Fecal–oral route

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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. F-diagram-01.jpg
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 (also called the oral–fecal route or orofecal route) describes a particular route of transmission of a disease wherein pathogens in fecal particles pass from one person to the mouth of another person. Main causes of fecal–oral disease transmission include lack of adequate sanitation (leading to open defecation), and poor hygiene practices. If soil or water bodies are polluted with fecal material, humans can be infected with waterborne diseases or soil-transmitted diseases. Fecal contamination of food is another form of fecal-oral transmission. Washing hands properly after changing a baby's diaper or after performing anal hygiene can prevent foodborne illness from spreading.

In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected.

Feces solid or semisolid remains of the food that could not be digested in the small intestine

Feces are the solid or semisolid remains of the food that could not be digested in the small intestine. Bacteria in the large intestine further break down the material. Feces contain a relatively small amount of metabolic waste products such as bacterially altered bilirubin, and the dead epithelial cells from the lining of the gut.

Sanitation public health conditions related to clean drinking water and adequate disposal of human excreta and sewage

Sanitation refers to public health conditions related to clean drinking water and adequate treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems aim to protect human health by providing a clean environment that will stop the transmission of disease, especially through the fecal–oral route. For example, diarrhea, a main cause of malnutrition and stunted growth in children, can be reduced through sanitation. There are many other diseases which are easily transmitted in communities that have low levels of sanitation, such as ascariasis, cholera, hepatitis, polio, schistosomiasis, trachoma, to name just a few.

Contents

The common factors in the fecal-oral route can be summarized as five Fs: fingers, flies, fields, fluids, and food. Analingus, the sexual practice of licking or inserting the tongue into the anus of a partner, is another route. Diseases caused by fecal-oral transmission include diarrhea, typhoid, cholera, polio and hepatitis.

Diarrhea Loose or liquid bowel movements

Diarrhea is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal.

Cholera Bacterial infection of the small intestine

Cholera is an infection of the small intestine by some strains of the bacterium Vibrio cholerae. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea that lasts a few days. Vomiting and muscle cramps may also occur. Diarrhea can be so severe that it leads within hours to severe dehydration and electrolyte imbalance. This may result in sunken eyes, cold skin, decreased skin elasticity, and wrinkling of the hands and feet. Dehydration can cause the skin to turn bluish. Symptoms start two hours to five days after exposure.

Polio Infectious disease

Polio, also called poliomyelitis or infantile paralysis, is an infectious disease caused by the poliovirus. In about 0.5 percent of cases there is muscle weakness resulting in an inability to move. This can occur over a few hours to a few days. The weakness most often involves the legs but may less commonly involve the muscles of the head, neck and diaphragm. Many people fully recover. In those with muscle weakness about 2 to 5 percent of children and 15 to 30 percent of adults die. Another 25 percent of people have minor symptoms such as fever and a sore throat and up to 5 percent have headache, neck stiffness and pains in the arms and legs. These people are usually back to normal within one or two weeks. In up to 70 percent of infections there are no symptoms. Years after recovery post-polio syndrome may occur, with a slow development of muscle weakness similar to that which the person had during the initial infection.

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) Actions to end open defecation in a village in Malawi (2).jpg
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. CLTS triggering in Malda District, West Bengal, India.JPG
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.

F-Diagram

The foundations for the "F-diagram" being used today were laid down in a publication by WHO in 1958. [1] This publication explained transmission routes and barriers to the transmission of diseases from the focal point of human feces.

World Health Organization Specialised agency of the United Nations

The World Health Organization (WHO) is a specialized agency of the United Nations that is concerned with international public health. It was established on 7 April 1948, and is headquartered in Geneva, Switzerland. The WHO is a member of the United Nations Development Group. Its predecessor, the Health Organisation, was an agency of the League of Nations.

Human feces Solid or semisolid remains of the food that could not be digested or absorbed in the small intestine of humans

Human feces are the solid or semisolid remains of the food that could not be digested or absorbed in the small intestine of humans, but has been rotted down by bacteria in the large intestine. It also contains bacteria and a relatively small amount of metabolic waste products such as bacterially altered bilirubin, and the dead epithelial cells from the lining of the gut. It is discharged through the anus during a process called defecation. Human feces have similarities to feces of other animals and vary significantly in appearance, according to the state of the diet, digestive system and general health. Normally human feces are semisolid, with a mucus coating. Small pieces of harder, less moist feces can sometimes be seen impacted in the distal end. This is a normal occurrence when a prior bowel movement is incomplete, and feces are returned from the rectum to the large intestine, where water is absorbed.

