Tick Bites and Tick Borne Diseases

Ticks are small parasites that belong to the scientific classification Arachnida, which is the same family as spiders.

Ticks are excellent vectors for disease transmission and rank second after mosquitoes as vectors of infectious and toxic disease.

Tick-borne diseases can be caused by bacteria, parasites, or viruses, but the diseases caused by bacteria are the most common. Ticks need blood to complete their life cycle, and tick-borne diseases are transmitted to humans through the bite of infected ticks.

Ticks are common in many parts of the world, so tick-borne diseases are also common. Some tick-borne illnesses can lead to serious problems, but prompt antibiotic therapy can typically fix the problem. If left untreated, tick-borne diseases can be difficult to treat using conventional methods such as antibiotics.

Tick-borne illnesses have a wide range of symptoms from mild to severe. Though tick-borne illnesses share many of the same symptoms, symptoms and treatment may vary for each disease depending on the type of bacteria, parasite, or virus that causes the illness.

Tick-borne infections have symptoms that are similar to those of many other diseases, leading to misdiagnosis and persistent sickness.

Common tick species and diseases they spread:

Blacklegged or deer tick (Ixodes scapularis)
- Anaplasmosis
- Babesiosis
- Borrelia miyamotoi disease
- Lyme disease
- Powassan virus disease (which can also be spread by Ixodes cookei)

Lone star tick (Amblyomma americanum)
- Ehrlichia chaffeensis
- Tularemia

American dog tick (Dermacentor variabilis)
- Rocky Mountain spotted fever
- Tularemia

Tick-borne diseases

Ticks can carry multiple infectious organisms that cause many tick-borne diseases. Tick-borne illnesses include:

Anaplasmosis
Babesiosis
Borrelia miyamotoi infection
Colorado tick fever
Ehrlichiosis
Heartland virus infection
Lyme disease
Powassan encephalitis
Relapsing fever
Rocky Mountain spotted fever (RMSF)
Southern tick-associated rash
Tularemia

Anaplasmosis

Anaplasmosis, formerly known as human granulocytic ehrlichiosis (HGE), is a tick-borne bacterial disease caused by the bacterium Anaplasma phagocytophilum and transmitted through the bite of black-legged or deer ticks (Ixodes scapularis).

Symptoms of anaplasmosis

Symptoms appear within a week or two after the tick bite and may include one or more of the following:

Chills
Fever
Muscle aches
Diarrhea
Nausea or vomiting
Loss of appetite

If it is not treated promptly, later symptoms of the disease may include:

Bleeding complications
Organ shutdown
Respiratory failure
Death

A person is at a greater risk for complications if they are older, have a weakened immune system, or have delayed treatment.

Treatment for anaplasmosis

The antibiotic doxycycline is widely used to treat anaplasmosis. Treatment can be effective if the infection is diagnosed early and treatment is started immediately. Antibiotics are much less effective for late-stage infections.

Babesiosis

Babesiosis is caused by microscopic parasites that infect red blood cells. Most cases of babesiosis are caused by Babesia microti, while some are caused by other strains of Babesia that are transmitted by infected black-legged or deer ticks (Ixodes scapularis). About 20% of patients diagnosed with babesiosis also have Lyme disease.

Symptoms of babesiosis

Some people do not experience any symptoms. For those who do, symptoms include:

Fatigue
Flu-like symptoms
Headaches
Hemoglobinuria
Hemolytic anemia (due to the destruction of red blood cells)
High fever
Jaundice
Myalgia
Nausea
Renal failure
Sweating

Diagnosis of babesiosis

Babesiosis is diagnosed by presence of fever and hemolytic anemia, exposure history, and looking at red blood cells under a microscope and finding Babesia parasites and protozoa in a "Maltese cross" pattern on the periphery of the smear. Serologic testing and polymerase chain reaction tests are also used for diagnosis.

Treatment for babesiosis

Conventional treatment usually consists of a combination of atovaquone plus azithromycin or quinine plus clindamycin. Mild disease requires only symptomatic treatment. Exchange transfusions can be used in severely ill patients.

Borrelia miyamotoi infection

Borrelia miyamotoi infection is a recently identified tick-borne infection in humans. It is caused by Borrelia miyamotoi, a spiral-shaped bacteria that is distantly related to the bacteria that causes Lyme disease and is transmitted through the bite of a black-legged or deer tick (Ixodes scapularis).

Symptoms of Borrelia miyamotoi

Chills
Fatigue
Headaches
Joint and body pain
Relapsing fever

Treatment for Borrelia miyamotoi

Treatment typically involves a course of antibiotics.

Colorado tick fever

Colorado tick fever (CTF) is a rare disease that is spread by an infected Rocky Mountain wood tick (Dermacentor andersoni). CTF is caused by an RNA virus belonging to the genus Coltivirus.

