Tularemia: Causes, Symptoms & Treatment

Tularemia, commonly known as rabbit fever, is a rare but potentially serious bacterial infection that affects thousands of people worldwide each year. This tick-borne bacterial disease caused by Francisella tularensis, can lead to several forms of infection, depending on how the bacteria enter the body.

Understanding the causes and early symptoms of tularemia—and knowing when to seek treatment can make a significant difference in recovery outcomes.

What Is Tularemia?

Tularemia is an acute bacterial disease caused by Francisella tularensis, a highly infectious pathogen that naturally occurs in wild animals and their environment. This zoonotic infection spreads from animals to humans through multiple routes, posing a particular risk to those who spend time outdoors or work with animals. The bacterium is remarkably infectious, requiring only a small number of organisms to cause disease in humans.

According to data from the Centers for Disease Control and Prevention (CDC), the average number of tularemia cases reported between 2011 and 2022 was 56% higher than during 2001 to 2010, indicating a marked rise in incidence over the past decade.

Types of Tularemia

Understanding the different tularemia types helps in recognising symptoms and seeking appropriate treatment. Each form presents unique characteristics:

• Ulceroglandular tularemia: The most common form, featuring a skin ulcer at the infection site with nearby swollen lymph nodes
• Glandular tularemia: Characterised by swollen lymph nodes without visible skin ulcers
• Oculoglandular tularemia: Affects the eyes, causing redness, pain, and swollen lymph nodes near the ears or jaw
• Oropharyngeal tularemia: Affects the mouth, throat, and gastrointestinal tract following ingestion of contaminated food or water
• Pneumonic tularemia: The most severe form affecting the lungs, often resulting from inhaling contaminated particles
• Typhoidal tularemia: A systemic form with high fever but no obvious localised symptoms, making diagnosis challenging

Causes of Tularemia

Tularemia causes stem from infection with Francisella tularensis, a bacterium that thrives in various environmental conditions. This pathogen naturally circulates among wild animals, particularly rabbits, hares, rodents, and various arthropods including ticks and deer flies. The bacteria can survive for weeks in water, soil, and decaying animal matter, creating multiple exposure opportunities.

Two main subspecies exist — Type A strains, common in North America, tend to cause more severe illness, whereas Type B strains, found mainly in Europe and Asia, usually result in milder disease. Understanding these tularemia causes helps identify risk factors and implement appropriate prevention strategies.

How Tularemia Spreads

The transmission pathways for this tick-borne disease are diverse, reflecting the bacteria's adaptability:

• Tick bites from infected rabbits, dogs, or ticks such as the wood tick or lone star tick
• Bites from infected deer flies or other blood-feeding insects
• Direct contact with infected animal tissues through cuts or breaks in the skin
• Inhalation of contaminated dust particles during outdoor activities like mowing or farming
• Ingestion of contaminated water or undercooked meat from infected wild animals
• Laboratory exposure when handling infected cultures without appropriate biosafety precautions

Is Tularemia Contagious Between People?

Tularemia is not contagious between humans. Health authorities, including the World Health Organization (WHO), confirm that person-to-person transmission has never been documented. This means you cannot catch tularemia from someone who has the infection, even through close contact. The disease spreads exclusively through environmental or animal exposure, making it fundamentally different from many other infectious diseases that spread through respiratory droplets or direct contact.

Tularemia Symptoms

Recognising tularemia symptoms early is crucial for prompt treatment. The clinical presentation varies depending on the route of infection and the specific tularemia types involved:

• Sudden onset fever and chills: Often the first signs to appear
• Severe headache and malaise: Contributing to an overall feeling of illness
• Muscle and joint pain: Affecting daily activities and mobility
• Loss of appetite and weight loss: Particularly noticeable in prolonged cases
• Skin ulcers or sores: Typically appearing at the site of tick bites or animal contact
• Swollen, painful lymph nodes: Most commonly in the neck, armpit, or groin areas
• Eye symptoms: Including redness, pain, and discharge in oculoglandular forms
• Respiratory symptoms: Such as dry cough and chest pain in pneumonic cases

