Ehrlichiosis ewingii infection

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Human ewingii ehrlichiosis
Specialty Infectious disease

Ehrlichiosis ewingii infection [1] is an infectious disease caused by an intracellular bacteria, Ehrlichia ewingii . [2] The infection is transmitted to humans by the tick, Amblyomma americanum . This tick can also transmit Ehrlichia chaffeensis , the bacteria that causes human monocytic ehrlichiosis (HME).

Contents

Symptoms and signs

Patients can present with fever, headache, myalgias, and malaise. Laboratory tests may reveal thrombocytopenia, leukopenia, and evidence of liver damage.[ citation needed ]

Mechanism

Humans contract the disease after a bite by an infected tick of the species Amblyomma americanum .[ citation needed ] Those with an underlying immunodeficiency (such as HIV) appear to be at greater risk of contracting the disease. Compared to HME, ewingii ehrlichiosis has a decreased incidence of complications. [3]

Like Anaplasma phagocytophilum , the causative agent of human granulocytic ehrlichiosis, Ehrlichia ewingii infects neutrophils. Infection with E. ewingii may delay neutrophil apoptosis. [4]

Diagnosis

In endemic areas, a high index of suspicion is warranted, especially with a known exposure to ticks. The diagnosis can be confirmed by using PCR. [5] A peripheral blood smear can also be examined for intracytoplasmic inclusions called morulae.[ citation needed ]

Treatment

The treatment of choice is doxycycline.[ citation needed ]

See also

Related Research Articles

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Ehrlichiosis is a tick-borne bacterial infection, caused by bacteria of the family Anaplasmataceae, genera Ehrlichia and Anaplasma. These obligate intracellular bacteria infect and kill white blood cells.

<i>Ehrlichia</i> Genus of bacteria

Ehrlichia is a genus of Rickettsiales bacteria that are transmitted to vertebrates by ticks. These bacteria cause the disease ehrlichiosis, which is considered zoonotic, because the main reservoirs for the disease are animals.

<i>Amblyomma americanum</i> Species of tick

Amblyomma americanum, also known as the lone star tick, the northeastern water tick, or the turkey tick, is a type of tick indigenous to much of the eastern United States and Mexico, that bites painlessly and commonly goes unnoticed, remaining attached to its host for as long as seven days until it is fully engorged with blood. It is a member of the phylum Arthropoda, class Arachnida. The adult lone star tick is sexually dimorphic, named for a silvery-white, star-shaped spot or "lone star" present near the center of the posterior portion of the adult female shield (scutum); adult males conversely have varied white streaks or spots around the margins of their shields.

<span class="mw-page-title-main">Southern tick-associated rash illness</span> Medical condition

Southern tick-associated rash illness (STARI) is an emerging infectious disease related to Lyme disease that occurs in southeastern and south-central United States. It is spread by tick bites and it was hypothesized that the illness was caused by the bacteria Borrelia lonestari. However, there is insufficient evidence to declare this Borrelia strain as a causative agent.

Ehrlichia chaffeensis is an obligate intracellular, Gram-negative species of Rickettsiales bacteria. It is a zoonotic pathogen transmitted to humans by the lone star tick. It is the causative agent of human monocytic ehrlichiosis.

<i>Ehrlichia ewingii</i> Species of bacterium

Ehrlichia ewingii is a species of rickettsiales bacteria. It has recently been associated with human infection, and can be detected via PCR serological testing. The name Ehrlichia ewingii was proposed in 1992.

<span class="mw-page-title-main">Human granulocytic anaplasmosis</span> Medical condition

Human granulocytic anaplasmosis (HGA) is a tick-borne, infectious disease caused by Anaplasma phagocytophilum, an obligate intracellular bacterium that is typically transmitted to humans by ticks of the Ixodes ricinus species complex, including Ixodes scapularis and Ixodes pacificus in North America. These ticks also transmit Lyme disease and other tick-borne diseases.

