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Three Oregon Tularemia Cases in Humans

Case 1

In early 2009, a woman living in rural southern Oregon picked up a stray kitten and received multiple bites and scratches on her right arm and left hand. She immediately cleaned wounds with Betadine® (povidone – iodine) and her right arm healed without problems. Five days later her left finger became hot, red and sore. She went to Urgent Care where she was treated with Augmentin®. The next day the wounds were worse, so she returned to the Urgent Care and was given two intramuscular injections of Rocephin® and sent home. By the ninth day, the wound site was very inflamed and swollen. She went to her Primary Care Physician (PCP) who sent her to the Emergency room (ER) where a culture was taken. She was admitted for aggressive IV antibiotic treatment. The patient recovered uneventfully. The patient’s cats hunt in nearby fields. The perpetrator feral kitten had been hanging around her house and had presumably been hunting for food. The cat was not tested for tularemia. 

Case 2

A man’s leg was scratched after he accidentally stepped on his cat in southern Oregon.  The wound was small and his wife cleaned the wound site with hydrogen peroxide. During the next two days, the area around the scratch became red and swollen and the man experienced pain when walking  Three days after the scratch occurred, the man went to the ER where Ancef® 2 gms IV, and Keflex® 500 mg were administered orally. During the course of the week after the incident, the wound continued to worsen and a culture was taken. The patient recovered after changing antibiotic treatment based on the identification of the organism as tularemia.

Case 3

A woman’s right hand was bitten when she tried to remove a squirrel form her cat’s mouth in southern Oregon. The bite wound on her thumb and middle finger became infected and her PCP prescribed Amoxicillin®. In the course of the next 10 days, she developed a fever, the wound worsened and the woman presented to the ER with right axillary lymphadenopathy and fever. During her visit a culture was taken and the next day she was admitted for IV antibiotics and hand surgical debridement.The diagnosis was tularemia. She recovered well.

The diagnosis in all the previously mentioned cases was tularemia caused by Franciella tularensis.

Editorial

In the United States, most persons with tularemia acquire the infection from arthropod bites, particularly tick bites, or from contact with infected mammals, particularly rabbits. Historically, most cases of tularemia occurred in summer, related to arthropod bites, and in winter, related to hunters coming into contact with infected rabbit carcasses. The first report of a human case of tularemia  transmitted by a cat bite was reported in 1957[1]. Since then a handful of reports have been published. Outbreaks of tularemia in the United States have been associated with muskrat handling, tick bites, deerfly bites, and lawn mowing or cutting brush. Sporadic cases in the United States have been associated with contaminated drinking water and various laboratory exposures[2].

Tularemia, caused by the bacterium Francisella tularensis, is a zoonotic disease that occurs over much of the northern hemisphere. It has a broad host range and has been reported from at least 250 species. Four subspecies of F. tularensis are recognized, of which three occur in North America. Francisella tularensis subsp. tularensis (Type A) is found predominantly in North America. Francisella tularensis subsp. holarctica (Type B) is found throughout much of the northern hemisphere[3].

In our cases contact with 2 cats and 1 squirrel was a significant risk factor for acquiring F. tularensis infection. This can be important information for veterinarians, certified veterinarian technicians and other staff that may be in close contact with stray, feral or wildlife as this agent is found in nature. A cat with chronic subcutaneous masses infected with ulceroglandular form of tularemia was reported in the literature and more specifically in Oregon in 2004[4]. A greater awareness of this complication following a cat bite or cat scratch is important for recognizing this uncommon infection.

References

1. Miller LD, Montgomery EL. Human tularemia transmitted by bite of cat. J Am Vet Med Assoc 1957;130:314

2. Tularemia--United States, 1990-2000. MMWR Morb Mortal Wkly Rep 2002;51:181-4

3. Kugeler KJ, Pappert R, Zhou Y and Petersen JM. Real-time PCR for Francisella tularensis types A and B. Emerg Infect Dis 2006;12:1799-801

4. Valentine BA, DeBey BM, Sonn RJ, Stauffer LR and Pielstick LG. Localized cutaneous infection with Francisella tularensis resembling ulceroglandular tularemia in a cat. J Vet Diagn Invest 2004;16:83-5.

Reported by

Emilio DeBess, DVM, MPVM, State Public Health Veterinarian, Oregon Department of Human Services

Barbara A Progulske, DVM, MPH, Dipl ACVPM, Clinical Epidemiologist Preparedness program, Oregon Department of Human Services