Tularemia: Symptoms, Causes, and Treatment

What is Tularemia?

Tularemia, also known as "rabbit fever" or "deer fly fever," is a rare but potentially serious bacterial infection caused by the bacterium Francisella tularensis. It primarily affects animals, especially rodents, rabbits, and hares, but can be transmitted to humans through various routes. Tularemia is not known to spread from person to person.

The disease can manifest in several forms depending on how the bacteria enter the body, ranging from mild skin ulcers to severe pneumonia. Early diagnosis and treatment are crucial to prevent complications.

Source: Centers for Disease Control and Prevention (CDC)

Common Causes

Tularemia is caused by infection with Francisella tularensis. The bacteria can enter the body through:

• Tick and insect bites: Especially from dog ticks, wood ticks, or deer flies that have fed on infected animals.
• Direct contact with infected animals: Handling or skinning rabbits, hares, rodents, or other infected wildlife.
• Inhalation of contaminated aerosols: Breathing in bacteria from contaminated soil, hay, or grain, often during activities like mowing or farming.
• Consumption of contaminated food or water: Eating undercooked meat from infected animals or drinking contaminated water.
• Exposure to contaminated environments: Working or playing in areas where infected animals live or have died.
• Laboratory exposure: Accidental inhalation or contact with the bacteria in a lab setting.
• Biological warfare or bioterrorism: Though rare, F. tularensis is classified as a potential bioterrorism agent due to its high infectivity.

Source: Mayo Clinic

Associated Symptoms

The symptoms of tularemia vary depending on how the bacteria entered the body. The incubation period (time from exposure to illness) is typically 3 to 5 days but can range from 1 to 14 days. Common forms of tularemia and their symptoms include:

1. Ulceroglandular Tularemia (Most Common Form)

• A skin ulcer at the site of infection (e.g., tick bite or scratch).
• Swollen and painful lymph glands (e.g., in the armpit or groin).
• Fever, chills, and fatigue.
• Headache and muscle aches.

2. Glandular Tularemia

• Similar to ulceroglandular but without a visible skin ulcer.
• Swollen lymph nodes and fever.

3. Oculoglandular Tularemia

• Occurs when bacteria enter through the eye (e.g., rubbing the eye after handling an infected animal).
• Eye pain, redness, swelling, and discharge.
• Swollen lymph nodes near the ear or neck.

4. Oropharyngeal Tularemia

• Results from eating or drinking contaminated food/water.
• Sore throat, mouth ulcers, and swollen tonsils.
• Stomach pain, vomiting, and diarrhea.

5. Pneumonic Tularemia

• Occurs when bacteria are inhaled or spread to the lungs from another site.
• Dry cough, chest pain, and difficulty breathing.
• High fever, chills, and fatigue.
• This is the most severe form and can be life-threatening if untreated.

6. Typhoidal Tularemia

• A systemic (whole-body) infection without localized symptoms.
• High fever, extreme fatigue, and weight loss.
• Enlarged spleen or liver.

Source: National Institutes of Health (NIH)

When to See a Doctor

Seek medical attention if you experience any of the following, especially if you’ve been exposed to ticks, wild animals, or contaminated environments:

• A skin ulcer that doesn’t heal, especially if accompanied by swollen lymph nodes.
• Unexplained fever with chills, fatigue, or muscle aches.
• Eye pain, redness, or swelling with swollen glands near the ear or neck.
• Persistent sore throat, mouth ulcers, or difficulty swallowing.
• Cough, chest pain, or trouble breathing (seek immediate care).
• Symptoms that worsen or don’t improve within a few days.

Early treatment is key to preventing complications like pneumonia, meningitis, or sepsis.

Diagnosis

Diagnosing tularemia can be challenging because its symptoms mimic other illnesses. Doctors may use a combination of the following:

• Medical history and exposure assessment: Your doctor will ask about recent outdoor activities, tick bites, or contact with wild animals.
• Physical exam: Checking for skin ulcers, swollen lymph nodes, or other signs of infection.
• Blood tests: To detect antibodies to F. tularensis or signs of infection (e.g., elevated white blood cell count).
• Cultures: Samples from skin ulcers, lymph nodes, or respiratory secretions may be cultured to identify the bacteria.
• PCR testing: A molecular test to detect bacterial DNA in blood or tissue samples.
• Chest X-ray: If pneumonic tularemia is suspected.

Source: Cleveland Clinic

Treatment Options

Tularemia is treatable with antibiotics, which are most effective when started early. Treatment options include:

Medical Treatments

• Antibiotics: The first-line treatments are:
  • Streptomycin (injected)
  • Gentamicin (injected or IV)
  • Doxycycline (oral, for mild cases)
  • Ciprofloxacin (oral, for mild cases)
  Treatment typically lasts 10 to 21 days, depending on the severity.
• Hospitalization: Required for severe cases (e.g., pneumonic or typhoidal tularemia) or if the patient is unable to take oral medications.
• Supportive care: IV fluids, pain relievers (e.g., acetaminophen), and fever reducers may be used as needed.

Home Care and Recovery

• Take all prescribed antibiotics as directed, even if symptoms improve.
• Rest and stay hydrated to help your body recover.
• Use over-the-counter pain relievers (e.g., ibuprofen) for fever or discomfort, unless advised otherwise by your doctor.
• Avoid handling animals or engaging in outdoor activities that could lead to re-exposure.
• Monitor for worsening symptoms and follow up with your doctor as recommended.

Source: World Health Organization (WHO)

Prevention Tips

Preventing tularemia involves reducing exposure to the bacteria. Here’s how to protect yourself:

• Avoid tick and insect bites:
  • Use EPA-approved insect repellents containing DEET, picaridin, or IR3535.
  • Wear long sleeves, pants, and socks when outdoors in wooded or brushy areas.
  • Perform tick checks after outdoor activities and remove ticks promptly.
  • Treat clothing and gear with permethrin (an insecticide).
• Handle animals safely:
  • Avoid touching sick or dead wild animals, especially rabbits, hares, and rodents.
  • Use gloves and protective clothing when skinning or handling wild game.
  • Cook meat thoroughly before eating (internal temperature of at least 165°F).
• Protect yourself in high-risk environments:
  • Wear a mask when mowing, farming, or working in areas with animal carcasses.
  • Avoid drinking untreated water from streams, lakes, or ponds.
• Educate yourself: Be aware of tularemia risks if you live in or visit areas where the disease is common (e.g., rural or woodland regions in the U.S., Europe, or Asia).

Source: CDC Prevention Guidelines

Emergency Warning Signs

Seek immediate medical attention or go to the emergency room if you experience any of the following:

• Difficulty breathing or severe chest pain: Could indicate pneumonic tularemia, which requires urgent treatment.
• High fever (over 103°F or 39.4°C) with confusion or lethargy: May signal a systemic infection or sepsis.
• Severe headache with stiff neck: Could indicate meningitis, a rare but serious complication.
• Persistent vomiting or inability to keep fluids down: Risk of dehydration, especially in children or older adults.
• Signs of shock: Rapid heartbeat, low blood pressure, cold/clammy skin, or mental confusion.
• Worsening symptoms despite treatment: May indicate antibiotic resistance or complications.

Tularemia can become life-threatening if left untreated. Do not delay seeking care if you suspect you have been exposed or are experiencing severe symptoms.