Tick Borne Diseases

This course is intended to provide information necessary for a nurse to teach strategies for reducing the risk for tick bites and provide support to patients with tick-borne illnesses.

Upon completion of this course, the learner will be able to:

1. Describe the prevalence, life cycle, and feeding activity of hard and soft ticks. 
2. Describe the signs, symptoms, diagnosis, and treatment of common U.S. tick-borne illnesses.   
3. Describe the strategies to reduce tick encounters and prevent prolonged exposure to tick attachments.
4. Differentiate between proper and improper methods of tick removal.
5. Identify resources for additional information.

According to the CDC (2014), the incidence of tick-borne illnesses in the United States and around the world has increased significantly over the last 30 years. The higher incidence correlates with changes in human behavior that increase the risk of exposure along with a lack of understanding about strategies to reduce the risk (University of Florida, 2014). Additionally, many travel-related diseases are associated with tick bites (CDC, 2014).

Ticks are vector anthropods that temporarily attach to humans and animals during blood feedings. There are two well established families of ticks, the Ixodidae (hard shell), and Argasidae (soft shell). Most ticks go through four life stages that include the egg, six-legged larva, eight-legged nymph, and adult. Between each life cycle, the tick must have at least one feeding (Vredevoe, 2014). During periods of detachment between meals, female ticks lay multiple batches of eggs.

Soft ticks live in rodent burrows and humans come in contact with them when they sleep in rodent-infested cabins, explore caves, or work in crawl spaces beneath buildings (Simon, 2013). Hard ticks are most commonly found perched in weed and shrub-filled areas, and attach to unsuspecting animals and humans that brush past. Sometimes ticks will attach quickly to the area of initial contact, but sometimes they will move around in search of areas where the skin is thin such as the ear, ankle, or back of the knee before biting (Simon, 2013).

The life span of a hard tick is approximately three years, while a soft tick can live ten years or more (CDC, 2014). Ticks die if they do not find a host for their next feeding, though soft ticks are believed to be quite resilient to long periods of starvation (Vredevoe, 2014). Ticks are present in all 50 states and are most active in southern and coastal states especially during the warmer months between April and October. Incidence of tick-borne disease is highest among children 5-9 years of age and among adults 55-59 years of age (Sheen et al, 2011).

It is through the process of feeding that ticks transmit pathogens including bacteria, rickettsiae, protozoa, and viruses (Vredevoe, 2014). In the United States, the most prevalent tick-related illnesses of concern are Anaplasmosis, Babesiosis, Ehrlichiosis, Lyme disease, Rocky Mountain Spotted Fever (RMSF), southern tick-associated rash illness (STARI), tick-borne relapsing fever (TBRF), and Tularemia (CDC, 2014).

Not all species of ticks bite and transmit disease to humans. The CDC identifies eight ticks primarily responsible for tick-borne disease in the continental U.S. and the geographic distribution of each (see table 1)

Table 1
(Photos retrieved from the Public Health Image Library)

Species	Transmits	Feeds on	U.S. distribution
American dog tick PHIL ID # 170	RMSF and Tularemia	Small rodents, dogs, and medium-sized mammals	East of the Rocky Mountains and along the west coast of California
Black-legged tick (deer tick) PHIL ID # 1669	Anaplasmosis, Babesiosis, and Lyme disease	Larvae and nymphs feed on small mammals and birds; adults feed on deer and larger mammals	Northeastern and upper mid-western states
Brown dog tick PHIL ID # 7646	RMSF	Primarily dogs	Prevalent throughout U.S, but heavily concentrated in the southwestern states and along the border into Mexico
Gulf Coast tick PHIL ID # 10876	A form of spotted fever	Larvae and nymphs feed on birds and small rodents; adults feed on deer	Atlantic and Gulf Coast regions
Lone star tick PHIL ID # 4407	Ehrlichiosis, Tularemia, and STARI.	Birds and white-tail deer	Southeastern and eastern states
Rocky Mountain wood tick PHIL ID #: 10868	RMSF, Tularemia	Larvae and nymphs feed on small rodents; adults feed on larger mammals	Rocky Mountain states
Western blacklegged tick PHIL ID # 8686	Anaplasmosis and Lyme disease	Larvae and nymphs feed on small rodents and birds; adults feed on deer and larger mammals	Northern Pacific coast states
Soft tick PHIL # 5970	TBRF	Feed on rodents, usually in brief attachments of less than 30 minutes	Rodent infested cabins, caves, and crawl spaces across the continental U.S.

