Fecal-oral route

The "F-diagram" (feces, fingers, flies, fields, fluids, food), showing pathways of fecal-oral disease transmission. The vertical blue lines show barriers: toilets, safe water, hygiene and handwashing.

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.

Background

Villagers during a CLTS triggering exercise go to the place where meals are prepared to observe how flies are attracted to human feces and carry diseases by landing on the food (village near Lake Malawi, Malawi)

School children during a CLTS triggering event in West Bengal, India looking at a glass of water and fresh human feces where the flies pass from the water to the feces and back... This demonstrates how water can get polluted with pathogens.

The "F-diagram" explaining transmission routes and barriers was first proposed in a publication by Hesperian Foundation for the United Nations Development Programme (UNDP) in 2005. It has been widely used in many other sanitation publications since then. It was set up in a way that fecal-oral transmission pathways are shown to take place via nouns that start with the letter F: fingers, flies, fields, foods, and fluids (fluids stands here for polluted water - be it polluted drinking water, surface water or groundwater).^[1]

The F-diagram is also used to show how proper sanitation (in particular toilets, hygiene, handwashing) can act as effective barriers to stop transmission of diseases via fecal-oral pathways.

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.^[2]

Examples

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;
• 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):

Bacteria

• vibrio cholerae (Cholera)
• Clostridium difficile
• Shigella (Shigellosis / bacillary dysentery)^[3]
• Salmonella typhii (Typhoid fever)^[4]
• Vibrio parahaemolyticus^[5]
• Escherichia coli^[6]

Viruses

• Hepatitis A^[7]
• Hepatitis E^[8]
• Enteroviruses
• Norovirus acute gastroenteritis
• Poliovirus (Poliomyelitis)
• Rotavirus^[6] - Most of these pathogens cause gastroenteritis.

Fungi

• Entameba histolytica^[6]

Parasites

• Tape worms^[6]
• Ascariasis and other soil transmitted helminthiasis
• Cryptosporidium (Cryptosporidiosis)
• Giardia (Giardiasis^[9])

Other

• Waterborne diseases

Transmission of Helicobacter pylori by fecal-oral route has been demonstrated in murine models.^[10]

See also

• Neglected tropical disease
• Vector control

References