Table of Contents
Definition of Tick-borne Disease
There are many tick species, and relatively few will bite humans. However, those that do carry disease-causing microorganisms, such as parasites, viruses, or bacteria, usually acquired from other animals on which the tick has fed before latching on to a human host.
Common Tick-borne Diseases
- Lyme disease
- Human Monocytic Ehrlichiosis
- Human Granulocytic Ehrlichiosis (now known as Anaplasmosis)
- Rocky Mountain spotted fever
Rare Tick-borne diseases
- Colorado tick fever
- Tick-borne relapsing fever
- Q fever
- Southern tick-associated rash illness
- Powassan encephalitis
Lyme disease is the most common tick-borne disease in the US, especially in the northeast and north-central regions. It is caused by the transmission of Borrelia burgdorferi through the bite of infected ticks. Early signs and symptoms appear 3 to 30 days after a tick bite. Late symptoms present after weeks to months. Black-legged ticks and deer ticks spread it.
There are three major stages of the disease:
|Stage||Time of onset||Clinical presentation|
|Early local disease||1-2 weeks||Erythema migrans rash, fever, myalgia, arthralgia, fatigue, headache, lymphadenopathy|
|Early disseminated disease||1 month||Disseminated E. migrans rash, meningitis, facial palsy, carditis, radiculopathy|
|Late disease||2-12 months||Arthritis|
Early signs and symptoms
- Joint aches
- Swollen lymph nodes
- Tender local adenopathy
- E. migrans rash: This rash is seen in about 80% of infected individuals. It appears at the site of a tick bite on average about 7 days and gradually expands to an area of 12 inches or more. It appears as a bullseye and is rarely painful or itchy.
Later signs and symptoms
- Severe headaches
- Neck stiffness
- E. migrans rash on areas other than the site of the tick bite
- Arthritis particularly involving large joints
- Facial palsy
- Intermittent pain (bones, muscles, and joints)
- Lyme carditis (palpitations, chest pain, vertigo, and syncope)
- Dizziness episodes
- Shortness of breath
- Tingling, numbness, or shooting pains in the hands and feet
- Problems related to short-term memory
- Blood titers with confirmatory Western Blot test-enzyme immunoassay
- During the early stage of the disease, blood titers may give false-negative results
- Rule of 7: A headache for 7 days, seventh nerve palsy (Bell palsy), and 70% monocytes in CSF
- Joint aspiration may be necessary to exclude other diseases
- CSF analysis will be used to ascertain Lyme disease for patients suffering from meningitis
- ECG may be necessary to identify the presence of Lyme carditis
Early lime disease
Adults: Doxycycline 100 mg bid (10-21 days) or Amoxicillin 500 mg t.i.d (2-3 weeks)
Children: Doxycycline 4 mg/kg per day
Ceftriaxone is used for Lyme meningitis and other neurological manifestations.
Late Lyme Disease
Adults: Doxycycline 100 mg bid (28 days)
Children: Doxycycline 4 mg/kg per day
Late Lyme disease with neurological manifestations
Adult patient: IV ceftriaxone – 2 to 4 weeks
Cefotaxime and cefuroxime axetil may also be administered if there is no contraindication.
Management of the Lyme Disease in children:
|Children under 8||Children 8 or over||Chronic Lyme|
|Meningitis – ceftriaxone||Meningitis – ceftriaxone||Therapy and psychiatric support|
|Other Lyme-associated diseases – oral amoxicillin||Other Lyme-associated diseases – doxycycline||Antibiotics are ineffective|
Rocky Mountain Spotted Fever
It is a disease caused by the bacterium Rickettsia rickettsii, which is transmitted to humans through tick bites. It can be fatal without appropriate management. The disease presents itself as a sudden onset of fever and headache. It easily disguises itself as another disease; thus, sophisticated tests may be necessary for a definitive diagnosis.
Common signs and symptoms are as follows:
- Sudden onset of fever
- The petechial rash starts on the hands and feet and spreads inward. It occurs 2-5 days after a fever and presents in up to 90% of the cases
- Red eyes
- Disseminated intravascular coagulation (DIC)
- Frontal headache
- Abdominal pain
- Loss of appetite
Diagnosis is made based on the patient’s clinical presentation and symptoms. It is later confirmed through specialized lab tests.
The first-line treatment for adults and children is doxycycline. It is given until the patient is afebrile for 3 days.
There are at least three different ehrlichial species in the United States that cause human ehrlichiosis:
- Ehrlichia chaffeensis
- Ehrlichia ewingii
- Ehrlichia muris-like
Typically, symptoms appear within 1-2 weeks after the tick bite.
- Muscle aches
Diagnosis is made by clinical presentation and symptoms of the patient. It is later confirmed through lab tests. The gold standard serologic test for ehrlichiosis is an indirect immunofluorescence assay.
The first line of treatment for adults and children of all ages is doxycycline. After treatment, symptoms usually resolve within 24-48 hours. Physicians may prescribe a longer course of doxycycline if the patient lives in an area endemic to Lyme disease since both diseases are transmitted by the same type of tick.
This disease is caused by the Anaplasma phagocytophilum . A tick (usually a black-legged tick) that has bitten an infected rodent or deer will transmit the infection to humans. It is common in mid-Atlantic, north-central states, California, and the northeast. Anaplasmosis may be more severe in individuals who are immunocompromised or elderly.
- Joint pain
- Muscle aches
- Nausea and vomiting
- Respiratory failure
- Seizures or coma
- Bleeding problems
- Organ failure
- Septic shock
The standard serologic test for the diagnosis of anaplasmosis is the indirect immunofluorescence antibody (IFA) assay for immunoglobulin G (IgG) using the A. phagocytophilum antigen.
The first line of treatment for adults and children of all ages is doxycycline. When treated early with doxycycline, the symptoms resolve within a few days to a few weeks.
Preventing Tick Bites
When you spend time outdoors, take the following precautions to reduce the risk of tick bites, especially in endemic areas.
- Wear bright-colored clothing to spot ticks more easily
- Wear a hat and tie back long hair
- Wear long sleeves and trousers
- Tuck trousers into socks
- Use insect repellent (Composition: 20% DEET, or Picaridin)
- Avoid areas with leaf litter and tall grass
- Avoiding areas with tall grass
When you return from spending time outdoors, take the following precautions.
- Take a bath or shower as soon as you come indoors to help get rid of ticks that may still be crawling on the body.
- Check the entire full body to find areas of tick bites. Pay special attention to parts that bend, such as the knees, and pressure points, such as the area behind the ears.
If you live in a rural area, keep the area surrounding the home clear of weeds and brushy areas to deter wild animals.
If you have pets, examine them carefully for ticks. Fit dogs with anti-tick collars. All dogs are susceptible to Lyme disease as well as babesiosis, a malaria-like infection that usually affects dogs by attacking their red blood cells. Cats tend to be more resistant to tick-borne diseases and are hypersensitive to the chemicals in anti-tick collars; consult a veterinarian before using anti-tick collars with cats.