Tick Borne Diseases

Lyme Disease is a spirochetal infection caused by the bite of infected ticks of the Ixodes Ricinus complex. In the United States, Lyme disease is primarily caused by the bacterium Borrelia burgdorferi, and, rarely, by Borrelia mayonii(CDC, 2024a; Lantos et al., 2020). It is one of the most well-known tick-borne illnesses, transmitted by the infected blacklegged tick, also known as the deer tick, which is most frequently encountered in backyards and outdoor recreational areas. In the northeastern United States, rodents such as the white-footed mouse are the primary reservoir of Borrelia species.

Figure 1: Blacklegged Ticks

Figure 2: Close-up of blacklegged Tick

It was first recognized clinically in 1977 as “Lyme arthritis” during studies of a cluster of children in Connecticut who were thought to have juvenile rheumatoid arthritis (Steere et al., 1977).It is currently the most reported tick-borne disease in the United States and Europe.The peak incidence of early Lyme disease onset occurs during the summer months of June, July, and August. Arthritis, a late disease manifestation, may present at any time of the year (Lantos et al., 2020).

The incubation period for Lyme disease is 3-30 days. Early signs include Erythema migrans (EM), a red ring or homogeneous rash at the site of the tick bite that expands gradually over several days to more than five centimeters in diameter. “There is a central clearing that may develop as the rash expands, resulting in a “target” or “bull’s eye” appearance; however, this “classic bull’s eye does not always appear”. The rash may be warm to the touch but is rarely itchy or painful (CDC, 2024b; Lantos et al., 2020).

In the early stages, a client may experience:

• A high fever
• Chills
• Fatigue
• Headache
• Malaise
• Myalgia
• Arthralgia.
• Lymphedema is common

Untreated Lyme disease will progress to disseminated disease in about 60% of clients. Most manifestations will appear in the first few weeks to months of infection, but may be delayed (CDC, 2024b; Lantos et al., 2020).

Neurological manifestations are also found, including:

• Cranial neuritis, most commonly Bell’s palsy (facial paralysis that can be bilateral).
• Lymphocytic meningitis.
• Painful radiculoneuritis involving one or more dermatomes.
• Painful peripheral motor and sensory neuropathy (mononeuritis multiplex).
• In rare instances, intracranial hypertension (CDC, 2024b; Lantos et al., 2020).

Cardiac manifestations commonly found include Lyme carditis, resulting in conduction abnormalities (e.g., atrioventricular node block; myopericarditis) that are rarely fatal.

Rheumatological manifestations include oligoarticular arthritis (transient, migratory arthritis and effusion in one or multiple joints) and Baker’s cyst. Migratory pain in tendons, bursae, muscles, and bones is also common (CDC, 2024b; Lantos et al., 2020; Steere et al., 1977). Severe headaches and neck stiffness may also occur (CDC, 2024b).

Submit the removed tick for species identification if possible. Diagnosis is based on clinical findings rather than laboratory testing if one or more skin lesions are present, suggestive of erythema migrans. If no lesion is present, antibody testing should be completed, followed by a convalescent-phase serum sample if the initial result is negative (Ho et al, 2021; Lantos et al., 2020).

The Infectious Disease Society of America, the American Academy of Neurology, and the American College of Rheumatology all guide treatment regimens for Lyme disease. The most recent treatment guidelines were published in 2020. Even with early and aggressive treatment, clients may continue to have persistent post-infection symptoms of pain, fatigue, and impaired cognition. Prophylactic antibiotic treatment is recommended for adults and children within 72 hours of identifying a high-risk tick bite, but not for equivocal or low-risk bites (Lantos et al., 2020).

A bite is considered high risk if it meets the following three criteria:

1. The tick bite was from an identified Lxodes spp. Species
2. It occurred in a highly endemic area
3. The tick was attached for > 36 hours

“If a bite cannot be classified with a high level of certainty as a high-risk bite, a wait-and-watch approach is recommended (Lantos et al., 2020).”

