Cholera

Lethal, epidemic capability caused by Vibrio cholerae, “rice-water” stool

Last outbreak Mexico 2013

Disease Polymorphism: 70% Asymptomatic, 20-25% Symptomatic, 5% Cholera gravis, 2% Die

Risk factors: very young/old, gastric pH (use of PPIs), blood group O, intercurrent illness, immunosuppressed

Mechanism: secretory diarrhoea caused by Vibrio burrowing into mucosa, produces cholera toxin (A subunit surrounded by 5 B units) that produces cAMP, pumps out Cl-, water follows -> secretory diarrhoea (15-20L/day)

Transmission: fecal-oral limited person-to-person

Dehydration Status

	Mild	Mod	Severe
Alert	Yes	Yes	Lethargy
Eyes	Normal	+/-	Sunken
Drinking	Yes	Yes (Eager?)	No
Skin Pinch	Normal	+/-	Reduced
Pulse	Normal	Sl. rapid	Thready/rapid

Treatment: supportive with ORS or IVF (Hartmann’s, Ringers lactate), antibiotics (doxycycline) shorten duration but don’t affect mortality, zinc (20mg/day < 5 y.o., 10mg/day < 1 y.o. x 10-14d)

ORS: 1L + 6 teaspoons sugar + 1 teaspoon salt

Malnutrition, children, pregnant women are special cases

Testing: Cary Blair Medium (4-5 cases) can be sent from national lab, Rapid test (01 and 0139), test 10-20 people (with rapid labs): need one positive test to confirm outbreak

Cholera Outbreak Management

Cholera treatment centre
- Build 100m away from market and school
- Away from water source: Sandy (40m), Clay (15 m)
- Use tents, sheds, schools, churches/mosques
- Floor: Plastic sheet or concrete (need to mop)
- Space: 2.5 m2 per person + attendent
- Clean it twice a day

Door: disinfectant foot mat (Chlorine 0.5%) changed 2x/day OR spray people feet; chlorine hand-wash station (also between rooms)
Triage: based on dehydration (connects to #3 and #4)
Oral rehydration point -> home
ITU (then to 4)
Stepdown (then back to 3)
Staff area: kitchen, showers
Latrines: 1 per 20 people, 2% chlorine; 1.5m away from water table
Morgue: seal orifices with cotton wool soaked in chlorine, wash in 2% chlorine

Water supply: 40-60L/day/pt, 15L/d/caregiver -> 600+L water/day for only 10 patients, 1800L/3 days (2 m3)

Chlorine Dilutions: