Sometimes insects can give a person quite serious trouble. One of them is Chagas disease, or Chagas, caused by blood-sucking bugs. It was described more than 100 years ago by a Brazilian doctor Carlos Ribeiro Chagas, which immortalized himself. The name of the disease sounds differently, depending on the pronunciation of the name of its discoverer. Is Chagas disease dangerous and how serious is it? The answer to this question is positive. Yes, it is dangerous, although there are people who live with this disease for many years, not even suspecting that they are infected. But this is more the exception than the rule. A more common outcome of the disease is sad: patients die within the first months after infection. How and where can you catch this infection and why do people have such a different reaction to it? Let's try to answer.
Chagas disease: geographical location
For Russians, toFortunately, while this disease is exotic. But once AIDS was far away from us, somewhere out there, in overseas America. The same situation is currently demonstrated by Chagas disease. Where is it distributed now? Among people, it is registered en masse on the South American continent and in some Caribbean countries, in Brazil, Venezuela, Panama, Mexico, Peru, Argentina, Guatemala, Colombia, Ecuador, Costa Rica, Paraguay, Bolivia, Suriname, El Salvador, French Guiana, Belize, Nicaragua, Honduras. As for wild animals that also become infected with Chagas disease (squirrels, rats, opossums, cats, dogs and others, 150 species in total), infection has been noticed much further north. This gives rise to fears that the disease will soon spread deep into the North American continent. There are already cases in Texas, Arizona, southern California and Maryland. The promotion of American trypanosomiasis around the planet is facilitated by population migration, in the last 15-20 years occurring on a scale that is no longer controllable. Residents of Latin American countries travel the world in search of a better life, tourists in search of adventure. Another reason for the spread of infection is that the poor from the above regions not only grab any job, but donate blood for money and even sell their organs (kidneys, eyes, etc.). When checking at some blood transfusion points in the United States of America, it was found that there are more donor material with Chagas disease than with hepatitis and AIDS. And at the autopsy of those who died from heart attacks or acute cardiacInsufficiency of persons from the Latin American region revealed that every second suffers from the same disease, only suffers it in a chronic form. So in the near future, the boundaries of the range of Chagas disease are likely to disappear.
Pathogens
Chagas disease, little known so far, is an infection with microscopic single-celled living parasites - trypanosoma cruzi. So they were named Carlos Chagas in honor of the Oswaldo Cruz Institute. These creatures are colorless (in the photo they are shown in the patient's blood, stained with a marker), with an elongated body that looks like a spindle. At one end there is a flagellum that helps the trypanosomes to move through the body of the victim (mainly through the blood). Reaching the organ they need, they penetrate through the membranes into the cells and form a non-flagellated egg-like form (amastigote). In the cells, trypanosomes actively multiply, again forming spindle-shaped "children" with flagella, which penetrate the victim's blood for further settlement throughout the body. A very bad feature of these microscopic killers is that they can influence the immunity of the victim, forcing him to give up the fight. Trypanosomes lead an exclusively parasitic way of life, making the path: a person (animal) - a bug - a person (animal). On these circles of the life cycle, changes in their forms occur: from an egg to an adult. They also actively multiply in the stomachs of bedbugs, which are used to move into the bodies of he althy people.
Routes of infection
Chagas disease, which is transmitted by a special type of blood-sucking triatomine bug, is caught mainly at night, while sleeping in the premises where these insects live. Someone for fun called them "kissers", because they prefer to bite mainly on the lips. The name stuck. True, not everywhere. In Chile and Argentina they are called plainly - vinchuca, which means an insect, and in Brazil - a barber bug. In total, among the large army of triatomic bugs, numbering 130 species, more than 10 varieties were found in America alone, which are carriers of such a microorganism as the causative agent of Chagas disease. In addition to insects, it is possible to become infected from a sick person through close contact, if his blood enters the body of a he althy contactee through wounds on the skin. Why not the new AIDS? Therefore, infection often occurs in hospitals during blood transfusions or organ transplants. Babies become infected while still in the womb if the mother is a carrier of the disease. The most peaceful way to catch an infection is through food that has been contaminated with bedbug feces. This can happen if people infected with Chagas disease who are not distinguished by cleanliness cook. Therefore, when traveling through countries that are unfavorable for triatomic bugs, it is advisable to choose a more civilized place to stay (a better hotel), thoroughly wash purchased fruits and vegetables, and refrain from homemade food helpfully offered by local merchants.
