Chagas disease, also known as American trypanosomiasis, is an infectious disease caused by the parasite Trypanosoma cruzi ( T. cruzi ). This parasite normally has as an intermediate host an insect popularly known as a barber, which, during the bite, defecates or urinates, releasing the parasite. After the bite, the person's normal reaction is to scratch the spot, however this allows T. cruzi to enter the body and develop the disease.
The infection by Trypanosoma cruzi can bring several complications to the person's health, such as heart disease and disorders of the digestive system, for example, due to the chronicity of the disease.
The barber has a nocturnal habit and feeds exclusively on the blood of vertebrate animals. This insect is usually found in crevices of wooden houses, beds, mattresses, deposits, bird nests, tree trunks, among other places, and it has a preference for places close to its food source.
Main symptoms
Chagas disease can be classified into two main phases, the acute and the chronic phase. In the acute phase there are usually no symptoms, it corresponds to the period in which the parasite is multiplying and spreading through the bloodstream through the body. However, in some people, especially in children due to the weaker immune system, some symptoms can be noticed, the main ones being:
- Sign of Romaña, which is the swelling of the eyelids, indicating that the parasite has entered the body; Chagoma, which corresponds to the swelling of a skin site and indicates the entry of T. cruzi into the body; Fever; Malaise; Increase lymph nodes; Headache; Nausea and vomiting; Diarrhea.
The chronic phase of Chagas' disease corresponds to the development of the parasite in the organs, mainly the heart and digestive system, and may not cause symptoms for years. When they appear, the symptoms are severe, and there may be an enlarged heart, called hypermegaly, heart failure, megacolon and megaesophagus, for example, in addition to the possibility of an enlarged liver and spleen.
The symptoms of Chagas' disease usually appear between 7 and 14 days after infection by the parasite, however when the infection occurs through the consumption of infected foods, the symptoms can appear after 3 to 22 days after the infection.
The diagnosis of Chagas disease is made by the physician based on the stage of the disease, clinical-epidemiological data, such as the place where he lives or visited and eating habits, and present symptoms. The laboratory diagnosis is made using techniques that allow the identification of T. cruzi in the blood, as a thick drop and blood smear stained by Giemsa.
Transmission of Chagas disease
Chagas disease is caused by the parasite Trypanosoma cruzi , which has the barber insect as an intermediate host. This insect, as soon as it feeds on the blood, has the habit of defecating and urinating immediately afterwards, releasing the parasite, and when the person itches, this parasite manages to enter the body and reach the bloodstream, this being the main form of transmission disease.
Another form of transmission is the consumption of food contaminated with the barber or its excrement, such as sugarcane juice or açaí. The disease can also be transmitted through transfusion of contaminated blood, or congenitally, that is, from mother to child during pregnancy or childbirth.
Rhodnius prolixus is also a dangerous vector of the disease, especially in areas close to the Amazon rainforest.
Life cycle
The life cycle of Trypanosoma cruzi begins when the parasite enters the person's bloodstream and invades the cells, becoming an amastigote, which is the stage of development and multiplication of this parasite. Amastigotes can continue to invade cells and multiply, but they can also be transformed into trypomastigotes, destroy cells and become circulated in the blood.
A new cycle can begin when the barber bites an infected person and acquires this parasite. The trypomastigotes in the barber transform into epimastigotes, multiply and return to become trypomastigotes, which are released in the feces of this insect.
How the treatment is done
Treatment for Chagas' disease can be done initially with the use of medications for about 1 month, which can cure the disease or prevent its complications while the parasite is still in the person's blood.
But some individuals do not reach the cure of the disease, because the parasite leaves the blood and starts to inhabit the tissues that form the organs and for that reason, it becomes chronic attacking especially the heart and the nervous system in a slow but progressive way. Learn more about the treatment of Chagas disease.
Research advances
In a recent study, it was found that a drug used to fight Malaria has effects on Trypanosoma cruzi , preventing this parasite from leaving the barber's digestive system and contaminating people. In addition, it was verified that the eggs of the infected barber females were not contaminated with T. cruzi and that they started to lay fewer eggs.
Despite having positive results, this drug is not indicated for the treatment of Chagas disease, because because it has an effect, very high doses are necessary, which is toxic for people. Thus, researchers are looking for drugs with the same or similar mechanism of action and that in concentrations that are low in toxicity to the organism have the same effect.
