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Vibrio cholerae
Asiatic or Epidemic CholeraPage 360
Readings Question #1
• Describe the Vibrio cholerae bacterium. Where is it found?
Outbreaks
• no major outbreaks in U.S. since 1911• sporadic: 1973-1991• 1991: South America – Peru– 1,099,882 cases and 10,453 deaths (1991-95)
• 1992: new strain – Bangladesh and India– 1 case in U.S.
• 2010: Haiti (confirmed 10/21/10)
Symptoms of Cholera
• “rice-water” stools (Color Plate 54)• viscous blood• sudden onset, incubation: 6 hrs- 5 days• violent vomiting• No fever• abdominal cramps, nausea, dehydration,
shock• 1 million organisms
Progression of Disease
Diagnosis
• isolated from feces• recovered from foods• pathogenic and non-pathogenic forms exist• test for presence of cholera enterotoxin
Treatment of Cholera
• water and electrolyte replacement– oral rehydration therapy– sodium chloride, sodium bicarbonate, potassium
chloride and dextrose– intravenous rehydration
• tetracycline• untreated – 50% mortality rate• death occurs from dehydration and loss of
essential electrolytes
Bacillus anthracis
• Page 361: note embalming implications• 1877 isolated by Robert Koch
Readings question #2:List 5 characteristics of the Bacillus anthracis
bacterium.
People at Risk
• handle animals, hides, wool, and other animal products
• goat hair and handicrafts containing animal hides from the Middle East
• infection initiated by endospores• 2 exotoxins: edema toxin and lethal toxin• capsule does not stimulate a protective response
Readings Question #3
What are the 3 forms of anthrax that affect humans?
Treatment of Anthrax
• antibiotics• ciprofloxacin and doxycycline• preventive doses of antibiotics (60 days)• vaccination of livestock– live attenuated
• human vaccine: inactivated form– 6 injections over 18 months– Annual boosters
Biological Weapons
• “the use of living pathogens for hostile purposes”
• 14th century: 1346 Tartar army catapulted “plague-ridden” bodies over the walls of Kaffa (Ukraine)- Kaffa “fell” and survivors escaping introduced the “plague” to Europe(began the plague pandemic from 1348 – 1350)
U.S. Epidemic Intelligence Service
• formed in 1951 (after start of Korean War)• served as early warning system• important role in combating epidemics and
tracking outbreaks of disease
• 1940s-1960s: research on biological weapons– develop vaccines or treatments
Biological Weapons
• 2001: U.S. Postal Service– Bacillus anthracis– gave rise to a new term:“bioterrorism”
• new vaccines being developed & existing vaccines stockpiled for use when needed
• military personnel and first-responders are vaccinated if biological agents are a “risk”
Bordetella(Page 362)
• Whooping Cough (Pertussis)– 2 basic toxins: 1) tracheal cytotoxin
- damages ciliated cells 2) pertussis toxin
- systemic symptoms• small children: violence of coughing can break
ribs• infants: irreversible damage to the brain
occasionally occurs• adults: misdiagnosed as bronchitis
Diagnosis of Pertussis
• clinical signs and symptoms• throat swab culture• culture on special media• rapid tests available
Treatment of Pertussis• Erythromycin• Antibiotics render the patient noninfectious.• Immunity following recovery is good.
• DTap Vaccine: 1996, minimal side effects- lowered annual cases- fewer than 10 deaths/year- effectiveness wanes after 12 years of age- elderly and infants