How infection occurs
Many people think that Chagas disease is caught when the bug bites through the skin and begins to drink blood. Actually it is not. You can be bitten ten times and stay he althy. And all because the infection occurs when the victim introduces trypanos cruzi, which are in the feces of the bug, into their skin or mucous membranes. These insects belong to the persons who, where they eat, crap there. A person in a dream involuntarily scratches (and animals lick) a bitten place. This is how parasites enter the body of their new host. By itself, a he althy bed bug is not dangerous. But, biting infected people, it is almost completely infected with trypanosomes, and with the next bites, it transmits Chagas disease to new victims. The pathogen lives and multiplies in the insect's stomach. The bed bug remains contagious all its life (about 2 years). Mature parasites are localized in the intestines of the victim and are excreted with feces. Once in the human body, trypanosomes first multiply massively in the blood, and then settle in the muscles (mainly in the heart and in the epithelium of the gastrointestinal tract). Poor people in Latin America live in crowded, large families, in dilapidated houses, where there are many secluded corners for bedbugs. Often, all family members and even entire neighborhoods are infected with Chagas disease. Food for thought: Lab animals were infected with trypanosomes even when their skin was intact.
Acute disease
It is noted that the moment of biting through the skin by a bug is painless and imperceptible. Subsequently, a slight reddening appears in that place (and sometimesnothing), some people experience swelling and itching. The latent (incubation) period, while the parasite in the blood of the victim diligently multiplies, can take from a couple of days to 10 days, depending on the strength of the patient's body and his tendency to allergies. Then comes the so-called acute form. It was during this period that Chagas disease is extremely dangerous with lethality. Symptoms are as follows:
- a sharp rise in temperature to critical levels;
- fever;
- severe headaches;
- breathing problems;
- heart failure;
- significant pain in the abdomen, chest, all muscles;
- adrenal lesion;
- enlargement of the thyroid gland, spleen, lymph nodes.
When parasites invade nerve fibers, Chagas disease is especially severe. The symptoms in this case are:
- paralysis;
- speech disorder;
- athetosis;
- intelligence disorder.
Appearances:
- lip swelling;
- swollen eyes;
- bronze skin tone.
The acute form can last for two months, during which many (especially children) die. In those who survived the crisis, the main symptoms disappear, and the disease passes into the next stage. An infected person becomes contagious 10-11 days after the bite.
Chronic form
At this stage, Chagas disease may not manifest itself at all for a long time, which is observed in approximately 80% of patients. Trypanosomes inblood no longer dominate, but settle in the tissues and cells of the patient and gradually destroy them. The "chronics" periodically experience exacerbations, followed by complete remission. Chagas identified the following types of chronic course of the disease:
- pseudomyxedematous;
- myxedematous;
- nervous;
- hearty.
Pseudomyxedematous type has been reported in children aged 15 and younger. It is characterized by a slight increase in the thyroid gland and lymph nodes. During periods of exacerbations in children, fever begins, the temperature rises, tachycardia is observed. Parasites infiltrate into the subcutaneous tissue, which especially disfigures the face. By characteristic swelling and redness, Chagas disease can be visually recognized. Photos presented in a wide range on specialized medical resources cause, to put it mildly, unpleasant sensations.
The myxedematous type differs from the previous one by much greater disturbances in the functioning of the thyroid gland.
