Tick-Borne Diseases

pathology perspectives

By Ruth Werner

Originally published in Massage & Bodywork magazine, November/December 2008.

When we think of contagious diseases, we often focus on infections that are communicable directly from one host to another: common cold and flu viruses are spread through respiratory secretions; hepatitis A is spread through oral-fecal contamination; and ringworm (a fungal infection) is spread through direct contact with an infected person or animal, or with a contaminated surface. Some contagious diseases are not directly communicable, however. They must be transmitted by way of an animal vector.

Common disease carriers include mosquitoes (West Nile virus, malaria), lice (typhus), or fleas (bubonic plague). Ticks might not come to the top of our mental list of these pests, but it turns out they are the most common disease vector found in the United States.

It is important for massage therapists to recognize the signs and symptoms of tick-borne diseases and to understand how to address clients with them.

Image 1 is probably a familiar picture, especially to people who live on the East Coast or in the Midwest. Ticks are common parasites, taking blood meals from all vertebrates except fish. Ticks are arthropods, in the same class (Arachnida) with spiders, scorpions, and mites. In addition to being parasites, ticks can also be carriers of a variety of pathogens, including bacteria, protozoa, viruses, and nematodes. Further, any combination of these disease-causing microorganisms can be transmitted with a single tick bite.

Deer ticks (also called black-legged ticks), American dog ticks (image 2), and lone star ticks (image 3) are responsible for most tick-borne infections in the United States. In this article we will discuss some of these infections, with special emphasis on Lyme disease. But first we need to take a brief look at the life cycle of the deer tick: this is similar to the cycle of most hard tick species. (Soft ticks are a little different and are not common in the United States, so won’t be discussed here.)

Deer Tick Life Cycle

Most ticks live about two years. Typically they hatch in spring, but a second hatching occurs in late summer. The tiny larvae stay close to the hatch site (often in leaf mold), hoping to latch onto a passing host, usually a bird or small mammal like a chipmunk or mouse. Any larvae that don’t find a host die. If this initial host is a carrier for any pathogens, the tick becomes an intermediate reservoir.

After its first blood meal, the larva drops off and molts into a small nymph that overwinters in woody, leafy areas. Nymphs become active again in spring, climbing up grass or bushes to seek out a new host. Humans are most likely to encounter them at this stage; the majority of tick bites are from nymphs and are reported between May and August.

When the nymph has finished its meal (which can take five days or more), it drops off the host and molts for several weeks to become an adult. At this stage the tick seeks a larger host, like a deer. Ticks may live and mate on this host for months. In the fall, the females fall off into leafy underbrush to lay thousands of eggs that will begin the cycle again the following spring.

Lyme Disease

In 1974, the town of Old Lyme, Connecticut, saw a sudden spike in the incidence of what was assumed to be juvenile rheumatoid arthritis (JRA). Because JRA is not considered to be communicable, another cause for this sudden outbreak was postulated. A research team led by Willy Burgdorfer, PhD, investigated, and in 1982 they definitively identified a spirochetal bacterium that lives in the midgut of deer ticks as the causative agent of these mysterious cases of childhood arthritis.

Lyme disease is an infection with Borrelia burgdorferi (image 4) that is transmitted through the bite of deer ticks. This is the most common tick-borne disease in the United States, infecting about 20,000 people each year. The vast majority of infections, about 90 percent, occur in 10 key states, including Connecticut, Delaware, Maryland, Massachusetts, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island, and Wisconsin. Lyme disease does occur outside these areas, however. It has been reported in 46 states and the District of Columbia, although in much lower numbers.

When a person is bitten by a deer tick, the parasite typically feeds for several days before falling off (if it isn’t discovered before that time). Not every tick bite results in infection; it is estimated that Lyme disease occurs in only 3–5 percent of all recognized tick bites. It can take several hours, or even a couple of days for the bacteria in the midgut of the tick to enter the bloodstream of the host. If this transfer is made, then symptoms develop, and complications may occur.

Signs And Symptoms

Early symptoms of Lyme disease generally appear 7–30 days after a tick bite. They include a circular red rash that clears in the center (a bull’s eye rash, image 5) that is hot and itchy, but not raised from the skin. This is often called erythema migrans. Fever, fatigue, night sweats, headache, swollen lymph nodes, and neck ache may mimic flu or mononucleosis.

Later symptoms can include irregular heartbeat and dizziness, confusion, facial paralysis, numbness, tingling, and poor coordination. Finally, the infection can cause extreme and painful inflammation of one or more large joints: knees, elbows, and shoulders are most typically involved.

Lyme disease is common, and its symptoms are easily mistaken for other conditions. People who live in areas with a high incidence and who develop symptoms of Bell’s palsy or chronic fatigue syndrome are often routinely tested for Lyme disease.

Diagnosis And Treatment

The diagnostic procedure for Lyme disease begins a description of symptoms, followed by blood tests. These tests are sensitive and can give accurate information about exposure to B. burgdorferi, but they cannot determine whether symptoms are related to a current or a past infection. (The markers for B. burgdorferi are with us forever: these are the antibodies that show we’ve been exposed.) Because the symptoms of Lyme disease can so easily mimic other common problems (arthritis, chronic fatigue syndrome, fibromyalgia), this makes getting an accurate picture of the source of a person’s symptoms challenging.

