Sennetsu fever

Sennetsu fever
ICD-9	082.4
MeSH	D016873

WikiDoc Resources for Sennetsu fever
Articles
Most recent articles on Sennetsu fever Most cited articles on Sennetsu fever Review articles on Sennetsu fever Articles on Sennetsu fever in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Sennetsu fever Images of Sennetsu fever Photos of Sennetsu fever Podcasts & MP3s on Sennetsu fever Videos on Sennetsu fever
Evidence Based Medicine
Cochrane Collaboration on Sennetsu fever Bandolier on Sennetsu fever TRIP on Sennetsu fever
Clinical Trials
Ongoing Trials on Sennetsu fever at Clinical Trials.gov Trial results on Sennetsu fever Clinical Trials on Sennetsu fever at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Sennetsu fever NICE Guidance on Sennetsu fever NHS PRODIGY Guidance FDA on Sennetsu fever CDC on Sennetsu fever
Books
Books on Sennetsu fever
News
Sennetsu fever in the news Be alerted to news on Sennetsu fever News trends on Sennetsu fever
Commentary
Blogs on Sennetsu fever
Definitions
Definitions of Sennetsu fever
Patient Resources / Community
Patient resources on Sennetsu fever Discussion groups on Sennetsu fever Patient Handouts on Sennetsu fever Directions to Hospitals Treating Sennetsu fever Risk calculators and risk factors for Sennetsu fever
Healthcare Provider Resources
Symptoms of Sennetsu fever Causes & Risk Factors for Sennetsu fever Diagnostic studies for Sennetsu fever Treatment of Sennetsu fever
Continuing Medical Education (CME)
CME Programs on Sennetsu fever
International
Sennetsu fever en Espanol Sennetsu fever en Francais
Business
Sennetsu fever in the Marketplace Patents on Sennetsu fever
Experimental / Informatics
List of terms related to Sennetsu fever

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]

Overview

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

The average reported annual incidence is 0.7 cases per million population.

Species

Five (see note below) species have been shown to cause human infection:

• Anaplasma phagocytophilum (which causes human granulocytic anaplasmosis, formerly known as human granulocytic ehrlichiosis). A. phagocytophilium is endemic to New England and the north central and Pacific regions of the United States.

• Ehrlichia ewingii (which causes human ewingii ehrlichiosis). E. ewingii primarily infects deer and dogs (see Ehrlichiosis (canine)). E. ewingii is most common in the south central and southeastern states.

• Ehrlichia chaffeensis (which causes human monocytic ehrlichiosis). E. chaffeensis is most common in the south central and southeastern states.

• Ehrlichia canis

• Neorickettsia sennetsu

The latter two infections are not well studied.

Note: In 2008, human infection by Panola Mountain (Georgia, USA) Ehrlichia species was reported. On August 3, 2011, infection by a yet-unnamed bacterium in the genus Ehrlichia carried by deer ticks that has caused flu-like symptoms in at least 25 people in Minnesota and Wisconsin was reported; human ehrlichiosis was thought to be very rare or absent in Minnesota and Wisconsin. The new species, which is very similar genetically to an Ehrlichia species found in Eastern Europe and Japan called E. muris, was identified at Mayo Clinic Health System's Eau Claire hospital.

Ehrlichia are transported between cells through the host cell filopodia during initial stages of infection, whereas, in the final stages of infection the pathogen ruptures the host cell membrane.

Symptoms

The most common symptoms include headache, muscle aches, and fatigue. A rash may occur, but is uncommon. Ehrlichiosis can also blunt the immune system, which may lead to opportunistic infections such as candidiasis.

Most of the symptoms of ehrlichiosis can likely be ascribed to the immune dysregulation that it causes.

Early in infection, production of TNF-alpha, a cellular product that promotes inflammation and immune response, is suppressed.

Late in infection, however, production of this substance can be upregulated by 30 fold, which is likely responsible for the "toxic shock-like" syndrome seen in some severe cases of ehrlichiosis. Some cases can present with purpura and in one such case the organisms were present in such overwhelming numbers that in 1991 Dr. Aileen Marty of the AFIP was able to demonstrate the bacteria in human tissues using standard stains, and later proved that the organisms were indeed Ehrlichia using immunoperoxidase stains.

Experiments in mouse models further supports this hypothesis, as mice lacking TNF-alpha I/II receptors are resistant to liver injury caused by ehrlichia infection.

3% of human monocytic ehrlichiosis cases result in death, however these deaths occur "most commonly in immunosuppressed individuals who develop respiratory distress syndrome, hepatitis, or opportunistic nosocomial infections."

Treatment

Doxycycline is the drug of choice. For people allergic to drugs of the tetracycline class, rifampicin is an alternative. Early clinical experience suggested that chloramphenicol may also be effective, however in vitro susceptibility testing revealed resistance.