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Microbio Lecture 17


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Causative agent of Anthrax?
Bacillus anthracis, G+, spore forming rod
Transmission of Anthrax?
- spores germinate on contact with human tissues
- violin bows, leather jackets, bioterrorism
Types of anthrax (3):
- Pulmonary/inhalation: Woolsorter's disease (worst kind)
- Gastrointestinal: consumption of contaminated meat
- Cutaneous (inoculation of spores into skin)
Pathogenicity of Anthrax?
- thick capsules on cells hard to phagocytose
- produce 3 types of toxins that work together to kill host
1. Edema factor (EF): convert ATP to cAMP and causes swelling
2. Protective antigen (PA): helps bacteria bind human cells
3. Lethal factor (LF): causes death of human cells
Symptoms of Anthrax?
- bloody black fluid results from tissue destruction
1. Pulmonary leads to blood infection with hemorrhaging; initial symptoms are common cold, is fatal
2. GI- violent dysentery: 25-60% fatal
3. Cutaneous: black crusted lesions, death is rare unless infection gets to blood
Treatment and Prevention of Anthrax?
- Penicillin
- cipro and doxycycline used if bacteria is resistant to penicillin
- Prevent by burying in lime or incineration
- Vaccinate with Cell free filtrate of B. anthracis - 6 shots in 18 months
Causative agent of Tetanus?
Clostridium tetani, G+, anaerobic spore former
- found in intestines of many animals
Transmission of Tetanus?
animal bites, rusty nails, broken glass, body piercing
- feces excreted in soil, soil introd. to wound, anaerobic environ. spurs vegetative growth
Pathogenicity of Tetanus:
Toxins are produced (Tetanospasmin), inhibits relaxation pathway following muscle contraction. Toxin spreads not bacteria
Symptoms of Tetanus (3):
rapid developing muscle stiffness, reduced breathing
1. Trismus: lockjaw, clenched teeth, jaw muscle spasm
2. Risus Sardonicus: grinning caused by facial spasms
3. Opisthotonus: arching of back
Treatment of Tetanus:
dark quiet rooms, sedatives, antitoxin and antibiotics
- vaccinate with DTaP - tetanospasmin toxoid requires boosters
Three different types of plagues: the agent and the vector.
Causative agent for all: Yersinia Pestis, G- rod, bipolar staining like safety pin

Sylvatic: vector= fleas from ground squirrels, prarie dogs, wild rodents
Urban plague: rats- Xenopsylla cheopsis (rat fleas)
Pneumonic plague: person to person airborne droplets- death in 2 days: 100% mortality
Causative agent of Bubonic plague?
Yersinia pestis, G- rod
Transmission of Bubonic Plague?
Xenopsylla cheopsis: rat flea, bites different animals; and airborne droplets from humans
Pathogenicity of Bubonic plague?
Blood disease- bacteria multiply in blood stream and localize in lymph nodes.
Symptoms of Bubonic plague?
Buboes: hemorrhaging and swelling in lymph nodes
Rosies: hemorrhaging on skin resultin in dark purplish spots
Treatment of Bubonic plague:
antibiotics (Erythromycin, streptomycing)
Vaccinate with deat Y. pestis for high risk professions like forest rangers
What is Septicemic plague?
Yersinia pestis; bacilli overwhelms circulatory system; 50% mortality rate
Causative agent of Lyme disease?
Borrelia burgdorferi, G- microaerophilic spirochete
Transmission of Lyme disease?
Ticks are vectors:
Ixodes scapularis: deer ticks in NE and MW
Ixodes pacificus: woodrat tick in W
Pathogenicity of Lyme disease?
Human picks up infected ticks. Tick penetrates skin and eats blood meal and efecates into wound depositing spirochetes.
Symptoms of Lyme disease? (3 stages)
1. Early localized: Erythema chronicum migrans: does not itch, flu like symptoms; bullseye rash
2. Early disseminated: joint pain- irreversitble arthritis
3. Late chronic: headaches, loss of muscle tone, losing hearing and vision, damage to CVS and NS, mortality rate not high
Treatment of Lyme disesase?
tetracycline or penicillin at early localized stage
Causative agent of Rocky Mountain Spotted Fever?
Rickettsia rickettsii
Transmission of Rocky Mountain Spotted Fever?
Dermacentor andersonii: wood tick
Dermacentor variabilis: dog tick
Amblyomma: tick
Pathogenicity of R. Mtn. Spotted Fever?
Tick defecates into host and transmits agent
Symptoms of Rocky Mtn. spotted fever?
high fever, spotted rash: starts as Macules (pink spots), then as Papules (pimples showing small blood vessel damage), then Maculopapular rash from extremities to trunk
Treatment of Rocky Mtn. Spotted Fever?
Tetracycline, chloramphenicol
- Diagnose with Weil-Felix test (agglutination) serum w/ Proteus OX19- Abs agglutinate with O polysaccharide on Proteus just like Rickettsiae
Mortality rate of Rocky Mtn. Spotted Fever?
75% if not diagnosed early
Causative agent of typhus?
Rickettsiae prowazekii
Transmission of Typhus?
Pediculus: head/body lice
Pathogenicity of Typhus?
infected lice defecates into host and transmits agent
Symptoms of Typhus?
-maculopapular rash (trunk to extremities) REVERSE of ricketssiae ricketsii
- 104 F fever causes hallucinations/delerium
Treatment of Typhus, Diagnosis, and Prevention?
- tetracycline, chloramphenicol
- good hygiene needed
- Weil-Felix test

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