Because symptoms for tick-borne diseases can range from a mild rash to life threatening, they sometimes are not recognized as tick-related, which delays treatment (Shas, 2013). This module provides an overview of the most common tick-borne diseases in the U.S., including a discussion of the pathogen, signs and symptoms, diagnosis, and treatment.

Caused by the bacterium Anaplasma phagocytophilium, anaplasmosis infects the white blood cells and can be serious enough to require hospitalization or cause fatality in persons with compromised immunity (CDC, 2014). The black-legged tick and western black-legged tick are primarily responsible for transmission, but, rarely, transmission has been linked to blood transfusions. 

The onset of symptoms occur three weeks after the tick bite and are initially non-specific to include some combination of fever, headache, myalgia, chills, malaise, nausea, abdominal pain, cough, and confusion (CDC, 2014). Rashes are infrequently present. Left untreated, symptoms can progress to hemorrhage, neurological deficits, and respiratory distress. 

An increase in antibody titer detected via indirect immunofluorescence assay (IFA) facilitates diagnosis (CDC, 2014). Within the first week of illness, whole blood can also be tested using a polymerase chain reaction (PCR) assay , but false negative results are not uncommon (CDC, 2014). Specific cultures are only available at specialized laboratories. 

People who are treated early have the best response, so treatment should be initiated based on clinical suspicion and not wait for a confirmative diagnosis. The standard treatment is Doxycycline until three days after symptoms subside. Prophylaxis, in the absence of symptoms, is not recommended (CDC, 2014).

Caused by the microscopic parasite, Babesia, babesiosis infects the red blood cells and can also be serious enough to require hospitalization or cause fatality, particularly in persons with impaired immunity (CDC 2014). The black-legged tick is primarily responsible for transmission. Like anaplasmosis, babesiosis has also been transmitted by blood transfusions, though rarely (American Red Cross, 2014). 

Babesiosi presents with flu-like symptoms such as fever, chills, myalgia, weakness, and fatigue (Simon, 2014). In severe cases, the infection can advance to cause serious hemodynamic, renal, and hepatic compromise (CDC, 2014). 

Lab results associated with babesiosis include thrombocytopenia, hemoglobinuria, proteinuria, and elevated blood urea nitrogen, creatinine, and liver enzymes (CDC, 2014). History may include a tick-bite or recent travel to the northeastern and upper mid-western United States. Diagnosis is based on positive blood smears, but it may be difficult to differentiate the parasite from malarial parasites (CDC, 2014). 

In adults, symptomatic babesiosis is treated with a 7-10 day treatment combination, using either (a) atavaquone plus azithromycin or (b) clindamycin plus quinine (CDC, 2014). Though considered more aggressive, the latter option is associated with side effects such as tinnitus, vertigo, and gastrointestinal distress and is, therefore, reserved for the severely ill (Simon, 2014). The CDC does not recommend treating asymptomatic babesiosis infections (CDC, 2014).

Ehrlichiosis is a group of bacterial infections caused by Ehrichia chaffeensis, Ehrlichia ewingii, or Ehrlichia muris-like bacteria (CDC, 2014). The primary vector is the lone star tick, found abundantly in the southeastern and eastern United States (Simon, 2013). 

The onset of symptoms occur two weeks after the tick bite and resemble flu-like symptoms of fever, chills, headache, myalgia, arthralgia, malaise, nausea, vomiting, confusion (CDC, 2014). Approximately half of those infected will have a non-pruritic rash which can range in appearance from sunburn-like to petechial, making ehrlichiosis difficult to differentiate from RMSF. (CDC, 2014). Serious complications of untreated infection can include respiratory failure, kidney failure, heart failure, and neurological deficits (CDC, 2014).

As with other tick-borne diseases, the diagnosis is initially based on the patient's history and symptoms. Routine laboratory studies may demonstrate thrombocytopenia, leukopenia, and elevated liver enzymes (CDC, 2014). Confirmative diagnosis is made using immunofluorescence assay (IFA), performed on paired serum samples collected two to four weeks apart, to detect up to four-fold increases in immunoglobulin G and immunoglobulin M (CDC, 2014). 

The standard treatment is Doxycycline until three days after symptoms subside and the patient demonstrates clinical improvement.

