Trypanosoma cruzi it is an euglenozoan (phylum Euglenozoa) of the order Kinetoplastida that is characterized by being an obligate parasite of humans and other vertebrates. It has a flagellum and a simple mitochondrion, in which the kinetoplast is located, a specialized organelle that contains about 25% of the organism's DNA.
The life cycle of this flagellate is complicated, with more than one host and several body forms, which are identified based on the position of the kinetoplast in relation to the nucleus and the level of development of the flagellum. The body forms are called trypomastigote, epimastigote, amastigote, and promastigote..
Trypanosoma cruzi It is the causal agent of Chagas disease, also known as American trypanosomiasis or Chagas-Mazza disease, which is transmitted by triatomine insects (chipos). There are more than 130 species of insects capable of transmitting the parasite and several species of mammals that serve as hosts..
Chagas disease presents an asymptomatic initial phase, but symptoms appear later and can present in different forms, such as fever, anorexia, myocarditis, weight loss, cardiomyopathy, dementia and even death if not treated. Treatment includes nifurtimox and benzonidazole, which have multiple side effects.
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Trypanosoma cruzi It is a flagellated protozoan, an obligate parasite of mammals, including man, that uses insects as intermediate hosts, mainly those of the triatomine group..
Its reproduction is asexual by fission and its life cycle presents various body forms, there is also polymorphism within the trypomastigotic phase.
Trypanosoma cruzi It cannot be transmitted by casual contact between definitive hosts, but by transfusions and organ transplants, also by the consumption of contaminated organisms, as well as from mother to fetus through the placenta and rarely through breast milk.
The kinetoplast of T. cruzi it is located in a capsular expansion of the mitochondrion, which presents ridges, except in the trypomastigotic phase, where it is limited to a small channel devoid of ridges.
The size of the kinetoplast varies in the different phases of the parasite and is a discoidal structure that presents three spirals of DNA-fibrillar, circular and also has about 25,000 minicircles whose function remains unknown..
This species has a membrane with eight surface glycoproteins below which it presents a cytoskeleton organized with microtubules that participates in several functions, including differentiation and mobility. It also participates in the tissue migration process.
The body shape of Trypanosoma cruzi It will change throughout its life cycle, each of them being distinguished, mainly by the relative position of the kinetoplast in relation to the nucleus, by the degree of development or emergence of the flagellum and by the presence or absence of an undulating membrane.
It basically has an elongated shape, with some variations, for example in width, apparently correlated with its biological characteristics. The kinetoplast is located in the posterior part of the animal, that is, posterior to the nucleus.
The flagellum emerges from the flagellar sac, located near the kinetoplast and folds towards the anterior part of the body, forming an undulating membrane along the parasite and emerging freely at its most distal end. In humans, it is 20 μm long by 1 μm wide and has a shape that can resemble a C or an S.
This form does not reproduce, but constitutes the infectious form. It is located extracellularly in the host's blood.
In this phase, the kinetoplast is located anterior to the nucleus, in the middle part of the organism. It is elongated in shape, with the flagellum emerging in front of the nucleus and forming an undulating membrane of smaller size than that found in the previous form..
The kinetoplast and the flagellum are located in the anterior part of the parasite, and the latter emerges free, without developing a wavy membrane.
This stage has a spherical or oval shape, with an approximate size of 2 to 5 μm in diameter. The kinetoplast appears as a dark mass near the nucleus and the flagellum is inconspicuous.
The life cycle of Trypanosoma cruzi It begins when the vector insect bites the human being, or any other mammal and subsequently defecates. The parasite was deposited together with the feces in the form of metacyclic trypomastigote. This can enter the new host through the wound or through the mucous membranes with the help of the flagellum..
It can also penetrate through scratches and wounds produced by the host when scratching. The host cell surface contains some macromolecules, including laminin, fibronectin, and heparin sulfate, which are essential for allowing parasite adhesion and for the cell invasion process..
