Understanding Tularemia: Causes, Symptoms, and Effective Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Editorial note: This article is provided for educational purposes only. It is not medical advice. If you develop a sudden fever, chills, or swollen lymph nodes after outdoor activity or animal contact, contact a healthcare provider promptly.
Quick Answer: What is tularemia?
Tularemia, often called rabbit fever, is a zoonotic infection caused by the bacterium Francisella tularensis. It spreads through infected tick or deer fly bites, contact with animals like rabbits and rodents, or contaminated food and water. Symptoms include fever, chills and painfully swollen lymph nodes. It can be severe, but a 2-to-3-week antibiotic course treats it.
What the research says
Antibiotics work well across all forms of tularemia. In a systematic review of 870 cases from 35 countries (1993–2023), the fatality rate was 0.7% among patients treated with aminoglycosides, 0.9% with fluoroquinolones and 1.2% with tetracyclines. No patient with pneumonic disease who received ciprofloxacin died (Nelson et al., Clinical Infectious Diseases, 2024) [3].
Treatment appears to matter during pregnancy, too. Across 52 pregnant patients in 30 articles, no mothers died. Among 28 treated patients, 1 pregnancy loss and 1 fetal death were reported, versus 1 pregnancy loss and 3 fetal deaths among 24 untreated patients (Fleck-Derderian et al., Clinical Infectious Diseases, 2024) [4].
The Nature and Transmission of Tularemia
Tularemia is a significant infectious disease that bridges the gap between wildlife and human health. Caused by the bacterium Francisella tularensis, it is categorized as a zoonotic disease, meaning it primarily circulates among animals but can be transmitted to people. [1] In the United States, the infection is relatively rare, with fewer than 200 cases reported annually, yet it remains a serious concern due to its high infectivity—only a small number of bacteria are required to cause illness.
Transmission occurs through various pathways, most commonly via the bites of infected insects such as ticks and deer flies. Direct contact with the tissues or bodily fluids of infected animals, particularly rabbits, hares, and rodents, is another frequent route. In some cases, the bacteria can be inhaled, such as when a lawnmower accidentally runs over an infected animal, or ingested through contaminated food or untreated water.
Transmission route | Common sources |
Insect bites | Ticks, deer flies, and occasionally mosquitoes. |
Animal contact | Handling infected rabbits, hares, or rodents. [1] |
Inhalation | Breathing in dust or aerosols contaminated with bacteria. [1] |
Ingestion | Consuming untreated water or undercooked, contaminated meat. |
Skin/eye contact | Splashing contaminated water or fluids into the eyes or onto broken skin. |
Clinical Forms and Symptoms
The symptoms of tularemia are highly dependent on how the bacteria entered the body and which organs are primarily affected. Most individuals experience general flu-like symptoms, including a sudden high fever, chills, headache, and muscle aches. However, the specific form of the disease will dictate the secondary signs, such as skin ulcers at the site of an insect bite or severe respiratory distress if the bacteria were inhaled.
Healthcare providers categorize tularemia into several types based on these clinical presentations. Ulceroglandular tularemia is the most common form, characterized by an open sore (ulcer) and swollen lymph nodes. The most dangerous form, pneumonic tularemia, results from inhaling the bacteria or the spread of the infection to the lungs, leading to symptoms similar to severe pneumonia.
Tularemia type | Primary symptoms |
Ulceroglandular | Skin ulcers at the infection site and painfully swollen lymph nodes. |
Glandular | Swollen lymph nodes without the presence of skin ulcers. |
Oculoglandular | Inflammation, pain, and discharge in the eyes, often affecting only one side. |
Oropharyngeal | Severe sore throat, mouth ulcers, and digestive issues like abdominal pain. |
Pneumonic | Cough, chest pain, and difficulty breathing; this is the most severe form. |
Typhoidal | High fever and extreme exhaustion, potentially affecting multiple organ systems. |
Diagnosis, Treatment, and Prevention
Early diagnosis is critical for a positive outcome, as tularemia can be fatal if left untreated. Physicians typically rely on a combination of health history, physical examinations, and specialized laboratory tests. These tests may include blood cultures, biopsies of affected lymph nodes, or throat swabs to identify the presence of F. tularensis. Because the disease can progress rapidly, treatment is often initiated even before final test results are confirmed.
