Rickettsial Diseases Flashcards
What are rickettsial diseases?
Range of infections causes by intracellular gram negative bacilli causing small vessel vasculitis
All have fever, head ache and rash
How do you treat rickettsial illnesses?
Doxycycline for 1 week
What causes scrub typhus and where do you get it?
Orientia tsutsugamushi
SE Asia, Asia, Oceania
What is the vector of scrub typhus?
Chigger mite
Trombiculidae
What are the signs/symptoms of scrub typhus?
An eschar 5-10 days after bite Fever, rash (central and macular), headache Delirium Hepatosplenomegaly LNs Pneumonia
How do you prevent scrub typhus?
Wear permethrin clothing
Prophylactic doxycycline for at risk groups
What causes epidemic typhus and where do you find it?
Rickettsia prowazekii
Mostly Africa and South America
Areas of over crowding
How does epidemic typhus spread?
Body louse
Pediculus humanus corporis
Scratch it’s faeces into skin
What are the symptoms if epidemic typhus?
Conjunctive suffusion Rash Headache Fever Delirium Pneumonia Meningitis
How do you prevent epidemic typhus?
Delouse with DDT
In epidemic- mass Tx one off doxy dose, boiling of clothes and bedsheets
What causes murine/endemic typhus and where is it found?
Rickettsia typhi
Worldwide
What are the symptoms of murine typhus?
Eschar Headache Fever Rash Hepatosplenomegaly
What spreads murine typhus?
Rat flea
Xenopsylla cheopis
How do you identify a rat flea?
Meral rod present
No pronotal or genal comb
What causes African tick typhus and where is it found?
Rickettsia africae
Central/South Africa and West Indies
What are the symptoms of African tick typhus?
Eschar Headache Fever Rash Virtually no mortality
What are spotted fevers and how are they spread?
Tick typhus
Hard ticks
Amblyoma
Where is Rocky Mountain spotted fever found and what causes it?
USA
Rickettsia ricketsii
How can you tell a hard tick from a soft one?
Can see mouthparts and leg bases from above
How can you identify a body louse?
6 legs
Bigger and lighter than a head louse
Abdominal indentations are more shallow
What is the genus of hard tick that spreads typhus?
Amblyomma
Family: ixodidae
