Bunny Rabbit. Getty

Two teenagers mowed their lawn. They became critically ill with pneumonia. The reason: Rabbits. Cottontail Rabbits. The bacteria Tularemia found in rabbits can be spread in the air and breathed if  a lawn mower or a weed whacker unfortunately hits a poor rabbit.

Tularemia is a very rare disease. It is also called "Rabbit Fever". There are about 100-200 cases a year found in the US.

It is however a serious disease.

Because it is rare, it is often not diagnosed immediately. Its treatment  (usually streptomycin injections) is different than other common bacterial diseases. Delays in treatment will affect how patients do. Without treatment, a serious form of the disease can have a mortality as high as 60%. With treatment, mortality is 1-2.5%.

What is the disease?

Tularemia is caused by the bacterium called Francisella tularensis (which is gram negative - for the micro folks).  It can be spread in different ways.

If it is inhaled it can cause a severe lung infection (pneumonia) with chest pain, coughing up blood, severe problems breathing. It often starts with sudden fever and chills, headache, muscle aches, joint pains, dry cough, and fatigue. This is very rare.

Most cases come from tick bites or touching dead rabbits or other affected rodents (including squirrels and beavers).  

The disease is marked by swollen glands and possibly skin lesions, eye irritation, and a sore throat - with symptoms depending on how infection occurred and what sort of infection developed.


More specifically, there are 6 different forms of the disease:

  • Ulceroglandular tularemia - Swollen and tender lymph nodes with ulcerated skin lesion

  • Glandular tularemia - Swollen and tender lymph nodes without skin lesions

  • Oculoglandular tularemia - Eye irritation on one side (conjunctivitis, corneal ulceration, tearing, swollen eyelid, pain looking at light), swollen lymph nodes

  • Oropharyngeal tularemia - Sore throat or tonsillitis with mucus, swollen lymph nodes in the neck,  abdominal pain, nausea, as well as vomiting and diarrhea with possible bleeding.

  • Pneumonic tularemia - Dry cough, shortness of breath, chest pain with breathing

  • Typhoidal tularemia - Fever, chills, muscle ache, fatigue, weight loss

How exactly does it spread?

Tularemia needs only a very low number of bacteria to infect someone: 10 if under the skin by a needle, 25 if breathed in.

The bacteria also is pretty hardy. It can survive for weeks in hay, water, soil or dead animals that have been contaminated often by rabbits that carry the bacteria. Sometimes exactly how it spread isn't clear - especially among landscapers and others who work outside.

 It may develop in just one day, but usually 3-5 days, or up to 14 days after exposure.

There are different ways to become infected with Tularemia

  • Touching Infected Animals (skin contact)
  • Bites from ticks or deer flies
  • Inhalation of contaminated material (such as by mowing or weed whacking the lawn)
  • Laboratory accident
  • Drinking contaminated water

How to avoid Tularemia

This results in an unusual set of advice:

  • Be careful mowing. Odd as it sounds, don't mow over animals.
  • Wear gloves when touching dead or sick animals 
  • Use bug repellent (like DEET) and wear pants and long sleeves outdoors
  • Be aware of any exposures and symptoms if working with Tularemia in a lab

There are different forms of the disease, are there different forms of the bacteria?

Yes, there are different strains A and B. Type B is milder, found in beavers, lemmings, muskrats, and even deer mice, and is the only type found in Europe, while both A and B are found in North America. Type A is found in rabbits (and related hares and pikas). Type B has even been reported from a pet hamster bite, but is very rare.

Where is it found?

Tularemia has been naturally found in each US state, except Hawaii. Over half of cases in the US are found in one of 4 states Arkansas, Missouri, South Dakota, and Oklahoma. Cases are also found in higher numbers in Martha's Vineyard, an island off the coast of Massachusetts. Cottontail rabbits were imported to Martha's Vineyard in the 1930's from Arkansas.

In 2014, Tularemia was found to have infected people in 4 counties in Colorado.

It is more likely to be found in the summer months, but can be found at other times of the year.

Animals may have died off for no clear reason before the disease is noted in a human patient.

This is a laboratory safety issue

Laboratory workers should be notified if Tularemia is suspected in a patient and should not work on growing the organism without special precautions.

There was a laboratory accident which led to 3 infections in Boston in 2004. It was not clear how the three were infected.

Prophylaxis can be taken after exposure, especially if exposure is realized quickly.

What else is worrisome about this disease?

There is concern that Tularemia could be a Bioterrorism agent. It is a serious illness when breathed in - if aerosolized, but is treatable.

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