Lyme disease does respond to antibiotics, but many patients are often counseled to use a longer course of medication than is recommended for most bacterial infections.

Prevention

A vaccine for Lyme disease was developed at one time, but it is no longer available. Instead, people are advised to practice good tick prevention measures: wear light-colored clothing that covers most skin—especially from the waist down—when walking through grassy, wooded areas. Use a tick repellant containing DEET and/or treat clothing with tick-repellant chemicals. Keep a barrier of gravel or bark around the edge of playgrounds and backyards where children spend time near wooded areas. And finally, do a thorough tick check when coming in from areas where ticks are common.

If a tick is found, experts recommend removing it as quickly as possible. Because deer ticks are slow feeders, removing an unwanted passenger within a few hours significantly reduces the risk of infection. The correct way to remove a tick is to use fine tweezers to grasp the animal as close to the skin as possible and to pull firmly outward. Then wash the area carefully, and treat it with antiseptic. Touching the tick with a hot match or Vaseline or other substances may actually make it regurgitate into the host—this raises rather than lowers the risk for transmitting bacteria.

Massage

Cautions regarding massage for a client who has Lyme disease include several issues. Because the joint inflammation can be acute and painful, this obviously limits intrusive bodywork in painful areas. Any neurological defect, especially numbness or tingling, requires adjustments because the client may not be able to give accurate feedback about pressure or comfort. And finally, cardiovascular complications may make some types of massage impractical. Communicating with the client’s healthcare team can inform these choices for everyone’s best benefit.

Other Tick-Borne Diseases

B. Burgdorferi is not the only pathogen that ticks can share with other hosts. In fact, a single tick bite can transfer several microbial pathogens that can cause a wide range of diseases. Below is a short list of other tick-borne infections that are found in the United States. Because they are not as common as Lyme disease, they may not be well- researched, and less is understood about how they affect human function.

Ehrlichiosis

Ehrlichiosis is infection with any of a group of bacteria in the genus Ehrlichia. Lone star ticks and black legged ticks are vectors. It was first identified in 1935 and can affect dogs, cattle, sheep, goats, and horses, as well as humans.

Early signs resemble those of Lyme disease, but when it occurs in young children a spotty rash may be present as well. Ehrlichiosis can cause extensive damage to several body systems and must be treated aggressively, especially in immunocompromised people. It is responsive to antibiotics, but these must be administered as quickly as possible to minimize the risk of organ damage.

Babesiosis

Babesiosis is an infection with one of a group of protozoa called Babesia. This pathogen has part of its life cycle in the blood of common white-footed mice. In a secondary mammalian host, it invades and disables red blood cells in a mechanism that is similar to the protozoa that cause malaria. Indeed, symptoms of babesiosis mimic malaria to the extent that it can be difficult to distinguish between the two.

Babesiosis is most dangerous for people who are immunocompromised. In the United States it occurs in the same regions where Lyme disease is prevalent. It is treatable, and most patients recover fully.

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is an infection with a bacterium called Rickettsia rickettsii. This was named for Howard T. Ricketts, an early pathologist who ironically died of typhus, another rickettsial disease.

RMSF is spread through the bite of the American dog tick, the Rocky Mountain wood tick, and other species of hard ticks. Its name is a bit misleading: it was first identified in the Snake River Valley of Idaho, but it ranges from Canada to South America. It is especially common in Florida, Georgia, Oklahoma, North Carolina, and South Carolina.

RMSF is rare (about 250–1,200 cases are reported each year), but quite serious. R. rickettsii live and multiply in the endothelial linings of blood vessels, resulting in localized internal bleeding. On the skin, this shows as a spotty rash: a nickname for this infection is “black measles.” Internally, it can cause extensive organ damage. Fortunately, it is sensitive to antibiotics, and can be treated successfully if caught early.

Southern Tick-Associated Rash Illness

A final tick-borne illness creates a similar rash to that seen with Lyme disease, but the causative agent has not been identified. This is Southern tick-associated rash illness (STARI), and it is spread by lone star ticks. Unlike Lyme disease, it does not cause arthritic, cardiovascular, or neurological problems. It is treatable with antibiotics.

Further Study Needed

It’s hard to make a case that ticks are anything but disgusting, nasty, disease-carrying parasites. But the truth is, they were here first. We are now dealing with tick-borne infections in greater numbers than ever before, because we have expanded into territory where we become their accidental hosts. Further, tick saliva is rich with a number of fascinating substances: analgesics, anti-inflammatories, and anticoagulants that allow them to suck our blood without our even noticing. As we study them we are adding to our own arsenal of potentially beneficial chemicals that may someday promote, rather than threaten, our health.

Ruth Werner is a writer and educator who teaches several courses at the Myotherapy College of Utah and is approved by the NCTMB as a provider of continuing education. She wrote A Massage Therapist’s Guide to Pathology (Lippincott Williams & Wilkins, 2009), now in its fourth edition, which is used in massage schools worldwide. Werner is available at www.ruthwerner.com or wernerworkshops@ruthwerner.com.

NOTE

1. Dave Simser, “Got Blood? Deer Ticks (Ixodes scapularis) and Lyme Disease (Borrelia burgdorferi),” Conservation Perspectives: The On-line Journal of the New England Chapter of the Society for Conservation Biology Inc. 2005. www.nescb.org/epublications/spring2001/gotblood.html (accessed summer 2008).