While walking in a grassy or wooded area, there is an increasingly prevalent infectious disease that can be contracted from the bite of an unseen tick.
Annually, half a million people in the United States develop Lyme disease. Over the last two decades, there has been a sharp rise in both the number of cases and the geographic distribution of the disease.
The disorder’s clinical course is variable; the majority of the afflicted have mild symptoms and usually recover after taking antibiotics. In those that are untreated or have a therapeutic failure, complications involving multiple organ systems may ensue; it can last from months to years. The condition is rarely fatal.
Lyme disease is caused by the spirochete bacterium borrelia burgdorferi that is transmitted to humans through the bite of an infected black-legged tick, commonly known as a deer tick.
While the garlic is primarily observed on the East Coast, it has been reported in all states except Hawaii. The disorder can occur in any season but is most common from May to August.
Only a minority of tick bites lead to an infection. The longer the insect remains attached to the skin, the higher the threat of getting the disorder. If affixed less than 36-48 hours, the risk of contracting the illness is greatly reduced.
Once the bacteria enter the blood stream, the pathogens spread throughout the body. Feeling ill stems from the immune system’s response to the microorganisms in various tissues and organs.
Untreated individuals go through several stages with different clinical characteristics in each phase that frequently overlap.
During the initial manifestations, flue-like symptoms of fever, chills, body pain, headaches, neck stiffness and swollen lymph nodes occur. These indices are associated with a distinctive rash (erythema migrans) that develops 3-30 days after an infected tick bite.
This skin eruption — which appears as a bulls eye — is annular, reddish, with or without a central clearing and neither itchy nor painful. It expands slowly and can spread up to 12 inches. Up to 30% of those infected may not form a rash, or its presence was overlooked.
In those with untreated disease and a small subset of victims with treatment failure, serious more broadly distributed findings can appear. These include facial palsy, meningitis, cardiac abnormalities, severe joint pain, arthritis and eye inflammation.
An early diagnosis can be a difficult task.
An article in “Frontiers of Medicine” notes that outside of the disease’s nascent ruddy rash, proof of the disorder relies on non-specific clinical signs that in the initial stages may not be supported by laboratory data.
A delay in confirmation of the condition occurs in upwards of 40% of those ultimately diagnosed. Frequently these individuals will have advanced clinical findings as a consequence of the stalled recognition of the disease.
One explanation for the lag in diagnosis is that many who have been exposed to ticks often ignore non-specific symptoms particularly when there is an absence of a rash. They do not seek timely medical advice.
For those with classic clinical findings, doctors can make the diagnosis with near certainty when an expanding bull’s eye red rash is present. For the less-apparent cases, a combination of a history of tick exposure, physical examination and blood tests to detect antibodies can usually confirm the diagnosis.
Humans have been inflicted with the tick-borne bacteria since ancient times.
The oldest known case was documented in a 5,300-year-old iceman found in a glacier in the Italian alps. Closer to the present, in Colonial America there were many early settlers who suffered from Lyme-like symptoms. An abundance of ticks dwelled in the forests in the northeastern colonies. The disease’s modern moniker emanated from the town of Lyme, Connecticut, where the disorder was documented in the 1970s.
Unlike in the 17th and 18th centuries, preventive measures are known today. These include using insect repellents, wearing light-colored clothing and checking for and safely removing ticks after a walk. When these precautionary measures fail, and one is faced with the diagnosis of LD, effective treatment is available for most cases.
The earlier the therapy begins, the better the prognosis.
Antibiotics are the definitive medications for Lyme disease. When more advanced symptoms are present, the drug is continued for a longer period. For those with post-treatment recurrence, there is less of a consensus as to the treatment regimen for this poorly understood subsegment of the disorder.
While there are ongoing investigations for new therapeutic modalities, a safe and efficacious vaccine has become a priority.
Historically, a Lyme disease vaccine for adults was approved by the FDA in the late 1990s, but it was withdrawn in 2002 by the manufacture because of the limited response in the marketplace. Currently, a vaccine has renewed research attention; there are some promising products in the preclinical phase.
Lyme disease is not only a human disorder — it’s common in man’s best friend.
Veterinarians in endemic areas are familiar with the affliction’s symptoms, diagnosis and treatment for their tic-prone furry patients. The clinical signs are largely non-specific in dogs; the humans’ signature bulls eye lesion does not develop. The treatment process generally mimics the same approach as with humans, except for canines there are commercially available vaccines. Lucky dogs!
While the infection cannot be directly transmitted from a pet to a human, an outside dog or cat may act as a carrier and bring a tick hidden in its fur into a home; once inside, it could bite a human.
While scientists continue working to unravel the mysteries of Lyme disease, remember, when out for a walk in a grassy field, infected ticks are eagerly waiting on the tips of vegetation ready to crawl onto a person or dog and then find a place to bite. Take precautions.
Dr. Jonathan L. Stolz is a retired physician and author of the book “Medicine from Cave Dwellers to Millennials.”