Dysentery

Shigellosis

A patient reached of Shigellose will be often restored without antibiotic treatment. However, this kind of treatment is usually recommended because the disease is relatively serious and very contagious. It can be transmitted by Contage, for example clothing, the buttons of door, the seats of toilet, etc the antibiotics (norfloxacine, ampicilline and Co-trimoxazole) can be used. The hospitalization can be necessary if the disease becomes serious.

Treatment

In the adults, the dysentery caused by the bacteria usually cures spontaneously. But in the children and other vulnerable groups, it is necessary to employ antibiotics. Unfortunately, during the last years, Shigella dysenteriae of the type 1 (Sd1) became increasingly resistant to the drugs. At the people who were dehydrated following the disease, it is necessary to reconstitute the organic liquids as quickly as possible. One can for that use oral salts of rehydration or intravenous liquids. One generally treats the amoebic dysentery with a combination of drugs. It includes/understands a amoebicide intended to kill the parasite, an antibiotic to treat any associated bacterial infection and a drug to fight the infection striking the liver and other fabrics.

Amoebic dysentery

The amoebic dysentery or amoebiasis or amabiase, transmitted by contaminated water, are well-known like the dysentery of the travellers, the tourista , because it is very widespread in the countries in the process of development (in Latin America, each year, 100.000 people, in particular the children, are victims). An infection of the liver, and thereafter of the amoebic abscesses, can occur. One treats it with the metronidazole or with drugs attached to the group of azoles.

This pathology originates in the Entameba histolytica , a hematophagous Protozoaire from 20 to 40 micrometers diameter. It is Monoxène: its only host is the Man. He initially will place himself in the light of the Large intestine in the form minuta , where he nourishes remains of the colon. Then it evolves/moves in form histolytica when the Immunité of the Man decreases. It reaches then the cystic form , Hématophage, which lyse fabrics and penetrates in the intestinal mucous membrane where it will create ulcerations. Then the Foie infects, then the Poumon and the Cerveau. This parasitosis prevails mainly under the hot climates and is propagated in the form of Kyste S releasing from the amibules (tiny amoebas) in the Feces. There exist also free amoebas, or “trophozoïtes”, which does not form cysts. The symptoms are bloody Diarrhées, abdominal pains, and are never treated with 100%. This parasite is propagated in soiled water.

Parasite

The Amibe is a Protozoaire which belongs to the class of the Rhizopode S.

There exist three kinds which can infest the man, but only Entameba histolytica is really pathogenic. One finds amoebas known as commensales digestive tract because they do not cause a disease, such as for example Entameba coli or Entameba dispar.

Morphology

The shape trophozoïte of the ameba indicates its vegetative cellular form able to multiply. It can be presented under two different aspects:

Entamoeba histolytica minuta : of small size (of Latin minuta, small), that is to say 10 to 15 µm.
Form histolytica histolytica : bulkier, 20 to 30 µm up to 40 µm.

Entameba histolytica histolytica presents the same general aspect as the form minuta , but because of its hematophagous capacities, it has additional characters with in particular presence of red blood corpuscles in the process of digestion in cytoplasmic vacuoles (from where the name of histolytica ).

The shape cyst of the ameba is its form of passive dissemination and resistance in the external medium. The cyst survives at least 15 days in water 18°C, 10 days in the saddles, dry 24:00. It resists the chemical agents well. One notes a spherical aspect, from 10 to 14 µm diameter with 4 cores with maturity. The immature cysts contain a vacuole, 1 or 2 cores and are larger.

Parasitic cycle

It is about an obligatory parasite of the man. This last constitutes only the Hôte able to lodge it as well as the tank of the parasite. The transmission is passive by ingestion of ripe cysts.

Cycle of amoebiasis infection :

After ingestion of a ripe cyst with 4 cores, one assists with the blossoming of eight amoebules minuta type which multiply by binary division in contact with the mucous membrane colic. Intermittent and irregular elimination, in the external medium, in the form of fecal cysts makes it possible to buckle a cycle without intermediate host. At this stage, there is no clinical symptom.

