Intestinal amebiasis: what is it? This is a fairly common infectious disease, which is accompanied by a primary lesion of the intestinal tube, as well as other organs and systems after the generalization of the process. This is a very dangerous pathological process, the result of which can be fatal.
Definition
Intestinal amebiasis is a disease caused by the pathogenic species Entamoeba histolytica. This is the simplest microorganism, widespread in countries with a humid and hot climate. In addition, in countries located in the tropics and subtropics, the level of social hygiene is extremely low, so intestinal infections occur in a large part of the population. This is a pressing public he alth problem in third world countries.
In order to understand how dangerous amoebiasis is for humans, it is important to know that it ranks second in mortality after malaria. Almost half a billion people in the world are carriers of Entamoeba histolytica. Ten percent of them have clinical symptoms, and another twenty percent die from complications without first manifesting the disease.
Constantthe migration of people from developing countries to more prosperous ones contributes to the spread of the pathogen and an increase in the incidence. In Russia, due to emigration from the countries of the Middle East, the disease is becoming widespread.
Etiology
Intestinal amebiasis is caused by a histolytic or dysentery amoeba that inhabits the lumen of the human large intestine. Amoeba can exist in three forms: cystic, tissue, luminal, and pre-cystic.
- The tissue form is found in patients only in the acute period of the disease and only in the tissues of the intestine, and not in the feces. This is a small amoeba that has a soft ectoplasm and an endoplasm that does not contain organelles. It moves in the body with the help of pseudopods. This form can absorb red blood cells, as well as secrete enzymes that help it get into the mucosal and submucosal layers of the intestine. This causes tissue death and ulceration.
- The translucent form is found in the lumen of the large intestine. It feeds on bacteria that make up the normal flora of a person, as well as tissue detritus that forms during ulceration. It often occurs in people who have had an acute form of the disease or are carriers. Its dimensions are smaller, the movements are slower than the fabric one.
- The pre-cystic form is transitional and occurs only in this species of amoeba. It is unstable to disinfection methods and quickly dies outside the host organism.
- Cysts are a dormant form of the dysenteric amoeba. So she canexist in the environment. These are round, colorless cells that have four nuclei and a vacuole. This form is found in the intestinal contents of convalescents and carriers.
Epidemiology
Intestinal amebiasis is an anthroponotic infection. That is, the pathogen lives only in a person and is transmitted from person to person. The mechanism of transmission is fecal-oral, the routes of transmission can be different: through water, food, household items or skin-to-skin contact. A person who is a carrier can excrete millions of cysts from the body every day and potentially infect everything around. This form of amoeba can remain viable in the open air for more than a month, and when frozen - up to six months. In tap water, the pathogen lives for more than two months, and on the soil surface - a little less than two weeks.
Doctors try to diagnose intestinal amoebiasis as early as possible. Symptoms in women and children develop quickly and the disease is severe. Therefore, given the intensity of excretion of amoebae from the body and their resistance in the external environment, it is necessary to observe the rules of personal hygiene and carry out regular wet cleaning of residential premises with disinfectants.
Prevalence
Intestinal amoebiasis is ubiquitous, regardless of climate or race. In tropical countries, the percentage of cases is higher, but in other areas this infection is also quite common. The spread of the disease is facilitated by the low sanitary culture of the population and poorhygienic conditions: lack of centralized water supply, untimely garbage collection and cleaning of sewers.
The number of people who are carriers of the pathogen and are not even aware of their illness is many times greater than the number of those who have clinical symptoms. In some countries, this figure reaches forty percent of the population. In countries with a temperate climate, sporadic incidence is recorded. The literature describes outbreaks of amoebiasis in prisons and barracks.
In the CIS countries, amoeba excretors, as a rule, are people with the human immunodeficiency virus, injection drug addicts and AIDS patients. The transmission of the exciter occurs during the warm run.
Pathogenesis
Intestinal amebiasis - what is it? This is a severe intestinal infection that develops when the large intestine is affected. The development of the disease is due to the properties of the pathogen. When a cyst is ingested by humans, it is exposed to the acidic environment of the stomach and enzymes in the small intestine and becomes a vegetative form.
One cyst produces eight amoebae that move to the upper colon. While human immunity suppresses the mass reproduction of amoebas, they do not manifest themselves in any way: they feed on bacteria and chyme. But if circumstances begin to favor them, for example, there is a violation of the acidity of the environment, injury to the intestinal wall, a violation of peristalsis, the appearance of helminths or stress, then the pathogen begins to multiply actively.and penetrate from the lumen of the intestinal tube into its wall.
The parasite secretes proteases, hemolysin and other enzymes that destroy tissues and help the pathogen penetrate into the thickness of the organ. Neutrophils (tissue macrophages) try to engulf the amoeba, but instead melt and release monooxidants that increase inflammation and necrosis. In the places of ulcers, the conditionally pathogenic and pathogenic microflora mixes, the pathogen sinks deeper into the tissues and multiplies intensively. This is how the primary focus or abscess is formed.
Over time, it opens up and in its place an ulcer forms with undermined edges and necrosis in the center. The mucosa tries to close the defect with new tissue and granulations. Ultimately, mucosal fibrosis, scarring and strictures are observed. Abscesses do not appear at the same time. On the colonic mucosa, one can detect both freshly opened ulcers and already epithelializing ones, as well as scars.
Ulcers can be so deep that they penetrate the entire thickness of the wall, and can cause perforation of the organ with the development of peritonitis and intestinal bleeding. This contributes to the generalization of the disease and the migration of amoebae with the bloodstream to other organs and tissues.
Symptoms
The World He alth Organization identifies several forms in which intestinal amoebiasis can develop. The symptoms of each of them are quite pathognomonic, so the diagnosis does not cause significant difficulties for the doctor.
