Chagas disease, named after Carlos Chagas, who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine bugs and via blood transfusion. Chagas disease has two successive phases: acute and chronic. The acute phase lasts six-eight weeks. Several years after entering the chronic phase, 20-35% of infected individuals, depending on the geographical area, will develop irreversible lesions of the autonomous nervous system in the heart, oesophagus and colon, and of the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980s as a result of the demographically representative cross-sectional studies in countries where accurate information was not previously available. A group of experts met in Brasilia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country programme in the Southern Cone countries, the transmission of Chagas disease by vectors and via blood transfusion was interrupted in Uruguay in 1997, in Chile in 1999 and in Brazil in 2006; thus, the incidence of new infections by T. cruzi across the South American continent has decreased by 70%. Similar multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been reported towards the goal of interrupting the transmission of Chagas disease, as requested by a 1998 Resolution of the World Health Assembly. The cost-benefit analysis of investment in the vector control programme in Brazil indicates that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the programme is a health investment with very high return. Many well-known research institutions in Latin America were key elements of a worldwide network of laboratories that carried out basic and applied research supporting the planning and evaluation of national Chagas disease control programmes. The present article reviews the current epidemiological trends for Chagas disease in Latin America and the future challenges in terms of epidemiology, surveillance and health policy.

/pdf/current-epidemiological-trends-for-chagas-disease-in-latin-28pneod8u0.pdf

Current epidemiological trends for Chagas disease in Latin America and future challenges in epidemiology, surveillance and health policy

Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Brasilia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering Committee on Chagas Disease of the Special Program for Research and Training in Tropical Diseases of the World Health Organization (TDR), the objective was set to promote and finance research aimed at the development of new methods and tools to control this disease. The well known research institutions in Latin America were the key elements of a world wide network of laboratories that received - on a competitive basis - financial support for projects in line with the priorities established. It is presented the time line of the different milestones that were answering successively and logically the outstanding scientific questions identified by the Scientific Working Group in 1978 and that influenced the development and industrial production of practical solutions for diagnosis of the infection and disease control.

/pdf/chagas-disease-current-epidemiological-trends-after-the-3ufj7dfbvn.pdf

Chagas disease: current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries

Chagas disease began millions of years ago as an enzootic disease of wild animals and started to be transmitted to man accidentally in the form of an anthropozoonosis when man invaded wild ecotopes. Endemic Chagas disease became established as a zoonosis over the last 200-300 years through forest clearance for agriculture and livestock rearing and adaptation of triatomines to domestic environments and to man and domestic animals as a food source. It is estimated that 15 to 16 million people are infected with Trypanosoma cruzi in Latin America and 75 to 90 million people are exposed to infection. When T. cruzi is transmitted to man through the feces of triatomines, at bite sites or in mucosa, through blood transfusion or orally through contaminated food, it invades the bloodstream and lymphatic system and becomes established in the muscle and cardiac tissue, the digestive system and phagocytic cells. This causes inflammatory lesions and immune responses, particularly mediated by CD4+, CD8+, interleukin-2 (IL) and IL-4, with cell and neuron destruction and fibrosis, and leads to blockage of the cardiac conduction system, arrhythmia, cardiac insufficiency, aperistalsis, and dilatation of hollow viscera, particularly the esophagus and colon. T. cruzi may also be transmitted from mother to child across the placenta and through the birth canal, thus causing abortion, prematurity, and organic lesions in the fetus. In immunosuppressed individuals, T. cruzi infection may become reactivated such that it spreads as a severe disease causing diffuse myocarditis and lesions of the central nervous system. Chagas disease is characterized by an acute phase with or without symptoms, and with entry point signs (inoculation chagoma or Romana's sign), fever, adenomegaly, hepatosplenomegaly, and evident parasitemia, and an indeterminate chronic phase (asymptomatic, with normal results from electrocardiogram and x-ray of the heart, esophagus, and colon) or with a cardiac, digestive or cardiac-digestive form. There is great regional variation in the morbidity due to Chagas disease, and severe cardiac or digestive forms may occur in 10 to 50% of the cases, or the indeterminate form in the other asymptomatic cases, but with positive serology. Several acute cases have been reported from Amazon region most of them by T. cruzi I, Z3, and a hybrid ZI/Z3. We conclude this article presenting the ten top Chagas disease needs for the near future.

