Tularemia 

Tularemia, a disease that affects both animals and man, is caused by the bacteria Francisella tularensis. Its name relates to the description in 1911 of a plague-like illness in ground squirrels in Tulare county, California (hence the name tularemia) and the subsequent work done by Dr. Edward Francis. Rabbits and rodents are most often involved in disease outbreaks. Some examples of animals, other than rabbits, that carry tularemia are meadow mice, ground hogs (woodchucks), ground squirrels, tree squirrels, beavers, coyotes, muskrats, opossums, sheep, and various game birds.

Tularemia occurs throughout North America and is also found in Europe and Asia. Approximately 150-300 tularemia cases are reported in the United States annually, with a majority of those from Alaska, Arkansas, Illinois, Oklahoma, Missouri, Tennessee, Texas, Utah, and Virginia. The frequency of tularemia has dropped markedly over the last 50 years and there has been a shift from winter disease (usually from rabbits) to summer disease (more likely from ticks). Tularemia in humans is relatively rare in Arizona. There were five cases reported in Arizona over the last ten years and 28 cases over the last twenty-five years.

F. tularensis, like the plague and anthrax bacteria, was weaponized by the U.S. (until the 1960's) and the former Soviet Union (until the 1990's). Other countries have been or are suspected to have weaponized this bacteria. This organism can potentially be produced in either a wet or dry form and introduced by aerosolization or contamination of food and water sources.

Anyone can get tularemia if they spend time outdoors in areas where infected animals, deer flies, or ticks can be found. Rabbit hunters, trappers, and laboratory workers exposed to the bacteria are at higher risk.

Many routes of human exposure to the tularemia germ are known to exist. The common routes include direct contact with blood or tissue while handling infected animals, through the bite of arthropods (e.g., ticks, mosquitoes), or handling or eating undercooked small game animals (e.g., rabbit). The bacteria can remain viable in frozen rabbit meat for longer than 3 years. Less common means of transmission are drinking or swimming in contaminated water, from animal scratches or bites of animals contaminated from eating infected animals, and inhaling dust from contaminated soil or handling contaminated pelts or paws of animals. Tularemia is not directly transmitted from person to person.

Symptoms

The most common form of tularemia is usually acquired through the bite of blood-sucking arthropods or from contact with infected animals. Patients will develop an ulcer at the site of infection and regional lymph nodes become inflamed and swollen. Severe fever and flu-like symptoms may accompany the ulcer or lesion. Ingestion of the organism in contaminated food or water may result in painful pharyngitis, abdominal pain, diarrhea, and vomiting. Inhalation of the organism will result in sudden chills, fever, weight loss, abdominal pains, tiredness, and headaches. Inhalation of F. tularensis may result in tularemia pneumonia. Patients with this form of tularemia may develop a fever alone or a fever combined with an unusual pneumonia-like illness that can be fatal.

Symptoms generally appear between 1 and 14 days, but usually within 3-5 days.

Treatment

Certain antibiotics such as streptomycin are effective in treating tularemia. Others such as gentamycin and tobramycin have also been reported to be effective.