Caused by the spirochete Borrelia burgdoferi, Lyme disease is the most common vector-borne illness in the United States and is transmitted by the bite of the black-legged tick (CDC, 2014).

In the 1990s, two pharmaceutical companies developed Lyme disease vaccines, but both were later voluntarily withdrawn from the market and it is believed that the vaccine recipients no longer have any protective immunity (Shen et al, 2011). 

Early symptoms of Lyme disease include fever, headache, fatigue, and a characteristic skin rash called erythema migrans that resembles a bulls-eye. 

Case study: A six year old presents to a walk-in clinic with flulike symptoms and a red, expanding target lesion on his abdomen where his mother removed a tick twelve days ago. 

The characteristic erythema migrans rash of Lyme disease develops at the site of the tick attachment and is typically an expanding target lesion, usually accompanied by viral symptoms (Pearson, 2014). The rash is the best clinical marker and treatment should be started without waiting for the diagnosis to be confirmed (Wright et al, 2012).

The diagnosis for Lyme disease is initially based on symptoms, physical findings, and the possibility of exposure to infected ticks. Confirmative diagnosis is based on antibodies tested with a two-step process (IFA and Western blot), using the same serum sample for both tests (CDC, 2014). If the IFA is negative, Lyme disease is ruled out. If positive or unequivocal, the diagnosis is then confirmed or ruled out with the Western blot (CDC, 2014). 

The standard treatment for Lyme disease is two to four weeks of doxycycline, amoxicillin, or cefuroxime axetil (Wright et al, 2012). Approximately 10 to 20% of patients go on to develop lingering symptoms of fatigue, pain, or joint and muscle aches lasting more than six months (CDC, 2014). Although often called "chronic Lyme disease," this condition is properly known as "Post-treatment Lyme Disease Syndrome" (PTLDS) and is believed to be auto-immune related. Fortunately, most patients with PTLDS respond to a more prolonged regime of antibiotic therapy (CDC, 2014).

Caused by the bacteria Rickettsia, Rocky Mountain spotted fever (RMSF) infects the endothelial cells that line blood vessels (CDC, 2014). The title is misleading, as RMSF incidence is not limited to the Rocky Mountain regions. Instead, RMSF has been confirmed in all continental states and is most prevalent in Oklahoma, Tennessee, Arkansas, Maryland, Virginia, and South Carolina (Simon, 2014). Left untreated, this disease can progress to life-threatening vasculitis, hemorrhage, and thrombosis (CDC, 2014). 

The clinical presentation varies, but includes some combination of fever, headache, nausea, vomiting, abdominal pain, myalgia, anorexia, and a rash which varies in description (CDC, 2014). 

Case study:A 54 year old female is seen in the emergency department with a sudden onset of fever, headache, and abdominal pain for two days. Examination reveals a macular rash that is small, flat, pink, and non-itchy on the wrist, forearms, ankles, and feet. She denies awareness of a recent tick bite.

The classic clinical triad of RMSF is headache, fever, and a rash (Simon, 2013). The reddish-purple petechial rash of RMSF is usually not apparent until a week after the onset of symptoms in 35-60% of infected persons and is an ominous sign that the infection is progressing (CDC, 2014). It is not uncommon for people with tick-borne illnesses to lack awareness of the bite. (Vredevoe, 2014). 

Diagnosing RMSF can be challenging because the symptom presentation is so variable and non-specific. If a rash is present, skin biopsy taken for immunohistochemical (IHC) staining will be positive in 70% of cases (CDC, 2014). Lab studies may indicate hyponatremia, thrombocytopenia, and elevated liver enzymes (CDC, 2014). Definitive diagnosis based on serology can not be made until 7-10 days after symptoms present (Simon, 2013). Like ehrlichiosis, IFA on paired serum samples demonstrate a four-fold rise in antibody titers (CDC, 2014). 

As with anaplasmosis and ehrlichiosis, the standard treatment is an outpatient course of Doxycycline until three days after symptoms subside (Simon, 2013). More serious cases require hospitalization for intravenous antibiotics. Treatment is most successful if initiated early and should begin based on symptoms and clinical suspicion until the diagnosis is confirmed.

STARI presents with a bulls-eye rash that is similar, though smaller, than the one associated with Lyme disease (Simon, 2013). Unlike Lyme disease, the STARI rash is associated with a lone star tick bite (CDC, 2014). Other viral-like symptoms such as fatigue, headache, fever, and muscle pain usually accompany the rash (CDC, 2014).

