Environmental sanitation and fecal-oral route

Environmental sanitation is the control of all those factors in the physical environment that harm, or may harm, human health and well-being. In practice it means safe disposal of human excreta, management of solid waste and waste water, safe water supply, food hygiene, vector control and clean housing, so that disease transmission is cut.

Components of environmental sanitation

1. Excreta disposal – sanitary toilets (pit latrine, VIP latrine, pour-flush, septic tank), sewerage.
2. Safe water supply – protected sources, treatment and safe storage.
3. Solid waste management – collection, segregation, recycling, composting and sanitary landfill.
4. Waste water (sullage) and drainage – soak pits, drains, treatment plants; no stagnant water.
5. Food sanitation – hygienic handling, storage and cooking.
6. Vector and rodent control – control of flies, mosquitoes, rats.
7. Housing and personal hygiene – ventilation, clean kitchens, hand washing.
8. Control of air and noise pollution.

Importance: prevents diarrhoea, cholera, typhoid, hepatitis, worm infections and vector-borne diseases; lowers child mortality; improves dignity (especially for women), school attendance and productivity; and protects water sources. Nepal's national sanitation campaign led to the ODF declaration in 2019 and now focuses on "total sanitation".

Pathways of fecal-oral infection transmission

Pathogens in faeces of an infected person reach a new person's mouth by the F-diagram routes:

             +--> Fluids (water) ------+
             +--> Fingers -------------+
 FAECES -----+--> Flies ---------------+--> FOOD --> MOUTH
             +--> Fields/soil ---------+       (new host)

1. Fluids – water sources contaminated by sewage, open defecation or leaking pipes; drinking it untreated.
2. Fingers – hands not washed after defecation or handling a baby; hands then touch food or mouth.
3. Flies – carry pathogens from open faeces and waste to food.
4. Fields – open defecation and raw excreta used as manure; contaminated soil and vegetables; children playing on soil.
5. Food – the final vehicle when contaminated by water, hands, flies or soil.

Diseases: cholera, typhoid, diarrhoea, dysentery, hepatitis A/E, polio, worms.

Barriers: toilets and safe excreta disposal (primary barrier); safe water, hand washing with soap, food hygiene and fly control (secondary barriers); supported by health education and vaccination.