When the parasite penetrates the host's cells, it undergoes a reduction of the flagellum, and becomes an amastigote. In that place, asexual reproduction begins through binary fission, a process similar to that which occurs in bacteria..
After several reproductions, a large number of amastigotes have originated, which form a pseudocyst, subsequently the amastigotes are transformed again into trypomastigotes and cell lysis occurs.
The trypomastigotes that have been released from this cell penetrate into other new cells, infecting them and repeating the reproductive cycle.
When an insect vector, which is generally a triatomine insect, ingests the blood of a human being, or any other infected mammal, some trypomastigotes are ingested as well..
When the parasites reach the intestine of the insect, they transform into epimastigotes, which can reproduce by mitosis, constituting the second reproductive phase. After 15 days to a month, the parasites migrate to the rectum of the insect and transform into metacyclic trypomastigotes.
Later, when the insect feeds again and defecates, the trypomastigotes will be deposited along with the feces, and the cycle will begin again..
Trypanosoma cruzi is the causal agent of Chagas disease, also called American trypanosomiasis or Chagas-Mazza disease, which is transmitted by triatomine insects, known in some localities as chipos.
This disease affects several species of mammals, in addition to man, including both wild and domestic species. It cannot be transmitted by direct contact between mammals, but it can be transmitted by ingestion of sick animals, vector insects or their feces. It can also be acquired by transfusion and transplants.
The disease mainly affects people who do not have access to adequate housing and presents three phases: acute, indeterminate and chronic. Without proper treatment it can be fatal.
The symptoms of the disease will vary depending on the phase in which it is. Three phases are generally defined: acute, indeterminate, and chronic. In the first of them the parasites can be easily found in the blood and then disappear in the indeterminate stage.
The signs are variable, with an asymptomatic stage, especially in adults. If admission occurs through the eyes, Romaña syndrome or sign may occur, which consists of painless edema in one or both eyes, conjunctivitis, and swollen lymph nodes and may persist for one to two months..
Other symptoms of the disease may include general body weakness and discomfort, fever, headache and joint pain, poor appetite, nausea, vomiting, diarrhea, and myalgia or muscle aches..
In some cases, there may be generalized or limited edema to the face or lower extremities, abnormal enlargement of the liver or spleen, as well as generalized or localized lymphadenopathy..
The disease in this phase can be fatal for children and for people with compromised immune systems.
This phase can last up to 40 years; is characterized by the disappearance of parasites from blood samples and because patients do not have any symptoms of the disease.
In this phase there are insufficiencies of the heart or digestive system. In the case of heart failure, chest pain, heart failure in the left ventricle or both ventricles, aneurysms, peripheral edema, liver enlargement, pulmonary congestion, and shortness of breath may occur..
Pulmonary embolisms, strokes, and even sudden death are also possible..
Chagas disease can also cause megacolon, whose symptoms include constipation (constipation), intestinal obstruction, asymmetric abdominal distention, among others..
Chagas disease, if not treated, can cause death, there are antiparasitics that can be applied, but require prolonged treatments. They are more efficient in the acute stage of the disease, and present significant side effects that may require discontinuation of treatment.
If the disease in its acute phase is detected and confirmed in children, the recommended treatment consists of nifurtimox, 8 mg / kg divided into three doses administered orally, for a period that can last between 50 and 120 days..
The adverse effects of this medicine include loss of appetite, insomnia and nervousness, hallucinations or seizures may also occur, as well as peripheral neuritis, in which case the treatment should be discontinued..
If doctors detect the disease in its chronic phase, treatment consists of benzonidazole, 4 to 7 mg / kg, for two months. Adverse effects include dizziness, nausea, vomiting, headache or abdominal pain, loss of appetite and weight, polyneuritis, decreased thrombocytes, as well as allergic purpura..
Special care should be taken when treating patients with a history of heart disease, such as arrhythmia or atrioventricular block, as well as those suffering from digestive tract diseases..
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