Bacterial Zoonoses Flashcards
What are the carriers of Brucella?
Sheep, cattle, pigs and dogs
How do humans get brucellosis?
- Consume unpasteurized dairy products
* Contact with infected animals
What populations are at high risk for brucellosis?
– Abattoirs (slaughterhouse workers)
– Veterinarians
– Farmers
– Lab Workers
What Category is Brucella?
Category B Infectious Agent
What is the pathogenesis of Brucella?
- Organisms penetrate skin or mucous membranes
- Phagocytosized by macrophages and monocytes
- Carried to spleen, liver, bone marrow, lymph nodes and kidneys
- Organisms multiply in macrophages in the reticuloendothelial system
- Host reaction is the formation of small granulomas
What type of immunity is necessary to fight Brucella?
T cell immunity determines recovery
Ab are ineffective as it is intracellular
What are the major symptoms of brucellosis?
- Undulant Fever (kind of like in B. recurrentis)
- Splenomegaly, lymphadenopathy, hepatomegaly
What are the requirements for Brucella culture?
Requires enriched media and prolonged incubation to grow
What does Brucella look like under the microscope?
Grains of sand - they are very small in size
What is the treatment for Brucella infection?
Oral tetracyclines along with aminoglycosides for a prolonged time
What is the cause of tularemia?
Francisella tularensis
What is the transmission of F. tularensis?
Deer flies and ticks
Does F. tularensis have ovarian transfer in ticks?
Yes. there is transovarial transmission in ticks
What populations are at the greatest risk for tularemia?
- Hunters
- Lab workers
- People exposed to ticks
What states in the US have high tularemia incidence?
Missouri
Arkansas
Oklahoma
What are the reservoirs of tularemia?
Rabbits
Rodents
What Category is F. tularensis?
Category A
What is the pathogenesis of tularemia?
• Organisms enter through breaks in the skin or mucous membranes
• Limited number of organisms are needed for infection
• Ulcer may develop at entry site
• Organisms may disseminate via the
bloodstream
• Host response is granuloma formation
What kind of immunity is required to fight tularemia?
Cellular immunity
What are clinical manifestations of tularemia?
- Fever, chills, malaise 2-5 days after exposure
- Ulceroglandular infections
- Oculoglangular
- Typhoidal infection (ingestion of high number of organisms)
How is tularemia diagnosed?
- Immuno-fluorescent stain of smears for rapid diagnosis
- Acute and convalescent agglutinin antibody titers over time to assess Ab reaction
What are the requirements for F. tularensis culture?
- Requires sulfhydryl compounds for growth
- Requires extended incubation time
- Strict aerobe
What is the treatment for tularemia?
Streptomycin, gentamicin, tetracycline or choramphenicol
Removal of ticks promptly
What are characteristics of Pasteurella?
- Gram-negative, non-motile bacilli
- Facultative anaerobes
- Fermentative