Rocky Mountain spotted fever

American rock mountain fever, new world tick-bite fever.

Rickettsiosis caused by Rickettsia rickettsii.

• Widespread worldwide.
• Mostly in the Americas (especially during the spring or summer months).
• Mostly affecting children between 4-10 yrs.

• Pathogen: Rickettsia rickettsii, Rickettsia rickettsii is transmitted by tick bites.

• Incubation period: 2-14 days.
• At the site of inoculation, a partly ulcerated, possibly crusted papule appears.
• Maculopapular exanthema (initially on wrists and ankles).
• Nosebleed, fever, splenohepatomegaly.
• There may be involvement of kidney, liver and CNS.

• Travel history.
• Clinical.
• Lice infestation.
• BB, liver and kidney values, electrolytes.
• From the 2nd week of illness Weil-Felix reaction (agglutination test).
• From the 3rd week of illness, complement fixation reaction. 
• From the 3rd week of illness, indirect immunofluorescence test.

Lethality: 5–25%.

1. Consequences of Delayed Diagnosis of Rocky Mountain Spotted Fever in Children—West Virginia, Michigan, Tennessee, and Oklahoma, May-July 2000. JAMA, 2000. 284(16): p. 2049.
2. Elghetany, M.T. and D.H. Walker, Hemostatic Changes in Rocky Mountain Spotted Fever and Mediterranean Spotted Fever. American Journal of Clinical Pathology, 1999. 112(2): p. 159-168.
3. Helmick, C.G., K.W. Bernard, and L.J. D'Angelo, Rocky Mountain Spotted Fever: Clinical, Laboratory, and Epidemiological Features of 262 Cases. Journal of Infectious Diseases, 1984. 150(4): p. 480-488.
4. Holman, Robert C., et al., Analysis of Risk Factors for Fatal Rocky Mountain Spotted Fever: Evidence for Superiority of Tetracyclines for Therapy. The Journal of Infectious Diseases, 2001. 184(11): p. 1437-1444.
5. Kaplan, J.E., J.E. McDade, and V.F. Newhouse, Suspected Rocky Mountain spotted fever in the winter--epidemic typhus? N Engl J Med, 1981. 305(27): p. 1648.
6. Paddock, Christopher D., et al., Rickettsia parkeriRickettsiosis and Its Clinical Distinction from Rocky Mountain Spotted Fever. Clinical Infectious Diseases, 2008. 47(9): p. 1188-1196.
7. Ricketts, H.T., A Micro-Organism which Apparently Has a Specific Relationship to Rocky Mountain Spotted Fever. JAMA, 1909. LII(6): p. 491.
8. Spolidorio, M.G., et al., Novel spotted fever group rickettsiosis, Brazil. Emerg Infect Dis, 2010. 16(3): p. 521-3.
9. Thorner, A.R., D.H. Walker, and J.W.A. Petri, Rocky Mountain Spotted Fever. Clinical Infectious Diseases, 1998. 27(6): p. 1353-1359.
10. Walker, D.H., Rickettsia rickettsii and Other Spotted Fever Group Rickettsiae (Rocky Mountain Spotted Fever and Other Spotted Fevers), in Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 2010, Elsevier BV. p. 2499-2507.