Dysentery colitis. The most common form of the disease. There are both acute and chronic variants of the course. The incubation period is from two weeks to four months. The main symptom is diarrhea. At first, about six times a day, but then it becomes more frequent up to twenty or more times, impurities of blood and mucus appear in the feces. Over time, bowel movements become like raspberry jelly. The person does not complain about pain, temperature or fatigue. But in severe cases, cramping pains in the right lower abdomen (often confused with inflammation of the appendix) and high fever are possible.
Acute process lasts no more than six weeks, after which a period of remission begins. Sometimes it turns into recovery, but this is rare. As a rule, after a couple of months the disease resumes, but already in a chronic form. Without treatment, the process drags on for years. Chronic amoebiasis can be roughly divided into recurrent and continuous forms.
In the recurrent course of the disease, periods of exacerbation are measured by remissions, but the symptoms do not completely go away, but only become less pronounced (at the level of mild stool disorder). During an exacerbation of dysentery, body temperature does not change significantly, abdominal pain appears, and visits to the toilet become more frequent (compared to remission). A continuous flow is manifested by an increase in all intestinal symptoms, the appearance of blood and mucus in the stool.
The long course of the disease greatly exhausts patients, they have anemia, weight loss up to cachexia, asthenovegetative symptoms.
Extraintestinal amoebiasis
The penetration of protozoan pathogens into the body can manifest itself not only as intestinal amoebiasis. The symptoms of the disease may be completely different from the classic disease, but nevertheless they will be caused by the same pathogen. Extraintestinal forms occur when amoebas enter the systemic circulation. The most common target organ is the liver, lungs, or brain.
Abscesses develop in the above organs. Their presence is manifested in an increase in the liver, an increase in temperature to high numbers (39 or more), with concomitant chills, sweating (especially at night). With a strong inhibition of liver function, jaundice may occur. Sometimes abscesses break through the diaphragm or melt it and the contents enter the pleural cavity. This provokes the formation of empyema, lung abscesses and atelectasis.
Intestinal amebiasis in children
There are many children among the sick and carriers of Entamoeba histolytica, as they do not follow the rules of personal hygiene and often get dirty. In addition, they have a weakened immune system. Anyone older than 5 years of age can develop intestinal amoebiasis. Symptoms, treatment and diagnosis do not differ much from those in adults. Clinical manifestations are expressed moderately, the temperature is often normal, rarely subfebrile. The diarrhea is cramping in nature, streaks of blood and mucus appear in the feces. The number of urges can vary from 2 to 15 times a day. Pain in the abdomen may be absent, due to the imperfection of the nervous system of a small child.
It can be difficult for a pediatrician to diagnose intestinal amoebiasis,symptoms in children are blurred and disguised as other intestinal infections. Therefore, you need to carefully collect an anamnesis, specify the time of departure abroad and the presence of symptoms in parents.
Diagnosis
In adults, too, it is quite difficult to diagnose "intestinal amoebiasis". Diagnosis begins with the collection of an epidemiological history. Living conditions, the presence of sick people in the environment, trips to Southeast Asia in the recent past play an important role in potential infection with the pathogen and can orient the doctor in the right direction.
Decisive in the diagnosis is a laboratory study of feces and tissues of the large intestine, the contents of abscesses in the liver and lungs. The disease amoebiasis of the intestine is confirmed by the presence of vegetative forms of dysenteric amoeba in the material. In order for the diagnosis to be effective, the study is carried out repeatedly, starting from the first day of illness or from the patient's admission to the hospital. Detection of exclusively luminal forms and cysts does not provide sufficient evidence for a diagnosis.
If the results of parasitological studies are negative or ambiguous, then the next step is to set up serological tests to detect antigens or antibodies to the pathogen in the patient's blood. The diagnostic criterion is a dynamic increase in antibody titer by 4 times or more from the initial level.
From instrumental studies, ultrasound of the liver, X-ray of the lungs, computed tomography or magneticresonant tomography. This is necessary to identify extraintestinal foci of the disease.
Treatment
Usually doctors don't wait until a diagnosis of intestinal amoebiasis is made, treatment begins as soon as a person is admitted to the hospital. Initially, it is symptomatic: the loss of fluid and electrolytes is replenished, drugs are administered intravenously to support the functioning of the heart and lungs. If there is a high temperature, then it is lowered to acceptable numbers. After the final diagnosis is clarified, specific therapy is also connected.
If a person is a carrier of amoebas, then luminal amoebocytes are prescribed, which help to remove parasites from the body and inhibit their reproduction. In addition, this group of drugs is also prescribed to patients with other forms of the disease in order to completely eliminate the pathogen from the body.
For patients with acute amoebic dysentery, there are tissue amoebocytes that act directly on the vegetative forms of the pathogen and eliminate it in organs and tissues. It is important to complete the course of treatment, even after the disappearance of clinical symptoms. There are cases of recurrence of the disease decades after the first time.
Prevention
What should be done to prevent intestinal amoebiasis? Treatment is aimed at eliminating the parasite from the patient's body, and prevention affects his environment and living conditions. An infectious disease doctor should identify a risk group and conduct an examination of these people, as well as recommend themcarry out general cleaning in the house.
People fall into the risk group more often:
- having pathologies of the digestive system;
- residents of settlements where there is no centralized water supply;
- food workers;
- travelers;
- people of non-traditional sexual orientation.
Medical examination of discharged patients lasts a year. Studies for the isolation of amoebae are carried out every three months, and out of turn, if there are symptoms of a violation of the gastrointestinal tract. To break the transmission mechanism, disinfection of objects that have fallen into the discharge of the patient is carried out. In addition, recommendations are issued to improve the sanitary and epidemiological regime.
