Pat Barrett Morning Report July 2, 2010

 Tick borne, though 1/3 to 1/2 do not recall a tick bite  Dermacentor variabilis tick  Incidence 15/100,000 persons at the most endemic areas  1-3% ticks infected in endemic areas MMWR: 2006: 55RR04: 1

 Gram negative intracellular  Virulence depends on the status of the vector  Trophic for endothelial cells  Transits rapidly by activating actin within host’s cells  No exotoxins, will cause necrosis, lymphohistiocytic vasculitis

CDC /epidemiology

Vector# of Cases 2009Therapy RMSFAmerican Dog Tick (D. variabilis) 259Doxy, 2 nd line Chloramphenicol EhrlichiosisLone Star Tick (A. americanum) 31Doxy, 2 nd line Chloramphenicol or Rifampin LymeWhite TaiIed Dear Tick (I scapularis) 65 (only 2 confirmed in- state inoculations) Doxy, amox, or cefuroxime AnaplasmosisWhite TaiIed Dear Tick (I scapularis) Doxy, 2 nd line Chloramphenicol or Rifampin STARILone Star Tick (A. americanum) Doxy, 2 nd line amox

 Usually develop 5-7 days after tick exposure  Fever, headache, myalgia, arthralgia, nausea, vomiting  Spotless RMSF occurs approx 10% of the time

 Typically at 5-7 days  Begins on wrists, ankles, palms and soles, then spreads centripetally  Often macularpapular then petechial  Rarely pruritic

 Case Series from Duke (1)  61% male  66% African American  53% mortality in the case series  22.9% mortality in separate case series (2) where treatment was delayed past 5 days  6.5% mortality if treated w/in 5 days 1: Clin Infect Dis 1992: 15:439 2: Clin Infect Dis 1995: 20:1118

 Clinical impression followed by acute and convalescent sera  Typically the latex agglutination has the fastest turn around time  IFA test for IgG and IgM, felt to be the standard, used by CDC.  False positives w/ other rickettsial exposures  PCR not widely available  Also hyponat, elevated transaminases, prolonged PT, aPTT

 Gold Standard: 4 fold increase from acute to convalescent, convalescent IFA > 1:64, isolation of Rickettsiae, fluorescent ab of specimen from bx or autopsy  Indirect hemagglutination 94% sens  Indirect fluorescent antibody 96% sens  Latex agglutination 71% sens Am J Trop Med Hyg: 1986: 35: 840

 Doxycycline 7 days, in severe cases  2 nd Line Chloramphenicol  No preventive therapy recommended for tick bites w/o illness – shown to delay symptom onset but not prevent infection. J Clin Microbiol 1978;8:102

 Ticks are awful  RMSF and Ehrlichia should be considered during any FUO work-up while a resident at UNC  There is some variability in when serology is positive  Rashless and rashalittle RMSF does exist  The benefits of not treating empirically must be carefully weighed against the risks

 NC DHHS:  CDC/epidemiology:  Chapman, AS et. MMWR: 2006: 55RR04: 1  Up To Date: RMSF  Sexton, DJ, et al. Clin Infect Dis 1992: 15:439  Kirkland, KB, et al. Clin Infect Dis 1995: 20:1118  Kaplan, JB, et al. Am J Trop Med Hyg: 1986: 35: 840  Kenyon RH, Williams RG, Oster CN, Pedersen CE Jr. Prophylactic treatment of Rocky Mountain spotted fever. J Clin Microbiol 1978;8: