Describe the Virulence factors & pathogenesis of Y.pestis
Virulence plasmids; Changes in genes expression in response to environmental changes (1) Changes in flea behavior: agglutination in flea's GI tract; (2) Survival in human body: Capsule (F1 protein), plasminogen activator: prevents opsonization, important for dissemination (3) Damage: Type III secretion system: Yop proteins (cytotoxic effect); endotoxin (septic shock); intracellular grow in reticuloendothelial cells
Describe clinical features of the 3 kinds of plague due to Y. pestis infection
*Transmission = tick/fly bite, direct contact, inhalation/ingestion of contaminated food or water
F. tularensis infects RE organs, multiplies in T-cells. True or False.
False. Infects reticuloendothelial organs: multiplication in macrophages, hepatocytes and endothelial cells => necrosis and granuloma production in areas of multiplication; Survival: inhibition of phagosome-lysosome fusion; antiphagocytic lipid capsule
How does the causative pathogen for tularemia survive inside the macrophage.
F.tularensis inhibits the phagosome-lysosome fusion process & it has a antiphagocytic lipid capsule
What form of Tularemia is most common?
Ulceroglandular occurs at a 75% rate
Describe the different types of Tularemia
Ulceroglandular form (75%): painful ulcerating lesion at site of infection Oculoglandular form (1%): purulent conjunctivitis + lymphadenopathy Pneumonic, Gastrointestinal & Septicemic forms (10-15%, more severe)
True or False. Concerning diagnosis of Tularemia: Serologic tests (PCR, gram stain unsuccessful, it requires cysteine-glucose blood agar)
This is the process of diagnosing Tularemia
As is the agents used to treat plague, tularemia treatment is with Streptomycin or Gentamicin.
True or False? Brucella spp is a G(-) coccobacilli that is an obligate intracellular, zoonotic pathogen
To diagnose Lyme Disease, first perform a Western Blot & then do an ELISA or IFA test. Also, definitely do a culture to confirm diagnosis
False. To diagnose Lyme Disease, assess clinical presentation, then perform ELISA or IFA THEN a Western Blot. A culture is not recommended.
Identify the appropriate course of treatment for Lyme Disease
Lyme Disease Treatment: *Doxycycline or Amoxicillin
True or False? Borrellis recurrentis has a spiral morphology, it is motile & demonstrates slow growth. It is G(-) but is not seen on a gram strain. It is a zoonotic pathogen & has tight terminal hooks
False. That description is for Leptospira interrogans.
Borrelia recurrentis: Spiral morphology, large, gram(-); motile (endoflagella); zoonotic pathogens, hard to isolate in culture, complex nutritional needs, slow growth
True or False? B. recurrentis is responsible for Endemic relapsing fever
False. B. recurrentis is responsible for Epidemic Relapsing Fever.
The Reservoir, vector & transmission for B. recurrentis is humans, human body louse & louse bite, respectively. True or False?
True or False? B. recurrentis demonstrates antigenic variation & Osp
False. B. recurrentis does have antigenic variation, which aids in escaping immune clearance. It doesn't have Osp, but secretes endotoxin.
Describe Virulence factors & pathogenesis of B. recurrentis & other Borrelia spp.'s
Virulence factors/pathogenesis of B. recurrentis:
Antigenic variation - escape immune clearance; autoimmune activities of anti-Osp
Endotoxin (febrile illness); Recurrent episodes of fever + septicemia separated by afebrile periods; new set of surface antigens at each relapse
Identify the clinical features of Epidemic or Endemic Relapsing Fever
Epidemic Relapsing Fever:
High fever, headache, muscle pain, weakness. 2-4 days between relapses; 2-3 relapse cycles
Describe the diagnostic aspects of Epidemic or Endemic Relapsing Fever
Epidemic Relapsing Fever diagnostic process:
Microscopy (during febrile period) Giemsa or Wright staining; Serologic tests unhelpful (because of antigenic variation)
True or False? To treat Epidemic or Endemic Relapsing Fever, administer Penicillin or Doxycycline
False. Doxycycline or Erythromicin
True or False? Numerous Borrellia infections will cause Epidemic Relapsing Fever, but only B. recurrentis causes Endemic Relapsing Fever.
Borrellia recurrentis: Epidemic Relapsing Fever
Other Borrelia spp.: Endemic Relapsing Fever
What is the difference between reservoirs, vectors & transmission of Epidemic versus Endemic Relapsing Fever?
Epidemic Relapsing Fever: *Reservoir = Humans *Vector = Human body louse *Transmission = Louse bite
Endemic Relapsing Fever: *Reservoir = Rodents & other small animals *Vector = Tick *Transmission = Tick bite
Describe the characteristics of the Leptospira interrogans bug
Leptospira interrogans: Spiral morphology; motile; slow growth; gram(-) but not seen on gram stain; zoonotic pathogen, tight terminal hooks
True or False? Concerning Leptospirosis: *Reservoir = Dogs, livestock, rats, wild animals (colonize renal tubules) *Vector = in urine of infected animals *Transmission = Direct contact w/ urine, blood or tissues of infected animals. Contact w/ contaminated water.
True or False? L.interrogans multiplies inside macrophages
Describe the pathogenesis of L. interrogans
L. interrogans multiplies in blood & tissue, it damages the endothelium of small blood vessels. Supposedly it has no virulence factors, but it could be argued that the morphology of the hooks are in and of themselves virulence factors.
Describe the Septicemic & Immune phase of Leptospirosis
both febrile: Septicemic phase: flu-like symptoms
Immune phase: anicteric form (possible meningitis), icteric form or Weil's disease (jaundice, renal failure, subconjunctival hemorrhage)
True or False? Penicillin or Doxycycline are the appropriate therapeutic agents for Leptospirosis