Sometimes insects can cause a person quite serious trouble. One of them is Chagas or Chagas disease caused by blood-sucking bugs. The doctor from Brazil, Carlus Ribeiro Chagas, described it more than 100 years ago, than he immortalized himself. The name of the disease sounds differently, depending on the pronunciation of the surname of its discoverer. Is Chagas disease dangerous and how serious is it? The answer to this question is yes. Yes, it’s dangerous, although there are people who live with this ailment for many years, without even suspecting that they are infected. But this is rather an exception than a rule. The more common outcome of the disease is sad: patients die within the first months after infection. How and where can I catch this infection and why do people have such a different reaction to it? Let's try to answer.
Chagas disease: geographic location
For Russians, fortunately, while this ailment is exotic. But once AIDS was far from us, somewhere there, in overseas America. Chagas disease is currently demonstrating the same situation. Where is it now distributed? Among people in large numbers it is registered on the South American continent and in some countries of the Caribbean, 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, which also become infected with Chagas disease (squirrels, rats, possums, cats, dogs and others, a total of 150 species), infection is seen much to the north. This gives rise to fears that the disease will soon spread deeper into the North American continent. There are already cases in Texas, Arizona, southern California, and Maryland. The promotion of American trypanosomiasis on the planet is facilitated by the migration of the population, which over the past 15-20 years has occurred on a scale that is no longer controlled. Inhabitants 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 clutch for any work, but donate blood for money and even sell their organs (kidneys, eyes, etc.). An examination at some blood transfusion sites in the United States revealed that there is more donor material with Chagas disease than with hepatitis and AIDS. And at the autopsy of people from the Latin American region who died from heart attacks or acute heart failure , it turned out that every second one suffers from the same disease, only transfers it in a chronic form. So in the near future, the boundaries of the range of Chagas disease are likely to disappear.
Causative agents of the disease
Chagas disease, still little known, is infection with microscopic unicellular live parasites - trypanosoma cruzi (Trypanosoma cruzi). So they were named by Carlus 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 trypanosomes move through the victim's body (mainly by blood). Reaching the organ they need, they penetrate through the membranes into cells and form a flagellate egg-free form (amastigote). In the cells, trypanosomes actively multiply, again forming spindle-shaped “children” with flagella, which penetrate the victim’s blood for further distribution throughout the body. A very bad feature of these microscopic killers is that they can affect the victim’s immunity, forcing him to abandon the fight. Trypanosomes lead an exclusively parasitic lifestyle, while making the path: man (animal) - bug - man (animal). At these circles of the life cycle, changes in their forms occur: from an egg to an adult. They also actively reproduce in the stomachs of bedbugs, which are used to move healthy people into the bodies.
Infection pathways
Chagas disease, the carrier of which is a special type of blood-sucking triatomic bug, is picked up mainly at night, during sleep in the rooms where these insects live. Someone for fun called them “kissers” because they prefer to bite mainly on the lips. The name is fixed. True, not everywhere. In Chile and Argentina they are called straightforward - 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 species were found in America alone, which are carriers of such a microorganism as the pathogen of Chagas disease. In addition to insects, you can get infected from a sick person with close contact if his blood enters the body of a healthy contactee through wounds on the skin. What is not new AIDS? Therefore, often infection occurs in hospitals during blood transfusion or organ transplantation. Infants become infected in the womb, if she is the carrier of the disease. The most peaceful way to catch an infection is through food that gets the feces of a bug. This can happen if people infected with Chagas disease who are not cleanliness cooked. Therefore, traveling to countries that are disadvantageous with respect to triatomous bugs, it is advisable to choose a more civilized place for an overnight stay (a better hotel), thoroughly wash the fruits and vegetables, and refrain from homemade food, which is helpfully offered by local merchants.
How does infection happen?
Many people think that Chagas disease is picked up when a bug bites through the skin and begins to drink blood. This is actually not the case. You can be bitten ten times and stay healthy. And all because infection occurs when the victim puts crupan trypanosomes in the feces of the bug into his skin or mucous membranes. These insects belong to persons who eat where they spoil. A man in a dream involuntarily scratches (and animals lick) a bitten place. So parasites enter the body of their new owner. A healthy bug is not dangerous in itself. But, biting infected people, he is almost completely infected with trypanosomes, and with the next bites, he transfers Chagas disease to new victims. The causative agent lives and multiplies in the stomach of the insect. The contagious bug remains all his life (about 2 years). Mature parasites are localized in the intestines of the victim and excreted with feces. Once in the human body, trypanosomes first massively multiply in the blood, and then settle in the muscles (mainly in the heart and in the gastrointestinal epithelium). Poor people in Latin America live crowded, large families, in dilapidated houses, where for bedbugs there are many secluded corners. Often Chagas disease infects all family members and even entire neighborhoods. Information for consideration: laboratory animals were infected with trypanosomes even when there was no damage on their skin.
