Cholera

Cholera is an acute, severe diarrhoeal illness caused by infection with the bacterium Vibrio cholerae. It spreads through water or food contaminated with faecal matter from infected individuals. Cholera can cause profuse watery diarrhoea and rapid dehydration — a severe case can kill an otherwise healthy adult within hours if untreated. Nigeria experiences recurring cholera outbreaks, particularly in communities with limited access to clean water and sanitation. With prompt oral rehydration, the vast majority of patients survive. Cholera is considered a marker of inadequate access to water, sanitation, and hygiene (WASH) infrastructure.

Symptoms appear within hours to 5 days of infection and range from mild to severe: Mild-to-moderate: • Watery diarrhoea — sudden onset • Nausea and vomiting • Muscle cramps Severe cholera (a medical emergency): • Profuse "rice-water" diarrhoea — large volumes of pale, watery stool • Projectile vomiting • Rapid, severe dehydration: – Sunken eyes and cheeks – Dry mouth and extreme thirst – Reduced or absent urination – Skin that returns slowly when pinched (poor skin turgor) – Rapid, weak pulse – Low blood pressure – Muscle cramps – Lethargy and weakness • In severe cases: collapse, unconsciousness, and death within hours if dehydration is not corrected

Cholera is caused by Vibrio cholerae bacteria, most commonly the O1 and O139 serogroups that produce a potent toxin (choleratoxin). This toxin causes the intestinal lining to secrete massive quantities of fluid into the gut — producing the characteristic severe watery diarrhoea. Sources of infection: • Drinking untreated or contaminated water from wells, rivers, or boreholes • Eating raw or undercooked seafood (especially shellfish) from contaminated water • Eating food washed or prepared with contaminated water • Eating food handled by someone with cholera who has not washed their hands • Poor sanitation — open defecation contaminates water sources and soil

• Drinking untreated or poorly treated water • Living in communities without adequate sanitation (open defecation, pit latrines shared by many) • Eating raw or poorly cooked seafood from coastal or river areas • Flooding and natural disasters — destroy sanitation infrastructure • Internally displaced persons in camps with inadequate WASH facilities • Malnutrition — low stomach acid (common in malnourished children) reduces defence against Vibrio • Blood type O — people with type O blood have higher risk of severe cholera • Areas with poor health system infrastructure to contain outbreaks

• Severe dehydration and electrolyte imbalance — the primary cause of death • Hypovolaemic shock — from rapid fluid loss • Hypoglycaemia — dangerously low blood sugar, particularly dangerous in children • Kidney failure from severe dehydration • Acute tubular necrosis • Metabolic acidosis • Death — without treatment, severe cholera has a case fatality rate of 25–50%; with prompt rehydration, less than 1%

Safe water and food: • Drink only water that has been boiled, chlorinated, or bottled • Use safe water for food preparation, cooking, brushing teeth, and washing utensils • Wash fruits and vegetables with safe water • Eat food that is fully cooked and served hot; avoid raw shellfish • Avoid street food of uncertain hygiene during outbreaks Hand hygiene: • Wash hands with soap and water before eating and preparing food, and after using the toilet • Use hand sanitiser when soap and water are unavailable Sanitation: • Use proper latrines or toilets; avoid open defecation • Safely dispose of sewage and human waste away from water sources Vaccination: • Oral cholera vaccines (Shanchol, Euvichol-Plus) are recommended during outbreaks and in high-risk settings; they provide 65% protection for 3 years Oral rehydration: • Communities should have ORS sachets available to begin treatment immediately at home while seeking care