Page 263 - parasitology for medical and clinical laboratoryprofessionals

Organisms Borne by Ticks and Other Vectors 243

by general malaise, fatigue, fever, headache, muscle, and have yielded no evidence of serological antibodies to the
joint pains. This condition has been descriptively named organism B. lonestari. In all the cases of this disease that
Southern Tick–associated Rash Illness (STARI) because have been studied to the current time, the rash and ac-
of the characteristic “bull’s eye” rash called erythema companying symptoms have resolved promptly follow-
chronicum migrans that develops immediately around ing treatment with oral antibiotics.
the bite of a tick. This manifestation of the infection It is a certainty that STARI may be specifically
mimics that of the circular rash typically observed in linked to bites from the tick Amblyomma americanus,
most cases of Lyme disease. Borrelia lonestari, a patho- which is commonly known as the lone star tick, even
gen associated with STARI, also infects lone star ticks. though the identity of the causative organism is unknown.
Research suggests that up to 10 percent of the lone star The adult female is distinguished by an irregularly
ticks in an endemic area can be infected with any one of shaped white dot or lone star on her back but all three
these pathogens. These ticks may also be infected with a life stages including the nymph, larval, and adult forms of
spotted-fever group of rickettsia, Rickettsia amblyommii, A. americanum tend to aggressively bite humans.
but it is unknown at this time if this bacterium causes a
similar or the same disease. Preventing Infection Related
to STARI
Symptoms of STARI
In general, tick-borne illness may be prevented by avoid-
The symptoms accompanying this disease are somewhat ing tick habitats such as the edges of dense wooded areas
vague and are the same as or similar to several other tick- with tall grasses and brushy areas. The same precautions
borne diseases. Symptoms of STARI infections are mild that are used for other tick and insect vectors include the
and resemble respiratory illnesses similar to those found use of repellents containing DEET or permethrin and
in cases of influenza, accompanied by symptoms of mus- wearing light-colored clothing that includes long trousers
cle pains, headache, and fatigue. These symptoms may tucked into socks. Carefully conducted body searches to
also include a clinical finding of an elevated temperature, remove ticks before the vectors have the opportunity
but this is by no means characteristic. The rash found in to explore the body and to eventually become embedded
STARI usually appears within 7 days of a tick bite and is paramount following outdoor activity, particularly in
may expand to an area of the skin around the bite site an endemic area.
spanning up to 3 in. in diameter or even perhaps slightly Victims of tick bites should monitor their health
larger. Quite frequently, the mechanical act of having closely for several days to a few weeks following the inci-
been bitten will cause some redness and slight pain. But dent and should consult a physician if a rash appears of
an accompanying rash found in cases of STARI is much if headaches, elevated temperature, or unusual feelings of
more pronounced than any localized damage to the skin fatigue are experienced. If muscle pains and particularly
from an uncomplicated tick bite and the two should if swollen lymph nodes occur within a month of receiv-
not be confused. But unlike Lyme disease, STARI has ing a tick bite, these symptoms and signs should prompt
not been associated with any arthritic, neurological, or a visit to a physician. In most cases any treatment of
chronic symptoms. persons who merely have a tick bite without prolonged
exposure to an imbedded tick is not necessary. Epide-
Causative Organism of miologists at the CDC perform ongoing surveillance of
Lyme Disease STARI and are actively involved in seeking blood sam-
ples from patients who exhibit the signs and symptoms
The causative organism for STARI is currently not clear of STARI with the goal of eventually identifying the in-
and studies have shown that the disease is not caused by fectious organism that causes the disease called STARI.
Borrelia burgdorferi, the organism that causes Lyme dis-
ease. Another spirochete, Borrelia lonestari, was detected Causes of STARI
in the skin of one patient and in the lone star tick that
delivered the bite. Studies conducted on a number of The only certainty in the contraction of this disease is that
patients exhibiting the signs and symptoms of STARI the illness is a tick-borne disease undoubtedly transmitted