Balantidiasis( in the medical literature it is often called infusor dysentery) refers to the number of parasitic infections that provoke ulcerative lesions of the large intestine and are characterized by a severe course and a high level of mortality in case of untimely started treatment.
High mortality is due to a large number of intestinal complications, the development of cachexia( extreme exhaustion) and the attachment of sepsis.
Outbreaks of this intestinal infection are most often recorded in the southern regions of the globe, but individual cases are observed everywhere: usually in rural areas where the population is engaged in pig production.
Risk Factors
The main factors contributing to the spread of this severe zoonotic disease are:
- Complete lack of alertness to medical personnel. That's why cases of balantidiasis are relatively rare.
- The low level of sanitary culture of the rural population.
- Quite high( from 5 to 28%) level of infection in rural areas. People who care for natural carriers of ciliated infusoria - pigs - are most often exposed to infection. During outbreak balantidiasis, the source of infection can become a sick person.
Structure and life cycle of
The etiological agent of balantidiasis is balantidium cysts - the largest representatives of the intestinal protozoa family, capable of parasitizing in the human body.
These pathogenic microorganisms such as protozoa were first found in the intestines of pigs in the eighties of the XIX century.
Subsequent studies have shown that the level of infestation of these pets is at least 80%.
The native scientist N. Soloviev, who in 1901 proved the belonging of balantidium to the category of interstitial parasites, capable of developing in the human body, appropriated the disease status as a separate nosological unit.
Ciliated infusoria balantidium coli is ovoid in shape. Its outer surface is covered with a pellicle, generously strewn with a multitude of short cilia( arranged in longitudinal rows), which help the microorganisms to move. Being a very elastic structure, the pellicle allows a moving unicellular organism to break the symmetry of its body.
The infusoria balantidium coli has two openings: the oral( cytostom), located in the anterior part of the body, and the anal, located in its posterior part.
All absorbed food( starch grains, erythrocytes, bacteria and fungi) first appears in a slit-like cavity( peristome), at the very bottom of which is a mouth opening that passes into the pharynx. Hence the food is sent to the endoplasm, forming digestive vacuoles, moving along the body of the microorganism.
Each balantidium is the owner of two contractile( pulsating) vacuoles, located from opposite parts of the body and intended to remove excess fluid and waste products.
Consisting of a rounded reservoir and several suitable tubules, the pulsating vacuoles alternately contract, pushing the waste material out of the unicellular organism.
Each infusoria contains two nuclei:
- Macronucleus, which provides regulation of intracellular metabolism.
- Micronucleus, responsible for the transfer of genetic information in the process of cell division.
In the existence of ciliated infusorians, a certain cyclicity is observed. The life cycle of balantidium consists of two stages:
- Cystic, which is divided into sexual reproduction( conjugation), during which the infusorians meet exchange their nuclei, and asexual reproduction characterized by transverse division of balantidium.
Balantidia, caught in favorable conditions for them, begin to multiply rapidly by simple division, during which the length of both nuclei extends, accompanied by the appearance of transverse constrictions on them. The same transverse constriction is simultaneously formed on the body of the microorganism.
After the final formation of the septum, newly emerged cells diverge and begin an independent life.
The physiological development of infusorians balantidium coli involves mandatory passage through the conjugation phase. The two microorganisms meet tightly, touching each other with mouth cavities, creating conditions for the most complicated restructuring of the nuclear apparatus.
During this restructuring, a large nucleus( macronucleus) is destroyed and a small( for female and male micronucleus) is divided. As a result, the female core remains in its original place, and the male nucleus remains in the new microorganism through the plasmatic bridge formed between the infusoria to merge with its female core. This is how the transfer of genetic information is carried out.
In fecal masses( at room temperature air), balantidium cysts can survive for at least thirty hours;hitting in tap water or in sewage - up to seven days. In the conditions of large pig-breeding complexes, the viability of cysts increases to one hundred and twenty days, and if it enters the soil, it lasts up to two hundred days.
The life cycle of balantidium, which fell into the human body, is repeated.
- Vegetative. The length of infusoria, which are in the vegetative stage, can be from 30 to 150 microns, width - from 30 to 100 microns. The viability of the vegetative forms of balantidium is significantly inferior to the stability of cysts: being ejected from the body along with the excrements, they perish in five to six hours.
Pathways of infection
In the vast majority of cases balantidiasis is transmitted by zoonotic( from animals to humans) by:
- The main source of protozoal infection is pigs. It is established that approximately 80% of their livestock is infected with ciliated infusoria, which do not cause the slightest harm to their health.
- Mice, rats, dogs, rabbits, wild boars, monkeys can be carriers of pathogenic microorganisms that release their cysts into the environment along with the calves.
