|Other names||Bloody diarrhea|
|A person with dysentery in a Burmese hospital, 1943|
|Symptoms||Bloody diarrhea, abdominal pain, fever|
|Duration||Less than a week|
|Causes||Usually Shigella or Entamoeba histolytica|
|Risk factors||Contamination of food and water with feces due to poor sanitation|
|Diagnostic method||Based on symptoms, Stool test|
|Prevention||Hand washing, food safety|
|Treatment||Drinking sufficient fluids, antibiotics (severe cases)|
|Frequency||Occurs often in many parts of the world|
|Deaths||1.1 million a year|
Dysentery ( // ) is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications may include dehydration.
The cause of dysentery is usually the bacteria from genus Shigella , in which case it is known as shigellosis, or the amoeba Entamoeba histolytica ; then it is called amoebiasis.Other causes may include certain chemicals, other bacteria, other protozoa, or parasitic worms. It may spread between people. Risk factors include contamination of food and water with feces due to poor sanitation. The underlying mechanism involves inflammation of the intestine, especially of the colon.
Efforts to prevent dysentery include hand washing and food safety measures while traveling in areas of high risk.While the condition generally resolves on its own within a week, drinking sufficient fluids such as oral rehydration solution is important. Antibiotics such as azithromycin may be used to treat cases associated with travelling in the developing world. While medications used to decrease diarrhea such as loperamide are not recommended on their own, they may be used together with antibiotics.
Shigella results in about 165 million cases of diarrhea and 1.1 million deaths a year with nearly all cases in the developing world.In areas with poor sanitation nearly half of cases of diarrhea are due to Entamoeba histolytica. Entamoeba histolytica affects millions of people and results in greater than 55,000 deaths a year. It commonly occurs in less developed areas of Central and South America, Africa, and Asia. Dysentery has been described at least since the time of Hippocrates.
The most common form of dysentery is bacillary dysentery, which is typically a mild sickness, causing symptoms normally consisting of mild gut pains and frequent passage of stool or diarrhea. Symptoms normally present themselves after 1–3 days, and are usually no longer present after a week. The frequency of urges to defecate, the large volume of liquid feces ejected, and the presence of blood, mucus, or pus depends on the pathogen causing the disease. Temporary lactose intolerance can occur, as well. In some caustic occasions, severe abdominal cramps, fever, shock, and delirium can all be symptoms.
In extreme cases, people may pass more than one liter of fluid per hour. More often, individuals will complain of diarrhea with blood, accompanied by extreme abdominal pain, rectal pain and a low-grade fever. Rapid weight loss and muscle aches sometimes also accompany dysentery, while nausea and vomiting are rare. In many cases there can be cascading cramps that affect the muscles surrounding the entire upper intestine; sometimes severe enough to cause the lining of the intestine to separate from the wall, leading to systemic infection.[ citation needed ]
On rare occasions, the amoebic parasite will invade the body through the bloodstream and spread beyond the intestines. In such cases, it may more seriously infect other organs such as the brain, lungs, and most commonly the liver.
Dysentery results from bacterial, or parasitic infections. Viruses do not generally cause the disease. [ citation needed ]These pathogens typically reach the large intestine after entering orally, through ingestion of contaminated food or water, oral contact with contaminated objects or hands, and so on. Each specific pathogen has its own mechanism or pathogenesis, but in general, the result is damage to the intestinal linings, leading to the inflammatory immune responses. This can cause elevated physical temperature, painful spasms of the intestinal muscles (cramping), swelling due to fluid leaking from capillaries of the intestine (edema) and further tissue damage by the body's immune cells and the chemicals, called cytokines, which are released to fight the infection. The result can be impaired nutrient absorption, excessive water and mineral loss through the stools due to breakdown of the control mechanisms in the intestinal tissue that normally remove water from the stools, and in severe cases, the entry of pathogenic organisms into the bloodstream. Anemia may also arise due to the blood loss through diarrhea.
Bacterial infections that cause bloody diarrhea are typically classified as being either invasive or toxogenic. Invasive species cause damage directly by invading into the mucosa. The toxogenic species do not invade, but cause cellular damage by secreting toxins, resulting in bloody diarrhea. This is also in contrast to toxins that cause watery diarrhea, which usually do not cause cellular damage, but rather they take over cellular machinery for a portion of life of the cell.
