Diagnosis of Lyme Disease Often Elusive

Diagnosis of Lyme disease often can be elusive

Source: Mid-Iowa News

Diagnosis of Lyme disease often can be elusive

By: Colleen Rogers, Staff Writer
5/12/2001

A total of 34 cases of Lyme disease were reported in Iowa in 2000, according to Iowa Department of Public Health. Dr. Joseph Brewer, an infectious diseases physician in Missouri who treats Barker and Weeg, said diagnosis can be very difficult.

The department counts cases of Lyme disease with "the presence of an erythma migrans rash" (also known as a bull's eye or target rash) and "at least one manifestation of musculoskeletal, neurologic or cardiovascular disease with laboratory confirmation."

Neither Melanie Barker of Ames or Judy Weeg of Roland are counted in the state's Lyme disease statistics because they did not meet the criteria. Lyme disease testing is not all-inclusive and there are several strains that may not respond to the classic test.

Dr. Joseph Brewer, an infectious diseases physician in Missouri who treats Barker and Weeg, said diagnosis can be very difficult.

"The symptoms are non-specific and can mimic many other diseases," Brewer said. "The blood tests can have both false positives and false negatives. Physicians should not rely entirely on the blood test to make or exclude the diagnosis."

In the central and southern part of the United States the blood test may even be less accurate since patients may suffer a different strain of the Lyme bacteria, Brewer said.

"The rash after the tick bite is very important if it does occur, but it occurs in only 50 percent of cases," Brewer said. "The Centers for Disease Control and state health department criteria for identifying a case of Lyme are very narrow and limited. Thus, without question, Lyme is under-reported."

Brewer estimated he has seen at least 20 Lyme disease patients from Iowa.

Dr. Greg McDonald, an associate professor in the Department of Moleculary Microbiology and Immunology in the School of Medicine and in the Entomology Department in the School of Agriculture at the University of Missouri at Columbia, has researched an atypical Lyme disease-like illness known as either Masters' disease or STARI (Southern Tick Associated Rash Illness). Clinically, this disease is identical to Lyme disease.

In experiments on erythema migrans skin biopsies and blood taken from patients with Lyme disease-like illness, McDonald's research has proven the presence of Borrelia bacteria that are related to but different from Borrelia burgdorferi, the bacteria associated with Lyme disease.

McDonald has developed a polymerase chain reaction test for Lyme-disease like illnesses detects DNA from the organism in clinical samples instead of antibodies.

The classic antibody tests can be inaccurate, and this has been a major problem for people with Lyme-disease like illnesses that test antibody-negative, so patients go without treatment, he said.

Diagnosis and treatment are further complicated by the fact that "Most people in the U.S., including physicians, think that Lyme disease or related illnesses are only carried by deer ticks" McDonald said. "But the Lyme disease-like illness is associated with Lone Star ticks and dog ticks."

Brewer agreed the potential for several different tick species to carry Lyme is very real and probably much more of an issue than originally thought.

"Here in the Midwest and southern U.S., the Lone Star tick may be very important," Brewer said.

	Iowa Lyme Disease Network P.O. Box 631 carroll, IA 51401