Rickettsia typhi: Difference between revisions

Latest revision as of 13:46, 9 February 2022

Background

Causes murine typhus, flea-borne typhus, or endemic typhus

Microbiology

Flea-borne Gram-negative intracellular bacterium

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)
- 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

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 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 Rickettsia 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==
-= Murine typhus (''R. typhi'') =
-* Disease caused by the flea-borne Gram-negative intracellular bacterium ''Rickettsia typhi''
+*Causes '''murine typhus''', '''flea-borne typhus''', or '''endemic typhus'''
-== Life Cycle ==
+===Microbiology===
+*Flea-borne [[Stain::Gram-negative]] intracellular bacterium
-* Flea bits, flea poops, feces get rubbed into the bite wound
-* Flea acquires infection from feeding on a rickettsemic host
-== Epidemiology ==
+===Life Cycle===
+*Flea bites, flea poops, feces get rubbed into the bite wound
-* Flea vector (''Xenopsylla cheopis'') with a rat reservoirs (''Rattus'' spp.)
+*Flea acquires infection from feeding on a rickettsemic host
-** Also, cat flea vector (''Ctenocephalides felis'') in sourthern US
-** Possibly opossums as reservoirs
-* Worldwide distribution
-* In the US, most cases are in southern Texas and California
+===Epidemiology===
-== Clinical Presentation ==
+*Flea vector (''[[Vector::Xenopsylla cheopis]]'') with a rat reservoirs ([[Rattus species|''Rattus'']])
-* Incubation period of 1 to 2 weeks, but rarely remember flea exposure
+**Also, cat flea vector ([[Vector::Ctenocephalides felis]]) in southern US
-* Fever, headache, nausea and vomiting are common, as well as myalgias
+**Possibly opossums as reservoirs
-* Rash develops over the course
+*Worldwide distribution
-** Usually described as maculopapular, sometimes with petechiae
+*In the US, most cases are in southern Texas and California
-** 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''
+==Clinical Manifestations==
-== Diagnosis ==
+*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|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 ''[[Rickettsia 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]]