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