Symptoms by Tularemia Type

Risk Factors for Tularemia

Certain activities and circumstances increase your likelihood of encountering this tick-borne disease:

• Outdoor occupations: Such as farming, landscaping, veterinary work, and wildlife management
• Recreational activities: Such as hunting, fishing, camping, and hiking in endemic areas
• Geographic location: Living in or visiting areas with high tick populations
• Seasonal factors: Higher risk during spring and summer months when ticks are most active
• Animal exposure: Handling wild rabbits, rodents, or their carcasses
• Laboratory work: Involving Francisella tularensis cultures or infected specimens

Complications of Untreated Tularemia

• Pneumonia and respiratory failure: Particularly dangerous in pneumonic forms
• Meningitis: Infection spreading to the brain and spinal cord coverings
• Pericarditis: Inflammation of the heart's protective membrane
• Osteomyelitis: Bone infections requiring prolonged antibiotic therapy
• Sepsis: Life-threatening systemic infection requiring immediate medical intervention

When to Seek Emergency Care

• High fever above 39°C (102°F) with severe chills
• Difficulty breathing or chest pain suggesting pneumonic involvement
• Signs of sepsis, including confusion, rapid heartbeat, or low blood pressure
• Severe eye symptoms with vision changes or intense pain
• Rapidly spreading skin infection or multiple ulcers

How Tularemia Is Diagnosed

1. Clinical assessment: Evaluating symptoms, exposure history, and physical examination findings
2. Laboratory testing: Including blood cultures, serology, and molecular diagnostics
3. Imaging studies: Chest X-rays for suspected pneumonic cases
4. Tissue sampling: Collecting specimens from ulcers or lymph nodes when appropriate
5. Differential diagnosis: Ruling out similar conditions like plague or Lyme disease

Tests for Tularemia

• Blood cultures: Culturing bacteria from blood samples using specialised media
• Serology tests: Detecting antibodies through tube agglutination or ELISA methods
• PCR testing: Detects bacterial DNA from blood, tissue, or respiratory samples
• CBC Test: Assessing white blood cell counts and inflammatory markers
• ESR Automated Blood Test: Measuring inflammation levels in the body
• Liver Function Test (LFT): Evaluating potential liver involvement
• Electrolytes Test: Monitoring fluid balance and organ function

Treatment Options for Tularemia

Effective tularemia treatment relies primarily on appropriate antibiotic therapy. Streptomycin remains the gold-standard antibiotic for tularemia treatment, typically administered intramuscularly for 10-14 days. Alternative antibiotics include gentamicin, doxycycline, and ciprofloxacin, depending on the specific tularemia types and patient factors.

Early treatment significantly improves outcomes, with most patients recovering completely when therapy begins promptly. Supportive care addresses symptoms like fever and pain, while monitoring ensures treatment effectiveness and identifies potential complications.

Hospital Care for Severe Tularemia

Severe cases of this tick-borne disease may require hospitalisation:

• Intravenous antibiotic administration: Ensuring optimal drug levels and absorption
• Respiratory support: Including oxygen therapy or mechanical ventilation for pneumonic cases
• Fluid management: Maintaining proper hydration and electrolyte balance
• Intensive monitoring: Tracking vital signs and organ function
• Isolation precautions: Standard precautions only, as person-to-person transmission doesn't occur

Is There a Tularemia Vaccine?

Currently, there is no licensed vaccine for tularemia available for public use. Research continues into developing effective vaccines, but prevention through risk reduction remains the primary strategy for avoiding this glandular infection.

How to Prevent Tularemia

• Avoid direct contact with wild animals, especially rabbits and rodents
• Use protective equipment when handling potentially infected animals
• Implement tick prevention measures during outdoor activities
• Treat pets with appropriate tick and flea control products
• Maintain clean water sources and avoid drinking from potentially contaminated sources
• Practice food safety by thoroughly cooking wild game meat
• Use insect repellents containing DEET when outdoors in endemic areas

Tick Bite Prevention Tips

1. Wear appropriate clothing: Long sleeves, long trousers, and closed shoes when outdoors
2. Use effective repellents: Apply EPA-registered insect repellents to skin and clothing
3. Stay on cleared paths: Avoid walking through tall grass and dense vegetation
4. Perform regular tick checks: Examine your body thoroughly after outdoor activities
5. Remove ticks promptly: Use fine-tipped tweezers to extract attached ticks completely

Tularemia and Pets: Can Animals Transmit It?