The recommended initial treatment is Doxycycline, Amoxicillin, or Cefuroxime, depending on the client's health status (CDC, 2024b; Lantos et al., 2020). For high-risk bites, a single dose of Doxycycline is recommended, 200 mg for adults and 4.4 mg/kg (up to a maximum dose of 200 mg) for children (Lantos et al., 2020).

RMSF is caused by the intracellular bacteriumRickettsia rickettsiiand is one of several diseases categorized as “Spotted fever rickettsiosis” (SFR) (CDC, 2024c). SFR is found in all 48 lower states but has a higher incidence in North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri. Peak transmission occurs during May-August, although cases are reported in every month of the year (CDC, 2024c). It is transmitted primarily through American dog ticks (Dermacentor variabilis), Rocky Mountain wood ticks (Dermacentor andersoni), and Brown dog ticks (Rhipicephalus sanguineus). (CDC, 2024c).Infection with R. rickettsia is extremely rare via blood transfusion and, although physiologically possible, has never been documented via organ transplant (CDC, 2024c).

RMSF is one of the deadliest of all tick-borne illnesses in the United States. It is a bacterial infection that presents with common flu-like symptoms, including:

• Fever.
• Headache.
• Nausea.
• Vomiting.
• Stomach pain.
• Myalgia.
• Rash. The rash usually occurs within 48-72 hours after infection. It is non-descript but, in some cases, will appear as red splotches or pinpoint dots all over the body.

Late illness symptoms may develop 5 days or later following the bite and may include (CDC, 2024d):

• Altered mental status
• Coma
• Cerebral edema
• Respiratory compromise 
• Skin and soft tissue necrosis
• Multiorgan damage. 

Severe forms of RMSF can result in amputation of limbs, hearing loss, paralysis, mental disability, and or death (Ho et al., 2021; CDC, 2024d; Lantos et al., 2020).

Thrombocytopenia; elevated hepatic transaminases and hyponatremia. A fourfold rise in IgG-specific antibody titer by indirect immunofluorescence antibody (IFA) assay is often seen. Immunohistochemical (IHC) staining of organisms from the skin or a tissue biopsy can also be completed. IgG antibody testing is likely to generate a false positive (Ho et al, 2021; CDC, 2024d).

Early treatment with doxycycline is approved for adults, children of all ages, and pregnant women, but prophylactic treatment is not recommended. People who were bitten by a tick should watch for signs and symptoms to develop within two weeks of a bite (CDC, 2024e). Treatment should be initiated if signs of illness develop. Doxycycline is the preferred treatment to prevent death and severe illness, and is most effective at preventing severe complications if started within the first 5 days of illness. Use of antibiotics other than Doxycycline is associated with a higher risk of fatal outcomes (CDC, 2024e).

Anaplasmosis is a bacterial disease that is transmitted to humans by tick bites, primarily from the blacklegged tick (Ixodes scapularis) and the western blacklegged tick (Ixodes pacificus) (CDC, 2025a). “Ehrlichiosis is the general name used to describe diseases caused by the bacteria Ehrlichia chaffeensis, E. ewingii, or E. muriseauclairensis in the United States. These bacteria are spread to people primarily through the bite of infected ticks, including the lone star tick (Amblyomma americanum) and the blacklegged tick (Ixodes scapularis)” (CDC, 2024f).

The incubation period for both Anaplasmosis and Ehrlichiosis is between 5 and 14 days. Signs and symptoms include:

• Fever
• Chills
• Rigors
• Severe headache
• Malaise
• Myalgia
• Gastrointestinal symptoms (nausea, vomiting, diarrhea, anorexia)

A rash is uncommon in Anaplasmosis infection (CDC, 2024g). If a rash develops, it often appears as red splotches or pinpoint dots all over the body.

• Anaplasmosis: Mild anemia, Thrombocytopenia, Leukopenia, and mild to moderate elevations in hepatic transaminases. Detection of DNA by PCR of whole blood is more sensitive during the first week of illness (Ho et al., 2021; CDC, 2024 g.).
• Ehrlichiosis: Thrombocytopenia, Leukopenia (absolute), Anemia, and mild to moderate elevations in hepatic transaminases (Ho et al., 2021; CDC, 2024f).