Modifications have been made over the course of history to derive modern-looking F-diagrams. These diagrams are used in many sanitation publications. [2] They are set up in a way that fecal–oral transmission pathways are shown to take place via water, hands, arthropods and soil. To make it easier to remember, words starting with the letter "F" are used for each of these pathways, namely fluids, fingers, flies, food, fields, fomites (objects and household surfaces).

Arthropod phylum of animals

An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and paired jointed appendages. Arthropods form the phylum Euarthropoda, which includes insects, arachnids, myriapods, and crustaceans. The term Arthropoda as originally proposed refers to a proposed grouping of Euarthropods and the phylum Onychophora. Arthropods are characterized by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages. The rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. Arthopods are bilaterally symmetrical and their body possesses an external skeleton. Some species have wings.

Fly order of insects

Flies are insects with a pair of functional wings for flight and a pair of vestigial hindwings called halteres for balance. They are classified as an order called Diptera, that name being derived from the Greek δι- di- "two", and πτερόν pteron "wings". The order Diptera is divided into two suborders, with about 110 families divided between them; the families contain an estimated 1,000,000 species, including the familiar housefly, horse-fly, crane fly, and hoverfly; although only about 125,000 species have a species description published. The earliest fly fossils found so far are from the Triassic, about 240 million years ago; phylogenetic analysis suggests that flies originated in the Permian, about 260 million years ago.

Fomite non living object capable of carrying infectious agent

A fomes or fomite is any inanimate object, that when contaminated with infectious agents, such as bacteria or viruses, can transfer disease to a new host.

Rather than only concentrating on human feces, animal feces should also be included in the F-diagram. [2]

The sanitation and hygiene barriers when placed correctly prevent the transmission of an infection through hands, water and food. The F-diagram can be used to show how proper sanitation (in particular toilets, hygiene, handwashing) can act as an effective barrier to stop transmission of diseases via fecal–oral pathways.

Hygiene set of practices performed for the preservation of health

Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refers to maintaining the body's cleanliness.

Toilet Piece of hardware for the collection of disposal of human excreta

A toilet is a piece of hardware used for the collection or disposal of human urine and feces. In other words: "Toilets are sanitation facilities at the user interface that allow the safe and convenient urination and defecation". Toilets can be with or without flushing water. They can be set up for a sitting posture or for a squatting posture. Flush toilets are usually connected to a sewer system in urban areas and to septic tanks in less built-up areas. Dry toilets are connected to a pit, removable container, composting chamber, or other storage and treatment device. Toilets are commonly made of ceramic (porcelain), concrete, plastic, or wood.

Examples

Transmission

The process of transmission may be simple or involve multiple steps. Some examples of routes of fecal–oral transmission include:

Prevention

Modified F-diagram including interventions that can block human exposure to animal feces. Modified F-Diagram.jpg
Modified F-diagram including interventions that can block human exposure to animal feces.

One approach to changing people's behaviors and stopping open defecation is the community-led total sanitation approach. In this process "live demonstrations" of flies moving from food to fresh human feces and back are used. This can "trigger" villagers into action. [3]

Diseases

The list below shows the main diseases that can be passed via the fecal–oral route. They are grouped by the type of pathogen involved in disease transmission.

Bacteria

Viruses

Protozoans

Helminths

Waterborne diseases are diseases caused by pathogenic microorganisms that most commonly are transmitted in contaminated fresh water. This is one particular type of fecal-oral transmission.

Neglected tropical disease s also contains many diseases transmitted via the fecal-oral route.

See also

Related Research Articles

Trichuriasis Infection by the parasitic worm Trichuris trichiura (whipworm)

Trichuriasis, also known as whipworm infection, is an infection by the parasitic worm Trichuris trichiura (whipworm). If infection is only with a few worms, there are often no symptoms. In those who are infected with many worms, there may be abdominal pain, tiredness and diarrhea. The diarrhea sometimes contains blood. Infections in children may cause poor intellectual and physical development. Low red blood cell levels may occur due to loss of blood.

El Tor is a particular strain of the bacterium Vibrio cholerae, the causative agent of cholera. Also known as V. cholera biotype eltor, it has been the dominant strain in the seventh global cholera pandemic. It is distinguished from the classic strain at a genetic level, although both are in the serogroup O1 and both contain Inaba, Ogawa and Hikojima serotypes. It is also distinguished from classic biotypes by the production of hemolysins.

Ingestion is the consumption of a substance by an organism. In animals, it normally accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms, ingestion can take place through taking the substance through the cell membrane.

Human waste refers to the waste products of the human digestive system and the human metabolism, namely feces and urine. As part of a sanitation system that is in place, human waste is collected, transported, treated and disposed of or reused by one method or another, depending on the type of toilet being used, ability by the users to pay for services and other factors.

An ECHOvirus is a type of RNA virus that belongs to the species Enterovirus B, genus Enterovirus of the Picornaviridae family. Echoviruses are found in the gastrointestinal tract and exposure to the virus causes other opportunistic infections and diseases, notably aseptic meningitis.