Cycle of amoebiasis disease :

Accidentally, the forms Entameba histolytica minuta colics are transformed into Entameba histolytica histolytica , causing abscesses of the mucous membrane of the digestive tract where the amoebas multiply.

The amoebiasis disease in this acute form lasts approximately three weeks until the return of the parasite to the form Entameba histolytica minuta and to the temporary cure.

There is no formation of cyst at the time of this phase, therefore the form Entameba histolytica histolytica does not have a direct epidemiologic role because this vegetative form is unable to survive in the external medium.

There exists a possibility of blood and/or lymphatic metastases starting from an abscess colic, leading to localizations extra-colics (liver, lung, brain, etc). In these localizations extra-colics, the parasite does not find its form Entameba histolytica minuta , it does not have there a spontaneous tendency to cure.

Transmission

The amoebiasis is transmitted by fecal contamination of drinking water and food, but also by direct contact with the hands or the objects soiled like by sexual way. Incidentally, the Géophagie is a source of infection spread in certain cultures.

Prevention

To prevent the diffusion of the amoebiasis in the domestic entourage, it is necessary:

to carefully wash the hands with the soap and warm water immediately after having used the toilets or to have changed a baby.
To often clean the bathroom and the toilets. To give an special attention to the seats of the toilets and the taps of the wash-hand basins.
To avoid dividing the towels or the gloves of toilet.

Physiopathology

In asymptomatic infections, the ameba nourishes bacteria and particles of food present in the intestine. It usually does not come in contact with the intestine itself because of the protective coating of mucus which papers the intestine. The disease occurs when the ameba comes into contact with the cells of the intestinal wall. It secretes toxic substances then, including Enzyme S which destroy the membrane of the cells and allow them to penetrate and destroy human tissues, with for result the formation of ulcers called “in button of shirt” in the intestine. It uses for that the same enzymes which are normally used to digest the bacteria. Entameba histolytica also nourishes cells destroyed by Phagocytose and one often sees under the microscope of the red Globules inside the vacuoles of his cytoplasm. In Latin America in particular, one can observe a granulomateuse mass (known under the name of amoebôme, but sometimes confused with a cancerous tumor) which can be formed in the wall colic because of a cellular reaction of delayed immunity. Theoretically, the ingestion of only one viable cyst can be enough to cause the infection.

Nature of the disease and symptomatology

The usual Symptôme S of the amoebiasis are gastro-intestinal disorders: Diarrhea, Vomiting S, abdominal pains or indisposition with general signs like a Fever. The symptoms can appear at the end of a few days at a few weeks, but usually they appear after approximately two to four weeks. The majority of the infected people are asymptomatic but this disease can appear very dangerous, particularly on a ground of immunodépression.

Infections which last sometimes during years can be accompanied by various clinical pictures:

Absence of symptom (in the majority of the cases),
an acute diarrheal form (80% of the cases), strong Diarrhea, pasty or liquid saddles, normal temperature,
the acute dysenteric form (20% of the cases), 5 to 15 saddles glairo-sanguinolentes per day having the aspect of rectal spittles, with pain and Ténesme but not of fever.

The majority of the infections occur in the digestive sphere but other bodies can be reached. Among the complications, let us quote ulceration as well as the Abcès, generally hepatic and, more rarely, the Obstruction of the bowels.

The duration of incubation is very variable and the asymptomatic infection persists on average during more than one year. It is supposed that the absence or the presence of symptoms as their intensity can depend on various factors like the virulence of the amoebic stock, the immune reaction of the host, and perhaps the action of the bacteria and the associated viruses.

Evolution

The amoebiasis has a tendency to chronicity with relapses colics which can occur constantly and degrade the intestinal mucous membrane a little each time, there leaving cicatricial lesions. It is what is called the post-amoebic colitis with alternation of diarrhea and constipation, and pains colics.

The embolisation of the forms histolytica and swarming towards the internal organs giving a syndrome of amoebiasis extra-colic, primarily hepatic.

