Ehrlichiosis

Infection of a cell by Ehrlichia. 1: bacteria entering the cell. 2, 3, 4: reproduction and Morula in the cytoplasm of a neutrophil

Ehrlichiosis or anaplasmosis is anthropozoonosis caused by obligatory intracellular bacteria and transmitted by ticks.

• it is a newly diagnosed disease - previously thought to be infectious to dogs only
• may resemble some forms of Lyme borreliosis
• occurs very rarely in the Czech Republic
  

Etiology

• gram-negative bacteria of the genus Ehrlichia, in our country Anaplasma (formerly Ehrlichia) phagocytophila
• transmission tick (genus Ixodes, Amblyoma, Dermacentor)
• the morphology of bacteria is variable, usually cocci or cocobacillus

• 

  Intracytoplasmic vacuolar microcolonies of Ehrlichia chaffeensis in leukocytes

  is located inside leukocytes in membrane-bounded vacuoles, forming intracytoplasmic vacuolar microcolonies called "morulas"

Pathogenesis

Bacteria penetrate:

1. granulocytes - the so-called human granulocyte ehrlichiosis / anaplasmosis - HGE, IGA - originates of the Anaplasma phagocytophilum, transmitted by ticks of the genus Ixodes, the reservoir is small mammals, wild animals and horses; co-infection possible Borrelia burgdorferi
2. monocytes - human monocytic ehrlichiosis / anaplasmosis is formed - HME, IME - causative agent E. chaffeensis, transmitted by ticks of the genera Amblyoma and Dermacentor, the reservoir is dogs and wild animals

Clinical picture

• diverse and non-specific:
  • headache, fatigue, muscle pain, fever, dyspepsia, cough, nausea, (maculopapular rash is present in monocytic ehrlichiosis)
  • internal organ involvement - most often lungs, liver, CNS.

Diagnostics

• indirect - detection of antibodies by immunofluorescence test (IFA)
• direct - PCR
• in blood count: leukopenia (especially neutropenia), thrombocytopenia, sometimes anemia
• elevated liver tests

Therapy

• broad-spectrum antibiotics - doxycycline, tetracycline, chloramphenicol

Sources

• BENEŠ, Jiří. Studijní materiály [online]. [cit. 2009]. <http://jirben.wz.cz>.

Literature

• Státní zdravotní ústav. Lidská granulocytární anaplazmóza (HGA) [online]. ©2020. [cit. 2021-01-18]. <http://www.szu.cz/tema/prevence/lidska-granulocytarni-anaplazmoza-hga-1>.

• HAVLÍK, Jiří. Infektologie. 2. edition. 1990. ISBN 80-201-0062-8.

• LOBOVSKÁ, Alena. Infekční nemoci. 1. edition. 2001. ISBN 80-246-0116-8.