Zoonotic skin infections Flashcards
General initial presentation of zoonotic infections
Flu-like symptoms
What is the microbiological structure of Rickettsia
Gram negative Bacilli, obligate intracellular parasites
What is significant about htem being obligate intracellular parasites?
It is damn near impossible to grow them in lab culture
If you can’t culture rickettsia, how do you diagnose it?
Diagnosis is by appearanceand pt history, confirmed by serology
All Rickettsia are sensitive to:
Doxycycline
True Rickettsia infection features what
The Rickettsia Triumvirate
Fever
Headache
Rash
Rickettsia replicate where?
Endothelial cells of small blood vessels
This replication in Endothelial cells ultimatley causes
vasculitis
Rocky Mountain spotted fever occurs in large part where?
East of the mississippi river (not in the rocky mtns at all.
First symptom of RMSF
flu like headache
Rash comes on a few days later and has what pattern?
Starts on the ankles and the wrists, moves radially from there (to the palms, soles, trunk)
Muscle soreness (especially calves)
RMSF
Major complications in RMSF
Septicemia, DIC
Diagnosis of RMSF
Immunoflourescence assay. IF antigens against rickettsiae
Used to be Weil Felix Test. Anti-rickettsiae antibodies cross-react with Proteus OX antigens. MUST BE confirmed by 4x rise in titers
Treatment for RMSF
Doxy….25% mortality if untreated
How is Rickettsiae prowazekii spread?
Lice who contain the organism, bite you defacate in the bite spot, the bite spot itches and you scrath it thus working the feces into the bite. You then have the organism inside you
Do we see R Porwazekii in the US
Nah….seen in regions of extreme poverty
EPIDEMIC TYPHUS
Rash pattern
Spreads from trunks to extremities
complications from R Prowazekii
myocarditis, CNS involvement
R. Typhii?
Causes endemic typhus
Where is R Typhii endemic in US?
Southern Texas, Southern Cal, Hawaii
Transmitted by the rat flea