Trypanosoma cruzi is an euglenozoan (phylum Euglenozoa) of the order Kinetoplastida that is characterized as 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 body'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 Taken and edited from: CDC.
Later, when the insect feeds again and defecates, the trypomastigotes will be deposited along with the feces, and the cycle will begin again.
Diseases
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 places 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.
Trypanosoma cruzi in monkey heart. Taken and edited from: Photo Credit: Content Providers (s): CDC / Dr. LL Moore, Jr..
Symptoms
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.
Acute phase
The signs are variable, with an asymptomatic stage, especially in adults. If admission occurs through the eyes, Romaña syndrome or sign may occur, consisting 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.
Indeterminate phase
This phase can last up to 40 years; It is characterized by the disappearance of parasites from blood samples and because patients do not present any symptoms of the disease.
Chronic phase
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, lung 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.
Treatments
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.
Side effects
The adverse effects of this drug include loss of appetite, insomnia and nervousness, hallucinations or seizures may also occur, as well as peripheral neuritis, in which case 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 in treating patients with a history of heart disease, such as arrhythmia or atrioventricular block, as well as those with digestive tract diseases.
References
- C. Lyre. Mastigophora (flagellates): Characteristics, taxonomy, morphology, habitat, diseases. Recovered from: lifeder.com.
- C. Cobelli. Trypanosoma cruzi life cycle: the 8 main phases. Recovered from: lifeder.com.
- Z. Brener (1992). Trypanosoma cruzi: taxonomy, morphology and life cycle In: S. Wendel, Z. Brener, ME Camargo & A. Rassi (Edt.). Chagas Disease - American Trypanosomiasis: its impact on transfusion and clinical medicine. ISBT Brazil'92, Sao Paulo, Brazil.
- Trypanosoma cruzi. On Wikipedia. Recovered from: en.wikipedia.org.
- JA Marin-Neto, E. Cunha-Neto, BC MacIel & MV Simões (2007). Pathogenesis of Chronic Chagas Heart Disease. Circulation.
- ARL Teixeira, MM Hecht, MC Guimaro, AO Sousa & N. Nitz (2011). Pathogenesis of Chagas' disease: parasite persistence and autoimmunity. Clinical Microbiology Reviews.