Synonym(s)
Human monocytic ehrlichiosis; Sennetsu fever
HistoryThis section has been translated automatically.
Donatia and Lestoquard (description of Ehrlichia canis), 1935; Gordon (description of E. phagocytophila), 1940; Moshkovski, 1945; Tachibana, 1986
DefinitionThis section has been translated automatically.
Mostly tick-borne bacterial infectious disease caused by Ehrlichia species.
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PathogenThis section has been translated automatically.
- Ehrlichia species are obligatory intracellular, Gram-negative bacteria from the Rickettsiaceae family. The different species have developed a specific cell affinity during evolution. Some live exclusively in granulocytes, others only in monocytes. E. platys, a species not yet found in humans, lives in thrombocytes.
- Honestly, 0.5 µm in diameter are small, obligatory intracellular coccobacilli rods, with sometimes elipsoid and polymorphic appearance.
- Transmission by ticks: Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, Ixodes pacificus, Ixodes ricinus, Ixodes dammini.
- Double or triple infections with Borrelia and Babesia are possible.
- Ehrlichia sennetsu lives naturally in fish parasites and is often transmitted by eating raw fish.
- Ehrlichia show tropism for mononuclear cells and multiply densely packed in membrane-enclosed cytosplasmic vacuoles. During further propagation, characteristic morules are formed, which are composed of vacuoles stuck together like mulberries.
- Ehrlichia infest horses, sheep, goats, cattle, bison, deer, jackals, whitefoot mice, dogs and humans.
- Exceptions: Anaplasma phagocytophilum (previously Ehrlichia equi and phagocytophila) as the trigger of human granulocytic anaplasmosis. They were formerly counted among the Ehrlichioses. The pathogens live obligatory intracellularly in granulocytes, where they multiply in cytoplasmic vacuoles.
ClassificationThis section has been translated automatically.
A distinction is made between Ehrlichia sennetsu (Sennetsu fever) and Ehrlichia chaffeensis (human monocytic ehrlichiosis).
Occurrence/EpidemiologyThis section has been translated automatically.
- E. sennetsu. western Japan and Southeast Asia.
- E. chaffeensis: USA, South America, Europe, Africa.
ManifestationThis section has been translated automatically.
80% are men infected.
Clinical featuresThis section has been translated automatically.
- In the case of transmission by tick bite there is little itching at the bite site, sometimes the brown-red to black round tick body is still detectable.
- Sennetsu fever: incubation period 9 days, fever, chills, malaise, headache, insomnia, generalized lymphadenopathy, especially in the neck and throat, possibly spleno- and hepatomegaly. The disease is self-limiting.
- Human monocyte monocyte ehrlichiosis: fever (in 97% of cases), headache (80%), limb and joint pain (70%), myalgia, anorexia, nausea, vomiting, infectious maculopapular exanthema (approx. 30-40% of cases), possibly pneumonia, cough, diarrhoea, lymphadenopathy (25%), drop in hematocrit, pancytopenia with severe thrombocytopenia (70%), leukocytopenia (60%) in the first 3-7 days, lymphocytosis in the 2nd week, increase in transaminases (86%).
- Human granulocytic ehrlichiosis (anaplasmosis): 67-75% of all infections are asymptomatic. Incubation period: 5-30 days. Fever (100% of symptomatic cases) and flu-like symptoms with headache, limb, muscle and joint pain, rarely abdominal pain, nausea, vomiting and diarrhea, dry cough and infectious maculo-papular exanthema (2-3% of cases). Leukopenia (50%), thrombopenia (92%), increase in transaminases (91%). Rare pancytopenia.
LaboratoryThis section has been translated automatically.
- Decrease of hematocrit, pancytopenia with strong thrombocytopenia, leukocytopenia in the first 3-7 days, lymphocytosis in the 2nd week.
- Elevated aspartase and ALT levels.
DiagnosisThis section has been translated automatically.
- Microscopy of the blood and bone marrow with detection of morules.
- QBC: Buffy coat microscopy.
- Indirect fluorescent antibody detection.
- PCR with detection of DNA.
Differential diagnosisThis section has been translated automatically.
Complication(s)This section has been translated automatically.
- Acute renal and pulmonary failure.
- Encephalopathy.
- Mortality up to 2%.
- Complicated course especially in HIV-infected persons.
TherapyThis section has been translated automatically.
Tetracycline (e.g. tetracycline-ratiopharm) 4 times/day 500 mg p.o. or doxycycline (e.g. doxycycline AL) 1.5 to 2 mg/kg bw/day or once/day 200 mg p.o. for 14 days are considered sufficient. Alternatively: Rifampicin 10 mg/kg bw/day (maximum 600 mg/day) for 7-10 days. If necessary therapy until the blood count normalizes. Penicillins and cephalosporins (no pharmacological intracellular targets) are generally not effective.
Progression/forecastThis section has been translated automatically.
- Human monocyte monocyte ehrlichiosis: lethality: up to 2%.
- Human granulocytic monocyte anaplasmosis: lethality: 2-3%.
ProphylaxisThis section has been translated automatically.
Tick protection and control.
TablesThis section has been translated automatically.
Ehrlichia species with predominantly terrestrial distribution | |||
|
Vectors |
Hosts/infested species |
Cell affinity |
HGE agent |
Ixodes ticks |
People |
Granulocytes |
E. pahgozytophilia |
Ixodes ticks |
Hoofed animals |
Granulocytes |
E. equi |
Ixodes ticks |
Horses, people |
Granulocytes |
E. chaffeensis |
Amblyomma ticks |
People, deer |
Monocytes |
E. canis |
Haemaphysialis and Riphicephalus ticks |
Dogs |
Granulocytes |
E. ewingii |
Ticks |
Rabbit |
Granulocytes |
E. platys |
Ticks |
Dogs |
Platelets |
| |||
Ehrlichia species with predominantly aquatic distribution | |||
E. sennetsu |
Trematodes in raw fish (peroral route of infection) |
People |
Monocytes |
E. resticii |
Cercaria (infestation through peroral route of infection or when bathing in waters contaminated with cercaria) |
Horses, dogs |
Monocytes |
NeoReckettsia helminthocea |
helminths in raw fish (peroral route of infection) |
Dogs, bears, people |
|
LiteratureThis section has been translated automatically.
- Ismail N et al (2017) Tick-Borne Emerging Infections: Ehrlichiosis and Anaplasmosis. Clin Lab Med 37:317-340.
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Doxycycline; Hiv infection; Lyme borreliosis; Mononucleosis infectious; Rash; Rocky mountain spotted fever; Tetracycline; Tick bite;Disclaimer
Please ask your physician for a reliable diagnosis. This website is only meant as a reference.
Prof. Dr. med. Peter Altmeyer