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.

Pat BarrettMorning 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 2009

Therapy

RMSF American Dog Tick (D. variabilis)

259 Doxy, 2nd line Chloramphenicol

Ehrlichiosis Lone Star Tick (A. americanum)

31 Doxy, 2nd line Chloramphenicolor Rifampin

Lyme White TaiIed Dear Tick (I scapularis)

65 (only 2 confirmed in-state inoculations)

Doxy, amox, or cefuroxime

Anaplasmosis White TaiIed Dear Tick (I scapularis)

Doxy, 2nd line Chloramphenicolor Rifampin

STARI Lone Star Tick (A. americanum)

Doxy, 2nd 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: 15:4392: 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% sensAm J Trop Med Hyg: 1986: 35: 840

Doxycycline 7 days, 10-14 in severe cases

2nd 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: http://www.epi.state.nc.us/epi/gcdc/pdf/cdtable2009.pdf CDC/epidemiology:

http://www.cdc.gov/ncidod/dvrd/rmsf/epidemiology.htm 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;8:102--4.