specific antibodies were found in New York (23% of 491 samples; geometric mean endpoint titer [GMT] = 441), Connecticut (11% of 100 samples; GMT = 481), California (9% of 32 samples; GMT = 323), Colorado (2% of 212 samples; GMT = 256), Florida (7% of 27 samples; GMT = 362), Maryland (7% of 15 samples; titer = 64), New Jersey (4% of 76 samples; titer = 256), and Wisconsin (13% of 8 samples; titer = 128). Samples from Georgia (n = 16), Illinois (n = 27), Nevada (n = 27), North Carolina (n = 52), Ohio (n = 57), and Utah (n = 100) were not reactive. The earliest seroreactive sample was from aPeromyscus leucopus mouse collected in June 1986 in Connecticut, and the majority of the seroreactive samples (68%) were from this species. Samples from other Peromyscus species (P. boylii, P. maniculatus, and P. gossypinus) were also found to be reactive, with a GMT for the genus of 410. Several species of Neotoma woodrats (N. fuscipes, N. lepida, N. albigula, and N. mexicana) from California and Colorado had antibodies that reacted with the HGE agent (genus GMT = 194), suggesting that enzootic cycles of Ehrlichia spp. exist outside of the areas of confirmed human disease. Attempts to amplify and detect ehrlichial DNA from the limited tissues available (n = 40 animals) were unsuccessful. Further studies are needed to determine the identity of the organisms inducing antibody production in these rodent species and to elucidate the epidemiology and public health importance of these agents.

scholarly journals Ehrlichia chaffeensis Infections in Drosophila melanogaster

2009 ◽  
Vol 77 (11) ◽  
pp. 4815-4826 ◽  
Author(s):  
Alison Luce-Fedrow ◽  
Tonia Von Ohlen ◽  
Stephen K. Chapes
Keyword(s):  
Drosophila Melanogaster ◽  
Amblyomma Americanum ◽  
Immune Defense ◽  
Ehrlichia Chaffeensis ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Defense Induction ◽  
Humoral Responses ◽  
Human Monocytic Ehrlichiosis

ABSTRACT Ehrlichia chaffeensis is an obligate, intracellular bacterium, transmitted by the tick Amblyomma americanum, and is the causative agent of human monocytic ehrlichiosis infections. We previously demonstrated that E. chaffeensis is capable of growing in Drosophila S2 cells. Therefore, we tested the hypothesis that E. chaffeensis can infect adult Drosophila melanogaster. Adult Drosophila organisms were experimentally challenged with intra-abdominal injections of bacteria. Ehrlichia-infected flies showed decreased survival compared to wild-type flies, and bacteria isolated from flies could reinfect mammalian macrophages. Ehrlichia infections activated both the cellular and humoral immune responses in the fly. Hemocytes phagocytosed bacteria after injection, and antimicrobial peptide pathways were induced following infection. Increased pathogenicity in flies carrying mutations in genes in both the Toll and Imd pathways suggests that both immune defense pathways participate in host defense. Induction of Drosophila cellular and humoral responses and the in vivo replication of E. chaffeensis suggests that D. melanogaster is a suitable host for E. chaffeensis. In the future, it will be a useful tool to unlock some of the in vivo mysteries of this arthropod-borne bacterium.

scholarly journals Low rates of ehrlichiosis and Lyme borreliosis in English farmworkers

1998 ◽  
Vol 121 (3) ◽  
pp. 609-614 ◽  
Author(s):  
D. Rh. THOMAS ◽  
M. SILLIS ◽  
T. J. COLEMAN ◽  
S. M. KENCH ◽  
N. H. OGDEN ◽  
...  
Keyword(s):  
Rural Communities ◽  
Lyme Borreliosis ◽  
Companion Animals ◽  
Tick Bites ◽  
Serological Evidence ◽  
Granulocytic Ehrlichiosis ◽  
Human Granulocytic Ehrlichiosis ◽  
History Of ◽  
Delays In Diagnosis ◽  
Human Monocytic Ehrlichiosis

To determine the occupational significance of tick-borne zoonoses we sought serological evidence of Lyme borreliosis, human monocytic ehrlichiosis (HME) and human granulocytic ehrlichiosis (HGE) in a representative sample of farmworkers. Although around 20% reported ticks on their domestic and companion animals, few (<2% per year) reported being bitten by ticks. Seroprevalence of Lyme borreliosis (0·2%), HME (0·2%) and HGE (1·5%) was low. Those seropositive for HGE were no more likely to report tick bites nor more likely to report ticks on their animals. This study provides evidence that farmworkers in England are exposed to tick-borne zoonoses but that they are uncommon. Since the severity of these diseases is linked to delays in diagnosis and treatment, clinicians should be aware of these diagnoses in patients from rural communities, with or without a self-reported history of tick bite.

