Tularemia is a bacterial disease that affects people and many species of wild and domestic animals. It is caused by toxins in the blood produced by the bacterium Francisella tularensis. The bacteria can survive for weeks or months in a moist environment. There are 2 types of organisms that differ based on the severity of the disease they produce. Type A is more likely to cause severe disease and is found most commonly in North America. Disease resulting from Type B infection is less severe and occurs most commonly as a result of contact with aquatic animals or ingestion of contaminated water in North America and Eurasia. Cats and other carnivores may also acquire infection from eating an infected carcass.
In domestic animals, sheep are most often infected, but clinical infection has been reported in dogs, pigs, horses, and cats. Cats are at higher risk than many other domestic animals due to their predatory behavior. Cats also appear to have a greater susceptibility than other domes-ticated animals.
The disease can be transmitted from animals to humans by several routes. These include direct contact with bacteria in the tissue of infected animals, eating infected undercooked meat, being bitten by ticks or deer flies, and contact with contaminated water. Rarely, the bite of a cat that has recently fed on an infected animal has been found to be a source of human infection.
In most mammals, signs of illness may include heavy tick infestation, the sudden onset of high fever, swollen glands, lethargy, and poor appetite. Other signs such as stiffness, reduced mobility, increased pulse and respiratory rates, coughing, diarrhea, and frequent urination are occasionally seen. Prostration and death may occur in a few hours or days. In most cases, infection of domestic animals does not result in obvious signs of illness.
Animals with signs of disease are treated with an antibiotic. Early treatment should prevent death; however, prolonged treatment may be necessary. Control is difficult and is limited to reducing tick infestation, keeping pets confined to reduce predatory behavior, and rapid diagnosis and treatment. Animals that recover develop a long-lasting immunity.
Last full review/revision July 2011 by Otto M. Radostits, CM, DVM, MSc, DACVIM (Deceased); Eugene D. Janzen, DVM, MVS; Jodie Low Choy, BVMS; Dennis W. Macy, MS, DACVIM; Dudley L. McCaw, DVM, DACVIM (Small Animal, Oncology); Barton W. Rohrbach, VMD, MPH, DACVPM; J. Glenn Songer, PhD; Richard A. Squires, BVSc (Hons), PhD, DVR, DACVIM, DECVIM-CA, MRCVS; Bert E. Stromberg, PhD; Joseph Taboada, DVM, DACVIM; Charles O. Thoen, DVM, PhD; John F. Timoney, MVB, PhD, Dsc, MRCVS; Ian Tizard, BVMS, PhD, DACVM; Max J. Appel, DMV, PhD; David A. Ashford, DVM, MPH, DS; Stephen C. Barr, BVSc, MVS, PhD, DACVIM; J. P. Dubey, MVSc, PhD; Paul Ettestad, DVM, MS; Craig E. Greene, DVM, MS; Delores E. Hill, PhD; Johnny D. Hoskins, DVM, PhD