The fecal–oral route (or alternatively the oral–fecal route or orofecal route) is a route of transmission of a disease, when pathogens in fecal particles passing from one host are introduced into the oral cavity of another host. One main cause of fecal–oral disease transmission in developing countries is lack of adequate sanitation and, often connected to that problem, water pollution with fecal material.
The foundations for the "F-diagram" being used today were laid down in a publication by Wagner, E. G and Lanoix, J. N. in the WHO monograph series no 39 explaining transmission routes and barriers to the transmission of diseases from the focal point of feces. Modifications have been made over the course of history to give modern day F-diagrams which has been widely used in many other sanitation publications. It was set up in a way that fecal–oral transmission pathways are shown to take place via water, hands, arthropods and soil. The sanitation barrier however when placed prevents the transmission of infection through the hands, water and food.
One approach to changing people's behaviors and stopping open defecation, the community-led total sanitation approach, uses "live demonstrations" of flies moving from food to fresh human feces and back to "trigger" villagers into action.
The process of transmission may be simple or involve multiple steps. Some examples of routes of fecal–oral transmission include:
- water that has come in contact with feces (for example due to groundwater pollution from pit latrines) and is then not treated properly before drinking.
- by shaking someone's hand that has been contaminated by stool, changing a child's diapers, working in the garden or dealing with livestock or house pets.
- food that has been prepared in the presence of fecal matter.
- disease vectors, like houseflies, spreading contamination from inadequate fecal disposal such as open defecation.
- poor or absent hand washing after using the toilet or handling feces (such as changing diapers. 
- poor or absent cleaning of anything that has been in contact with feces;
- sexual practices that may involve oral contact with feces, such as anilingus, coprophilia or "ass to mouth".
Diseases by pathogen type
Some of the diseases that can be passed via the fecal–oral route are (grouped by the type of pathogen involved in disease transmission):
- Vibrio cholerae (cholera)
- Clostridium difficile (pseudomembranous enterocolitis)
- Shigella (shigellosis / bacillary dysentery)
- Salmonella typhii (typhoid fever)
- Vibrio parahaemolyticus
- Escherichia coli
- Hepatitis A
- Hepatitis E
- Norovirus acute gastroenteritis
- Poliovirus (poliomyelitis)
- Rotavirus – Most of these pathogens cause gastroenteritis.
- Entameba histolytica (amoebiasis)
- Giardia (giardiasis)
- Cryptosporidium (cryptosporidiosis)
- Toxoplasma gondii (toxoplasmosis)
- Clean surfaces and toys often. Wash, sanitize, and rinse toys after children have played with them, especially if they were placed in the mouth. Wash and sanitize counter tops, tables, and chairs before preparing or eating
food. Keep bathroom and toilet areas cleaned.
- People with diarrhea should not swim. Protect others by not swimming in pools or other recreational water sources if experiencing diarrhea. People can spread germs in the water even without having an “accident”.
Avoid swallowing water while swimming.
- Do wash your hands and bottom thoroughly with soap and water after a bowel movement or changing diapers.Germs on hands are easily spread to objects, and surfaces such as food and swimming water.
- Avoid food that might be contaminated by washing all raw fruits and vegetables before peeling and eating. Wash all food that will be eaten raw with water from a safe source, and avoid eating uncooked foods when
traveling in developing countries where the water supply might be unsafe. 
- Wagner, E. G., and Lanoix, L. N. (1958). Excreta disposal for rural and small communities. (PDF). WHO, Geneva, Switzerland. p. 12.
- Kal, K and Chambers, R (2008) Handbook on Community-led Total Sanitation, Plan UK Accessed 2015-02-26
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