A small survey of St. Louis-area physicians found doctors greatly overestimate the prevalence of Lyme disease and underestimate the prevalence of other tick-borne illnesses in Missouri.
Scientists at the University of Southern Illinois-Edwardsville sent a survey to 81 St. Louis-area infectious-disease specialists and family physicians. About a fifth of the doctors responded.
According to the results, published earlier this month in the journal Ticks and Tick-borne Diseases, 82 percent of respondents believed Lyme disease was among the most common tick-borne infections in the state. But state health officials say there were only 10 probable or confirmed cases of Lyme in Missouri in 2016.
The physicians correctly named Rocky Mountain Spotted Fever, another bacterial disease, as another one of the most common tick-borne infections in the state. Rocky Mountain Spotted Fever was the most common disease spread by ticks in Missouri, affecting 351 residents in 2016.
Several tick-borne illnesses present similar symptoms and can be difficult to connect to a particular pathogen, survey co-author Catherine Santanello said. For example, Rocky Mountain Spotted Fever, Bourbon Virus and Ehrlichiosis all cause flu-like symptoms such as fever, headaches and muscle aches.
“A doctor may prescribe an antibiotic against that bacterium, but they may not necessarily report it as Rocky Mountain Spotted Fever, because it hasn’t necessarily been diagnosed properly,” Santanello said.
If a person doesn’t know they were bit by a tick, doctors could miss the disease, or misdiagnosed it as the flu.
That’s what happened to a St.. Louis County resident earlier this year. According to the Missouri Department of Health and Senior Services, the patient’s test for the Bourbon Virus originally came back negative. After health officials recognized symptoms, the patient was re-diagnosed and has since recovered.
Lyme disease, in contrast with other illnesses, presents with a distinctive bullseye-pattern rash and is easy to identify.
“There are more signs and symptoms of Lyme disease that are clear-cut,” Santanello said. “If a person comes in knowing they had been bitten by a tick, and they have a bullseye rash, you’re not going to misdiagnose that as anything else.”
Most tick-borne diseases require the same kind of treatment: an antibiotic such as doxycycline. However, a person may additional treatment if the illness is misdiagnosed and doctors miscalculate the duration of necessarily antibiotic treatment.
The survey also found a wide variability in how long physicians treated the illnesses with antibiotics, with some ordering treatment either shorter or longer than the Centers for Disease Control and Prevention's recommended two-to-three week antibiotic use.
That could be because some diseases are more severe, Santanello said. Diseases that have been in the body longer require longer flights of medication.
Both Santanello and officials from the Missouri health department encourage doctors and patients to be aware of different tick-borne diseases in Missouri and their symptoms.
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