Tularemia: Causes, Symptoms, and Treatment Options

Tularemia: What Is It?

Tularemia, which is also known as rabbit fever or deer fly fever, is an uncommon infectious disease that affects the eyes, lymph nodes, skin, and lungs. The causative organism is Francisella tularensis, which is a bacterium. Tularemia in humans is rare but serious. Mammals, more specifically rodents, rabbits, and hares, are most commonly affected by this disease. The disease can also affect birds, domestic animals, sheep, and others. There are various routes of spread of this infection, such as a tick bite and exposure to an infected animal directly. It is very contagious and can be life-threatening. Notably, tularemia does not spread between people.

How Tularemia Can Spread to Humans?

This disease naturally does not occur in human beings, and human-to-human transmission hasn't been observed as yet. It is more prevalent in rural communities because of the availability of birds and mammals. The organism persists in soil, dead animals, and water for weeks. This infection does not have a single route like other infections. It can spread through various routes. The tularemia symptoms and severity of the infection depend on the route of infection. The various routes through which this infection can spread are as follows:

1. Bites From Ticks and Deer Flies:

Some ticks, including the dog tick (Dermacentor variabilis), wood tick (Dermacentor andersoni), lone star tick (Amblyomma americanum), and deer flies (Chrysops species), have been known to carry the tularemia bacteria. When such bugs bite individuals, they transmit the bacteria, resulting in a type of disease referred to as ulceroglandular or glandular tularemia.

2. Handling Infected Animals:

Individuals can be infected through contact or handling animals with the bacteria, particularly if the skin is broken with cuts or abrasions. This occurs with activities such as hunting or skinning animals, including rabbits, muskrats, prairie dogs, and other rodents. Domestic cats are also at risk and can transfer the infection to humans. Animal-handling infections can cause glandular, ulceroglandular, or oculoglandular tularemia. Moreover, consumption of raw meat from infected animals may lead to oropharyngeal tularemia.

3. Inhalation of Contaminated Aerosols or Dust:

Tularemia bacteria can be aerosolized or dusted into the air from activities such as farming or gardening. For example, operating heavy machinery like tractors or lawnmowers over fields where infected animals have died can aerosolize the bacteria into the air. Inhalation of these particles can cause pneumonic tularemia, a serious form of the disease.

4. Contaminated Water Consumption:

Water sources are infected with the tularemia bacteria by coming into contact with contaminated animals. Drinking untreated water from infected sources leads to oropharyngeal tularemia. This type of tularemia transmission is more frequently occurring in Europe than in America.

Precautions must be taken to decrease the possibility of infection, including using repellent to avoid tick and deer fly bites, wearing gloves when dealing with animals, cooking meat well, and avoiding the ingestion of untreated water.

What Are the Symptoms of Tularemia?

The initial symptoms of the disease are visible in affected people within three to five days, but it can take up to 14 days. The symptoms of tularemia depend on the type of infection and where it affects your body. Most types cause a fever and sometimes a tularemia rash, along with other symptoms based on how the germs enter your body.

1. Ulceroglandular and Glandular Tularemia

These are the most common forms.

You may have:

• Fever.

• Very swollen, painful lymph nodes.

• A skin sore or open wound (only in ulceroglandular tularemia).

2. Oculoglandular Tularemia (Affects the Eyes):

You may have:

• Eye pain.

• Watery or teary eyes.

• Sensitivity to light.

• Swollen, painful lymph nodes near the ears or neck.

• An open sore on the eye (corneal ulcer).

3. Oropharyngeal Tularemia (From Eating or Drinking Contaminated Food or Water):

You may have:

• Fever.

• A severe sore throat.

• Red, swollen throat with white patches.

Some people may also get:

• Vomiting.

• Diarrhea (sometimes with blood).

• Stomach pain.

4. Pneumonic Tularemia (From Breathing in the Bacteria):

You may have:

• Fever.

• Cough.

• Shortness of breath.

• Chest pain or tightness.

• Muscle aches.

• Red bumps or rash on the skin.

• Coughing up blood.

5. Typhoidal Tularemia (A Rare and Serious Form):

You may have:

• High fever and chills.

• Headache.

• Muscle aches.

• Sore throat.

• Loss of appetite.

• Stomach pain.

• Diarrhea, nausea, or vomiting.

• Confusion (especially in severe cases).

What Is the Pathophysiology of Tularemia?

Francisella tularensis may infect a wide variety of immune and non-immune cells and lead to necrosis and microabscesses in multiple sites. Macrophages are the initial primary target cells and may disseminate infection from the primary site into regional lymph nodes and beyond. Ongoing research aims to identify immune evasion mechanisms, such as caspase-3-mediated cell death, which could become targets for future therapies.

The disease can result from inhaling as few as ten organisms. Once within the body, the bacteria multiply rapidly. Ulceration commonly occurs at the entry site, typically followed by local lymphadenopathy. Granuloma formation is prevalent, often leading to misdiagnosis as Mycobacterium tuberculosis.

F. tularensis can evade phagocytosis and persist in infected cells for extended periods. The time between infection and the onset of symptoms varies from two to nine days. While a few individuals may remain asymptomatic, most experience an acute septic reaction that can result in death.

What Is the Toxicokinetics of Tularemia?

The organism is classified as a category A biowarfare agent due to its high infectivity, stability in liquids, ease of cultivation, ability to spread easily, and potential to cause severe illness and morbidity. Its environmental resilience can lead to repeated outbreaks and relapses over several months (tularemia cases in the US increase). Any infection should be promptly reported to local authorities.

What Are the Causes of Tularemia?

Tularemia is caused by a bacterium (a type of germ) called Francisella tularensis.

