​Infectious Diseases and Microbiology - Rocky Mountain Spotted Fever ( Rickettsia rickettsii)

​Infectious Diseases and Microbiology - Rocky Mountain Spotted Fever ( Rickettsia rickettsii) 
Rocky Mountain Spotted Fever is caused by Rickettsia rickettsii which is an obligate intracellular Gram-negative coccobacillus.
Long-term contact with infected ticks (Dermacentor variabilis, D andersoni, Epidemiology Amblyomma americanum) is the mode of transmission. Numerous regions of the United States, particularly the south Atlantic, southeast, and south central states, are home to the endemic organism. Tick season in a particular region is correlated with transmission.
Clinical R rickettsii is the causal agent of RMSF. A typical petechial rash, an intense fever, chills, headaches, and myalgia are among the symptoms. The rash begins on the ankles and wrists and works its way inside toward the trunk. 
DIC, renal failure, and encephalitis are examples of systemic consequences. In the absence of treatment, death rates are closer to 20–30%.

Obligate intracellular parasites called R rickettsii reproduce in endothelial cells, damaging blood vessels and resulting in vasculitis. Increased vascular permeability and petechial bleeding are symptoms of systemic infection, which can result in DIC.

Diagnostic complement fixation assays, enzyme immunoassay, and indirect fluorescent antibodies can all be used to confirm the diagnosis. Skin biopsy specimens stained with immunofluorescent dye have been used to identify R rickettsii. Usually, no attempt is made at culture.
 Medication for rickettsial infections can include antibiotics like chloramphenicol and doxycycline.
Sulfonamides are not recommended because they exacerbate the condition. Tick removal must be done quickly in order to prevent.

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