Nervous type is fraught with a delay in the development of children and infantilism.
Cardiac leads to pericarditis, bradycardia and other heart problems.
When trypanosomes cruzi are localized in the walls of the organs of the gastrointestinal tract, achalasia of the cardia is observed, that is, disorders of the peristalsis of the muscles of these organs. This leads to obstruction of the esophagus and an increase in the sections of the stomach and intestines. Patients experience pain when swallowing food and its passage through the esophagus, vomiting, belching, weight loss, despite a satisfactory appetite. These symptoms are independent offood textures and appear even from liquid food.
Diagnosis
Chagas disease is established by external signs during a clinical examination of the patient and through further laboratory blood tests under a microscope and serological tests. However, in the chronic form of the disease, there are few trypanosomes in the blood, and therefore it becomes more difficult to detect them.
When parasites cannot be isolated from a blood sample, their presence is checked in the lymph nodes (a biopsy is done).
Xenodiagnosis is also used. It lies in the fact that laboratory he althy bugs are planted on a sick person, and subsequently (after 14 days) they study whether parasites have appeared in their intestines or not.
Another test is blood culture and inoculation in experimental animals.
Blood transfusion sites use methods based on fluorescent antibody reactions as well as gamma-glutination inhibition reactions, which are more sensitive, though not as specific.
Mashad-Guerreiro test also shows good results. It is based on the complement binding reaction, that is, on the detection of antibodies to the parasite antigen. This analysis is extremely valuable in the chronic stage of the disease, when other methods are not particularly strong.
Treatment
Currently, there are drugs that can completely defeat Chagas disease. Treatment is effective, unfortunately, only at the initial stage, until the trypanosomes have penetrated the vital organs. This is Nifurtimox and"Benznidazole". They can be purchased in the US and Latin America strictly by prescription. These medications are prescribed for patients with an acute form of the disease, for children, during relapses, if the chronic form of the disease is not running. In the later stages, it does not help at all. Therefore, all the actions of doctors are focused on the treatment of complications - diseases of the heart, gastrointestinal tract, nervous system, thyroid gland and other organs.
Forecast
Many people, especially those who seem to recover after an acute form, do not think about how dangerous Chagas disease is. Meanwhile, about 50 thousand inhabitants of the planet die from it every year. At the moment, according to various estimates, from 15 to 20 million people are infected, but these figures are not entirely reliable, since the poor, among whom Chagas / Chagas disease is especially widespread, go to doctors extremely rarely. The prognosis for this disease is favorable only in cases of early correct diagnosis and treatment. At the initial stage, if measures are taken in time, an absolute recovery is possible. In the later stages, it is no longer possible to recover. It is also impossible to restore the organs affected and destroyed by parasites. Many patients with chronic disease die every year from acute heart failure, heart attacks, strokes and other he alth problems caused by trypanosomes cruzi.
Prevention
To avoid Chagas disease, prevention is extremely important, as there is no vaccine against Trypanosa cruzi. For residents of dangerous regions, it consists innext:
- inspect your homes as closely as possible to detect nests of bedbugs, if possible, sanitize your homes with insecticides;
- if possible, build canopies over the beds;
- keep hygiene.
For tourists:
- avoid visiting the jungle, especially in open summer clothes;
- take a critical approach to choosing a place to sleep;
- don't be tempted by overseas goodies for snacks offered by street vendors and market vendors (unless you are sure the food was prepared in a hygienic way).
For sanitary and epidemiological services:
- examine infants and older children whose mothers have Chagas disease;
- reconstruct dilapidated buildings;
- regularly sanitize residential premises of citizens with insecticides;
- screen donated blood and carefully examine donors.
There is a proposal to examine all emigrants arriving from epidemic countries, which should prevent the spread of Chagas disease in other regions. However, given the high infestation of Cruzi trypanosomes in animals, the problem with the disease is unlikely to be resolved in the coming years.
