Suspected cases must be reported immediately by phone to the Thunder Bay District Health Unit at 625-5930 or toll-free 1-888-294-6630, ext. 5930 (Monday-Friday, 8:30am to 4:30pm). After hours and on weekends/holidays call Nurses Registry Thunder Bay at (807) 624-1280.
Tularemia (also known as rabbit fever) is a zoonotic bacterial disease caused by the bacterium Francisella tularensis (F. tularensis), which is a small, Gram-negative nonmotile coccobacillus. May be used as a potential bioterrorism agent.
Clinical presentation is typically sudden, with an abrupt onset of high fever, chills, fatigue, myalgia, nausea and headache. The nature of the illness depends on the site of inoculation and the virulence of the infecting organism, usually conforming to one of several clinical syndromes, including the following:
- Ulcero-glandular –cutaneous ulcer with regional lymphadenopathy at the entry site (most common)
- Glandular – regional lymphadenopathy with no ulcer
- Oculo-glandular – conjunctivitis with preauricular lymphadenopathy
- Oropharyngeal – stomatitis or pharyngitis, or tonsillitis and cervical lymphadenopathy
- Intestinal – intestinal pain, vomiting, and diarrhea
- Pneumonic – primary pleuropulmonary disease
- Typhoidal – febrile illness without early localizing signs and symptoms
Modes of transmission:
Humans become infected through tick bites, handling infected animal tissues, ingestion of contaminated food or water, and inhalation of contaminated aerosols (such as those generated while sorting contaminated hay or mowing). The average infectious dose for humans is estimated at 10 organisms by subcutaneous inoculation and 25 organisms by aerosol.
Related to size of innoculum; usually 3 – 5 days with a range of 1 – 14 days.
Period of Communicability:
Person to person transmission has never been reported; unless treated, infectious agent may be found in blood during first 2 weeks of disease and in lesions for a month; flies infective for 14 days and ticks throughout lifetime (two years); frozen rabbit meat has remained infective for more than three years.
All ages are susceptible, and long term immunity follows recovery; re-infection is extremely rare.
- History of tick or deerfly bite in last 14 days
- Contact with animals or animal products (i.e. veterinarian, pet industry worker, hunter, trapper, laboratory worker
- Consumption of contaminated water
- Contact with rodents or lagomorphs
- Consumption of game meat
Diagnosis & Laboratory Testing
Either of the following will constitute a confirmed case of Tularemia:
- Isolation of Francisella tularensis from an appropriate clinical specimen (e.g., blood, sputum)
- A significant (i.e., fourfold or greater) rise in serum antibody titre to F. tularensis antigen
Treatment & Case Management
Treatment is under the direction of the attending health care provider.
Provide education about the illness and how to prevent the spread (avoiding bites of deerflies, mosquitoes and ticks; using insect repellent, wearing light coloured clothing, long sleeved shirts and pants and checking for ticks frequently; cooking game meat thoroughly and using impermeable gloves when dressing game).