anaplasma phagocytophilum

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human granulocytotropic anaplasmosis

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/10/29 18:57:44」(JST)

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Ehrlichiaceae
Scientific classification
Kingdom:	Bacteria
Phylum:	Proteobacteria
Class:	Alpha Proteobacteria
Order:	Rickettsiales
Family:	Ehrlichiaceae
Genus:	Anaplasma
Species:	A. phagocytophilum
Binomial name
Anaplasma phagocytophilum

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophilum) is a gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture fever, and also causes the zoonotic disease human granulocytic anaplasmosis.

Light micrograph of Anaplasma phagocytophilum cultured in human promyelocytic cell line HL-60, showing A. phagocytophilum morulae as basophilic and intracytoplasmic inclusions (arrows). Wright–Giemsa stain, original magnification x1,000.

Anaplasma phagocytophilum is a Gram-negative, obligate bacterium of neutrophils. It causes human granulocytic anaplasmosis, which is a tick-borne rickettsial disease. Because this bacterium invades neutrophils, it has a unique adaptation and pathogenetic mechanism.

Biology

Anaplasma phagocytophilum is a small, obligate, intracellular bacterium with a Gram-negative cell wall. It is 0.2–1.0 μm and lacks a lipopolysaccharide biosynthetic machinery. The bacterium first resides in an early endosome, where it acquires nutrients for binary fission and grows into small groups called morulae. This bacterium prefers to grow within myeloid or granulocytic cells.

Role in human disease

Anaplasma phagocytophilum causes human granulocytic anaplasmosis. This disease was first identified in 1990, although this pathogen was known to cause veterinary disease since 1932. Since 1990, incidence of this disease has increased, and it is now recognized in Europe. This disease was first identified due to a Wisconsin patient who died with a severe febrile illness two weeks after a tick bite. During the last stage of the infection, a group of small bacteria were seen within the neutrophils in the blood. Other symptoms include fever, headache, absence of skin rash, leucopenia, thrombocytopenia and mild injury to the liver.

Clinical signs in animals

The disease is multisystemic, but the most severe changes are anaemia and leukopenia. This organism causes lameness which in often confused with Lyme disease, another tick-borne illness. It is a vector borne zoonotic disease whose morula can be visualized within neutrophils (a type of white blood cell) from the peripheral blood and synovial fluid. Can cause lethargy, ataxia, inappetence, and weak or painful limbs.

Bacterial mechanism

Anaplasma phagocytophilum binds to fucosylated and sialylated scaffold proteins on neutrophil and granulocyte surfaces. A type IV secretion apparatus is known to help in the transfer of molecules between the bacterium and the host. The most studied ligand is PSGL-1 (CD162). The bacterium adheres to PSGL-1 (CD162) through 44-kDa major surface protein-2 (Msp2). After the bacterium enters the cell, the endosome stops maturation and does not accumulate markers of late endosomes or phagolysosomes. Because of this, the vacuole does not become acidified or fused to lysosomes. A. phagocytophilum then divides until cell lysis or when the bacteria leave to infect other cells.

This bacterium has the ability to affect neutrophils by altering the function of the host cell. It can survive the first encounter with the host cell by detoxifying superoxide produced by neutrophil phagocyte oxidase assembly. It also disrupts normal neutrophil function, such as endothelial cell adhesion, transmigration, motility, degranulation, respiratory burst, and phagocytosis. It causes an increase in the secretion of IL-8, a chemoattractant that increases the phagocytosis of neutrophils. The purpose of this is to increase bacterial dissemination into the neutrophil.

Laboratory diagnosis

Three tests can be performed to determine an A. phagocytophilum infection:

1. Indirect immunofluorescence assay is the principal test used to detect infection. The acute and convalescent phase serum samples can be evaluated to look for a four-fold change in antibody titer to A. phagocytophilum.
2. Intracellular Inclusions (morulae) are visualized in granulocytes on Wright- or Giemsa- stained blood smears.
3. Polymerase chain reaction assays are used to detect A. phagocytophilum DNA.

Doxycycline

Antibiotic therapy

Patients suffering from human granulocytic anaplasmosis (HGA) undergo doxycycline therapy, 100 mg twice daily until the patient’s fever subsides for at least three days. This drug has been the most beneficial to these patients infected with the bacteria. Some other tetracycline drugs are also effective. In general, patients with symptoms of HGA and unexplained fever after a tick exposure should receive empiric doxycycline therapy while their diagnostic tests are pending, especially if they experience leukopenia and/or thrombocytopenia.

In animals, antibiotics such as oxytetracycline, sulphamethazine, sulphadimidine, doxycycline and trimethoprim-sulphonamides have been used.

References

External links

• Anaplasma phagocytophilum HZ Genome Page
• Anaplasma phagocytophilum at the US National Library of Medicine Medical Subject Headings (MeSH)
• Walid MS, Ajjan M, Patel N (2007). "Borreliosis And Human Granulocytic Anaplasmosis Coinfection With Positive Rheumatoid Factor And Monospot Test: Case-Report". The Internet Journal of Infectious Diseases 6 (1). doi:10.5580/1efc. 
• Zhang L, Liu Y, Ni D; et al. (November 2008). "Nosocomial transmission of human granulocytic anaplasmosis in China". JAMA 300 (19): 2263–70. doi:10.1001/jama.2008.626. PMID 19017912. 

