Rickettsia typhi: Difference between revisions

Revision as of 13:30, 5 August 2020

Background

Causes murine typhus or flea-borne typhus

Microbiology

Flea-borne Gram-negative intracellular bacterium Rickettsia typhi

Life Cycle

Flea bites, flea poops, feces get rubbed into the bite wound
Flea acquires infection from feeding on a rickettsemic host

Epidemiology

Flea vector (Xenopsylla cheopis) with a rat reservoirs (Rattus species)
- Also, cat flea vector (Vector::Ctenocephalides felis) in southern US
- Possibly opossums as reservoirs
Worldwide distribution
In the US, most cases are in southern Texas and California

Clinical Manifestations

Incubation period of 1 to 2 weeks, but rarely remember flea exposure
Fever, headache, nausea and vomiting are common, as well as myalgias
Rash develops over the course in about 50%
- Usually described as Causes::macular or maculopapular rash, sometimes with petechiae
- On trunk, but can involve extremities
- Rarely on palms and soles
May have leukopenia and thrombocytopenia early in the course
Elevated AST is common, as well as other liver enzymes
Further nausea/vomiting and anorexia, cough, and hepatosplenomegaly may all develop
Neurologic complications include confusion, seizures, and ataxia
They often develop hypoalbuminemia and electrolyte abnormalities such as hyponatremia and hypocalcemia
CSF shows aseptic meningitis
1 to 4% mortality
Sort of like a milder version of R. prowazekii

Diagnosis

Based on acute and convalescent serology looking for a 4-fold risk after about 4 weeks
Possibly PCR of skin biopsy

Management

doxycycline 100 mg PO bid for 7 to 10 days
Should be treated empirically, since cannot confirm diagnosis quickly

@@ Line 1: / Line 1: @@
+== Background ==
-* Causes '''murine typhus''' or '''flea-borne typhus'''
+*Causes '''murine typhus''' or '''flea-borne typhus'''
-== Microbiology ==
+===Microbiology===
-* Flea-borne Gram-negative intracellular bacterium ''Rickettsia typhi''
+*Flea-borne Gram-negative intracellular bacterium ''Rickettsia typhi''
-== Life Cycle ==
+===Life Cycle===
-* Flea bites, flea poops, feces get rubbed into the bite wound
-* Flea acquires infection from feeding on a rickettsemic host
+*Flea bites, flea poops, feces get rubbed into the bite wound
-== Epidemiology ==
+*Flea acquires infection from feeding on a rickettsemic host
+===Epidemiology===
-* Flea vector (''Xenopsylla cheopis'') with a rat reservoirs (''Rattus'' spp.)
-** Also, cat flea vector (''Ctenocephalides felis'') in southern US
-** Possibly opossums as reservoirs
-* Worldwide distribution
-* In the US, most cases are in southern Texas and California
+*Flea vector (''[[Vector::Xenopsylla cheopis]]'') with a rat reservoirs ([[Rattus species|''Rattus'' species]])
-== Clinical Manifestations ==
+**Also, cat flea vector ([[Vector::Ctenocephalides felis|''Vector::Ctenocephalides felis'']]) in southern US
+**Possibly opossums as reservoirs
+*Worldwide distribution
+*In the US, most cases are in southern Texas and California
+==Clinical Manifestations==
-* Incubation period of 1 to 2 weeks, but rarely remember flea exposure
-* Fever, headache, nausea and vomiting are common, as well as myalgias
-* Rash develops over the course
-** Usually described as maculopapular, sometimes with petechiae
-** On trunk, but can involve extremities
-** Rarely on palms and soles
-* May have leukopenia and thrombocytopenia early in the course
-* Elevated AST is common, as well as other liver enzymes
-* Further nausea/vomiting and anorexia, cough, and hepatosplenomegaly may all develop
-* Neurologic complications include confusion, seizures, and ataxia
-* They often develop hypoalbuminemia and electrolyte abnormalities such as hyponatremia and hypocalcemia
-* CSF shows aseptic meningitis
-* 1 to 4% mortality
-* Sort of like a milder version of ''R. prowazekii''
+*Incubation period of [[Usual incubation period::1 to 2 weeks]], but rarely remember flea exposure
+*[[Causes::Fever]], [[Causes::headache]], [[Causes::nausea]] and [[Causes::vomiting]] are common, as well as [[Causes::myalgias]]
+*[[Causes::Rash]] develops over the course in about 50%
+**Usually described as [[Causes::macular rash|Causes::macular]] or [[Causes::maculopapular rash]], sometimes with [[Causes::petechiae]]
+**On trunk, but can involve extremities
+**Rarely on palms and soles
+*May have [[Causes::leukopenia]] and [[Causes::thrombocytopenia]] early in the course
+*Elevated AST is common, as well as other [[liver enzymes]]
+*Further [[nausea]]/[[vomiting]] and [[Causes::anorexia]], [[Causes::cough]], and [[Causes::hepatosplenomegaly]] may all develop
+*Neurologic complications include [[Causes::confusion]], [[Causes::seizures]], and [[Causes::ataxia]]
+*They often develop [[Causes::hypoalbuminemia]] and electrolyte abnormalities such as [[Causes::hyponatremia]] and [[Causes::hypocalcemia]]
+*CSF shows [[Causes::aseptic meningitis]]
+*1 to 4% mortality
+*Sort of like a milder version of ''R. prowazekii''
+== Diagnosis ==
+* Based on acute and convalescent serology looking for a 4-fold risk after about 4 weeks
+* Possibly PCR of skin biopsy
+== Management ==
+* [[Is treated by::doxycycline]] 100 mg PO bid for 7 to 10 days
+* Should be treated empirically, since cannot confirm diagnosis quickly
 {{DISPLAYTITLE:''Rickettsia typhi''}}
 [[Category:Rickettsioses]]