Symptoms of Colorado tick fever

Symptoms usually appear within 1-14 days after a tick bite and may include:

Abdominal pain
Body aches
Chills
Encephalitis
Fatigue
Headache
Heart problems
Saddleback fever
Severe bleeding
Skin rash
Sore neck
Vomiting

It is common for patients to experience a 2- to 3-day remission and have a recurrence accompanied by a drop in white blood cells.

Diagnosis of Colorado tick fever

Diagnosis is usually made with blood smears stained with immunofluorescence. Laboratory findings may include leukopenia or thrombocytopenia.

Treatment for Colorado tick fever

There is no conventional medical treatment for CTF. Cases are usually treated symptomatically with pain relievers and fluids.

Ehrlichiosis

Ehrlichiosis is caused by Ehrlichia chaffeensis and spreads to people through the bite of infected ticks such as the Lone star tick (Ambylomma americanum) and dog tick (D. variabilis).

Symptoms of Ehrlichiosis

Early symptoms usually appear over the first 5 days of the initial infection and can include:

Severe headache
Chills
Fever
Muscle aches
Upset stomach or nausea
Loss of appetite
Diarrhea
Confusion
Rash

Late-stage symptoms may include:

Damage to the brain or nervous system
Organ shutdown
Respiratory failure
Uncontrolled bleeding
Death

Diagnosis of Ehrlichiosis

Laboratory findings include leukopenia, thrombocytopenia, and elevated serum transaminase levels. Diagnosis is also made with seroconversion during convalescence.

Treatment for Ehrlichiosis

Antibiotics doxycycline and tetracycline are commonly used to treat Ehrlichiosis. Severe illness can develop if initial antibiotic treatment is delayed. Very old or young people and those with a weakened immune system are particularly vulnerable.

Heartland virus infection

Heartland virus infection is a tick-borne viral disease that is caused by a virus belonging to the genus Phlebovirus and is spread through the bite of an infected Lone star tick (Amblyomma americanum).

Symptoms of Heartland virus infection

Most patients experience the following symptoms:

Decreased appetite
Decreased platelet counts
Decreased white blood cell counts
Fatigue
Fever
Headache
Increased levels of liver enzymes
Joint pain
Muscle or joint pain

Treatment for the Heartland virus

Currently, conventional medicine does not offer treatment for those diagnosed with the Heartland virus.

Lyme disease

Lyme disease is the most common tick-borne disease, which is caused by the bacteria Borrelia burgdorferi and transmitted through the bite of an infected black-legged tick (Ixodes scapularis), commonly known as a deer tick. The tick must be attached to human skin for about 36-48 hours for the disease to be transmitted.

Symptoms of Lyme disease

Stage 1 (early localized):

Erythema migrans, the characteristic “bull’s-eye” rash at the site of bite
Arthralgia
Fatigue
Fever
Flu-like symptoms
Headache
Lymphadenopathy

Stage 2 (early disseminated)

Adenopathy
Central nervous system symptoms
Cough and pharyngitis
Fever
Muscle and joint pain
Secondary cutaneous annular lesions

Stage 3 (late chronic)

Arthritis
Central nervous system impairment
Dermatitis
Facial palsy
Keratitis
Neurologic and myocardial abnormalities

Lyme disease may spread throughout the body for months or years after infection if left untreated, damaging the heart, joints, and neurological system, resulting in a wide range of symptoms.

Diagnosis of Lyme disease

Lyme disease is diagnosed on the basis of symptoms, an EM rash, a history of tick bites, and laboratory testing. A two-stage blood test, enzyme-linked immunosorbent assay (ELISA), confirmation by Western blotting, and polymerase chain reaction of the joint fluid may be helpful for diagnosis.

Treatment for Lyme disease

Treatment is most effective when detected and treated early with antibiotics. Commonly used antibiotics include doxycycline, amoxicillin, cefuroxime, or erythromycin. Antibiotics are often not effective after the first few weeks of infection.

Powassan encephalitis

Powassan encephalitis is a rare tick-borne disease caused by the Powassan virus, a flavivirus that belongs to a group of viruses that can cause encephalitis or meningitis. The virus is transmitted much faster than many other tick-borne microbes, usually in less than 15 minutes after tick attachment.

Symptoms of Powassan encephalitis

Initial symptoms may include:

Fever
Headache
Vomiting
Weakness

Symptoms of severe illness include:

Confusion
Dementia
Difficulty speaking
Encephalitis
Loss of coordination
Meningitis
Seizures
Death

Treatment for Powassan encephalitis

There are no conventional medical treatments for Powassan encephalitis. People who have severe symptoms will require hospitalization to reduce swelling in the brain, stay hydrated, and receive support for breathing.

