Human infection may occur following animal contact, such as through the practice of handling live or dead animals infected with tularemia. This organism may also be carried by hamsters and prairie dogs.
Dermacentor wood tick is another transmitter of the disease, and this tick is often found on rabbits. A tick bite therefore is a common route of infection. Important to note, Centers for Disease Control and Prevention (CDC), has classified tularemia as an agent used for potential bioterrorism exposure due to its ease of ability to spread.
The deer fly, often found on deer, is a common transmitter of the disease. Therefore, close contact with deer can predispose an individual to tularemia.
This bacteria stains gram negative which helps with identification.
This organism has an intermediate shape between a cocci (sphere) and bacilli (rod), hence the descriptor coccobacilli.
Francisella tularensis is an intracellular pathogen that can survive and replicate within host macrophages, but may also infect many other cell types.
Francisella can be cultured using charcoal yeast agar with cysteine and iron for diagnosis.
Ulceration may occur at the point of entry of the bacteria. This is usually the site of the tick or fly bite. It often presents as a papule progressing to an ulcer at the site of infection.
Fever is a presenting symptom of tularemia. The fever may resolve for a few days but eventually returns.
Lymphadenopathy is a common symptom of tularemia. It is common in ulceroglandular tularemia which presents with an ulcerative lesion at the site of the tick bite, with tender draining lymph nodes.
Granulomas may form and occasionally caseate, imitating tuberculosis. F. tularensis may remain alive in tissues for some time, despite this host reaction.
In most cases aminoglycoside antibiotics like streptomycin or gentamicin, are effective in treating the infection. Streptomycin being the drug of choice. Usually administered intramuscularly every 12 hours from 7–14 days. Please note, treatment will depend on the severity of infection.
Picmonic's rapid review multiple-choice quiz allows you to assess your knowledge.
*Average video play time: 2-3 minutes
Unforgettable characters with concise but impactful videos (2-4 min each)