Epidemiology of F. tularensis Infection

Rabbits, ticks & muskrats are main reservoirs in US

Two biochemical varieties

•F. tularensis bv. tularensis (a.k.a., Jellison Type A)

•F. tularensis bv. palaearctica (a.k.a., Jellison Type A)

Jellison Type A strains are the major biovar associated with severe disease in North America

•Most commonly, transmission by tick vectors from rabbit reservoirs or direct contact with rabbits

Biochemical Variants (Biovar) of

Francisella tularensis

Virulence Factors of

Fransicella tularensis

Antiphagocytic capsule

•Thin lipid capsule present in pathogenic strains

Facultative intracellular parasite that can survive in macrophages of the reticuloendothelial system

Laboratory Culture, Prevention &

Treatment of F. tularensis

Nonmotile

Fastidious and slow-growing

Requires cysteine-supplemented specialized media wi

Requires prolonged growth

Disease prevention:

•Avoidance of reservoirs and vectors

•Protective clothing and gloves

•Laboratory personnel should be made aware of potential for Fransicella in clinical specimens

Antibody Response to Francisella tularensis Infections

Brucella spp.

Brucella

Infections

Brucella

Infections

(cont.)

Epidemiology of Brucellosis

Animals are natural reservoir

•Cattle, goats, sheep, swine, bison, elk, dogs, foxes, coyotes

500,000 human cases per year worldwide

Less than 100 annual cases in the U.S. due to successful control of the disease in livestock and the animal reservoir

Transmission via i) ingestion of contaminated milk or cheese, or ii) direct contact with infected animals or animal products

Because it can be transmitted to humans, brucellosis is one of the most regulated diseases of cattle in the U.S.