Anaplasmosis, ehrlichiosis, and spotted fever group rickettsioses are all treated with doxycycline. It should be noted that any clinical suspicion of these diseases is grounds for beginning treatment, as delay in treatment may result in severe illness or death. Patients with suspected anaplasmosis should be treated with doxycycline for 10-14 days, providing an appropriate length of therapy for possible co-infection with Lyme disease. When treated with doxycycline, fever typically subsides within 24-48 hours (CDC, 2025b).

This bacterial disease is transmitted by the dog tick (Dermacentor variabilis), the wood tick (Dermacentor andersoni), and the lone star tick (Amblyomma Americanum). Tularemia is found throughout the continental United States” (CDC, 2024h). Please note that it is NOT transmitted by the same ticks that transmit Lyme Disease.

Generalized signs and symptoms include:

• Fever
• Chills
• Headache
• Malaise
• Anorexia
• Muscle pain
• Chest pain
• Cough and sore throat
• Vomiting and diarrhea
• Abdominal pain

All forms of Tularemia present with a fever that can go as high as 104 degrees Fahrenheit. There are several forms of tularemia; however, only ulceroglandular tularemia is associated with a tick bite. Oculoglandular, oropharyngeal, pneumonic, and typhoidal tularemia are associated with other modes of bacterial transmission.

In ulceroglandular tularemia, swelling of the lymph glands in the armpit or groin area is common, and a skin ulcer typically develops at the site of the tick bite. This is the most common form of tularemia.

Typhoidal and pneumonic forms are more serious forms of tularemia and usually develop when other forms of tularemia (e.g., ulceroglandular or glandular) are unrecognized or untreated. The incubation period typically ranges from one to 14 days (CDC, 2024h).

Isolation of F. tularensis in culture is preferred. This organism is a highly infectious, slow-growing bacterium. Blood cultures are often negative. Cultures of scrapings or swabs of ulcers, lymph node fluid, or respiratory specimens are recommended if Tularemia is suspected (Ho et al., 2021; CDC, 2024i).

For Tularemia in adults, treatment recommendations are as follows (CDC, 2025c):

• Doxycycline: 6mg/kg IM or IV every 24 hr x 10 days
• Flouroquinolones:
  • Ciprofloxacin: 400 mg IV or 750 mg orally every 12 hours x 10 days
  • Levofloxacin: 750 mg IV or orally every 24 hrs x 10 days
• Tetracycline: 200 mg loading dose, then 100mg orally or IV every 12 hrs. x 14-21 days

For Children ≥ 1 mo to ≤ 17 yrs;

• Doxycycline (Tetracycline): 4.4mg/kg loading dose orally or IV, then 2.2 mg/kg every 12 hr x 10 days
• Flouroquinolones:
  • Ciprofloxacin: 10 mg/kg every 8-12 hrs IV (maximum 400 mg/dose) or 15 mg/kg every 8-12 hrs PO (maximum 500 mg/dose every 8 hrs or 750 mg/dose every 12 hrs) x 10 days
  • Levofloxacin: Infants and children aged < 5 yrs: 10 mg/kg every 12 hours IV or orally (maximum 375 mg/dose). Children and adolescents aged ≥ 5 yrs: 10 mg/kg every 24 hours IV or orally (maximum 750 mg/dose) x 10 days
• Gentamicin: 5-7.5 mg/kg every 24 hrs IV x 10 days

It should be noted that ciprofloxacin, levofloxacin, and gentamicin have been approved by the Federal Drug Administration (FDA) for the treatment of tularemia; however, they have been frequently off-label for the treatment of naturally occurring tularemia in humans (CDC, 2025c).

Babesia microti are microscopic parasites transmitted to humans by the blacklegged tick (Ixodes scapularis). These parasites attack and infect red blood cells (CDC, 2024j).

