92
References: Hayes EB, Piesman J: How can we prevent Lyme disease? New Eng J
Med 2003;348:2424-2430.
Stewart RL, Burgdorfer W, Needham, GR: Evaluation of three commercial tick
removal tools. JWEM 1998; 9:137-142
II. GUIDELINES FOR ASSESSMENT AND TREATMENT
A.
Lyme Disease: Lyme disease is a worldwide, tick-borne infection caused by
Borrelia spirochetes. In the United States areas of high risk are the Northeast,
the upper Midwest, and California, southern Oregon, and western Nevada.
The organism is spread by deer ticks, Ixodes scapularais, in the Northeast and
Midwest, and by I. pacificus on the west coast. Most infections occur between
May 1 and November 30.
The first sign is usually an expanding circular red rash (erythema chronicum
migrans) that occurs at the site where the tick was attached. Flu-like symptoms
often develop with the rash.
In individuals who are not treated, disseminated infection, manifested by multiple
annular secondary rashes, neurologic abnormalities (meningitis, Bell's palsy,
peripheral neuropathy), arthralgias, and heart involvement (most commonly
atrioventricular block) may appear several weeks after the tick bite. Months after
an untreated infection, arthritis may develop, and usually affects the knees and
shoulders. Persistent and varied neurologic abnormalities may occur and persist
for years.
Early treatment shortens the duration of erythema migrans and diminishes the
likelihood of secondary and tertiary sequelae. Doxycycline for fourteen to twenty-
one days is recommended for localized and early disseminated infections except
in pregnant women and children eight-years-old and younger, who should receive
amoxicillin. An effective, but expensive, vaccine for Lyme disease has been
developed, but was removed from the market by the manufacturer in February
2002 because sales were low.
Reference: Steere AC: Lyme Disease. New Eng J Med 2001;345:115-125.
B.
Southern tick-associated rash illness (STARI)is characterized by a rash
essentially identical to erythema migrans, but the rash clears without treatment
and no further symptoms develop. This infection appears to be caused by another
species of Borrelia, although the organism has not been cultured. It is transmitted
by lone star ticks Amblyomma americanum, and is limited to the Southeastern
states where that tick is found.
C. Rocky Mountain Spotted Fever: In spite of its name, 90 percent of Rocky
Mountain spotted fever (RMSF) infections occur along the east coast of the
United States, although infections do occur in all forty-eight contiguous states
except Maine. The infection is spread by a number of Ixodes ticks, most
commonly the wood tick (Dermacentor andersoni) and the dog tick
(Dermacentor variabilis). The domestic dog is the major host.