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. ヒトエーリキア症およびアナプラズマ症 human ehrlichiosis and anaplasmosis
• 2. エーリキアの生物学 biology of ehrlichiae
• 3. ライム病の治療 treatment of lyme disease
• 4. 犬および猫以外のペットからの人畜共通感染症 zoonoses from pets other than dogs and cats
• 5. 好中球減少症における感染の原因 infectious causes of neutropenia

English Journal

• Wild boar (Sus scrofa) - reservoir host of Toxoplasma gondii, Neospora caninum and Anaplasma phagocytophilum in Slovakia.

• Reiterová K, Špilovská S, Blaňarová L, Derdáková M, Čobádiová A, Hisira V.
• Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland.Acta Parasitol.2016 Jun 1;61(2):255-60. doi: 10.1515/ap-2016-0035.
• In Central Europe the wild boar population is permanently growing and consequently Cf foodborne infections. In this study serological and molecular detection of Toxoplasma gondii and Neospora caninum in wild boars was evaluated. Moreover, same samples were screened for the presence and genetic varia
• PMID 27078648

• Molecular evidence for bacterial pathogens in Ixodes ricinus ticks infesting Shetland ponies.

• Skotarczak B1, Wodecka B2, Rymaszewska A2, Adamska M2.
• Experimental & applied acarology.Exp Appl Acarol.2016 Jun;69(2):179-89. doi: 10.1007/s10493-016-0027-4. Epub 2016 Feb 26.
• Ixodes ricinus has the potential to transmit zoonotic pathogens to humans and domestic animals. The feeding I. ricinus (n = 1737) collected from 49 Shetland ponies and questing ones from vegetation (n = 371) were tested for the presence and differentiation of the bacterial species. DNA of I. ric
• PMID 26920921

• Efficacy of sarolaner in the prevention of Borrelia burgdorferi and Anaplasma phagocytophilum transmission from infected Ixodes scapularis to dogs.

• Honsberger NA1, Six RH2, Heinz TJ1, Weber A1, Mahabir SP1, Berg TC1.
• Veterinary parasitology.Vet Parasitol.2016 May 30;222:67-72. doi: 10.1016/j.vetpar.2016.02.010. Epub 2016 Feb 20.
• The efficacy of sarolaner (Simparica™, Zoetis) to prevent transmission primarily of Borrelia burgdorferi and secondarily of Anaplasma phagocytophilum from infected wild-caught Ixodes scapularis to dogs was evaluated in a placebo-controlled laboratory study. Twenty-four purpose-bred laboratory Beag
• PMID 26906926

Japanese Journal

• Predomination shift of different P44-expressing <i>Anaplasma phagocytophilum</i> in infected HL-60, THP-1, NB4, and RF/6A cell lines

• Japanese Journal of Infectious Diseases, 2018
• NAID 130007501951

• Molecular detection and phylogenetic analysis of tick-borne pathogens in wild Korean water deer and farmed elk in Gyeongbuk and Gangwon Provinces of Korea

• Ｔｈｅ　Ｊｏｕｒｎａｌ　ｏｆ　Ｖｅｔｅｒｉｎａｒｙ　Ｍｅｄｉｃａｌ　Ｓｃｉｅｎｃｅ 80(9), 1473-1478, 2018
• NAID 130007490507

• Molecular detection and phylogenetic analysis of tick-borne pathogens in wild Korean water deer and farmed elk in Gyeongbuk and Gangwon Provinces of Korea

• Ｔｈｅ　Ｊｏｕｒｎａｌ　ｏｆ　Ｖｅｔｅｒｉｎａｒｙ　Ｍｅｄｉｃａｌ　Ｓｃｉｅｎｃｅ, 2018
• NAID 130007432093

Related Links

• Symptoms | Anaplasmosis | CDC - Centers for Disease ...

Anaplasmosis is a tickborne disease caused by the bacterium Anaplasma phagocytophilum. It was previously known as human granulocytic ehrlichiosis (HGE) and has more recently been called human granulocytic ...

• Anaplasma phagocytophilumとは - goo Wikipedia (ウィキペディア)

Anaplasma phagocytophilum (formerly Ehrlichia phagocytophilum) [1] is a gram-negative bacterium that is unusual in its tropism to neutrophils. It causes anaplasmosis in sheep and cattle, also known as tick-borne fever and pasture ...

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関連記事	「Anaplasma phagocytophilum」「Anaplasma」「phagocytophilum」

「Anaplasma phagocytophilum」

　　[★]

アナプラズマ・ファゴサイトフィルム

関

A. phagocytophilum、Ehrlichia equi、Ehrlichia phagocytophila、HGE agent

「Anaplasma」

　　[★]

アナプラズマ、ナプラズマ属、Anaplasma属

関

Anaplasmataceae、Ehrlichieae

「phagocytophilum」

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• Anaplasma phagocytophilum