This germ lives in some animals, especially:

• Rabbits and hares.

• Rodents (like mice or squirrels).

• Cats.

These animals act as “reservoirs,” meaning they carry the bacteria without always appearing sick. Tularemia can also spread through ticks and other biting insects that pick up the bacteria from these animals.

There are two main types of F. tularensis:

• Type A: Causes more serious illness and is found mainly in the United States.

• Type B: Usually causes milder symptoms and is found in North America and many other parts of the world.

Who Can Get Tularemia?

Tularemia can affect anyone, but certain jobs, hobbies, or health conditions can increase your risk, especially if they bring you into contact with infected animals or insects. You may be more likely to get tularemia if you:

• Hunt or handle raw game meat.

• Veterinary professionals, wildlife workers, and animal control officials who work with animals.

• Spend time outdoors where ticks or biting insects are common.

• Have a weakened immune system, such as from HIV, cancer, or medications that lower your immunity.

• Work in certain jobs, like farming, sheep shearing, or laboratory work with F. tularensis. These can increase your risk of getting a lung infection (pneumonic tularemia).

• Live in the central U.S - Most cases are reported in Arkansas, Oklahoma, Missouri, Nebraska, South Dakota, and Kansas.

How Can Tularemia Be Diagnosed?

Tularemia can be deadly if it is not diagnosed and treated promptly. To make a diagnosis of tularemia, a doctor will take a look at you, ask you about symptoms, and check your blood or other body fluids. Based on your symptoms, they may examine your lymph nodes, your throat, your eyes, and any ulcers, bumps, or rashes (tularemia rash)you have on your skin. To find out if you have tularemia, your healthcare provider may do one or more of these tests:

1. Blood Test:

• A small amount of blood is taken from your arm and sent to a laboratory.

• The lab tests the blood for signs of tularemia or tries to grow the F. tularensis bacteria from your blood.

• Because the bacteria grow slowly, early results might look normal, so you might need to repeat the test later.

2. Biopsy:

• If you have swollen lymph nodes or a skin sore (ulcer), your provider may take a small tissue sample.

• The lab checks the sample for F. tularensis or tries to grow the bacteria from it.

3. Nasal or Throat Swab:

• Your provider uses a soft swab (like a long Q-tip) to collect mucus from your nose or throat.

• The lab checks for signs of the bacteria in the sample.

4. Pleural Fluid Test (Thoracentesis):

• If there’s fluid around your lungs, your provider may remove some with a needle.

• The lab checks this fluid for F. tularensis.

How Is Tularemia Treated?

Tularemia is treated with antibiotics that kill the bacteria causing the illness.

• These antibiotics may be given by injection (a shot) or taken by mouth (as pills).

• If the infection is serious, you may need other treatments to help with complications.

It is very important to start tularemia treatment early. If your doctor thinks you might have tularemia, they may give you antibiotics even before the test results are back to prevent the illness from getting worse.

Antibiotics Used:

Doctors may use one or more of the following antibiotics to treat tularemia:

• Streptomycin.

• Gentamicin.

• Doxycycline.

• Azithromycin.

• Ciprofloxacin or Levofloxacin.

Are There Any Complications?

If this infection is left untreated, it can prove to be life-threatening. There can be certain other complications, as follows:

1. Pneumonia or Inflammation of the Lungs - This can lead to failure of the lungs, and hence, respiration will be compromised.

2. Meningitis - It is the inflammation or infection of the brain and spinal cord. This can be fatal sometimes.

3. Pericarditis - Irritation or inflammation of the surrounding tissues or covering of the heart.

4. Osteomyelitis - A bone infection.

How Can Tularemia Be Prevented?

No vaccine has been invented yet for this type of infection, but the following measures can be followed to prevent this infection, especially for those who are prone to this condition via their occupation.

• Protect against insects by using insect repellent. In mosquito-prone areas, wear long sleeves and apply mosquito repellents.

• Take precautions while gardening, like wearing face masks and more.

• Wash your hands after coming in contact with animals, and cook the meat completely at the proper temperature.

• Take enough precautions to keep the pet animals safe.

When Should I See My Healthcare Provider?

You should see a healthcare provider if:

• You have symptoms that might be tularemia (like fever, sore throat, swollen lymph nodes, or a skin sore).

• You think you were exposed to tularemia, for example, after a tick bite or handling a wild animal. Your provider may give you antibiotics to help prevent illness.

• Your symptoms return while you're being treated or come back after you finish tularemia treatment.

When Should I Go to the ER?

Go to the emergency room right away if you have any signs of a serious illness, including:

• A high fever of over 103 Degrees Fahrenheit (39.4 Degrees Celsius).

• Confusion or sudden changes in mental alertness.

• Vomiting or pooping blood.

• Coughing up blood.

• Blue lips, skin, or nails (a sign you’re not getting enough oxygen).

• Severe belly (abdominal) pain.

• Trouble breathing or sudden shortness of breath.

Conclusion:

Tularemia is an infection that can cause certain complications if not managed on time. It is easy for tularemia to spread, even with small amounts of bacteria. It is regarded as a possible biological weapon as well. Although there is currently no recognized vaccination, researchers are working on it. In order to lower the possibility of tularemia, one should apply mosquito repellent, avoid touching dead animals with their bare hands, and avoid swallowing contaminated food or water. For further information about this kind of infection, you can consult one of the specialists here at icliniq.com.

Key Takeaway From iCliniq:

Tularemia is rare but potentially life-threatening if not detected early. At iCliniq, you can get fast, expert guidance from infectious disease specialists, whether you've had a tick bite, unusual symptoms, or need help assessing your risk. Early diagnosis and treatment save lives. Consult a doctor on iCliniq anytime, from anywhere.