Lyme Disease

Context

Are we seeing more or less Lyme disease than previously and why?

Cases of Lyme have risen steadily over the past 25 years, having doubled between 2004 and 2016 (though this also takes into account cases that were probable but not confirmed). There are several possible reasons for this.

One is that climate change has caused the tick vector, the Ixodes tick, to expand its geographic range south and west from the Northeastern states.

Another is that the animals that ticks typically feed on, such as the white-footed mouse in the Northeast, have also increased their geographic range.

Lastly, there’s been an increase in travel to regions where Lyme is prevalent.

What are the areas of most concern in the United States?

The majority of cases (96%) are found in 14 states, mostly in the Northeast and upper Midwest, though there are cases reported in most states.

What time of year do we worry most about with Lyme transmission?

Lyme transmission increases during the summer months due to the life cycle of the ticks that carry it. Ticks go through three stages during their life cycle including larva, nymph, and adult. The nymphs are the most likely to transmit Lyme (though adults also transmit), and nymphs are most active from late spring to early summer.

What does a tick bite look like? Will there always be a tick attached?

While the classic early finding in Lyme is the “bull’s eye” rash (referring to the area of central clearing and red rings, making it look like a target), it’s very important to recognise that not all patients develop (or recall developing) this rash, and it doesn’t always have this bull’s eye appearance when they do. Additionally, ticks can be so small–sometimes the size of a poppyseed–that people sometimes don’t notice the tick at all while it’s attached.

Is Lyme disease contagious among humans, pets, etc., or can it only be contracted from ticks?

There is no evidence that Lyme disease is transmitted from person-to-person through sharing of utensils, sexual contact, or breast feeding. Women who have been treated for Lyme disease prior to becoming pregnant have no cause for concern in terms of transmission to the fetus. Women who contract the disease while pregnant should be treated appropriately, though it’s important that the selected medication is safe during pregnancy.

Having pets may increase the risk of exposure to ticks (but you can’t get Lyme directly from your pet), and pets are also at risk for contracting the disease from tick bites.

There is evidence that Lyme disease may live in the blood or tissues, and while there are no recorded cases of transmission through a blood transfusion, people who are actively being treated for the disease should avoid donating blood.

Symptoms and Causes

How does somebody get Lyme disease?

Lyme is transmitted by a bite from an infected tick. The tick attaches itself to the skin and feeds on the host blood for approximately two days. Transmission of the disease occurs during this feeding.

During the course of a tick lifespan, it typically feeds at least three times. It can feed on a variety of different hosts, including mammals, birds, reptiles, or amphibians. Some varieties of tick will feed on several different hosts, increasing the risk of picking up the bacteria from one host and transmitting it to another. Illnesses transmitted in this way are known as vector-borne diseases. Malaria and Zika virus are two other examples.

What are the usual symptoms of Lyme disease?

The progression of Lyme disease stages are broken up into three separate clinical phases: early localized, early disseminated, and late disease. It’s important to note that this is not an exhaustive list of potential symptoms, and that the presentation of symptoms can often be vague and difficult to pinpoint.

Early localized Lyme refers to the typical rash that people tend to associate with the disease. During this phase, patients may also experience other symptoms such as fever, chills, fatigue, muscle aches, joint pain, and headaches.

The early disseminated phase typically begins weeks-to-several-months following the bite, and includes neurologic and cardiac manifestations. Sometimes, this is the first indication of the disease in cases where the early localized phase goes unnoticed. Patients may present with meningitis, facial droop, or changes to sensation. During this phase, cardiac symptoms may also be present, such as palpitations. Other possible symptoms might include multiple rash sites, eye symptoms, swollen lymph nodes, muscle pain, and liver and kidney disease.

Late or chronic disease begins months-to-years following the transmission and typically involves persistent or recurrent arthritis in joints (most often the knee), sometimes leading to severe joint pain and swelling, and neurologic symptoms (most often cognitive disturbances and issues with nerves throughout the body causing pain and changes to sensation).

Some patients will go on to develop a post-Lyme syndrome, which typically consists of vague symptoms for months-to-years following treatment, though most people improve after 6-12 months. These symptoms may include, but are not limited to, headaches, fatigue, and joint pain.

Can Lyme disease be chronic?

Chronic Lyme disease is a term that’s controversial within the medical community. While some patients develop symptoms such as ongoing fatigue and muscle pain, the research is still not clear in terms of the relationship of these symptoms to the infection with B. burgdorferi.

Symptoms can often be similar to symptoms of fibromyalgia, though fibromyalgia does not include the inflammatory features of Lyme, nor does it include the organ involvement that can occur in patients with Lyme.

Without question, there are people who continue to have chronic health problems well after appropriate treatment. What is not clear is why some people are affected in this way, and what the best way to treat them may be.

Diagnosis

When would a blood test be used to test for Lyme disease, and how accurate is testing?

There is considerable controversy surrounding Lyme disease, and this includes testing, among other issues. Serological testing (or blood testing) is most commonly used in the diagnosis, though these tests don’t pick up the actual Lyme itself, but rather the immune response that someone is having to the Lyme (it does this by detecting antibodies).

