Tickborne disease puzzles scientists

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Tickborne disease puzzles scientists

By Steve

UPI Medical Correspondent

From the Science & Technology Desk

Published 7/23/2002 7:49 PM

A tick-borne disease similar to Lyme disease has been popping up in southern

states and other areas of the country since the 1990s and scientists still

are trying to figure out if this is a new disease or simply a Lyme variant.

The Centers for Disease Control and Prevention in Atlanta is funding studies

to determine the cause of the ailment, which has been dubbed Master's

disease, but so far the culprit has remained unidentified.

Sam Telford, a researcher at Harvard University who focuses on Master's

disease and will present an overview of it next month at the Ninth

International Conference on Lyme disease and other tickborne diseases in New

York City, told United Press International, " For the first time (at the

conference), Master's disease is being considered as an entity separate from

Lyme disease. "

" There's a lot of interest in it " and the conference should help extend the

knowledge about the disease, Telford said.

Although the symptoms of Master's disease are quite similar to Lyme disease

and include the " bulls-eye " rash that is Lyme's hallmark, as well as fever,

fatigue and achiness, it appears to be caused by a different tick and a

different bacterium.

Ned , a medical epidemiologist with the Lyme disease program at the

CDC, told UPI since the early 1990s more than 100 people have been diagnosed

with the mysterious condition. CDC prefers the name Southern tick-associated

rash illness, or STARI, but some scientists consider this designation

inaccurate.

Master's disease was first identified in Missouri in 1991 when 45 patients

developed the bulls-eye rash. However, subsequent investigation of these

patients failed to identify Borrelia burgdorferi, the Lyme bacteria.

In addition, the infected people did not produce the expected antibodies --

proteins produced by the body in response to an infection -- specific for

Lyme, which indicated their rashes were caused by some different germ.

Several more clusters of people developed this rash throughout the 1990s

without revealing Lyme disease as the culprit. There were 23 additional

cases in Missouri, 14 cases in North Carolina and 23 in Georgia. Sporadic

cases also have been reported " among military personnel doing field

maneuvers in southern states, " said.

Scientists eventually discovered in most of these cases people had reported

being bitten by a type of tick called a lone star tick -- Amblyomma

americanum -- so named because of a yellow star-shaped patch on its back.

This tick, which does not usually transmit the Lyme disease bacteria, is

quite different from the deer tick, which transmits Lyme bacteria to humans.

Lone star ticks occur in the southeastern states from Texas to Florida and

up to Virginia, whereas the deer tick's range primarily is in the

northeastern states, which is where most Lyme disease cases occur.

" We still don't know what causes (Master's disease), " said, but many

scientists now think it is caused by an as-yet-unidentified bacterium

similar to the Lyme disease germ. Although no one has seen this new organism

yet, researchers have detected its DNA in lone star ticks and in at least

one person's rash. " So we think its coming from a new species of

(bacteria), " said.

The bacterium has been named Borrelia lonestari and it may be similar to a

bacterium that caused fever in cattle at the turn of the 20th century,

Telford said.

The CDC currently is funding a study to identify the cause of the illness

definitively. The effort involves taking tissue samples from the rash site

and looking for the DNA of this new bacterium. The next step is to show

conclusively people with the rash are infected with Borellia lonestari,

said. But it could be that the bacterium is not the cause of the

problem, he noted.

Telford agreed, saying, " The evidence isn't there yet " to put the blame on

B. lonestari. He noted Ed Masters -- a family doctor in private practice in

Missouri for whom the disease was named -- has had hundreds of tissue

samples from patients with the illness tested for the DNA of B. lonestari

and no one yet has detected any indication of the organism in any of the

samples.

Telford thinks there " may be multiple causes of Master's disease, " including

a reaction to the tick bite itself, a new species of bacteria or some other

unrecognized agent. " Whatever it is, it's unique to the lone star tick, " he

said.

Masters told UPI the illness could have multiple causes and it might be too

early to call it a new disease. " We're still on the front end of a very

steep learning curve, " he said, noting the rash and the symptoms of the

disease are identical to Lyme and no one has proven which bacteria is the

true cause. So it very well could be a variant of Lyme carried by lone star

ticks instead of deer ticks.

The good news is although symptoms of Master's disease can be similar to

Lyme disease, they seem less severe and they disappear on their own. Lyme

disease's symptoms, on the other hand, can linger for years, if not

indefinitely, and can cause neurological problems and even affect the heart.

" Most of the time the rash is the most prominent symptom, " said. About

half the people who develop Master's disease report fatigue, 43 percent have

headache, about 36 percent have aching muscles and 29 percent have fever.

" Most physicians, if they see the (Master's disease) rash, will treat it

with doxycycline because they think its Lyme disease, " said.

Doxycycline is an antibiotic that can knock out Lyme disease if treatment is

begun early enough.

Doxycycline also seems to knock out the symptoms of Master's disease,

said. " But whether the symptoms would've went away anyway is anybody's

guess, " he said, noting in patients who did not receive treatment, the rash,

headache and muscle aches went away eventually.

Doctors are not required to report cases of this disease to state health

departments or the CDC, so it is unclear how many cases there have been

across the country. " There's no indication that this is spreading, "

said.

Telford and Masters disagreed, saying they believe the disease often is

confused with Lyme and therefore it is probably more prevalent than

expected. Telford said the incidence of Master's disease " must be huge

because these ticks are just a nightmare. They're so abundant and very

aggressive. They're places where you could get 2,000 ticks crawling up your

leg. "

Masters noted " the lone star tick is expanding its territory " and this could

increase the number of cases of people who develop Master's disease. The

disease may be expanding outside of the southern states to some northern

states such as Iowa because people have come down with Lyme disease symptoms

there even though they probably were not exposed to deer ticks, he said.

To prevent infection with Master's disease, people should observe the same

precautions to avoid Lyme disease, said. These include using insect

repellent, wearing light-colored clothing so the ticks can be spotted easily

and removing them from the body as soon as possible.

Copyright © 2002 United Press International