Ehrlichiosis: Difference between revisions
Content deleted Content added
ProfessorAM (talk | contribs) →Symptoms: added clinical details |
m →Cite journal with Wikipedia template filling, tweak cites |
||
| Line 19: | Line 19: | ||
==Species== |
==Species== |
||
Five species have been shown to cause human infection:<ref |
Five species have been shown to cause human infection:<ref>{{cite journal |author=Dumler JS, Madigan JE, Pusterla N, Bakken JS |title=Ehrlichioses in humans: epidemiology, clinical presentation, diagnosis, and treatment |journal=Clin. Infect. Dis. |volume=45 |issue=Suppl 1 |pages=S45–51 |year=2007 |month=July |pmid=17582569 |doi=10.1086/518146 |url=http://www.cid.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17582569}}</ref> |
||
* ''[[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. |
* ''[[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)]]).<ref name="Goddard"/> ''E. ewingii'' is most common in the south central and southeastern states. |
* ''[[Ehrlichia ewingii]]'' (which causes [[human ewingii ehrlichiosis]]). ''E. ewingii'' primarily infects deer and dogs (see [[Ehrlichiosis (canine)]]).<ref name="Goddard"/> ''E. ewingii'' is most common in the south central and southeastern states. |
||
| Line 28: | Line 28: | ||
The latter two infections are not well studied. |
The latter two infections are not well studied. |
||
Recently, human infection by the newly discovered [[Panola Mountain]] (Georgia, USA) Ehrlichia species has been reported.<ref>{{cite journal |author=Reeves WK, Loftis AD, Nicholson WL, Czarkowski AG |title=The first report of human illness associated with the Panola Mountain Ehrlichia species: a case report |journal=Journal of medical case reports |volume=2 |
Recently, human infection by the newly discovered [[Panola Mountain]] (Georgia, USA) Ehrlichia species has been reported.<ref>{{cite journal |author=Reeves WK, Loftis AD, Nicholson WL, Czarkowski AG |title=The first report of human illness associated with the Panola Mountain Ehrlichia species: a case report |journal=Journal of medical case reports |volume=2 |pages=139 |year=2008 |pmid=18447934 |pmc=2396651 |doi=10.1186/1752-1947-2-139 |url=http://www.jmedicalcasereports.com/content/2//139}}</ref> |
||
''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.<ref>Thomas S, Popov VL, Walker DH |
''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.<ref>{{cite journal |author=Thomas S, Popov VL, Walker DH |title=Exit Mechanisms of the Intracellular ''Bacterium Ehrlichia'' |journal=PLoS ONE |volume=5 |issue=12 |pages=e15775 |year=2010 |url=http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0015775}}</ref> |
||
==Symptoms== |
==Symptoms== |
||
| Line 39: | Line 39: | ||
Early in infection, production of [[TNF-alpha]], a cellular product that promotes inflammation and immune response, is suppressed. |
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 can present with purpura and in one such case, the number of organisms was present in such over whelming numbers that in 1991 Dr. Aileen Marty of the [[AFIP]] was able to demonstrate the bacteria in human tissues using standard stains and later prove that the organisms were indeed Ehrlichia using immunoperoxidase stains.<ref> |
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 can present with purpura and in one such case, the number of organisms was present in such over whelming numbers that in 1991 Dr. Aileen Marty of the [[AFIP]] was able to demonstrate the bacteria in human tissues using standard stains and later prove that the organisms were indeed Ehrlichia using immunoperoxidase stains.<ref>{{cite journal |author=Marty AM, Dumler JS, Imes G, Brusman HP, Smrkovski LL, Frisman DM |title=Ehrlichiosis mimicking thrombotic thrombocytopenic purpura. Case report and pathological correlation |journal=Hum. Pathol. |volume=26 |issue=8 |pages=920–5 |year=1995 |month=August |pmid=7635455 |url=http://www.humanpathol.com/article/0046-8177(95)90017-9/abstract}}</ref> |
||
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.<ref>{{cite journal|last=McBride|first=Jere W.|coauthors=Walker, David H.|title=Molecular and cellular pathobiology of Ehrlichia infection: targets for new therapeutics and immunomodulation strategies|journal=Expert Reviews in Molecular Medicine|date=31 January 2011|volume=13|doi=10.1017/S1462399410001730}}</ref> |
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.<ref>{{cite journal|last=McBride|first=Jere W.|coauthors=Walker, David H.|title=Molecular and cellular pathobiology of Ehrlichia infection: targets for new therapeutics and immunomodulation strategies|journal=Expert Reviews in Molecular Medicine|date=31 January 2011|volume=13|doi=10.1017/S1462399410001730}}</ref> |
||
Revision as of 12:45, 9 June 2011
| Ehrlichiosis | |
|---|---|
| Specialty | Infectious diseases  |
Ehrlichiosis is a tickborne[1] bacterial infection[2], 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.[3]
Species
Five species have been shown to cause human infection:[4]
- 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)).[3] 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.
