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Zoonosis: Disease human acquire from animals. They may or may not cause disease in animals as well. Name 4.
- Brucella
- Francisella
- Bartonella
- Yersinia
- (Bruce Found Barbara Yesterday)
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Risk factors for zoonosis (3)
- Poor hygiene after handling pets
- Pet selection (wounded or sick animals)
- Proper animal care
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Goats & Sheep
B. melitensis
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Cattle
B. abortus
Pasteurization was created due to this.
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Most common sources of infection due to Brucella?
- Contaminated milk products
- Direct contact with infected animal tissue
- Inhalation of bacteria
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Drenching sweating episodes; aches, chills and fever 7-21 days after exposure; can become chronic
Brucellosis (Malta fever or Undulant fever)- cause by Brucella bacteria
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Focal lesions occur in bones, joints, and genitourinary in what disease?
Severe acute febrile disease
Brucellosis
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Occupational exposure to Brucella bacteria can cause ___________
Hypersensitivity
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Brucella is an facultative intracellular bacteria in phagocytic cell and as such can spread to
- Bone marrow
- Lymph nodes
- Spleen
- Liver
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Which would be the best confirmation of a Brucella infection?
a) Blood cultures
b) Elevated serum titers of Ab
- Answer: Blood cultures. They are positive early in infection.
- Serological diagnosis is complicated due to the fact that antibodies persist after initial exposure; so Abs must be elevated from previous levels. Requires a 4x or greater rise in agglutination titer.
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Brucella:
1) Gram-P or Gram-N
2) Motility
3) Aerobic/Anaerobic
4) Rate of growth
5) Shape
- 1) Gram-N
- 2) Non-motile
- 3) Aerobic
- 4) Slow-growing (colonies form on solid medium in about 2-3 days)
- 5) Coccobacillus
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Like Acinetobacter baumannii, Brucella resists _____
Serum killing
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Are the smooth or rough colonies of Brucella virulent?
Smooth
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Brucella activates _______ in phagolysosomes.
virB operon
Keeps the organism alive in the phagolysosome
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How do you treat Brucellosis?
Doxycycline and rifampin for 4-6 weeks.
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How many Francisella tularensis bacteria are required to infect:
Susceptible animals?
Humans?
Aerosol acquired infection in lungs?
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Francisella tularensis, a facultative intracellular bacteria, causes
Tularemia (fever, chills, headaches, DIARRHEA, Dry cough, PROGRESSIVE WEAKNESS)
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Handling or eating insufficiently cooked rabbit meat results in infection with
Francisella tularensis --> Tularemia
Don't give junior the lucky rabbit foot or run over rabbits.
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Any mucous membrane can be a source of entry and infection of
Francisella tularensis
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What is the most common clinical form of Tularemia? How does it present?
Ulceroglandular (75%): Entry site ulcerates and regional lymph node swells
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Francisella tularensis:
1) Gram-P/N
2) Aerobe/Anaerobe
3) Grows on what media?
- 1) Gram-N
- 2) Obligate aerobe
- 3) Cysteine-glucose blood agar
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What bacteria grows on Cysteine-glucose blood agar (can take up to 3 weeks)?
Francisella tularensis
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Francisella tularensis has _____ onset, but can take up to _____ to grow on media
abrupt, 3 weeks
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Yersinia pestis:
1) Gram-P/N, shape
2) Encapsulated
3) Temp it grows best at?
- 1) Gram-N rod with bipolar staining (safety pin)
- 2) Encapsulated when first isolated; subsequently lost in passage and becomes avirulent
- 3) Grows better at 30 C
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Fleas can cause infection by what bacteria?
- Francisella tularensis
- Yersinia pestis
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Inhaling droplets exhaled by animals or humans with pneumonic form of the disease can cause infection by?
Yersinella pestis
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2 Major Cycles of Yersinella pesits:
- 1) Sylvatic (enzootic) cycle: transmission amond wild rodents by fleas...prairie dogs, ground squirrels in US.
- 2) Urban cycle: Transmission among urban rats with flea as vector. --Bubonic plague
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What disease causes plague?
Yersinella pestis
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3 Types of Plague
- Bubonic: 2-6 days after exposure; fever, headache, and buboes within day of symptoms
- Septicemic: Dissemination through the blood to many organs
- Pneumonic: Lung infection
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3 Symptoms of Black Death
- Endotoxin related symptoms
- DIC
- Cutaneous hemorrhage
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3 Virulence Factors of Yersinella pestis
- Endotoxin
- Exotoxin
- Yops: Yersinia outer membrane protiens, form pore into eukaryotic cell
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Which stains should you use for Y. pestis?
Giemsa or Wayson
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Prairie dog, flea, ground squirrel and rat control are important in control of what bacteria?
Y. pestis
Quarantine infected individuals
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Name 4 species of Bartonella genus.
- B. neselae
- B. quintana
- B. bacilliofomis
- B. elizabethae
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Which species of Bartonella is most commonly a cause of human disease? Associated with ____ and transmitted cat-to-cat by___
- B. henselae
- cats; fleas (result of cat scratch or bite in humans)
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What bacteria is associated with cats?
B. henselae
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How does Cat Scratch Disease (CSD)?
Localized lymphadenitis (common, benign)
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Two Types of Cat Scratch Disease
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What type of CSD develops a red-brown skin papule 7-12 days of being scratched that leads to regional lymph node enlargment? How do you treat this?
- Typical Cat Scratch Disease
- Self-limited (nodes enlarged for 2-3 months; painful and tender, may suppurate)
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What disease results in Transient blindness?
What other symptoms are associated with this illness?
- Atypical CSD (Cat Scratch Disease)
- Systemic Symptoms: Malaise, fatigue, weight loss, abdominal pain
- Liver & Spleen lesions possible
- This disease is NOT associated with lymphadenopathy or cat scratches
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Which type of CSD is not associated with cat scratches?
Atypical CSD
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Name 3 Clinical forms of Atypical CSD
- 1) Bacillary angiomatosis (in immunocompromised- AIDS) - A proliferative vascular lesion resembling Kaposi's sarcoma
- 2) Subacute endocarditis (culture negative)
- 3) Retinitis
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What is the best way to diagnose CSD?
In subacute endocarditis?
- Culture the organism and/or PCR
- Subacute endocarditis = serology
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CSD tx:
- Usually supportive
- Can treat with erythromycin or doxycycline
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