Cholera Flashcards
Pathogenic agent name:
Cholera
Vibrio cholera
Pathogenic agent description:
Cholera
- Highly motile
- Curved
- Gram negative rod/bacilli
- Facultative organism
Cholera is classified by what?
O cell wall that is made up of polysaccharide side chains of LPS
What are the two serogroups that cause cholera? And which is predominant
- O1
- O139
- O1 is predominant
Vector:
Cholera
- No known natural host besides humans
Grows in still water associated with copepods and zooplankton
What are the conditions in which cholera likes to grow?
- Low oxygen
- So it grows in still water with zooplankton and copepods
Where is there a current cholera outbreak happening?
Haiti
How is cholera transmitted to humans?
Ingestion of contaminated food (raw seafood) and water
Why does cholera require a high inoculum?
Because gastric acidity
Transmission Mechanism:
Cholera
- Vibrios pass the stomach and enter the small intestine and adhere to the luminal cells
- Produce mucinase to help penetrate mucus
- Cholera toxin binds to GM1 receptor and enters cells
Cholera binds to what receptor?
GM1 (activated by adenyl cyclase)
Reservoirs:
Cholera
No known besides humans
Large cargo ships take in water and contaminate new areas
“Rice water” stool is a symptom of what?
Cholera
Clinical Findings:
Cholera
- Diarrhea (mild, severe, death)
- “Rice water” stool
- Sunken eyes, dry mouth
- Lactic acidosis (breakdown of tissue)
- Renal failure
What is “Rice water stool”
Stool that is free of blood and has flecks of mucus with a fishy smell
Diagnosis:
Cholera
- Clinical suspicion
- Isolation of bacteria V. cholerae (easy to grow but needs special media)
Treatment (general):
Cholera
- Aggressive volume replacement (orally or IV)
- Antibiotics
- Complications treatment
Treatment (Drugs):
Cholera
- Tetracycline
- Doxycycline
(If resistant use fluoroquinolones and macrolides)
Prevention:
Cholera
- Safe water
- Hygiene
- Vaccines
What are the vaccines for cholera? (3)
- Dukoral (combo vaccine)
- Shanchole
- VaxChora
Describe Third Cholera Outbreak?
- Broad Street Pump in London killed hundreds in a few days
1852-1860
(the first careful epidemiologic experiment that is well documented)
Describe Fourth Cholera Outbreak?
30K Mecca pilgrims died
1863 - 1879
Describe Seventh Cholera Outbreak?
New strain called El Tor
Locations: Latin America
Haiti (post earthquake)
(1961- present)
If cholera is resistant to tetracycline and docycline what do you use?
- fluoroquinolones
- macrolides)