Diagnosis of the disease

The asymptomatic human infections are usually diagnosed by the discovery of cysts in the taking away of saddles. Various processes of enrichment or separation were developed to isolate the cysts contained in the feces as well as techniques from location of the cysts for the examination under the microscope. Since the cysts are not constantly present, the analysis of three successive taking away minimum is generally necessary to the diagnosis.

In symptomatic infections, the vegetative form (the trophozoïte) can often be found in the fresh saddles. Tests serologic exist and the majority of the individuals (presenting or not symptoms) will be tested positive for the presence of Anticorps. The levels of antibody are much higher at the individuals who present abscesses of the liver. Serology becomes positive only approximately two weeks after the beginning of the infection. Recent progress made it possible to develop a kit which detects the presence of proteins of amoebas in the saddles and another which detects DNA amoebas in the saddles. These tests are not current use because of their high cost.

The examination with the Microscope remains still the most widespread method of diagnosis by far in the whole world. However, this method is not also sensitive or specific for the diagnosis only the other examinations available. It is important to distinguish by its morphology the cyst from Entameba histolytica from the cysts from the nonpathogenic intestinal protozoa such as that from Entameba coli . The cysts of Entameba histolytica have to the maximum 4 cores, whereas the cyst of the ameba Commensal E Entameba coli has to 8 cores. Moreover, the core of Entameba histolytica is located at the center of the Cytoplasme, whereas it is eccentric for Entameba coli . Lastly, the chromatin clusters are rounded at Entameba histolytica , whereas they have irregular contours at Entameba coli . However, another species of ameba, Entameba dispar , which is also an ameba commensale at the man, cannot be distinguished from Entameba histolytica under the microscope. As Entameba dispar is much more widespread than Entameba histolytica in the majority of the areas of the world, that means that there are many false-positives in the diagnosis of infection to Entameba histolytica . WHO recommends not to treat the infections diagnosed by the only examination with the microscope if they are asymptomatic because there is no other reason of suspecter that the infection is really due to Entameba histolytica .

Relative frequency of the disease

Nevertheless, that means that there is each year approximately 50 million infections caused by Entameba histolytica involving seventy thousand deaths roughly, most of the time because of complications and generally of an abscess of the liver. Although usually regarded as a tropical parasite, the first case historically reported in 1875 was identified with Saint-Petersbourg in Russia, close to the Arctic circle. The infection is more common in the hottest regions, but it is as much for reasons of defective hygiene as parce the cysts of the parasite survive longer under conditions of high temperature and moisture.

Treatment

The infections with Entameba histolytica develop at the same time in the intestine and (for the people which presents symptoms) in the intestinal wall and/or the liver. Consequently, two categories different of drugs must be used to remove the organization from the parasite, for each possible localization of the infection.

The Metronidazole, or a similar drug like the Tinidazole, is used to destroy the amoebas which invaded organic fabrics. It passes quickly in blood circulation and is transported at once until the site of the infection. Since it is quickly absorbed, there does not remain almost any more active substance in the intestine. As the majority of the amoebas remain in the intestine when the invasion of fabrics occurs, it is important to also get rid of those, or else the patient will be likely to develop another case of invasive disease.

Several drugs are usable to treat the intestinal infections, the Paromomycine (also known under the name of Humatin) proved to be most effective of them. One also uses the Furoate of diloxanide, prescribed in the United Kingdom. The two types of drugs must be associated to treat the infections, with the metronidazole which is usually managed the first, follow-up of the paromomycin or of the diloxanide. Entameba dispar does not require treatment, but much of laboratories (even in the developed world) does not have the equipment necessary to distinguish it from Entameba histolytica . For the amoebic dysentery, an approach of Bi-therapy must be used, starting with one of the following treatments in the adult of average morphology:

Metronidazole 500-750mg three times per day during 5-10 days
Tinidazole 2g once per day during 3 days (which is an alternative to the metronidazole)

In addition to what precedes, one of the following amebicides (with action intraluminale) should be prescribed like auxiliary treatment, jointly or sequentially, to destroy Entameba histolytica in its form cyst , particularly in the colonist:

Paromomycine 500mg three times per day during 10 days
Diloxanide Furoate 500mg three times per day during 10 days
Iodoquinol 650mg three times per day during 20 days

For the amoebic abscess of liver:

Metronidazole 400mg three times per day during 10 days
the Tinidazole 2g once per day during 6 days is an alternative to the metronidazole
the furoate of Diloxanide 500mg three times per day during 10 days must always be given later on.

