Summary about Disease
Tularemia, also known as rabbit fever or deer fly fever, is a rare infectious disease caused by the bacterium Francisella tularensis. It can affect humans and animals, primarily rabbits, hares, and rodents. The disease is typically transmitted to humans through contact with infected animals, insect bites (ticks and deer flies), or inhalation of contaminated aerosols. Tularemia can manifest in various forms, depending on the route of infection, ranging from mild to life-threatening.
Symptoms
Tularemia symptoms vary depending on how the bacteria entered the body. Common symptoms include:
Ulceroglandular: Skin ulcer at the site of entry, swollen and painful lymph nodes.
Glandular: Swollen and painful lymph nodes without an ulcer.
Oculoglandular: Eye irritation, redness, swelling, and discharge, with swollen lymph nodes near the ear.
Pneumonic: Cough, chest pain, difficulty breathing (often from inhaling the bacteria).
Typhoidal: Sudden onset of fever, chills, muscle aches, sore throat, headache, fatigue, weight loss, and sometimes pneumonia.
Oropharyngeal: Sore throat, mouth ulcers, abdominal pain, vomiting, and diarrhea (usually from eating or drinking contaminated food or water). Other common symptoms may include:
Fever
Chills
Headaches
Fatigue
Causes
Tularemia is caused by the bacterium Francisella tularensis. The primary ways humans contract tularemia are:
Tick and Deer Fly Bites: Infected ticks and deer flies transmit the bacteria through their bites.
Contact with Infected Animals: Handling infected animals (rabbits, hares, rodents) or their carcasses.
Ingestion of Contaminated Food or Water: Eating undercooked meat from infected animals or drinking contaminated water.
Inhalation: Breathing in bacteria-containing dust or aerosols (e.g., during lawn mowing, construction).
Laboratory Exposure: Accidental exposure to the bacteria in a laboratory setting.
Medicine Used
Antibiotics are the primary treatment for tularemia. Common antibiotics include:
Streptomycin: Historically the drug of choice, but requires intramuscular injection.
Gentamicin: Another injectable antibiotic.
Doxycycline: An oral antibiotic.
Ciprofloxacin: An oral antibiotic. Treatment duration varies depending on the severity and form of the disease, typically lasting 10-21 days.
Is Communicable
Tularemia is not typically transmitted from person to person. However, direct contact with open wounds or bodily fluids of an infected person could potentially pose a risk, although this is extremely rare. The primary modes of transmission are animal-to-human or environmental-to-human.
Precautions
Avoid Tick and Deer Fly Bites: Use insect repellent containing DEET, wear long sleeves and pants in wooded areas, check for ticks regularly, and remove them promptly.
Handle Animals Carefully: Wear gloves when handling animals, especially rabbits, hares, and rodents. Cook meat thoroughly.
Water Safety: Drink treated or boiled water in areas where water contamination is suspected.
Dust Control: Wear a mask when mowing, gardening, or working in areas with potential dust exposure.
Protective Gear: Use appropriate personal protective equipment (PPE) in laboratories working with Francisella tularensis.
How long does an outbreak last?
The duration of a tularemia outbreak can vary significantly depending on the source of infection, the geographic area, and the effectiveness of public health interventions. A localized outbreak linked to a specific source (e.g., contaminated water supply) might be resolved within a few weeks to months after identifying and controlling the source. Larger outbreaks, particularly those affecting wildlife populations, could persist for longer periods, with sporadic human cases occurring over several months or even years. Surveillance and control efforts are crucial for limiting the duration and impact of outbreaks.
How is it diagnosed?
Tularemia is diagnosed through:
Blood Tests: Detecting antibodies to Francisella tularensis or identifying the bacteria itself using PCR (polymerase chain reaction).
Culture: Growing the bacteria from a sample (e.g., ulcer, lymph node aspirate, sputum), but this is less common due to the risk of laboratory exposure.
Clinical Presentation: Evaluating the patient's symptoms and medical history, including potential exposure to infected animals or insect bites. Diagnosis can be challenging because tularemia is rare, and its symptoms can resemble those of other diseases.
Timeline of Symptoms
The incubation period (time between exposure and symptom onset) for tularemia typically ranges from 1 to 14 days, with most people developing symptoms within 3 to 5 days.
Days 1-5: Initial symptoms such as fever, chills, headache, muscle aches, and fatigue usually appear.
Days 2-10: Depending on the form of tularemia, specific symptoms like skin ulcers, swollen lymph nodes, eye inflammation, or respiratory problems develop.
Days 7-14: Without treatment, symptoms can worsen, potentially leading to severe complications such as pneumonia, sepsis, or meningitis. With appropriate antibiotic treatment, symptoms usually improve within a few days, and recovery occurs over several weeks.
Important Considerations
Early Diagnosis and Treatment: Early diagnosis and antibiotic treatment are crucial to prevent serious complications and death.
Bioterrorism Agent: Francisella tularensis is considered a potential bioterrorism agent due to its high infectivity and ability to be aerosolized.
Veterinary Importance: Veterinarians and animal handlers should be aware of the risk of tularemia in animals and take appropriate precautions.
Geographic Distribution: Tularemia is found worldwide, but it is more common in certain regions, such as North America, Europe, and Asia.
Public Health Reporting: Tularemia is a reportable disease, meaning that healthcare providers are required to report cases to public health authorities to track and control the disease.