Typhus
Terms
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- Expression
- Rickettsial diseases – tiny Gm- rods
-
Expression
4 types -
Epidemic typhus
Brill-Zinsser disease
Endemic typhus
Scrub typhus -
Expression
Epidemic typhus - occurring in war, poverty, famine
-
Expression
Brill-Zinsser disease - reoccurrence of epidemic typhus, possibly endemic
-
Expression
Endemic typhus - present consistently in certain areas
-
Expression
Scrub typhus - areas with dense vegetation
- History
- Ancient disease (Greece 400-500 BCE)
-
History
Problem in what circumstances? -
Crowded places
Killed 20-30m people after WWI -
Epidemiology
Age important? - yea. >50 have 40-60% mortality (highest)
-
Epidemiology
Epidemic typhus -
humans sole host; vector is human body louse; crowding,
hygiene, and poverty have role; few cases in US; present in Africa, Central America, South America; cases increase during colder weather – why? -
Epidemiology
Endemic typhus (also called murine (mouse) typhus)
Reservoir: Vector? -
Reservoir = rodents
vector = flea -
Epidemiology
Scrub typhus
Reservoir? Vector? -
rodents reservoir
vectors are immature mites (chiggers) -
Etiology
Causative Agent of Epidemic typhus - Rickettsia prowazekii
- Transmission of Epidemic typhus
-
carried by body lice; lice bites skin
can infect eye or respiratory tract directly or by inhalation -
Causative Agent
Endemic typhus - Rickettsia typhi
- Transmission of endemic typhus
-
infected fleas on mice or rats inoculate
human skin; rarely through inhalation -
Causative Agent
Scrub Typhus - Rickettsia (Orientia) tsutsugomushi
- Transmission of Scrub Typhus
-
humans become
accidental hosts when chigger bites skin and inoculates with bacteria -
Pathogenesis
Rickettsia infect: - macrophages, and grow inside other cells; also attack cells in walls of blood vessels
-
Pathogenesis
7-10 days of what? - Intracellular latent period
- first Symptoms/signs:
- frontal, headache, high fever, chills, muscle pain
- day 15-17 symptoms/signs
- rash appears, first trunk then extremities except face, palms, soles
- Severe cases outcomes
- personality changes, low urine output due to renal effects, hypotension, gangrene, mortality
- Age matters with typhus?
- hell yea nukka>>>>Adults are fooked
- Treatment:
-
Rx: tetracycline or chloramphenicol
if signs are present it's challenging - recurrance possible?
- yea. Brill-Zinsser Disease
- Vaccine?
- yea. not approved in US but it's around
- what is the best way to eradicate Typhus?
- kill the vectors; best in endemic typhus