The amounts for children are calculated according to the body weight and a pharmacist should be consulted for opinion.

Treatment by phytotherapy

With the Mexico, dyeing-mothers of Chaparro amargo are usually used, with the amount of 30 drops in water glass the morning with jeun and 30 drops before the evening meal, during seven days. After a stop of the treatment during seven days, new a seven days cure is prescribed. So abdominal pains occur, it is supposed that means that the amoebas die and will be expelled of the organization. Many Mexicans use regularly the treatment by chaparro amargo , three times per annum. The effectiveness of such a treatment is not scientifically shown.

In 1998, a study in Africa suggested that two spoonfuls with soup of seeds of papaw could have an action amoebicide and help with the prevention of the amoebiasis, but this forever confirmed assumption.

Complications

In the majority of the cases, amoebas remain present in the intestinal tract of the host. Serious ulcerations of the intestinal wall occur in less than 16% of the cases.

Much more rarely, one attends the formation of masses pseudotumorales (amoebômes) which can cause obstructions of the bowels.

In some cases, the parasite invades other fabrics, generally the liver.

amoebic Abscess of the liver :

Approximately 3 months after a clinical or last amoebiasis unperceived. Initially signs of pre-suppurative hepatitis: - fever modérée
- painful hepatomegaly

Then table of deep suppuration : - high and oscillating fever then continue
- pain of the hypochondriac irradiant right towards the épaule
- Increased VS, hyperleucocytosis (15 to 20 g/l)
- bronchial dent hépato

The puncture of the cyst brings back pus color chocolate.

Reached pleuro-pulmonary :

By swarming or extension starting from a hepatic abscess (bases right lung):

- fever, cough, expectorations,
- possibility of vomic of color brown chocolate (spittle of abundant pus).

Other attacks :

They are possible but rare: skin, pericardium, spleen, brain.

Populations at risk

It is thought that all the people are likely to contract the infection, but the individuals with a defective or depressed immunity can suffer from the more serious forms of the disease. The infection with Entameba histolytica is associated with the malnutrition and the delay of growth in the child.

The patients reached of the AIDS are particularly vulnerable.

Analyzes food

Cysts of Entomoeba histolytica can be found in the food contaminated by methods similar to those used to highlight cysts of Giardia lamblia in the saddles. Filtration is probably the most practical method to make again drinkable the food water and liquids. The cysts of Entameba histolytica must be distinguished from the cysts of other protozoa parasitic (but nonpathogenic) and from the cysts of the wild protozoa like higher exposed. The methods of analysis are not very powerful; cysts are easily destroyed or damaged before the identification, which leads to many wrongfully negative results in parasitologic research (See the bacteriological analytical handbook of FDA).

Epidemics

The most dramatic incident which has occurred in the United States goes back to 1933 with the world fair of Chicago; it was caused by contaminated drinking water. A defective piping made it possible sewages to soil the water of the network. There were 1.000 cases of noted infections (including 58 death). At one more recent time, employees handling of the foodstuffs were suspectés to have caused many dispersed infections, but there was no grouped case.

Seek

The genetician Esther Orozco discovered the importance of a complex proteinic composed of an enzyme destroying fabrics and a protein at the height adhesive strength and which plays the key function to facilitate the phagocytage of the cell by the parasite.

Famous deaths

Dagobert I {{er}}, king of the Francs, in 639
Louis VI, king de France, in 1137
Jean of England, king of England, in 1216
Louis VIII, king de France, in 1226
Saint Louis, (Louis IX) king de France, in 1270
Philippe V, king de France, in 1322
Francis Drake, Corsair XVI century, in 1596
Giovanni Battista Belzoni, exploring Italian, in 1823
David Livingstone, exploring British, in 1873

External bonds

Course amoebiasis

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