An understanding of this disease is evolving, but currently the exact causative agent is still unknown (Simon, 2013). As a result, there is no diagnostic work-up to confirm the diagnosis (CDC, 2014). Instead the diagnosis is made based solely on clinical presentation. Fortunately, treatment consists of the same course of Doxycycline that is often prescribed for other tick-borne diseases.

STARI is generally a milder illness than Lyme disease. According to the CDC (2014), the primary differences in these tick-borne diseases include: (1) they are associated with different ticks, (2) patients with STARI are more likely to recall the tick bite, (3) onset of the rash is earlier in relation to the bite, (4) the rash is smaller and the accompanying symptoms are milder, and (5) patients with STARI recover more rapidly and without a post treatment syndrome.

Caused by the bacteria Borrelia, TBRF impacts the cardiovascular and neurologic systems (CDC, 2014). The illness is transmitted through the bite of soft ticks, typically encountered in rodent infested cabins and crawl spaces (Simon, 2013). Soft tick bites are usually briefer and less painful than the hard shell ticks, leaving many people completely unaware of the bite.

The disease manifest as recurring febrile episodes lasting approximately three days, followed by an afebrile period lasting approximately seven days (CDC, 2014). Multiple episodes recur, each ending with a sequence of symptoms referred to as a crisis that is divided into a chill phase and a flush phase (CDC, 2014). The chill phase is associated with temperatures as high as 106 F, with accompanying tachycardia, tachypnea, agitation, and delirium. In the flush phase that follows, the patient experiences a rapid drop in body temperature and becomes drenched in sweat. Often transient hypotension follows (CDC, 2014). These febrile-related symptoms are also accompanied with viral-like symptoms of nausea, vomiting, myalgia, arthralgia, eye pain, photophobia, cough, and rash (Simon, 2013). With each febrile cycle, the accompanying symptoms can intensify and may escalate to delirium, palsy, and meningismus (Simon, 2013).

The diagnosis is confirmed using blood smears to detect Borrelia spirochetes after Wright-Giemsa staining (Simon, 2013). The organism is best detected during the chill phase (CDC, 2014).

Treatment typically consists of a ten day course of tetracycline or erythromycin. The CDC (2014) emphasizes the importance of monitoring TBRF patients closely in the first four hours of antibiotic initiation for signs of a common reaction, Jarisch-Herxheimer. The reaction occurs in 50% of cases and is characterized by high fever, chills, rigor, hypotension, headache, tachycardia, hyperventilation, vasodilation, and extreme anxiety and agitation (CDC, 2014). These symptoms, at risk for being mistaken for another chill phase episode, are managed symptomatically with antipyretics and cooling blankets (CDC, 2014).

Caused by the bacterium Francisella tularensis, Tularemia is transmitted by the bite of an infected tick or by handling infected animals, as with hunting or skinning (Simon, 2013). House cats are a common vector and some cases of Tularemia have also been linked with the inhalation of bacteria-infested dust, usually related to farming (CDC, 2014). The three ticks associated with spread of the infection in the U.S. are the dog tick, lone star tick, and wood tick (CDC, 2013). The disease can take many forms including ulceroglandular, glandular, occuloglandular, pharyngeal, typhoidal, and pneumonic (Simon, 2013). The latter is considered the most serious and can be fatal (CDC, 2014).

The onset of symptoms occurs three to five days after exposure and includes non-specific flu-like complaints of fever, chills and general malaise (Simon, 2013). An ulcer often forms at the site of the tick bite, becoming inflamed and pus-filled with surrounding lymph nodes enlargement (Simon, 2013). The CDC (2014) recommends contact isolation for suspected cases of Tularemia.

The ulcer can be cultured to isolate the growth of F. tularensis (CDC, 2014). A definitive diagnosis can be determined serologically with a four-fold titer increase between the acute and convalescent period, which can takes up to a month (CDC, 2014).

Treatment should not wait for a confirmative diagnosis in symptomatic patients. Common treatment regimens include a ten day course of streptomycin, gentamycin, or doxycycline and dosing is based on individual responses (CDC, 2014).

The prevention of tick-borne disease depends primarily on reducing human exposure to infected tick bites. See table 2 for prevention strategies recommended by the CDC.

