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Chagas disease (Portuguese: doença de Chagas, Spanish: enfermedad de Chagas-Mazza, mal de Chagas in both languages; also called American trypanosomiasis) is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking assassin bugs of the subfamily Triatominae (family Reduviidae) most commonly species belonging to the Triatoma, Rhodnius, and Panstrongylus genera. The disease may also be spread through blood transfusion and organ transplantation, ingestion of food contaminated with parasites, and from a mother to her fetus.
The symptoms of Chagas disease vary over the course of an infection. In the early, acute stage, symptoms are mild and usually produce no more than local swelling at the site of infection. As the disease progresses, over the course of many years, serious chronic symptoms can appear, such as heart disease and malformation of the intestines. If untreated, the chronic disease is often fatal. Current drug treatments are generally unsatisfactory; available medications are highly toxic and often ineffective, particularly those used to treat the chronic stage of the disease.
Chagas disease occurs exclusively in the Americas, particularly in poor, rural areas of Mexico, Central America, and South America; very rarely, the disease has originated in the Southern United States. The insects that spread the disease are known by various local names, including vinchuca in Argentina, Bolivia and Paraguay, barbeiro (the barber) in Brazil, Pito in Colombia, chipo, chupança, chinchorro, and “the kissing bug”. It is estimated that as many as 8 to 11 million people in Mexico, Central America, and South America have Chagas disease, most of whom do not know they are infected. Large-scale population movements from rural to urban areas of Latin America and to other regions of the world have increased the geographic distribution of Chagas disease. Control strategies have mostly focused on eliminating the triatomine vector and preventing transmission from other sources.[1]
The disease was named after the Brazilian physician and infectologist Carlos Chagas, who first described it in 1909,[2][3] but the disease was not seen as a major public health problem in humans until the 1960s (the outbreak of Chagas disease in Brazil in the 1920s went widely ignored[4]). He discovered that the intestines of Triatomidae harbored a flagellate protozoan, a new species of the Trypanosoma genus, and was able to prove experimentally that it could be transmitted to marmoset monkeys that were bitten by the infected bug. Later studies showed that squirrel monkeys were also vulnerable to infection.[5]
Chagas named the pathogenic parasite Trypanosoma cruzi[2] and later that year as Schizotrypanum cruzi,[6] both honoring Oswaldo Cruz, the noted Brazilian physician and epidemiologist who fought successfully epidemics of yellow fever, smallpox, and bubonic plague in Rio de Janeiro and other cities in the beginning of the 20th century. Chagas’ work is unique in the history of medicine because he was the only researcher so far to describe solely and completely a new infectious disease: its pathogen, vector, host, clinical manifestations, and epidemiology.
Nevertheless, he believed (falsely) until 1925 that the main infection route is by the bite of the insect—and not by its feces, as was proposed by his colleague Emile Brumpt in 1915 and assured by Silveira Dias in 1932, Cardoso in 1938, and Brumpt himself in 1939. Chagas was also the first to unknowingly discover and illustrate the parasitic fungal genus Pneumocystis, later infamously to be linked to PCP (Pneumocystis pneumonia in AIDS victims).[3] Confusion between the two pathogens’ life-cycles led him to briefly recognize his genus Schizotrypanum, but following the description of Pneumocystis by others as an independent genus, Chagas returned to the use of the name Trypanosoma cruzi.
In Argentina the disease is called Mal de Chagas-Mazza[7], in honor of Salvador Mazza, the Argentine doctor who in 1926 began investigating the disease and over the years became the principal researcher of this disease in the country. The importance of the work of Salvador Mazza lay in pointing out that the disease was an important issue and to preach in the faculties of Medicine. However, this would only be widely accepted since the 1960s, along with the great impact of the disease to public health.
It has been hypothesized that Charles Darwin might have suffered from Chagas disease as a result of a bite of the so-called Great Black Bug of the Pampas (vinchuca) (see Charles Darwin’s illness). The episode was reported by Darwin in his diaries of the Voyage of the Beagle as occurring in March 1835 to the east of the Andes near Mendoza. Darwin was young and generally in good health, though six months previously he had been ill for a month near Valparaiso, but in 1837, almost a year after he returned to England, he began to suffer intermittently from a strange group of symptoms, becoming incapacitated for much of the rest of his life. Attempts to test Darwin’s remains at the Westminster Abbey by using modern PCR techniques were met with a refusal by the Abbey’s curator.[8]
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