Tularemia, also known as rabbit fever or deer fly fever, is an infectious disease caused by the bacterium Francisella tularensis. The bacteria are most commonly found in animals such as rabbits, rodents, and deer, and can be transmitted to humans through direct contact with infected animals, insect bites, or exposure to contaminated soil or water.

Tularemia can affect different parts of the body, depending on how the bacteria enter the body. Symptoms can include fever, chills, headache, muscle aches, and swollen lymph nodes. If left untreated, tularemia can cause more serious complications, such as pneumonia or sepsis.

Diagnosis of tularemia is typically based on clinical symptoms and confirmed through laboratory testing of blood, urine, or other bodily fluids. Treatment usually involves a course of antibiotics, such as streptomycin or gentamicin, and is generally effective if started early.

Prevention of tularemia includes avoiding contact with infected animals, using insect repellent to prevent bites from ticks and other insects that may carry the bacteria, and wearing protective clothing when handling infected animals or working in areas with contaminated soil or water. Good hygiene practices, such as washing hands frequently, can also help prevent the spread of the disease.

Tularemia doesn't occur naturally in humans and isn't known to pass from person to person. However, tularemia occurs worldwide, especially in rural areas, because many mammals, birds and insects are infected with F. tularensis. The organism can live for weeks in soil, water and dead animals.

Unlike some infectious diseases that spread from animals to people in just one way, tularemia has several modes of transmission. How you get the disease usually determines the type and severity of symptoms. In general, you can get tularemia through:

• Insect bites. Although a number of insects carry tularemia, ticks and deer flies are most likely to transmit the disease to humans. Tick bites cause a large percentage of cases of ulceroglandular tularemia.
• Exposure to sick or dead animals. Ulceroglandular tularemia can also result from handling or being bitten by an infected animal, most often a rabbit or hare. Bacteria enter the skin through small cuts and abrasions or a bite, and an ulcer forms at the wound site. The ocular form of tularemia can occur when you rub your eyes after touching an infected animal.
• Airborne bacteria. Bacteria in the soil can become airborne during gardening, construction or other activities that disturb the earth. Inhaling the bacteria can lead to pneumonic tularemia. Laboratory workers who work with tularemia also are at risk of airborne infection.
• Contaminated food or water. Although uncommon, it's possible to get tularemia from eating undercooked meat of an infected animal or drinking contaminated water.

There's currently no vaccine available for tularemia. If you work in a high-risk occupation or live in an area where tularemia is present, these measures may help reduce your chance of infection:

• Protect yourself from insects. Tularemia in the United States is often related to a tick bite. In other parts of the world, tularemia is more commonly contracted through mosquito bites.
• If you spend time in tick- or mosquito-infested areas, wear long-sleeved shirts and long pants, tuck your pants into your socks, and use a broad-brimmed hat to help protect your face and neck. Use an insect repellent with 20% to 30% DEET, picaridin or IR3535, but follow the manufacturer's directions carefully. Apply insect repellent in moderation, and wash it off at the end of the day.
• Check yourself for ticks often and remove them immediately if you find any. Be sure to check your pets too.
• Take care when gardening. Home gardeners and professional landscapers should consider wearing a face mask when excavating the soil, clearing weeds or brush, or mowing lawns.
• Handle animals carefully. If you hunt or handle wild rabbits or hares, wear gloves and protective goggles, and wash your hands thoroughly with soap and hot water after touching the animal.
• Don't eat undercooked meat. Cook all wild meat thoroughly, and avoid skinning or dressing any animal that appeared ill. Heat kills F. tularensis, so cook meat to the right temperature — a minimum of 160 F (71.1 C) for ground meat and game meat — to make it safe to eat. Poultry should be cooked to 165 F (73.8 C).
• Protect your pets. Livestock and pets can contract tularemia if they eat part of a diseased rabbit or are bitten by an infected tick. To help keep your pets safe, avoid letting them outside unsupervised, provide them with flea and tick protection, and don't let them come in close contact with wild or dead animals.

Tularemia can be effectively treated with antibiotics given by injection directly into a muscle or vein. The antibiotic gentamicin is typically the treatment of choice for tularemia. Streptomycin is also effective, but can be hard to get and may have more side effects than other antibiotics.

Depending on the type of tularemia being treated, doctors may prescribe oral antibiotics such as doxycycline (Oracea, Vibramycin, others) or ciprofloxacin (Cipro) instead.

You'll also receive therapy for any complications such as meningitis or pneumonia. In general, you should be immune to tularemia after recovering from the disease, but some people may experience a recurrence or reinfection.