<span class="mw-page-title-main">Human monocytotropic ehrlichiosis</span> Medical condition

Human monocytotropic ehrlichiosis is a form of ehrlichiosis associated with Ehrlichia chaffeensis. This bacterium is an obligate intracellular pathogen affecting monocytes and macrophages.

<span class="mw-page-title-main">African tick bite fever</span> Medical condition

African tick bite fever (ATBF) is a bacterial infection spread by the bite of a tick. Symptoms may include fever, headache, muscle pain, and a rash. At the site of the bite there is typically a red skin sore with a dark center. The onset of symptoms usually occurs 4–10 days after the bite. Complications are rare but may include joint inflammation. Some people do not develop symptoms.

Ehrlichia canis is an obligate intracellular bacterium that acts as the causative agent of ehrlichiosis, a disease most commonly affecting canine species. This pathogen is present throughout the United States, South America, Asia, Africa and recently in the Kimberley region of Australia. First defined in 1935, E. canis emerged in the United States in 1963 and its presence has since been found in all 48 contiguous United States. Reported primarily in dogs, E. canis has also been documented in felines and humans, where it is transferred most commonly via Rhipicephalus sanguineus, the brown dog tick.

<i>Rickettsia parkeri</i> Species of bacterium

Rickettsia parkeri is a gram-negative intracellular bacterium. The organism is found in the Western Hemisphere and is transmitted via the bite of hard ticks of the genus Amblyomma. R. parkeri causes mild spotted fever disease in humans, whose most common signs and symptoms are fever, an eschar at the site of tick attachment, rash, headache, and muscle aches. Doxycycline is the most common drug used to reduce the symptoms associated with disease.

Heartland bandavirus, sometimes called Heartland virus (HRTV), is a tick-borne phlebovirus of the Bhanja virus serocomplex discovered in 2009. The lone star tick transmits the virus to people when feeding on blood. As of 2017, only five states in the Central United States have reported 20 human infections, namely Arkansas, Indiana, Missouri, Oklahoma, and Tennessee; symptoms resemble those of two other tick-borne infections ehrlichiosis and anaplasmosis. The reservoir host is unknown, but deer, raccoon, coyotes, and moose in 13 different states have antibody titers against the virus. By 2023 over 50 human infections were reported in at least eleven states.

References

  1. Rapini, Ronald P., Bolognia, Jean L., Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. p. 1130. ISBN   978-1-4160-2999-1.
  2. Patnaik MM (June 2009). "Inclusion bodies in tick-borne diseases diagnosed in patients from northern Wisconsin". Clin Med Res. 7 (1–2): 45–7. doi:10.3121/cmr.2009.807.818. PMC   2705270 . PMID   19574488.
  3. Paddock CD, Folk SM, Shore GM, et al. (November 2001). "Infections with Ehrlichia chaffeensis and Ehrlichia ewingii in persons coinfected with human immunodeficiency virus". Clinical Infectious Diseases. 33 (9): 1586–94. doi: 10.1086/323981 . PMID   11568857.
  4. Xiong Q, Bao W, Ge Y, Rikihisa Y (April 2008). "Ehrlichia ewingii infection delays spontaneous neutrophil apoptosis through stabilization of mitochondria". The Journal of Infectious Diseases. 197 (8): 1110–8. doi: 10.1086/533457 . PMID   18462160.
  5. Gusa, Aa, Buller, Rs, Storch, Ga, Huycke, Mm, MacHado, Lj, Slater, Ln, Stockham, Sl, Massung, Rf (Nov 2001). "Identification of a p28 gene in Ehrlichia ewingii: evaluation of gene for use as a target for a species-specific PCR diagnostic assay". Journal of Clinical Microbiology. 39 (11): 3871–6. doi:10.1128/JCM.39.11.3871-3876.2001. PMC   88457 . PMID   11682500.