By Barry C. Fox, M.D., University of Wisconsin
Lyme disease is the most common tick-borne infectious disease in the United States. It is estimated that there are over 300,000 cases of Lyme disease in the United States each year. One patient who had the disease said it felt like having a thick band of steel compressing her neck.
The Bite of the Blacklegged Deer Tick
Lyme disease is caused by a spirochete called Borrelia Burgdorferi, through the bite of the blacklegged deer tick. The tick has to be attached for more than 24 hours to begin transmitting the spirochete, so it’s worth someone checking themselves after being in a wooded area so they can remove ticks as quickly as possible. If it has been less than 24 hours from tick exposure, Borrelia transmission is unlikely to occur.
The acute phase of Lyme disease includes symptoms that usually begin 3–14 days after infection, which include headache, fatigue, fever, and a telltale bull’s-eye rash known as Erythema Chronicum Migrans. This rash is found in nearly 80 percent of Lyme cases and can be at one or more locations on the skin.
The rash should not be confused with the few centimeters of redness often produced around the site of the actual tick bite. The rash of Lyme is usually so characteristic that it also establishes a clinical diagnosis without the use of any blood tests.
Up to 20 percent of people with the acute illness may develop a focal neurological deficit, especially a Bell’s palsy of the face, which fortunately is reversible. Non-fatal mild forms of meningitis can also occur. Much more rarely, an abnormally slow heart rate can lead to dizziness and fainting before a diagnosis is made.
This is a transcript from the video series An Introduction to Infectious Diseases. Watch it now, on Wondrium.
Are Tests for Lyme Disease Reliable?
Some individuals exposed to Borrelia never have any symptoms. Up to five percent of residents of certain Lyme-prevalent states may have a true positive blood test but no recollection of illness. Also, up to five percent of patients may also have a false-positive test, due to the non-specific nature of the IgM immune response mounted to any infection, not specifically Lyme disease.
A second confirmatory test, known as a western blot test, is used to confirm the first true antibody test as being a true positive result. But is it possible for someone who was infected with Borrelia to have a negative Lyme serological test? Many people who receive antibiotics early in their illness may not develop Lyme antibodies until several weeks later, but they almost uniformly will ultimately have a positive test, and this is a common misperception of the general public.
It might also be heard that there may be deficiencies in the blood antibody tests for Lyme and that a negative test does not exclude having contracted clinical Lyme disease. This can become an issue of contention in individuals who believe they have ongoing symptoms of Lyme disease but lack any serological evidence of infection.
Learn more about zoonosis—germs that leap from animals to humans.
Diagnosis of Lyme Disease Is Complicated
The infectious disease community holds relatively firm to the position that only patients with documented positive Lyme tests have the possibility of developing late sequelae, or after-effects of Lyme, while other advocacy groups disagree with this position.
Lyme positive test results also usually persist for life, but the magnitude of the test result does not correlate with any later symptoms. This makes Lyme disease more complicated to diagnose if individuals become reinfected.
Note that if a pregnant mother contracts Lyme during pregnancy, the fetus can be infected. If the mother isn’t treated, the placenta can become infected resulting in a possible stillbirth.
If the mother gets treated with antibiotics, however, there are usually no serious side effects to the fetus.
Good advice to pregnant women would probably be to avoid, if possible, any outdoor areas where ticks are prevalent, especially in the high-incident summer months.
Learn more about the history of antibiotic development.
Treatment for Lyme Disease
There are several oral antibiotic treatments for Lyme, which commonly include doxycycline and amoxicillin. Patients with more severe neurological illnesses or heart forms of the illness may require intravenous therapy.
In high-risk Lyme areas of the country, single-dose doxycycline prophylaxis has commonly been implemented for patients with tick bites that have been attached longer than 24 hours, and this 24-hour measure is as effective as 10 days of medication for prevention.
Left untreated, rare patients can develop late manifestations of Lyme, caused mostly by a non-specific, generalized immune over-response. This may include debilitating arthritis or nerve damage (in rare cases). Since these are immune-mediated, chronic long-term oral or intravenous antibiotics are not effective and hence not recommended.
Why There Isn’t a Vaccine
Why is there no Lyme vaccine if it’s so prevalent? There is a canine vaccine for Lyme and many dogs are vaccinated every year. But why is there no human vaccine? Two pharmaceutical companies developed a human vaccine for Lyme disease (proven to be 50–70 percent effective after two doses). However, over time, the number of vaccinations requested fell from 1.5 million to only 10,000, and the vaccines were discontinued due to lack of public interest.
Also, there were some legal disputes where patients actually claimed they developed autoimmune symptoms from the vaccine itself. This created a disincentive for pharmaceutical development, and production was halted. There are some companies in the process of testing new Lyme vaccines, so perhaps it will come back into favor.
Remember, once someone has tested positive for Lyme, they will likely always test positive for Lyme. While it is recognized that Lyme disease does not ‘reactivate’ months or years later, re-infection is possible with a new tick-carrying Borrelia. These cases may be more difficult to diagnose, especially if there is no ECM rash.
Common Questions about the Way Lyme Disease Works and How to Deal With It
The symptoms of Lyme disease include headache, fatigue, fever, and a bull’s-eye rash. This rash is seen in nearly 80% of cases. The symptoms begin between 3–14 days after the initial infection.
Yes, if a pregnant woman has Lyme disease, then the fetus can be infected, too, although if the mother gets treated with antibiotics, there are usually no serious side effects to the fetus.
After the vaccines for Lyme disease were made, the demand slowly declined but what also helped with the discontinuation were the lawsuits filed against the pharmaceutical companies by patients claiming they had developed autoimmune symptoms because of it.