Some microorganisms – for example, bacteria of the genus Shigella – secrete substances known as cytotoxins, which kill and damage intestinal tissue on contact. Shigella is thought to cause bleeding due to invasion rather than toxin, because even non-toxogenic strains can cause dysentery, but E. coli with shiga-like toxins do not invade the intestinal mucosa, and are therefore toxin dependent.
Definitions of dysentery can vary by region and by medical specialty. The U. S. Centers for Disease Control and Prevention (CDC) limits its definition to "diarrhea with visible blood". [ citation needed ]Others define the term more broadly. These differences in definition must be taken into account when defining mechanisms. For example, using the CDC definition requires that intestinal tissue be so severely damaged that blood vessels have ruptured, allowing visible quantities of blood to be lost with defecation. Other definitions require less specific damage.
Amoebiasis, also known as amoebic dysentery, is caused by an infection from the amoeba Entamoeba histolytica , [ citation needed ]which is found mainly in tropical areas. Proper treatment of the underlying infection of amoebic dysentery is important; insufficiently treated amoebiasis can lie dormant for years and subsequently lead to severe, potentially fatal, complications.
When amoebae inside the bowel of an infected person are ready to leave the body, they group together and form a shell that surrounds and protects them. This group of amoebae is known as a cyst, which is then passed out of the person's body in the feces and can survive outside the body. If hygiene standards are poor – for example, if the person does not dispose of the feces hygienically – then it can contaminate the surroundings, such as nearby food and water. If another person then eats or drinks food or water that has been contaminated with feces containing the cyst, that person will also become infected with the amoebae. Amoebic dysentery is particularly common in parts of the world where human feces are used as fertilizer. After entering the person's body through the mouth, the cyst travels down into the stomach. The amoebae inside the cyst are protected from the stomach's digestive acid. From the stomach, the cyst travels to the intestines, where it breaks open and releases the amoebae, causing the infection. The amoebae can burrow into the walls of the intestines and cause small abscesses and ulcers to form. The cycle then begins again.[ citation needed ]
Dysentery may also be caused by shigellosis, an infection by bacteria of the genus Shigella, and is then known as bacillary dysentery (or Marlow syndrome). The term bacillary dysentery etymologically might seem to refer to any dysentery caused by any bacilliform bacteria, but its meaning is restricted by convention to Shigella dysentery.
Some strains of Escherichia coli cause bloody diarrhea. The typical culprits are enterohemorrhagic Escherichia coli, of which O157:H7 is the best known.
A diagnosis may be made by taking a history and doing a brief examination. Dysentery should not be confused with hematochezia, which is the passage of fresh blood through the anus, usually in or with stools.
The mouth, skin, and lips may appear dry due to dehydration. Lower abdominal tenderness may also be present.
Cultures of stool samples are examined to identify the organism causing dysentery. Usually, several samples must be obtained due to the number of amoebae, which changes daily.Blood tests can be used to measure abnormalities in the levels of essential minerals and salts.
Efforts to prevent dysentery include hand washing and food safety measures while traveling in areas of high risk.
Although there is currently no vaccine that protects against Shigella infection, several are in development. [ citation needed ]Vaccination may eventually become a part of the strategy to reduce the incidence and severity of diarrhea, particularly among children in low-resource settings. For example, Shigella is a longstanding World Health Organization (WHO) target for vaccine development, and sharp declines in age-specific diarrhea/dysentery attack rates for this pathogen indicate that natural immunity does develop following exposure; thus, vaccination to prevent this disease should be feasible. The development of vaccines against these types of infection has been hampered by technical constraints, insufficient support for coordination, and a lack of market forces for research and development. Most vaccine development efforts are taking place in the public sector or as research programs within biotechnology companies.
Dysentery is managed by maintaining fluids using oral rehydration therapy. If this treatment cannot be adequately maintained due to vomiting or the profuseness of diarrhea, hospital admission may be required for intravenous fluid replacement. In ideal situations, no antimicrobial therapy should be administered until microbiological microscopy and culture studies have established the specific infection involved. When laboratory services are not available, it may be necessary to administer a combination of drugs, including an amoebicidal drug to kill the parasite, and an antibiotic to treat any associated bacterial infection.
