The Causes and Symptoms of Tularemia, or Rabbit Fever

09 January, 2021
Also known as rabbit fever, this is a type of bacterial infection, mainly registered in Europe, Asia, and North America. In this article, we'll you more about the causes and symptoms of tularemia.

Tularemia is an infectious disease caused by the bacteria Francisella tularensis. This bacteria resists cold climates and substances like bleach are not effective at destroying it. However, it’s quite sensitive to many common household disinfectants. In the article to follow, we’ll tell you more about the causes and symptoms of tularemia.

This disease is an infection that circulates among animals but is capable of spreading to humans at some point. The species that function as a reservoir for the bacteria are small mammals.

We can mention mice and squirrels, as well as hares and rabbits, as animals that serve as a reservoir for the bacteria. Its worldwide distribution is in the northern hemisphere: Europe, Asia, and North America.

Physicians have known about the disease since 1911. It was precisely in California where an outbreak took place that led to the identification of the bacteria.

To date, one hundred years later, it’s considered a disease capable of being used as a biological weapon, which is why there’s a legal obligation to notify the authorities when a confirmed case appears.

Data on tularemia

Tularemia has two preferential ages where it appears: children from five to nine years old and among the elderly over seventy-five.

It prevails in two periods of the year: Summer in the northern hemisphere – from May to August – and winter – from November to February.

Due to its form of contagion, there are certain people with certain professions or customs who are more prone to exposure, among them:

  • Gardeners: Exposure may occur by inhaling the bacteria.
  • Veterinarians: Due to their direct contact with animals.
  • Hunters: Those who practice hunting may come into contact with the bacteria through exposure to animal carcasses and ingestion if they eat them.

Ways of spreading tularemia

Tularemia spreads from animals to humans, and among animals themselves, but never among humans. A sick person cannot infect a healthy person. Therefore, it’s not necessary to isolate patients.

However, among the means of transmission from animals to humans we can mention the following:

  • Physical contact: This is the most frequent form of contagion. The human being comes into direct contact with the body of the animal that has tularemia. In general, transmission occurs through the existence of wounds and the exposure of mucous membranes. Those who are at the greatest risk are those in rural inhabitants, hunters, veterinarians, and farmers. The bacteria can spread through contact with live animals or corpses.
  • Stings: Some arthropods also function as carriers of the disease. Ticks and horseflies, for example. Since a decade ago, experts have also detected transmissions have from animals that they didn’t previously believe to be carriers, such as the crayfish.
  • Contaminated water: This is a minor form of contagion, but still important to consider. In the United States, experts estimate that up to 10 percent of infections occur from drinking water that’s been contaminated with the bacteria.
  • Inhalation: The bacteria can remain floating in the suspended dust that accumulates after agricultural activities. Humans inhale this dust and the disease attacks the respiratory system.
A skinned albow.
Skin wounds can be an entry point for tularemia.

Read more: Bats Are the Cause Behind Coronavirus

Symptoms of tularemia

The incubation period is short, which is the time that passes between contact with the bacteria and the appearance of symptoms. Usually, three to five days is all it takes. In some people, it can take up to fourteen days for the first symptom to appear.

The clinical picture will depend on the place of entry of the microorganism. It may appear with the following varieties:

  • Ulceroglandular: This the most common form of presentation. It happens when the contagion involved physical contact through the skin, leading to the formation of an ulcer at the site of contact. Then comes fever, swollen glands, severe exhaustion, and headache.
  • Glandular: This is a variant of the ulceroglandular form, only without the ulcer at the point of entry into the skin.
  • Ocular: This clinical picture involves symptoms having to do with the eye. Infected individuals experience ocular pain, secretions in the eyelids, reddening of the eyes, and swelling of the soft tissues near the palpebral zone.
  • Oropharyngeal: This is a manifestation of tularemia in the digestive system. It’s usually present when the route of infection was the ingestion of contaminated meat or water. Patients may suffer from fever, sore throat, vomiting, diarrhea, and ulcers inside the mouth.
  • Pulmonary: This is pneumonia caused by tularemia bacteria, so the symptoms are cough, fever, chest pain, and shortness of breath.
  • Typhoid: This is the least frequent manifestation, but possibly the most serious. Organs such as the spleen and liver increase in size, fever is very high, and digestive symptoms include vomiting and diarrhea.
A woman touching her neck.
Swelling of the lymph nodes is a characteristic sign of tularemia.

You may also want to read: What Should You Do About Swollen Lymph Nodes?

Treatment of tularemia

Antibiotics are effective in the treatment of tularemia. It’s a serious disease, but it’s entirely curable with timely detection and the proper administration of these drugs.

The antibiotic treatment can be oral or with injections, either intramuscular or intravenous. The drugs of choice are streptomycin and gentamicin. In the case of the oral route is preferred, doctors usually prescribe doxycycline. The professional will decide, according to the clinical picture and the characteristics of the patient, which one is appropriate.

Along with the antibiotic, doctors will prescribe the corresponding support measures for each symptom. They may administer fever reducers, antiemetics, and analgesics. Hospitalization is an option if there is dangerous organ involvement.

It’s assumed that once infected with tularemia, the person becomes immune to the bacteria for the rest of her or his life. This means that they cannot become infected again. However, science has recorded recurrences, so preventive measures are still mandatory for those who suffered from it.

So if you’ve been in environments where rodents are present, you’ve gone hunting, or have performed veterinary or farming work tasks, and after a few days, you start to have a fever or experience any of the symptoms of tularemia, consult a professional for an examination.

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  • Petersen, Jeannine M., and Martin E. Schriefer. “Tularemia: emergence/re-emergence.” Veterinary research 36.3 (2005): 455-467.
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