Recently, human infection by the newly discovered Panola Mountain (Georgia, USA) Ehrlichia species has been reported.[5]
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.[6]
Symptoms
The most common symptoms include headache, muscle aches, and fatigue. A rash occurs 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 can present with purpura and in one such case, the number of organisms was present in such over whelming numbers that in 1991 Dr. Aileen Marty of the AFIP was able to demonstrate the bacteria in human tissues using standard stains and later prove that the organisms were indeed Ehrlichia using immunoperoxidase stains.[7]
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.[8]
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."[9]
Treatment
Doxycycline is the drug of choice. For people allergic to drugs of the tetracycline class, rifampicin is an alternative.[3] Early clinical experience suggested that chloramphenicol may also be effective, however in vitro susceptibility testing revealed resistance.
External Links
- (RO) Ehrlichiosis in dogs. Real cases Ehrlichia cases in dogs. Case studies
References
- ^ CDC "Questions and Answers" page for tickborne rickettsial diseases
- ^ Jacqueline E. Dawson and Aileen M. Marty. Ehrlichiosis. in Pathology of emerging Infections, Volume 1 editied by Horsburgh CR, and Nelson AM. American Society for Microbiology, 1997
- ^ a b c Goddard J (September 1, 2008). "What Is New With Ehrlichiosis?". Infections in Medicine.
- ^ Dumler JS, Madigan JE, Pusterla N, Bakken JS (2007). "Ehrlichioses in humans: epidemiology, clinical presentation, diagnosis, and treatment". Clin. Infect. Dis. 45 (Suppl 1): S45–51. doi:10.1086/518146. PMID 17582569.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Reeves WK, Loftis AD, Nicholson WL, Czarkowski AG (2008). "The first report of human illness associated with the Panola Mountain Ehrlichia species: a case report". Journal of medical case reports. 2: 139. doi:10.1186/1752-1947-2-139. PMC 2396651. PMID 18447934.
{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Thomas S, Popov VL, Walker DH (2010). "Exit Mechanisms of the Intracellular Bacterium Ehrlichia". PLoS ONE. 5 (12): e15775.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Marty AM, Dumler JS, Imes G, Brusman HP, Smrkovski LL, Frisman DM (1995). "Ehrlichiosis mimicking thrombotic thrombocytopenic purpura. Case report and pathological correlation". Hum. Pathol. 26 (8): 920–5. PMID 7635455.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ McBride, Jere W. (31 January 2011). "Molecular and cellular pathobiology of Ehrlichia infection: targets for new therapeutics and immunomodulation strategies". Expert Reviews in Molecular Medicine. 13. doi:10.1017/S1462399410001730.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Thomas, Rachael J (1 August 2009). "Current management of human granulocytic anaplasmosis, human monocytic ehrlichiosis and ehrlichiosis". Expert Review of Anti-infective Therapy. 7 (6): 709–722. doi:10.1586/eri.09.44.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help)CS1 maint: date and year (link)