While pets rarely transmit tularemia directly to humans, they can serve as transport hosts for infected ticks, making comprehensive tick control essential for household protection. Rabbits, dogs, and cats may carry infected ticks into home and surrounding areas, or develop tularemia themselves after exposure.

Tularemia vs. Lyme Disease vs. Plague

Global Occurrence & High-Risk Regions

Tularemia occurs across the Northern Hemisphere, with significant regional variations in incidence and tularemia types. The United States reports approximately 200 cases annually, primarily from Arkansas, Kansas, and Oklahoma. European countries, particularly Scandinavia and Eastern Europe, experience periodic outbreaks.

High-risk regions typically feature abundant wildlife, suitable tick habitats, and frequent human outdoor activity increasing exposure risk. Climate change and ecological factors continue to influence the geographic distribution of this tick-borne disease.

Tularemia in Children

Children face similar risks as adults but may have different clinical presentations. Young children often develop more severe symptoms and require careful monitoring during tularemia treatment. Parents should be particularly vigilant about tick prevention when children play outdoors and seek medical attention promptly if children develop fever after potential exposure. This glandular infection can progress more rapidly in paediatric patients, making early recognition and treatment crucial for optimal outcomes.

Tularemia in Pregnancy

Pregnant women with tularemia require specialised medical care to protect both maternal and foetal health. Certain antibiotics used for tularemia treatment may not be suitable during pregnancy, necessitating careful drug selection. The infection itself can potentially affect pregnancy outcomes, making prompt diagnosis and appropriate therapy essential. Pregnant women should take extra precautions to avoid exposure, particularly during outdoor activities in endemic areas.

When to Consult a Doctor

You should seek medical attention if you develop fever, headache, or other concerning symptoms after potential exposure to ticks, infected animals, or contaminated environments. Early consultation is particularly important if you notice skin ulcers, swollen lymph nodes, or respiratory symptoms. Healthcare providers can assess risk factors, evaluate symptoms, and initiate appropriate diagnostic testing and treatment. Don't delay seeking care, as early tularemia treatment significantly improves outcomes and reduces complication risks.

Conclusion

Understanding tularemia empowers you to recognise risks and seek appropriate care when needed. At Metropolis Healthcare, we support your health journey with comprehensive diagnostic services spanning over 4,000 tests and profiles. Our extensive network of 220+ laboratories and 10,000+ touchpoints across India ensures accessible, accurate testing when you need it most. From routine blood work to specialised infection panels, our home sample collection service brings convenient, reliable diagnostics directly to you.

FAQs

What is tularemia, and how do you get it?

Tularemia is a bacterial infection caused by Francisella tularensis, spread through tick or fly bites, contact with infected animals, inhalation, or contaminated food or water.

What are the first signs of tularemia?

Early symptoms include sudden fever, chills, headache, muscle aches, and sometimes a skin ulcer or swollen lymph nodes.

How serious is tularemia?

It can be serious if untreated, but prompt antibiotic treatment usually leads to full recovery.

Can tularemia be cured?

Yes, tularemia is curable with appropriate antibiotics, especially when treated early.

Is tularemia contagious from person to person?

No, it does not spread between people.

How fast do tularemia symptoms appear?

Symptoms usually develop within 3–5 days but can appear anytime between 1 and 14 days.

What animals carry tularemia?

Rabbits, rodents, ticks, deer flies, and occasionally domestic animals like cats can carry the bacteria.

How can you prevent tularemia if you work outdoors?

Use insect repellent, wear protective clothing, avoid handling wild animals, and check for ticks regularly.

References

• https://pubmed.ncbi.nlm.nih.gov/32989563/
• https://www.cdc.gov/mmwr/volumes/73/wr/mm735152a1.htm
• https://www.webmd.com/a-to-z-guides/what-is-tularemia