scholarly journals Exploitation of Interleukin-8-Induced Neutrophil Chemotaxis by the Agent of Human Granulocytic Ehrlichiosis

2001 ◽  
Vol 69 (9) ◽  
pp. 5577-5588 ◽  
Author(s):  
Mustafa Akkoyunlu ◽  
Stephen E. Malawista ◽  
Juan Anguita ◽  
Erol Fikrig
Keyword(s):  
Neutrophil Migration ◽  
Interleukin 8 ◽  
Host Cells ◽  
Human Neutrophils ◽  
Immunodeficient Mice ◽  
Obligate Intracellular ◽  
Granulocytic Ehrlichiosis ◽  
Bacterial Dissemination ◽  
Human Granulocytic Ehrlichiosis ◽  
Infected Cells

ABSTRACT The agent of human granulocytic ehrlichiosis (HGE) is an obligate intracellular bacterium with a tropism for neutrophils; however, the mechanisms of bacterial dissemination are not yet understood. Interleukin-8 (IL-8) is a chemokine that induces neutrophil migration to sites of infection for host defense against pathogens. We now show that HGE bacteria, and the HGE-44 protein, induce IL-8 secretion in a promyelocytic (HL-60) cell line that has been differentiated along the neutrophil lineage with retinoic acid and in neutrophils. Infected HL-60 cells also demonstrate upregulation of CXCR2, an IL-8 receptor, but not CXCR1. Human neutrophils migrate towardsEhrlichia sp.-infected cells in a chemotaxis chamber assay, and this movement can be blocked with antibodies to IL-8. Finally, immunocompetent and severe combined immunodeficient mice administered CXCR2 antisera, and CXCR2−/− mice that lack the human IL-8 receptor homologue, are much less susceptible to granulocytic ehrlichiosis than are control animals. These results demonstrate that HGE bacteria induce IL-8 production by host cells and, paradoxically, appear to exploit this chemokine to enhance infection.

scholarly journals Human Granulocytic Ehrlichiosis Agent and Ehrlichia chaffeensis Reside in Different Cytoplasmic Compartments in HL-60 Cells

1999 ◽  
Vol 67 (3) ◽  
pp. 1368-1378 ◽  
Author(s):  
Jason Mott ◽  
Roy E. Barnewall ◽  
Yasuko Rikihisa
Keyword(s):  
Membrane Protein ◽  
Transferrin Receptor ◽  
Brefeldin A ◽  
Ehrlichia Chaffeensis ◽  
Inclusion Type ◽  
Granulocytic Ehrlichiosis ◽  
Histocompatibility Complex ◽  
Human Granulocytic Ehrlichiosis ◽  
Late Endosomes ◽  
Immunofluorescence Labeling

ABSTRACT The human granulocytic ehrlichiosis (HGE) agent resides and multiplies exclusively in cytoplasmic vacuoles of granulocytes. Double immunofluorescence labeling was used to characterize the nature of the HGE agent replicative inclusions and to compare them with inclusions containing the human monocytic ehrlichia, Ehrlichia chaffeensis, in HL-60 cells. Although both Ehrlichiaspp. can coinfect HL-60 cells, they resided in separate inclusions. Inclusions of both Ehrlichia spp. were not labeled with either anti-lysosome-associated membrane protein 1 or anti-CD63. Accumulation of myeloperoxidase-positive granules were seen around HGE agent inclusions but not around E. chaffeensis inclusions. 3-(2,4-Dinitroanilino)-3′-amino-N-methyldipropylamine and acridine orange were not localized to either inclusion type. Vacuolar-type H+-ATPase was not colocalized with HGE agent inclusions but was weakly colocalized with E. chaffeensisinclusions. E. chaffeensis inclusions were labeled with the transferrin receptor, early endosomal antigen 1, and rab5, but HGE agent inclusions were not. Some HGE agent and E. chaffeensis inclusions colocalized with major histocompatibility complex class I and II antigens. These two inclusions were not labeled for annexins I, II, IV, and VI; α-adaptin; clathrin heavy chain; or β-coatomer protein. Vesicle-associated membrane protein 2 colocalized to both inclusions. The cation-independent mannose 6-phosphate receptor was not colocalized with either inclusion type. Endogenously synthesized sphingomyelin, from C6-NBD-ceramide, was not incorporated into either inclusion type. Brefeldin A did not affect the growth of either Ehrlichia sp. in HL-60 cells. These results suggest that the HGE agent resides in inclusions which are neither early nor late endosomes and does not fuse with lysosomes or Golgi-derived vesicles, while E. chaffeensis resides in an early endosomal compartment which accumulates the transferrin receptor.

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