- Infectious flies can be synanthropic flies( represented by ovaries, real flies, bloodsuckers, blue and green meat flies) that live near human settlements.
The cases of transmission of pathogenic microorganisms by humans are quite rare. Infusion of diarrheal dysentery occurs alimentary( fecal-oral) way.
Cysts( sometimes vegetative forms) of balantidium fall into the human digestive tract:
- , along with their infected food( unwashed fruits and vegetables) and water;
- from contaminated soil;
- through dirty hands.
More often than not all this parasitic infection affects people working in pig breeding complexes, meat processing plants and slaughterhouses. From the digestive tract cysts of ciliated infusorians move into the stomach, and from it into the small intestine, where they can remain for a long time without giving out their presence and without causing their master any discomfort.
The most common location of pathogenic microorganisms at this stage are the lower parts of the small intestine. What is the reason for the sudden activation of balantidium, which prompts them to start introducing into the structures of the large intestine( this process occurs in the body of only a small fraction of infected people), remains a mystery to this day.
The vegetative forms of balantidium( trophozoites), formed from cysts, begin to actively parasitize and multiply in the epithelial tissues of the colon( most often they affect the zones of the bends of the intestinal loops, straight, sigmoid and the cecum).
The special enzyme, hyaluronidase, which is capable of dissolving the mucous membranes of the colon, contributes to the process of introduction of microorganisms. It is the site of the damaged mucosa and is the "entrance gate" of the protozoal infection that begins.
These processes provoke hyperemia, edema and suppurative abscessing of tissues at the place of introduction of balantidium. After a while pathogenic microorganisms, penetrating into the thickness of epithelial tissues, provoke the appearance of erosions with foci of hemorrhages and necrosis. The severed necrotic masses leave after themselves cavities( ulcers) communicating with the lumen of the affected bowel.
The area of ulcerative defects that are irregularly shaped, crater-shaped, thickened, edged, and filled with dying cells may be several centimeters. On the uneven bottom of ulcers, dark necrotic masses accumulate, having the form of a bloody-purulent deposit.
The main points of pathogenesis( the mechanism of origin and development) of balantidiasis, determining the features of its clinical course, are as follows:
- the presence of ulcerative-destructive changes in the intestine;
- absorption of toxic substances released by infusoria into the patient's body;
- feeds parasitic microorganisms at the expense of its host.
Symptoms of
The clinical picture of balantidiasis depends on the form in which it occurs.
Depending on the nature of the course, the researchers distinguish the following forms of pathology:
- Hidden, often referred to as baldi-bearish and having neither clinical nor morphological manifestations, as the introduction of trophozoites into the intestinal mucosa does not occur with it.
- Sharp.
- Subacute.
- Chronic constant.
- Chronic recurrent( recurrent).
- Subclinical( asymptomatic).Since there are no signs of dysfunctional intestinal disorders and organism intoxication with this form of infusorial dysentery, it is possible to recognize pathology only with the help of endoscopy and laboratory tests. As a rule, the asymptomatic form of balantidiasis is revealed quite accidentally, during a preventive examination, a medical examination prescribed for another disease, in preparation for pregnancy or for surgical intervention. A blood test will indicate an elevated level of hepatic transaminases and the presence of eosinophilia( an increase in the number of eosinophils-leukocyte sprouting cells-in the blood).
Balantidiasis may occur in parallel with shigellosis( bacterial dysentery), amoebiasis( amoebic dysentery) and a number of other infectious diseases. Such forms of pathology are called combined.
Incubation period
The duration of an incubation period that does not have a fixed length is usually ten to fifteen days, although medical statistics indicate that in some cases, from the onset of infection to the appearance of the first clinical manifestations of balantidiasis, it can take five to thirty days.
Acute
Acute balantiosis has three degrees of severity:
- is mild;
average;
heavy.
Patients develop febrile fever, characterized by alternating chills and intense heat. Sharp temperature fluctuations, independent of the time of day, are of an irregular nature, clearly visible on the temperature chart.
Patients with marked signs of general intoxication of the body:
- progressive weakness;
- severe headaches;
- persistent nausea and periodical excruciating vomiting.
Symptomatic of acute hemorrhagic colitis develops at the same time, manifested in the appearance of:
- Cutting cramping pains in the lower abdomen.
- Liquid mucopurulent-purulent, and then bloody stool, the multiplicity of which can be from 18 to 22 times during the day. Abundant feces of the patient produce a sharp putrefactive smell. Due to the loss of a large amount of fluid along with the calves, a rapid decrease in body weight is observed in the patient. In the most severe cases, cachexia may develop( extreme exhaustion).
- Tenesmus( painful false urges for defecation on the background of almost complete absence of fecal masses), observed with lesions of sigmoid, rectum and colon.