Relapsing fever

Tick-borne relapsing fever is caused by Spirochete bacteria of Borrelia species such as B. hermsii, B. parkeri, B. duttoni, and B. miyamotoi and transmitted by ticks of the Ornithodoros species.

Symptoms of relapsing fever

Signs and symptoms can include:

Recurring high fevers with an irregular pattern
Arthralgias
Coma
Cranial nerve palsy
Dizziness
Epistaxis
Hemoptysis
High-fever delirium
Influenza-like symptoms
Iridocyclitis

May include:

Meningeal signs
Myocarditis
Nausea
Pneumonitis
Rupture of the spleen
Splenomegaly
Vomiting

Diagnosis of a relapsing fever

It can be diagnosed by detecting spirochetes in the blood, bone marrow, and cerebrospinal fluid during a febrile episode. Laboratory findings may include a normal or elevated leukocyte count and thrombocytopenia.

Treatment of relapsing fever

Antibiotics such as doxycycline, tetracycline, or erythromycin are the treatment of choice for relapsing fever. Treatment may lead to a Jarisch-Herxheimer reaction.

Rocky Mountain spotted fever

Rocky Mountain spotted fever (RMSF) is one of the deadliest tick-borne diseases. RMSF is caused by the bacteria Rickettsia rickettsii and transmitted by the Rocky Mountain wood tick (Dermacentor andersoni), American dog tick (Dermacentor variabilis), and brown dog tick (Rhipicephalus sangunineus). RMSF is particularly dangerous because the onset is abrupt and the disease can progress rapidly to a serious, life-threatening illness.

Symptoms of Rocky Mountain spotted fever

Signs and symptoms can include:

Headache
Fever
Chills
Rash
Nausea
Vomiting
Stomach pain
Lack of appetite

Symptoms of severe illness include:

Altered mental status
Coma
Delirium
Dementia
Difficulty speaking
Encephalitis
Hypotension
Insomnia
Loss of coordination
Meningitis
Seizures

Without treatment, the following can occur:

Brain and heart damage
Cardiac arrest
Circulatory failure
Pneumonia
Tissue necrosis

Diagnosis of Rocky Mountain spotted fever

It can be diagnosed through clinical signs and symptoms, a skin biopsy of the rash with immunofluorescent staining, and laboratory testing, which has limited usefulness. Routine findings include thrombocytopenia and hyponatremia.

Treatment for Rocky Mountain spotted fever

Antibiotic therapy, typically consisting of doxycycline, tetracycline, or chloramphenicol, is used. Doxycycline is the first-line medication for adults and children of all ages. It is important to start antibiotics early.

Southern tick-associated rash

STAR, also known as Masters disease, is transmitted by the Lone Star tick (Ambylomma americanum). The rash looks like that of Lyme disease and generally appears 7 days after the tick bite, growing to a diameter of 3 inches or more.

Symptoms of a Southern tick-associated rash

The symptoms of STAR are similar to those seen in Lyme disease:

A red, expanding “bull’s-eye”
Fatigue
Headache
Fever
Joint and muscle pains

Treatment for Southern tick-associated rash

It is often treated with oral antibiotics.

Tularemia

Tularemia is a potentially serious illness that is caused by the bacterium Francisella tularensis and transmitted by the lone star tick (A. americanum), wood tick (D. andersoni), and dog tick (D. variabilis).

Symptoms of tularemia

Symptoms may include:

Acute respiratory distress syndrome
Chills
Cough and sore throat
Fatigue
Fever
Headache
Malaise
Myalgia
Nausea or vomiting
Pericarditis
Pleural effusions
Pneumonia
Skin ulcers

Diagnosis of tularemia

It can be diagnosed through clinical signs and symptoms; acute and convalescent titers; presence of leukocytosis; and chest X-ray, which usually shows a triad of oval opacities, hilar adenopathy, and pleural effusions.

Treatment for tularemia

Antibiotics used to treat tularemia include doxycycline, streptomycin, gentamicin, and ciprofloxacin.

Prevention of tick-borne diseases

Currently, there are no vaccines to prevent these diseases, and the most effective way to prevent tick-borne diseases is to prevent tick bites.

Here are some steps that people can take before going outdoors to reduce the risk:

Wearing covered shoes, long-sleeved shirts, and tucking pants into socks
Tying up long hair
Avoiding sitting on the ground
Wearing light-colored clothing to make it easier to spot ticks
Apply insect repellents containing DEET (less than 30%), picardin, or ethyl butyl acetylaminopropionate to skin and clothing
Do not use insect repellents on children less than 2 months old
Tick bites often go unnoticed as they are usually painless and small. With the prevalence of tick-borne diseases on the rise, it is important to look for signs of tick bites and remove attached ticks after spending time outdoors.