An important factor to take into account is the amount of time between when the test was performed and when the disease was contracted. If testing is done too early, a measurable immune response may not yet be detectable. If it’s done too late, immune response may have waned.

What are the most common Lyme disease tests?

Two tests are typically used for Lyme: the ELISA and Western Blot. Unfortunately, both have issues with reliability, with the ELISA yielding frequent false negatives and the Western Blotbeing inconsistent in its ability to accurately diagnose Lyme.

Because of this, two-tiered testing is generally recommended. This involves first performing an ELISA, followed by a Western Blot, but only if the ELISA comes back positive. The current CDC guidelines recommend this two-tiered testing approach, while the International Lyme and Associated Diseases Society (ILADS) feels that even this testing is inadequate.

Testing in people with non-specific symptoms is not recommended because there are frequently false positive results in this population. It is also not necessary to test people with clear, classic symptoms, such as erythema migrans, as the diagnosis can be made clinically (based on symptoms and examination), as false negative results may result in a delay in treatment.

The important thing is that each case is evaluated individually. The provider ordering the testing should be looking at the whole picture, including history, symptoms, and physical exam findings. They must also consider the strengths and limitations of tests ordered when interpreting the results. Galileo can assist with evaluating specific cases and determining if testing is appropriate.

Treatment

Is Lyme disease curable?

Lyme disease is curable in the early stages, provided that appropriate treatment is given based on the symptom presentation of the patient. For the majority of people, symptoms resolve with treatment, though some patients do continue to experience symptoms even after treatment.  

Treatment does become more challenging as the disease progresses, often requiring longer courses of medication. It is possible to become infected with Lyme more than once.

How is acute Lyme disease treated? Which antibiotic is used?

Early Lyme disease, without complications, is treated with a course of antibiotics, most commonly doxycyline, amoxicillin, or cefuroxime. Treatment typically ranges from 10-21 days, depending on the medication used and the presentation of the patient. (For example, patients demonstrating multiple areas of the EM rash are usually treated with a longer course.)

These courses differ from the length of prophylaxis (taking the medication after a bite to prevent development of the disease) in that the course for prophylaxis is just one dose.

When is prophylaxis used after a tick bite and how do medical providers decide if that is necessary?

There are different sets of guidelines addressing prophylaxis for Lyme after a tick bite. While current guidelines recommend Lyme prophylaxis in situations where the tick has been attached for more than 36 hours (among other criteria), there is some debate about what the minimal time for transmission actually is. This is compounded by the fact that some data suggests that most patients don’t recall being bitten in the first place, let alone know how long the tick was attached for.

Having said all that, the Infectious Diseases Society of America (ISDA) guidelines followed by most providers state that in order to be a candidate for prophylaxis following a tick bite, the following five criteria must be met:

• The tick attached must be an adult or nymphal I. scapularis tick.
• The tick was attached for at least 36 hours (this can be estimated by amount of engorgement).
• The patient must be able to begin prophylaxis within 72 hours after the tick is removed.
• Local infection rates with B. burgorferi must be 20% or greater.
• The patient must be able to take doxycycline (not allergic or contraindicated).

What’s the treatment window? How soon should treatment be started?

According to current guidelines, prophylaxis must be initiated within 72 hours of removal of the tick and involves a single dose of doxycycline.

If, for some reason, this medication is contraindicated, the current recommendation is that it not be replaced with another medication, and that prophylaxis is simply not given. There is no time window for treating active disease, though treatment is dependent on specific symptoms.  

Can Lyme disease go away on its own without treatment? What happens if you go untreated?

Untreated Lyme can progress from early Lyme into early disseminated Lyme and then into late Lyme. More bodily systems become involved as the spirochetes make their way through the tissues and the blood. Because the spirochetes stick to the cells of the host, the immune system does not easily detect them, making it difficult to fight the infection.

Prevention

What aspects of prevention are most important to remember?

The most important part of prevention against Lyme, or indeed any type of tick-borne illness, is reducing the risk of exposure to ticks and removing ticks that do become attached.

Being aware of surroundings and dressing appropriately when in outdoor areas where ticks are likely to be encountered are initial steps in avoiding contact. Ticks love areas such as woods, long grass, or bush, so it’s important to be aware when hiking, camping, or even just walking the dog. Try to avoid contact with long grass or brush, and stick to the center of walking trails.

Wearing clothes that cover your legs and arms–areas likely to come into contact with long grass or brush–is helpful in terms of avoiding ticks becoming attached to the skin.

Pre-treating clothing, socks, and shoes with 0.5% permetherin or buying clothing that has been pretreated is an option. Using insect repellents recommended by the EPA is another effective prevention strategy.

What’s the best way to remove a tick?

For effective tick removal, use tweezers to grasp it firmly and close to the skin, and pull straight up. Do not twist, as this might actually break the tick, causing parts to remain embedded in the skin. If parts of the mouth do remain embedded, these should be left alone to heal on its own. The area and your hands should be cleaned carefully with either soap and water or rubbing alcohol.

Useful Links

CDC resources on Lyme disease (Centers for Disease Control and Prevention))

ISDA resources on Lyme disease (Infectious Disease Society of America)

ILADS resources on Lyme disease (International Lyme and Associated Diseases Society)

Article discussing controversy surrounding Lyme disease (British Medical Journal)