The standard treatment for tularemia involves a rigorous course of broad-spectrum antibiotics, typically lasting between two and three weeks. Common medications include streptomycin, gentamicin, and doxycycline. While the mortality rate for untreated cases can be as high as 50%, prompt antibiotic therapy reduces this risk to approximately 1%. Prevention focuses on avoiding exposure by using insect repellent, wearing protective clothing when handling wildlife, and ensuring that all drinking water is properly treated.
Essential Prevention Strategies
Insect protection: Use repellents containing DEET and perform regular tick checks after being outdoors.
Safe animal handling: Wear gloves and masks when handling or skinning rabbits and other rodents.
Water safety: Avoid drinking water from lakes, streams, or other untreated sources.
Environmental awareness: Use caution when mowing lawns in areas where infected wildlife may be present. [1]
Conclusion
Tularemia is a complex and highly infectious disease that requires careful attention, especially for those who spend significant time in outdoor or animal-related environments. While the various forms of the infection can be severe, the effectiveness of modern antibiotics means that a full recovery is highly likely with prompt medical intervention. By staying informed about transmission risks and practicing consistent prevention measures, individuals can safely enjoy the outdoors while minimizing their risk of infection.
Your next step: If you experience a sudden fever, chills, or swollen lymph nodes after spending time outdoors or handling animals, contact a healthcare provider immediately. Inform them of any recent insect bites or animal contact to ensure a prompt and accurate diagnosis, which is vital for a successful recovery.
Frequently Asked Questions
1. What is tularemia?
Tularemia is a highly infectious bacterial disease caused by Francisella tularensis, primarily spreading from animals to humans.
2. Is tularemia contagious between people?
No, there is no evidence that tularemia spreads directly from person to person.
3. What is "rabbit fever"?
Rabbit fever is a common name for tularemia, referring to the fact that rabbits are frequent carriers of the bacteria.
4. How do humans get tularemia?
Common ways include insect bites (ticks, deer flies), touching infected animals, or inhaling contaminated dust.
5. Can you get tularemia from mowing the lawn?
Yes, if a lawnmower runs over an infected animal, the bacteria can become airborne and be inhaled.
6. What are the first signs of infection?
Early symptoms often include a sudden high fever, chills, headache, and muscle aches.
7. What is the most common form of tularemia?
Ulceroglandular tularemia, which causes skin sores and swollen lymph nodes, is the most frequent type.
8. Which form is the most dangerous?
Pneumonic tularemia, which affects the lungs, is the most severe and potentially life-threatening form.
9. How is tularemia diagnosed?
Tularemia is diagnosed through physical exams and laboratory tests like blood cultures or lymph node biopsies.
10. What is the treatment for tularemia?
The primary treatment is a 2-to-3-week course of broad-spectrum antibiotics.
11. Can tularemia be fatal?
Yes, if untreated, the mortality rate can be high, but prompt antibiotic treatment reduces it to about 1%.
12. Where is tularemia most common in the U.S.?
Cases are most frequent in the south-central U.S., the Pacific Northwest, and parts of Massachusetts.
13. How can I prevent tularemia?
Use insect repellent, wear gloves when handling wildlife, and avoid drinking untreated water.
14. Do all animals carry tularemia?
No, but it is most common in rabbits, hares, and rodents like squirrels and voles.
15. What should I do if I suspect I have tularemia?
Seek medical attention immediately and inform your doctor about any recent outdoor activities or animal contact.
References
Centers for Disease Control and Prevention. About tularemia. CDC. August 27, 2026. https://www.cdc.gov/tularemia/about/index.html
Centers for Disease Control and Prevention. Tularemia data and statistics. CDC. March 12, 2025. https://www.cdc.gov/tularemia/data-research/index.html
Nelson CA, Winberg J, Bostic TD, et al. Systematic review: clinical features, antimicrobial treatment, and outcomes of human tularemia, 1993-2023. Clin Infect Dis. 2024;78(Suppl 1):S15-S28. PMID 38294108. https://doi.org/10.1093/cid/ciad736
Fleck-Derderian S, Davis KM, Winberg J, et al. Systematic review of tularemia during pregnancy. Clin Infect Dis. 2024;78(Suppl 1):S47-S54. PMID 38294114. https://doi.org/10.1093/cid/ciad686
Medical disclaimer
This content is for informational purposes only and does not constitute medical advice. Always seek the guidance of a qualified healthcare provider regarding any infectious disease concerns or symptoms.
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