Intestinal amoebiasis: 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 amoebiasis is a disease that is caused by pathogenic species of 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, there is an extremely low level of social hygiene, so intestinal infections are found in most of the population. This is a pressing public health concern in the Third World.
In order to understand how dangerous amoebiasis is for a person, it is important to know that in terms of mortality, he takes second place 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.
The constant migration of people from developing countries to more prosperous ones contributes to the spread of the pathogen and increase the incidence. In Russia, due to emigration from the Middle East, the disease is widespread.
Etiology
Intestinal amoebiasis is caused by a histolytic or dysenteric amoeba, which populates the lumen of the human large intestine. Amoeba can exist in three forms: cystic, tissue, luminal and precystic.
- The tissue form is found in patients only in the acute period of the disease and only in the intestinal tissues, and not in the feces. It 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 mucous and submucous layer of the intestine. This causes tissue necrosis and the appearance of ulcers.
- The luminous form is found in the lumen of the large intestine. It feeds on the bacteria that make up the normoflora of a person, as well as tissue detritus formed during ulceration. Often found in people who have suffered an acute form of the disease or are carriers. Its size is smaller, the movement is slower than tissue.
- The precystic form is transient and is found only in this type of amoeba. It is unstable to disinfection methods and quickly perishes outside the host organism.
- Cysts are a sleeping form of dysenteric amoeba. So it can exist in the external environment. These are round, colorless cells that have four nuclei and a vacuole. This form is found in the contents of the gut recovering and carriers.
Epidemiology
Intestinal amoebiasis is an anthroponotic infection. That is, the pathogen lives only in a person and is transmitted from person to person. The transmission mechanism is fecal-oral; transmission routes may be different: through water, food, household items, or skin-to-skin contact. A carrier person can release millions of cysts from the body every day and potentially infect everything around. This form of amoeba can remain viable outdoors for more than a month, and when frozen, for up to six months. The pathogen lives in tap water for more than two months, and on the surface of the soil a little less than two weeks.
Doctors try to diagnose intestinal amebiasis as early as possible. Symptoms in women and children develop quickly and the disease is severe. Therefore, given the intensity of amoeba excretion from the body and their stability in the external environment, it is necessary to observe the rules of personal hygiene and conduct regular wet cleaning of 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 also occurs quite often. The spread of the disease contributes to the low sanitary culture of the population and poor hygienic conditions: lack of a centralized water supply, untimely garbage collection and cleaning of gutters.
The number of people who are carriers of the pathogen and are not even aware of their disease 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 temperate countries, sporadic incidence is recorded. The literature describes outbreaks of amoebiasis in places of imprisonment and in barracks.
In the CIS countries, amoeba excipients, as a rule, are people with the human immunodeficiency virus, injecting drug addicts and AIDS patients. The transmission of the pathogen occurs in the warm running time.
Pathogenesis
Intestinal amoebiasis - what is it? This is a severe intestinal infection that develops when the colon is affected. The development of the disease is due to the properties of the pathogen. After a person swallows a cyst, it is exposed to the acidic environment of the stomach and small intestine enzymes and goes into a vegetative form.
From one cyst, eight amoebas are obtained, which move to the upper sections of the large intestine. While human immunity suppresses the mass reproduction of amoeba, 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 medium, injury to the intestinal wall, impaired peristalsis, the appearance of helminths or stress, then the pathogen begins to multiply and penetrate from the lumen of the intestinal tube into its wall.
The parasite secretes proteases, hemolysin and other enzymes that destroy tissue and help the pathogen to penetrate the body. Neutrophils (tissue macrophages) try to absorb amoebas, but instead melt and secrete monoxidants, which increase inflammation and necrosis. In places of ulcers, a combination of conditionally pathogenic and pathogenic microflora occurs, the pathogen is sinking deeper into the tissue and multiplying intensively. So the primary focus or abscess is formed.
Over time, it opens and in its place an ulcer forms with saped edges and necrosis in the center. The mucosa tries to close the defect with new tissue and granulations. Ultimately, there is fibrosis of the mucosa, the formation of scars and strictures. Abscesses do not appear at the same time. On the mucous membrane of the colon, you can simultaneously find freshly opened ulcers and already epithelizing, as well as scars.
Ulcers can be so deep that they penetrate the entire thickness of the wall, and can cause organ perforation with the development of peritonitis and intestinal bleeding. This contributes to the generalization of the disease and the migration of amoebas with blood flow to other organs and tissues.
Symptoms
The World Health Organization identifies several forms by 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.