Babesiosis is a Parasitic disease. This malaria-like parasite infects red blood cells and causes flu-like symptoms. Older populations and those who are immunocompromised can have more severe symptoms that can be fatal (Krause et al., 2020).

Identification of Babesia parasites is made by light microscopic examination of a peripheral blood smear or positive Babesia (or B. microti) polymerase chain reaction (PCR) analysis or demonstration of a Babesia-specific antibody titer by indirect fluorescent antibody (IFA) testing for total immunoglobulin (Ig) or IgG. Antibody detection by serologic testing cannot distinguish between active or prior infection (Ho et al, 2021; CDC, 2024k).

According to Krause et al. (2020), treatment for Babesiosis should include a combination approach of atovaquone plus azithromycin. An alternative recommended treatment would be clindamycin plus quinine. The clindamycin and quinine approach is recommended more for patients who are immunocompromised or have relapsed while on the initial treatment. In severe cases, Krause et al. (2020) recommend transfusion of red blood cells to reduce parasitemia quickly.

The blacklegged tick (Ixodes scapularis) is the culprit again, although the groundhog/woodchuck tick (Ixodes cookei) or the squirrel tick (Ixodes marxi) should also be a suspected cause of this viral infection (CDC, 2025d). The bite of an infected tick can transmit this virus very quickly.

Powassan Virus Disease, like all other tick-borne diseases, initially mimics the flu and is present at the onset of illness. The Powassan virus can progress to more severe illnesses such as encephalitis, seizures, and death. Half of all people who experience severe illness have long-term complications, including recurring headaches, loss of muscle mass, and memory issues. One in ten people with severe disease die (CDC, 2025d).

Laboratory testing of blood or spinal fluid. Cerebrospinal fluid (CSF) findings include lymphocytic pleocytosis (neutrophils can predominate early), normal or mildly elevated protein, and normal glucose (Ho et al., 2021; CDC, 2025d).

There are no medications to treat Powassan Disease. Medications to relieve symptoms include fever-reducing drugs, breathing support, and other therapies as required.

This virus is transmitted by the Rocky Mountain wood tick (Dermacentor andersoni). It occurs in the Rocky Mountain states at elevations of 4,000 to 10,000 feet (CDC, 2024l).

The defining symptom of Colorado Tick Fever is a biphasic fever, meaning that the infected client will have several days of high fever, a respite for a few days, and then a recurring fever.

Colorado Tick Fever is typically self-limited and presents with:

• Fever
• Chills
• Headache
• Myalgia
• Malaise
• Sore throat
• Vomiting
• Abdominal pain
• A maculopapular rash

Colorado Tick Fever is a rare illness, and it usually resolves without complications (Ho et al., 2021).

Preliminary diagnosis is based on clinical findings. RNA or virus-specific immunoglobulin (Ig)M and neutralizing antibodies can be found by RT-PCR (reverse transcriptase polymerase chain reaction). However, it may not be detectable until 2 to 3 weeks post-infection. General laboratory findings include Leukopenia and moderate thrombocytopenia (Ho et al., 2021; CDC, 2025e).

There are no medications to treat Colorado Tick Fever. Medications to relieve symptoms include fever-reducing drugs, breathing support, and other therapies as required.

This infection has been “identified in a limited number of patients in the Midwest and southern United States. At this time, we do not know if the virus might be found in other areas of the United States” (CDC, 2024m).

Bourbon Virus Disease is named after Bourbon County, Kansas, where the first man who carried this disease resided and was first diagnosed in 2014. Previously, the virus was only found in Africa, southern Europe, and Central Asia.

Tick bites occur approximately two weeks before the onset of symptoms, and like other viruses, signs and symptoms mimic the flu (e.g., fever, fatigue, arthralgia, myalgia, nausea, diarrhea, etc.) (Ho et al., 2021; CDC, 2024m).

Leukopenia, Thrombocytopenia, and mild to moderate elevation of hepatic transaminases (Ho et al., 2021; CDC, 2025f).

There are no medications for Bourbon Viral Disease. Medications to relieve symptoms include fever-reducing drugs, breathing support, and other therapies as required.