If shigellosis is suspected and it is not too severe, letting it run its course may be reasonable — usually less than a week. If the case is severe, antibiotics such as ciprofloxacin or TMP-SMX may be useful. However, many strains of Shigella are becoming resistant to common antibiotics, and effective medications are often in short supply in developing countries. If necessary, a doctor may have to reserve antibiotics for those at highest risk for death, including young children, people over 50, and anyone suffering from dehydration or malnutrition.
Amoebic dysentery is often treated with two antimicrobial drugs such as metronidazole and paromomycin or iodoquinol.
With correct treatment, most cases of amoebic and bacterial dysentery subside within 10 days, and most individuals achieve a full recovery within two to four weeks after beginning proper treatment. If the disease is left untreated, the prognosis varies with the immune status of the individual patient and the severity of disease. Extreme dehydration can delay recovery and significantly raises the risk for serious complications.
Insufficient data exists, but Shigella is estimated to have caused the death of 34,000 children under the age of five in 2013, and 40,000 deaths in people over five years of age.Amoebiasis infects over 50 million people each year, of whom 50,000 die (one per thousand).
The seed, leaves, and bark of the kapok tree have been used in traditional medicine by indigenous peoples of the rainforest regions in the Americas, west-central Africa, and Southeast Asia in this disease.Bacillus subtilis was marketed throughout America and Europe from 1946 as an immunostimulatory aid in the treatment of gut and urinary tract diseases such as rotavirus and Shigella, but declined in popularity after the introduction of consumer antibiotics.
Entamoeba is a genus of Amoebozoa found as internal parasites or commensals of animals.
Diarrhea, also spelled diarrhoea, 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.
Shigellosis is an infection of the intestines caused by Shigella bacteria. Symptoms generally start one to two days after exposure and include diarrhea, fever, abdominal pain, and feeling the need to pass stools even when the bowels are empty. The diarrhea may be bloody. Symptoms typically last five to seven days and it may take several months before bowel habits return entirely to normal. Complications can include reactive arthritis, sepsis, seizures, and hemolytic uremic syndrome.
Shigella is a genus of bacteria that is Gram-negative, facultative anaerobic, non-spore-forming, nonmotile, rod-shaped and genetically closely related to E. coli. The genus is named after Kiyoshi Shiga, who first discovered it in 1897.
Entamoeba histolytica is an anaerobic parasitic amoebozoan, part of the genus Entamoeba. Predominantly infecting humans and other primates causing amoebiasis, E. histolytica is estimated to infect about 35-50 million people worldwide. E. histolytica infection is estimated to kill more than 55,000 people each year. Previously, it was thought that 10% of the world population was infected, but these figures predate the recognition that at least 90% of these infections were due to a second species, E. dispar. Mammals such as dogs and cats can become infected transiently, but are not thought to contribute significantly to transmission.
The fecal–oral 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, 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.
Entamoeba coli is a non-pathogenic species of Entamoeba that frequently exists as a commensal parasite in the human gastrointestinal tract. E. coli is important in medicine because it can be confused during microscopic examination of stained stool specimens with the pathogenic Entamoeba histolytica. This amoeba does not move much by the use of its pseudopod, and creates a "sur place (non-progressive) movement" inside the large intestine. Usually, the amoeba is immobile, and keeps its round shape. This amoeba, in its trophozoite stage, is only visible in fresh, unfixed stool specimens. Sometimes the Entamoeba coli have parasites as well. One is the fungus Sphaerita spp. This fungus lives in the cytoplasm of the E. coli. While this differentiation is typically done by visual examination of the parasitic cysts via light microscopy, new methods using molecular biology techniques have been developed. The scientific name of the amoeba, E. coli, is often mistaken for the bacterium, Escherichia coli. Unlike the bacterium, the amoeba is mostly harmless, and does not cause as many intestinal problems as some strains of the E. coli bacterium. Some of these harmful strains are inside raw or uncooked meat that is consumed. For example, the bacterium, E. coli O157:H7, which can cause illness, and even death, if eaten. To make the naming of these organisms less confusing, "alternate contractions" are used to name the species for the purpose making the naming easier; for example, using Esch. coli and Ent. coli for the bacterium and amoeba, instead of using E. coli for both.
Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In most classification schemes, Amoebozoa is ranked as a phylum within either the kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup" within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Most phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as some 300 species of unicellular protists. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta, Amorphea or Opimoda.
Travelers' diarrhea (TD) is a stomach and intestinal infection. TD is defined as the passage of unformed stool while traveling. It may be accompanied by abdominal cramps, nausea, fever, headache and bloating. Occasionally bloody diarrhea may occur. Most travelers recover within three to four days with little or no treatment. About 10% of people may have symptoms for a week.
Endolimax is a genus of amoebozoa that are found in the intestines of various animals, including the species E. nana found in humans. Originally thought to be non-pathogenic, studies suggest it can cause intermittent or chronic diarrhea. Additionally, it is very significant in medicine because it can provide false positives for other tests, notably the similar species Entamoeba histolytica, the pathogen responsible for amoebic dysentery, and because its presence indicates the host has consumed fecal material. It forms cysts with four nuclei which excyst in the body and become trophozoites. Endolimax nana nuclei have a large endosome somewhat off-center and small amounts of visible chromatin or none at all.
Shigella dysenteriae is a species of the rod-shaped bacterial genus Shigella. Shigella species can cause shigellosis. Shigellae are Gram-negative, non-spore-forming, facultatively anaerobic, nonmotile bacteria. S. dysenteriae has the ability to invade and replicate in various species of epithelial cells and enterocytes.
Bacillary dysentery is a type of dysentery, and is a severe form of shigellosis.
Dientamoebiasis is a medical condition caused by infection with Dientamoeba fragilis, a single-cell parasite that infects the lower gastrointestinal tract of humans. It is an important cause of traveler's diarrhea, chronic abdominal pain, chronic fatigue, and failure to thrive in children.
Diloxanide is a medication used to treat amoeba infections. In places where infections are not common, it is a second line treatment after paromomycin when a person has no symptoms. For people who are symptomatic, it is used after treatment with metronidazole or tinidazole. It is taken by mouth.
Human feces is the solid or semisolid remains of food that could not be digested or absorbed in the small intestine of humans, but has been further broken 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.
Protozoan infections are parasitic diseases caused by organisms formerly classified in the Kingdom Protozoa. They are usually contracted by either an insect vector or by contact with an infected substance or surface and include organisms that are now classified in the supergroups Excavata, Amoebozoa, SAR, and Archaeplastida.
Shigella sonnei is a species of Shigella. Together with Shigella flexneri, it is responsible for 90% of shigellosis cases. Shigella sonnei is named for the Danish bacteriologist Carl Olaf Sonne. It is a Gram-negative, rod-shaped, nonmotile, non-spore-forming bacterium.
Amoebiasis, or amoebic dysentery, is an infection caused by any of the amoebae of the Entamoeba genus. Symptoms are most common during infection by Entamoeba histolytica. Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include lethargy, loss of weight, colonic ulcerations, abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation and ulceration of the colon with tissue death or perforation, which may result in peritonitis. People affected may develop anemia due to prolonged gastric bleeding
Enteroinvasive Escherichia coli (EIEC) is a type of pathogenic bacteria whose infection causes a syndrome that is identical to shigellosis, with profuse diarrhea and high fever. EIEC are highly invasive, and they use adhesin proteins to bind to and enter intestinal cells. They produce no toxins, but severely damage the intestinal wall through mechanical cell destruction.
Entamoeba moshkovskii is part of the genus Entamoeba. It is found in areas with polluted water sources, and is prevalent in places such as Malaysia, India, and Bangladesh, but more recently has made its way to Turkey, Australia, and North America. This amoeba is said to rarely infect humans, but recently this has changed. It is in question as to whether it is pathogenic or not. Despite some sources stating this is a free living amoeba, various studies worldwide have shown it contains the ability to infect humans, with some cases of pathogenic potential being reported. Some of the symptoms that often occur are diarrhea, weight loss, bloody stool, and abdominal pain. The first known human infection also known as the "Laredo strain" of Entamoebic mushkovskii was in Laredo, Texas in 1991, although it was first described by a man named Tshalaia in 1941 in Moscow, Russia. It is known to affect people of all ages and genders.