Dysenteric 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. First, about six times a day, but then it speeds up to twenty or more times, impurities of blood and mucus appear in the feces. Over time, bowel movements become like raspberry jelly. A person does not complain of pain, temperature or fatigue. But in severe cases, cramping pains are possible in the right lower abdomen (often confused with appendix inflammation) and high fever.
The acute process lasts no more than six weeks, after which the period of remission begins. Sometimes it goes 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 divided into relapsing and continuous forms.
With a recurring course of the disease, periods of exacerbation are moderated by remissions, but the symptoms do not completely disappear, but only become less pronounced (at the level of a mild stool disorder). During an exacerbation of dysentery, body temperature does not change significantly, abdominal pain appears, toilet visits become more frequent (compared with remission). A continuous course is manifested by an increase in all intestinal symptoms, the appearance of blood and mucus in the feces.
The long course of the disease greatly depletes the patients, they have anemia, weight loss up to cachexia, asthenovegetative symptoms.
Extraintestinal amoebiasis
The penetration of protozoan pathogens into the body can occur not only as intestinal amebiasis. Symptoms of the disease may be completely unlike a classic disease, but nevertheless they will be caused by the same pathogen. Extraintestinal forms occur when amoeba enter the systemic circulation. Most often, the liver, lungs, or brain becomes the target organ.
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 severe inhibition of liver function, jaundice may appear. Sometimes abscesses break through the diaphragm or melt it and the contents fall into the pleural cavity. This provokes the formation of empyema, lung abscesses and atelectasis.
Intestinal amoebiasis in children
Among children and carriers of Entamoeba histolytica there are many children, as they poorly observe the rules of personal hygiene and often get dirty. In addition, they have weakened immunity. Any person older than 5 years may experience intestinal amoebiasis. Symptoms, treatment and diagnosis are not much different from those in adults. Clinical manifestations are moderate, the temperature is more often normal, less often subfebrile. 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. Abdominal pain may be absent due to imperfection of the nervous system of a small child.
It is difficult for a pediatrician to diagnose intestinal amoebiasis, the symptoms in children are blurred and masked by other intestinal infections. Therefore, you need to carefully collect an anamnesis, specify the time of departure abroad and the presence of symptoms in parents.
Diagnostics
In adults, it is also rather laborious to diagnose intestinal amoebiasis. Diagnosis begins with a 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 guide the doctor in the right direction.
Decisive in the diagnosis is a laboratory study of feces and colon tissue, the contents of abscesses in the liver and lungs. The disease of intestinal amoebiasis is confirmed by the presence in the material of vegetative forms of dysenteric amoeba. In order for the diagnosis to be effective, the study is carried out repeatedly, starting from the first day of the disease or from the patient's admission to the hospital. Detection of exclusively luminal forms and cysts does not provide sufficient grounds for diagnosis.
If the results of parasitological studies are negative or ambiguous, then the next step is the formulation of serological reactions to identify antigens or antibodies to the pathogen in the patient's blood. A diagnostic criterion is a dynamic increase in antibody titer 4 times or more from the initial level.
Instrumental studies include ultrasound of the liver, lung radiography, computed tomography, or magnetic resonance imaging. This is necessary to identify extraintestinal foci of the disease.
Treatment
Usually, doctors do not wait until they are diagnosed with intestinal amebiasis, treatment begins immediately after the person is admitted to the hospital. At first it is symptomatic: the loss of fluid and electrolytes is compensated, drugs that support the work of the heart and lungs are administered intravenously. If there is a high temperature, then it is reduced to acceptable numbers. After the final diagnosis is clarified, specific therapy is also included.
If a person is a carrier of amoebas, then luminal amoebocytes are prescribed, which contribute to the removal of parasites from the body and inhibit their reproduction. In addition, this group of drugs is prescribed for 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 undergo a full course of treatment, even after the disappearance of clinical symptoms. Cases of recurrence of the disease are known decades after the first time.
Prevention
What should be done to prevent intestinal amebiasis? Treatment is aimed at eliminating the parasite from the patient’s body, and prevention affects its environment and living conditions. An infectious disease doctor should identify a risk group and conduct an examination of these people, as well as recommend that they conduct spring cleaning at home.
People most often fall into the risk group:
- having pathologies of the digestive system;
- residents of settlements in which there is no centralized water supply;
- food industry workers;
- Travelers
- gay people.
Clinical examination of discharged patients lasts a year. Studies on the allocation of amoebas are carried out every three months, and out of turn, if there are symptoms of a malfunction of the gastrointestinal tract. To break the transmission mechanism, objects that have been exposed to the patient are disinfected. In addition, recommendations are made to improve the sanitary-epidemiological regime.