Acute form of the disease
It is noted that the moment of biting by the bug with the skin is painless and imperceptible. Subsequently, a slight redness appears in that place (and sometimes there is nothing), in some people there is swelling and itching. The latent (incubation) period, while the parasite in the victim’s blood diligently reproduces, can take from a couple of days to 10 days, depending on the strength of the patient’s body and its tendency to allergies. Then comes the so-called acute form. It was during this period that Chagas disease was extremely dangerous with mortality. Symptoms are as follows:
- a sharp rise in temperature to critical levels;
- fever;
- severe headaches;
- trouble breathing
- malfunctions of the heart;
- significant soreness of the abdomen, chest, all muscles;
- adrenal gland damage;
- enlargement of the thyroid gland, spleen, lymph nodes.
When parasites are introduced into nerve fibers, Chagas disease is especially difficult. Symptoms in this case are:
- paralysis;
- speech impairment;
- athetosis
- impaired intelligence.
External manifestations:
- swollen lips;
- swollen eyes
- the acquisition of leather bronze.
The acute form can last two months, during which many (especially children) die. In survivors of the crisis, the main symptoms disappear, and the disease goes to the next stage. An infected person becomes contagious 10-11 days after a 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 in the blood no longer dominate, but settle in the tissues and cells of the patient and gradually destroy them. The "chronicles" periodically observed exacerbations, followed by complete remission. Chagas identified the following types of chronic disease:
- pseudomyxedematous;
- myxedema;
- Nervous
- heart.
The pseudo-myxedematous type is noted in children aged 15 years and younger. It is characterized by a slight increase in the thyroid gland and lymph nodes. During periods of exacerbation in children, fever begins, fever rises, and tachycardia is observed. Parasites infiltrate into the subcutaneous tissue, which especially disfigures the face. By characteristic edema and redness, you can visually recognize Chagas disease. Photos presented in a wide assortment on specialized medical-related resources cause, to put it mildly, unpleasant sensations.
The myxedematous type differs from the previous one in much larger disorders in the thyroid gland.
The nervous type is fraught with a delay in the development of children and infantilism.
Cardiac leads to pericarditis, bradycardia, and other heart problems.
With the localization of trypanosomes Cruz in the walls of the organs of the gastrointestinal tract, achalasias of the cardia, that is, disorders of the peristalsis of the muscles of these organs, are observed. This leads to obstruction of the esophagus and an increase in the departments of the stomach and intestines. Patients have pain when swallowing food and passing it through the esophagus, vomiting, belching, weight loss, despite a satisfactory appetite. These symptoms do not depend on the consistency of food and appear even on liquid food.
Diagnostics
Chagas disease is established by external signs during a clinical examination of the patient and by further laboratory blood tests under a microscope and serological tests. However, with a 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 in a blood sample, their presence is checked in the lymph nodes (biopsy is done).
Xenodiagnostics is also used. It lies in the fact that laboratory healthy bugs are planted on a sick person, and subsequently (after 14 days) they are examined whether parasites appeared in their intestines or not.
Another test is sowing blood and inoculating it with experimental animals.
At blood transfusion sites, methods based on reactions of fluorescent antibodies, as well as inhibition of gammaglutination, which are more sensitive, although not so specific, are used.
Good results are shown by the test of Mashad Guerreiro. It is based on the compliment 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 already such drugs with which you can completely defeat Chagas disease. Unfortunately, treatment is effective only at the initial stage, until trypanosomes penetrate vital organs. These are Nifurtimox and Benznidazole. They can be purchased in the USA and Latin America strictly according to the prescription. Prescribe these medications to patients with an acute form of the disease, 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 have an apparent recovery after an acute form, do not think how dangerous Chagas's disease is. Meanwhile, about 50 thousand inhabitants of the planet die from it every year. At present, 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, turn 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. It is no longer possible to recover in the later ones. It is also impossible to restore organs affected and destroyed by parasites. In the presence of a chronic disease, many patients die every year from acute heart failure, heart attacks, strokes and other health problems caused by cruzi trypanosomes.
Prevention
To bypass Chagas disease, prevention is extremely important, since there is no vaccine against cruzi trypanosomes. For residents of dangerous regions, it is as follows:
- as closely as possible to inspect their homes for the detection of nests of bugs, if possible, carry out sanitation with insecticides in the houses;
- if possible, erect canopies over the beds;
- observe hygiene.
For tourists:
- avoid visiting the jungle, especially in open summer clothes;
- critical approach to choosing a place to sleep;
- Do not be tempted by the overseas goodies for a snack offered by street and market traders (if you are not sure that the food was prepared in compliance with hygiene standards).
For sanitary and epidemiological services:
- to examine infants and older children whose mothers have had Chagas disease;
- reconstruction of dilapidated buildings;
- regularly carry out sanitation with insecticides of residential premises of citizens;
- screen blood donors 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 infection of animal Cruzi trypanosomes, the problem with the disease in the coming years is unlikely to be resolved.