micro zoonoses--brucella, yersinia and francisella
Terms
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- Brucella
-
a. B. melitensis: goats and humans
b. B. abortus: cattle and humans
c. B. Buis: swine, cats and humans rarely
d. B. canis: dogs, humans rarely - Bacteriology
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a. Small coccobacillary gram negative rods
b. B. abortus requires 5-10% C02 for initial growth. Other species not as fastidious - B. Clinical Manifestations in humans and animals.
- In the human, undulant fever most prevalent (B. abortus)
-
Three forms of the disease
1. serious? fatality? recovery and recovery time? morbidity? blood cultures positive vs. negative? relapse and blood culture with relapse?
2. serious? blood cultures? disease course?
3. serious? durat -
a. Acute Disease.
Not a serious disease, case fatality is low. Recovery spontaneous after 1-3 months. Morbidity is quite high. Blood cultures are positive in the first 2-3 weeks, negative after building up of antibodies. Relapse frequent-blood cultures become again positive.
b. Subacute or Latent Disease
May be weakly symptomatic. Blood cultures rarely positive. Agglutinins usually positive. Transient-usually clears up after a while with no further symptoms.
c. Chronic Disease
Persistent form of disease- 1-20 years. Nocturnal sweats with intermittent fever, anorexia. Undulating attacks. Probably an allergic response to the microorganism and its products. - Complications
- Osteomyelitis; acute inflammation of any of the viscera; focal lesions of the lungs; lymph nodes; spleen; kidneys; biliary tract; urinary tract; genital organs.
- Pathogenesis
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1. Flea infected from infected rat host
2. Growth of organism in the gut of the flea
3. Injection into the capillary bed upon feeding
4. Fleas find human host when rat not available -
Transmission and Epidemiology
1. Animal hosts -
a. Goats-melitensis
b. Cattle-abortus
c. Swine-suis
d. Dogs-canis -
Routes of Transmission
-
. Laboratory Diagnosis -
a. ingestion (raw milk)
b: direct contact
c. Inhalation
d. Inoculation (Laboratory
-ELISA test - E. Prophylaxis
-
1. Avoidance of contact
a. Sanitation
b. Pasteruiaztion of mild
c. Pulbic health measures
2. Protection of animals: vaccine (calf vaccination) - Therapy
-
1.Streptomycin is drug of choice; other aminoglycosides would work
2. Streptomycin should be supplemented with doses of tetracycline or chloramphenicol -
Francisella tularensis
. Bacteriology -
1. Highly pleomorphic gram negative rod
2. No capsules, nonmotile -
Pathogenesis
-what kind of parasite? is it destroyed?
-mortality and morbidity -
1. An intracellular parasite
2. Phagocytized but not destroyed by the phagocytic mechanisms
3. Mortality rate low. Untreated 5-7%
4. Morbidity rate very high. Highly infectious - 3 modes of Transmission
-
1. Direct contact
2. Insect vector transmission
a. Deer flies
b. Ticks
Reservoir of infection for rodent populations
3. Human to human transmission highly improbable, but increasing
reports of cat to human spread' -
Yersinia pestis
. Clinical Manifestations
1 Bubonic plague
a. Disease of the ..
1)Infection at ..
-what gets involved?
2. Pneumonic (pulmonary ) plague
a. Secondary to the lymphatic plague
b. transmissio -
-lymphatics
-the point of bite of flea.
-Regional lymph glands quickly involved.
-Aerosol transmission- cats to humans (humans to humans has not been seen since 1900, in US)
-100% -
a. Terminal stage of disease is accompanied by...
what is seen with this? -
fulminating septicemia.
-Subcutaneous hemorrhage results in petechial spots, necrosis - Primarily a disease of
- rodents