1Disease classification of Rocky Mountain Spotted Fever?
*Typhus fever, rickettsiosis
2What is causative organ of Rocky Mountain Spotted Fever?
Rickettsia rickettsii
3Provide classification information of Rickettsia rickettsii:
*gram negative rod
*obligate intracellular parasite
*intracelluar motility utlizing host cytoskeleton
*small 0.2 x 0.5 micro meters to 0.3 x 2.0 micro meters
4Epidemiology of Rickettsia rickettsii:
Reservoir: ticks and other animals (rodents)
Portal of entry: epidermis
Mode of transmission: arthropod vector (wood or dog) tick bite
5Incubation of Ricekttsia rickettsii?
*5-14 days (on average a week)
6What is pathogenesis of Rickettsia rickettsii?
*bacteria multiplies at site of tick bite
*bacteria invade endothelial
cells linning blood vessels
*bacteria spread leads to systemic inflammation and tissue damage
7Major signs and symptoms of Rickettsia rickettsii:
*rash (maculopapular) in 85-90% of people
> happens 2-5 dys after fever
>flate red lesions (non itchy) ussuallly smaller than 1 cm diameter
*Myalgia (muscle pain)
*damage at site of tick bite
*flu symptoms (fever, headache, loss of appetite, nausea, vomiting, stomach pain)
8Where does the Rickettsia rickettsii macularpapular rash first appear?
*starts at wrists and ankles
9What are complications of Rickettsia rickettsii?
*tissue necrosis (digit and limb loss, hearing loss, paralsis, mental disability, kidney failure, heart failure)
*death (0.5 % cases treated) (20-80% untreated)
10Risk of Death in children with Rickettsia rickettsii?
*5 x more likely in young children
11How can anthropod bites be prevented?
*avoid tick invested area
*treat areas with insecticides
*wear protective clothing
*treat clothing with 0.5% permethrin
*bug repellents (20% DEET)
12Treatment for Rickettsia Rickettsii?
*Tetracycline (doxycycline)
*Chlorampheniocol