<i>Vibrio parahaemolyticus</i> species of bacterium

Vibrio parahaemolyticus is a curved, rod-shaped, Gram-negative bacterium found in brackish, saltwater, which, when ingested, causes gastrointestinal illness in humans. V. parahaemolyticus is oxidase positive, facultatively aerobic, and does not form spores. Like other members of the genus Vibrio, this species is motile, with a single, polar flagellum.

Serotype infraspecific name

A serotype or serovar is a distinct variation within a species of bacteria or virus or among immune cells of different individuals. These microorganisms, viruses, or cells are classified together based on their cell surface antigens, allowing the epidemiologic classification of organisms to the sub-species level. A group of serovars with common antigens is called a serogroup or sometimes serocomplex.

<i>Cryptosporidium</i> genus of apicomplexan parasitic alveolate

Cryptosporidium is a genus of apicomplexan parasitic alveolates that can cause a respiratory and gastrointestinal illness (cryptosporidiosis) that primarily involves watery diarrhea with or without a persistent cough in both immunocompetent and immunodeficient humans.

Pasteurella is a genus of Gram-negative, facultatively anaerobic bacteria. Pasteurella species are nonmotile and pleomorphic, and often exhibit bipolar staining. Most species are catalase- and oxidase-positive. The genus is named after the French chemist and microbiologist, Louis Pasteur, who first identified the bacteria now known as Pasteurella multocida as the agent of chicken cholera.

Yersiniosis is an infectious disease caused by a bacterium of the genus Yersinia. In the United States, most yersiniosis infections among humans are caused by Yersinia enterocolitica.

<i>Campylobacter fetus</i> species of bacterium

Campylobacter fetus is a species of Gram-negative, motile bacteria with a characteristic "S"-shaped rod morphology similar to members of the genus Vibrio. Like other members of the genus Campylobacter, C. fetus is oxidase-positive.

Exogenous bacteria are microorganisms introduced to closed biological systems from the external world. They exist in aquatic and terrestrial environments, as well as the atmosphere. Microorganisms in the external environment have existed on Earth for 3.5 billion years. Exogenous bacteria can be either benign or pathogenic. Pathogenic exogenous bacteria can enter a closed biological system and cause disease such as Cholera, which is induced by a waterborne microbe that infects the human intestine. Exogenous bacteria can be introduced into a closed ecosystem as well, and have mutualistic benefits for both the microbe and the host. A prominent example of this concept is bacterial flora, which consists of exogenous bacteria ingested and endogenously colonized during the early stages of life. Bacteria that are part of normal internal ecosystems, also known as bacterial flora, are called Endogenous Bacteria. A significant amount of prominent diseases are induced by exogenous bacteria such as gonorrhea, meningitis, tetanus, and syphilis. Pathogenic exogenous bacteria can enter a host via cutaneous transmission, inhalation, and consumption.

<i>Histoplasma</i> genus of fungi

Histoplasma is a genus of dimorphic fungi commonly found in bird and bat fecal material. Histoplasma contains a few species, including—Histoplasma capsulatum—the causative agent of histoplasmosis; and Histoplasma capsulatum var. farciminosum, causing epizootic lymphangitis in horses.

M. Neal "Doc" Guentzel is a doctor working in the fields of infectious diseases, microbes, and bioremediation, as well as a researcher and professor of microbiology at both the University of Texas at San Antonio (UTSA) and the University of Texas Health Science Center at San Antonio. He currently serves as an Associate Dean in the College of Science at UTSA - Downtown Campus.

Bacterial cellular morphologies

Bacteria are classified by direct examination with the light microscope according to their morphology and arrangement.

Open defecation is the human practice of defecating outside rather than into a toilet. People may choose fields, bushes, forests, ditches, streets, canals or other open space for defecation. They do so because either they do not have a toilet readily accessible or due to traditional cultural practices. The practice is common where sanitation infrastructure and services are not available. Even if toilets are available, behavior change efforts may still be needed to promote the use of toilets. The term "open defecation free" (ODF) is used to describe communities that have shifted to using a toilet instead of open defecation. This can happen for example after community-led total sanitation programs have been implemented.

References

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  3. Kal, K and Chambers, R (2008) Handbook on Community-led Total Sanitation Archived 2015-04-10 at the Wayback Machine , Plan UK Accessed 2015-02-26
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  7. 1 2 3 4 Intestinal Parasites and Infection fungusfocus.com – Retrieved on 2010-01-21
  8. 1 2 "Stool-To-Mouth or Fecal–Oral Route of Transmission of Infection | Healthhype.com". www.healthhype.com. Retrieved 2016-04-18.
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