Physical examination of the patient reveals:
- pronounced weight loss;
- pallor of the skin;
- muscle weakness( adynamia), manifested by a sharp decline in strength and a significant decrease in motor activity;
- dryness and lagging of the tongue;
- bloating;
- tenderness and enlargement of the liver;
- spasm of the large intestine.
Endoscopic examination of the patient reveals the presence of focal or diffuse erosive-ulcerative colitis. A blood test indicates moderate anemia, eosinophilia and elevated erythrocyte sedimentation rate( ESR).
The duration of the form of balantidiasis is no more than eight weeks. If the manifestations of the acute form continue to be observed, this means that the disease has passed into a latent( subacute) or chronic form.
Chronic
Intoxication syndrome with chronic balantidiasis is rather weakly expressed.
The intestinal manifestations of the pathology, which are represented by:
- , have an accelerated( from two to five times a day) liquid stool, sometimes having an admixture of blood or mucus;
- with increased flatulence;
- moderate ascending tenderness and cecum by palpation.
The temperature response of the patient's body to the course of the pathological process may either be absent, or manifest itself in a slight increase in temperature to subfebrile( from 37.1 to 38 degrees) values. Headaches, as a rule, are not too intense and are unstable. Patients complain of general weakness.
The chronic continuous form of the infusor dysentery is characterized by a monotonous course, accompanied by a moderately expressed intestinal and toxic symptoms observed for several years.
There are no remission periods. Clinical manifestations of the disease( both general toxic and diarrheal syndrome) are of lesser intensity.
Characteristic features of the continuous form of chronic balantidiasis are bloating, a significant decrease in appetite and a gradual decrease in body weight. The lack of adequate treatment can lead to the development of cachexia.
If the pathology extends to the appendix, the patient develops the symptomatology of acute appendicitis, suggesting the onset of:
- elevated body temperature;
- signs of peritoneal injury;
- of the symptom of the roving, which is manifested by the appearance of pain in the right iliac region at the time of impulsive movements of the hand along the surface of the abdominal wall in the region of the left mesogastric region( lateral region of the umbilical region);
- symptom of Schetkina-Blumberg, which makes itself known for the sharp increase in abdominal pain resulting from the rapid removal of the palpable hand from the anterior abdominal wall immediately after the pressure is applied;
- Symptom Sitkovsky, consisting in the occurrence or strengthening of pain in the right ileal region in a patient lying on his left side;
- symptom of Bartome-Michelson, manifested by increased pain when performing palpation of the caecum in a patient who has a reclining position on the left side.
Complications of
Severity of complications of balantidiasis is determined by several factors: the duration of the disease, its shape and severity.
The main cause of complications in balantidiasis is the action of hyaluronidase, isolated by infusoria parasitizing in the patient's body, on the mucous membranes of the large intestine.
Infusion dysentery may result in:
- perforation( perforation) of ulcerative defects of the large intestine;
- occurrence of intestinal bleeding;
- development of abscesses in the abdominal cavity( in particular - to liver abscesses);
- diffuse( total) peritonitis - inflammation of the peritoneum( serous membrane lining the inner surface of the walls of the abdomen and internal organs);
- development of appendicitis;
- occurrence of hypochromic anemia - a disease caused by a significant decrease in hemoglobin in erythrocytes;
- rectal prolapse( rectal prolapse);
- for malignancy of affected tissues.
Diagnostics of
The first step in the diagnosis of balantidiasis is the consultation of the infectious disease specialist, to which patients are sent having a number of characteristic clinical manifestations of pathology( specific abdominal pains, irregular type of fever, multiple diarrhea with putrefactive odor).
After careful collection of the epidemiological anamnesis and physical examination of the patient the doctor will assign him a whole complex of laboratory and instrumental studies, on the basis of which the final diagnosis will be established.
Laboratory diagnostics presupposes a microscopic examination:
- A natural smear of liquid feces that has not been stained and therefore retained its natural color and structure. The main condition for the success of this procedure is that the patient's bowel movements should be freshly isolated( from the moment of defecation to the analysis should be no more than forty minutes).In the presence of balantidiasis in the stool of patients, vegetative forms of ciliated infusoria are easily found: they are very mobile and easily change their shape during movement. In order to examine in detail the pathogens of the disease, excess fluid is removed from the study drug and continues the study with a large magnification of the microscope. Parasitological analysis of fresh fecal masses of the patient is the only reliable diagnostic technique for revealing balantidiasis.
- Feces in preparations stained by the Heidenhain method. Carried out at low magnification, this type of research makes it possible to distinguish not only the outlines of balantidium having a characteristic ovoid form, but also the presence of a bean-shaped vegetative nucleus( macronucleus) in their cytoplasm.