Public health initiatives have also included Acaricide applications in tick infested common areas and use of Acaricide baited deer-feeding stations, but little research has been conducted to measure the impact of these strategies (Shen et al, 2011).

Patient education should include checking for ticks after any potential exposure and promptly removing, if found. The longer a tick is attached, the greater is the risk of disease transmission (University of Rhode Island, 2014). Ticks can travel undetected on clothing and pets, then attach to humans later so pets and gear should be carefully examined after outdoor activity. According to the CDC, clothing should be washed and dried immediately or, alternately, tumbled in the dryer for an hour. Nurses should encourage bathing or showering within two hours of being outdoors and demonstrate how to use mirrors to perform total body tick checks, paying close attention to the ears and umbilicus (CDC, 2014).

For removal, the CDC recommends using a set of fine-tipped tweezers and grasping the tick as close to the skins surface as possible. Nurses should instruct patients to pull upward in a steady, even motion without twisting or jerking. If mouth parts break off, the tweezers can be used to remove them. The bite area should be cleaned with rubbing alcohol and observed for redness or swelling. Additionally, any febrile illness in the following 30 days should be reported. The tick can be submerged in alcohol or flushed down the toilet, but should not be crushed with bare fingers.

Tick-borne Diseases of the U.S. is a 21 page manual written for health professionals and available free on the CDC website. It contains pictures and discussions to help identify ticks, recognize symptoms, and manage treatment. 

CDC also publishes Yellow Book: CDC Health Information for International Travel, which includes a discussion on preventing tick-related diseases. This resource, written for health professionals, can be requested at 1-800 451-7556 and sells for about $40.00. The Yellow Book is also available as an app for Android or iOS mobile devices. 

TickApp for smart phones is a user-friendly tick information tool with easy navigation. Written for the public, and sponsored by the Texas A&M University System, this free resource can be downloaded from this page.

An understanding of tick-borne diseases and their effect is necessary for nurses who may work with individuals at risk. Through patient teaching and application of the nursing process, nurses are in a key position to decrease incidence and facilitate early recognition and treatment of tick-borne diseases.

American Red Cross. American Red Cross participating in an investigational study to test the blood supply for a tick-borne parasite in donated blood. Retrieved online 10/5/14.

Center for Disease Control and Prevention. (2014). Anaplasmosis: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Ehrlichiosis: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Geographic distribution. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Life cycle of hard ticks that spread disease. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Lyme Disease: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Parasite - Babesiosis: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Preventing ticks on your pet. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Preventing ticks in the yard. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Preventing tick bites. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Rocky Mountain spotted fever: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014).STARI: Symptoms, diagnosis, and treatment. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Symptoms of tick-borne illness. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Tick-borne relapsing fever: Information for clinicians. Retrieved 10/4/14.

Center for Disease Control and Prevention. (2014). Tick removal. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Tick-borne diseases of the U.S. Retrieved online 9/3/14.

Center for Disease Control and Prevention. (2014). Tularemia: transmission. Retrieved 10/4/14.

Dahlgren, F., Holman, R., Paddock, C., Callinan, L., and McQuiston, J. (2012). Fatal Rocky Mountain spotted fever in the United States, 1999-2007. American Journal of Tropical Medicine and Hygiene, 86(4), p. 713-719. 

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Menis, M., Anderson, S., Izurieta, H., Kumar, S., Burwen, D., Gibbs, J., Kropp, G, Erten, T., MaCurdy, T., Worrall, C., Kelman, J., Walderhaug, M. (2012). Babesiosis among elderly medicare beneficiaries, United States, 2006-2008. Emerging Infectious Diseases, 18(1), p.128-131.

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Shah, R. and Sood, S. (2013). Clinical approach to known and emerging tick-borne infections other than Lyme disease. Current Opinions in Pediatrics, 25(3), p. 407-418.

Shen, A., Mead, P., Beard, C. (2011). The Lyme disease vaccine: A public health perspective. Center for Infectious Disease, 52(3), s247-252.

Simon, B. (2013) Hidden dangers: Non-Lyme tick-borne diseases. Nursing 2013, 43(9), p. 48-54.

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Vredevoe, L. (2014). Tick biology. Division of Agriculture and Natural Resources, University of California. Retrieved online 9/22/14.

Wright, W., Riedel, D., Talwani, R., and Gilliam, B. (2012). Diagnosis and management of Lyme disease. American Family Physician, 85(11), p. 1086-1093.