Since the separation of balantidium, subject to a certain periodicity, with feces is extremely uneven, a single study of the native smear can not always reveal the presence of pathology. That is why the study of the feces of the patient is carried out from three to six times.
- A biopsy( scraping from the ulcerated area of the large intestine) taken during endoscopic examination of the intestine. Smears prepared from these scrapings can detect balantidium much more often than drugs obtained from the patient's feces.
Thus, a reliable confirmation of balantidiasis is the detection of trophozoites( vegetative forms of balantidium) in scrapings of the affected intestinal walls, in smears of ulcer contents or in freshly excreted excreta of the patient.
Detection of cysts is evidence of transient carrier - a short-term( as a rule, one-time) isolation of pathogenic microorganisms against the background of a complete absence of clinical manifestations of the disease.
The complex of laboratory diagnosis includes mandatory blood testing. A blood test of a sick person will indicate the presence of:
- a moderate increase in the rate of erythrocyte sedimentation;
- reduced levels of albumins and proteins;
- eosinophilia;
- moderate anemia.
The group of instrumental studies aimed at revealing balantidiasis is represented by:
- Recto-manoscopy is a diagnostic technique designed for visual inspection of the mucous membranes of the distal sigmoid and rectum, performed with a special device called a sigmoidoscope. This apparatus is made in the form of a tube equipped with a lighting device and an air supply device. After injection of air into the cavity of the rectum, which allows to maximally smooth the folds of the mucosa, the air supply system is disconnected and the eyepiece is installed.
- Colonoscopy - a modern technique for endoscopic examination of the large intestine with the help of a thin, flexible and very long tube - a fibrocolonoscope. This device, equipped with a backlight and a miniature video system, allows you to transfer the image to the monitor screen. The procedure of colonoscopy is also accompanied by a careful supply of air, designed to expand the intestinal lumen and smooth out the folds of the mucous membranes.
Both of the above procedures allow patients with acute balantidiasis to detect focal infiltrative-ulcerative changes in the intestinal walls;when chronic form of protozoal infection on the walls of the intestine, ulcerous or catarrhal-hemorrhagic( hemorrhages and necrotic formations) are revealed.
Engaged in differential diagnosis, experts compare the clinical manifestations of balantidiasis and a number of diseases( cryptosporidiosis, amoebiasis, ulcerative colitis, giardiasis, dysbiosis) with similar symptoms.
Treatment of
When confirming balantidiasis, a sick person is necessarily placed in an infectious hospital( all carriers of pathogenic microorganisms are also strictly required).
Etiotropic( designed to eliminate the causes of pathology) treatment consists of:
- In the appointment of antibacterial drugs( represented by ampicillin, monomycin, oxytetracycline).
- In taking antiprotozoal drugs( represented by metronidazole, aminarsone, yatren, tinidazole).
- In the conduct of detoxification treatment.
- In the implementation of vitamin therapy( the patient needs vitamins A, B and C).
- In strict adherence to a special diet prescribing a plentiful drink and consumption of high-calorie food. The patient is absolutely counter-indicative of fatty and unopened dishes.
- In infusion of water-electrolyte solutions that prevent dehydration of the body.
An effective addition to systemic drug therapy is the execution of enemas with a solution of colloidal dispersed salt of norsulfazole.
The main criteria for the treatment of protozoal infection are:
- complete absence of the syndrome of "distal colitis"( or a colitis syndrome);
- negative results of repeated( at least three times per week) fecal examination of feces for the presence of cysts and vegetative forms of balantidium;
- absence of ulcerative defects of intestinal walls.
Forecast and prevention of baldiatidiasis
Forecast balantidiasis is considered conditionally favorable, because thanks to modern etiotropic treatment methods this protozoal infection is completely cured, and the patients' work capacity is fully restored.
In case of untimely diagnosis, late or inadequate treatment, the level of lethal outcomes with balantidiasis in lesions is usually 10-12%.With occasional lesions, mortality from infusional dysentery can reach 30%.
There is no specific prevention of balantiosis yet. Personal prophylaxis of diarrheal dysentery requires:
- to comply with the rules of personal hygiene;
- refusal to eat raw unboiled water;
- thorough washing of fruits and vegetables eaten;
- for long-term meat heat treatment.
Public prophylaxis of balantidiasis consists in:
- Health Education Population.
- Protection of the environment from contamination by its feces of sick people and animals. To this end, measures are being taken to protect water bodies from contaminated sewage. The complex of security measures at the pig-breeding complexes is aimed at preventing soil contamination.
- Timely detection and hospitalization of patients. For this purpose, regular medical examinations of the population and constant strict control over people at risk are conducted.