/pdf/chagas-disease-what-is-known-and-what-is-needed-a-background-5afhp6ahap.pdf

Chagas disease: what is known and what is needed - A background article

The existence of a number of different species of Leishmania, the persistent increase in the infection rate of diseases caused by this parasite (tegumentary and visceral forms), the different epidemiological situations found in regions of both recent and older colonization, and the trend towards urbanization have led to the adoption of different strategies to control leishmaniases in Brazil. The control measures involve studies related to the parasite, vectors, sources of infection (animal and human), clinical aspects, geographical distribution, historical and socioeconomic factors, integration of health services, and adequate technologies for diagnosis, treatment, and immunoprophylaxis. Finally, successful control requires work with human communities, involving education, provision of information, health promotion, and participation of these communities in the planning, development, and maintenance of control programs.

/pdf/tegumentary-and-visceral-leishmaniases-in-brazil-emerging-4m1y93oiez.pdf

Tegumentary and visceral leishmaniases in Brazil: emerging anthropozoonosis and possibilities for their control

Sudden death is one of the most expressive phenome-na of the natural history of Chagas’ disease, affecting indi-viduals in the most productive phases of their lives. In gene-ral, considering all evolutionary stages of the disease, wecan say that sudden death is the major cause of death in thisdisease. It is worth noting that in 1912 the Brazilian CarlosRibeiro Justiniano Chagas

/pdf/sudden-death-in-chagas-disease-3c2sm5bk3t.pdf

Sudden death in Chagas' disease

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.

/pdf/morbidade-da-doenca-de-chagas-iv-estudo-longitudinal-de-dez-3j0zxab2wd.pdf

Morbidade da Doença de Chagas. IV. Estudo longitudinal de dez anos em Pains e Iguatama, Minas Gerais, Brasil

A cross-section study, type "case-control" was performed in four endemic areas for Chagas' disease in Brazil, two of them in Minas Gerais State, one in the State of Piauiand the other in the State of Paraiba. A total of 716 pairs of persons with same age and sex, one with a positive serology and the other with a negative serology for Chagas' disease were included in the study. This kind of study was performed to determine the chagasic component responsible for the morbidity of the disease in different areas of the country. The clinical symptoms and signs and the eletrocardiographic changes between the serologic positive and serologic negative groups studied in 264 pairs of persons in the district of Iguatama-Pains and 274 in Virgem da Lapa, both in Minas Gerais State, when compared with the same parametres applied in 109 pairs studied in the localities of Colonia and Oitis in the district of Oeiras, State of Piaui and 69 in the districts of Aguiar and Boqueirao dos Cochos in the State of Paraiba, both in northeast of Brazil, showed a marked difference in the morbidity of the disease in different areas. In the areas of Minas Gerais State, although the natural transmission of Chagas' disease had been interrupted since 15 years ago in Iguatama-Pains and 5 years ago in Virgem da Lapa, the cardiac morbidity by the chagasic component was approximately of 30% at he moment of the study. In the areas of Piaui and Paraiba States, although the natural transmission of Chagas' disease is still active, the cardiac morbidity by the chagasic component was lower than 15 and 10%, respectively.

/pdf/morbidade-da-doenca-de-chagas-ii-estudos-seccionais-em-1ub4ay0ffq.pdf

Morbidade da doença de Chagas. II. Estudos seccionais em quatro áreas de campo no Brasil

A study of morbidity was made among 510 patients with positive serology for Chagas' disease, originating from various states in Brazil. The study began in 1960 when the patients were submitted, in Rio de Janeiro, to clinical, electrocardiographic and radiological examinations as well as to serological, xenodiagnostic and other serial laboratory tests. The patients were classified according to their clinical state as: asymptomatic (indeterminate form), cardiac, and carriers of "megas" or associated clinical forms. The prevalence of cardiopathy was 52.1% and of "megas" was 14,3%. An association of cardiopathy and "megas" was observed in 10.7% of the patients whereas the association of megacolon and megaesophagus appeard in 10.9% of the cases. The indeterminate form (asymptomatic) was observed in 39% of the patients. The proportion of cardiopathic cases increased progressively between the first and the fifth decade of life, whereas the proportion of "megas" increased until the 7th decade. However, the highest number of cases in both forms appeard during the 4th decade of life. No significant differences were observed among the clinical forms by sex, in spite of a discrete predominance of cardiopathy in the male and of "megas" in the female. In relation to the patient's race (whites, blacks and of mixed race, it was not possible to observe a significant correlation with the different clinical forms since constitution of the cohort's origin was unknown. Even if the smal number of cases cannot be considered as representative of the clinical form prevalent in the area of origin, using te data of the four states with the larger number of cases, we observed that the proportion of cardiopathy/"megas" was respectively 65.7% and 20.1% in Bahia, 55.7% and 14.7% in Minas Gerais, 50.9% and 15% in Pernambuco and 23,.% and 0% in Paraiba. The small number of cases from the other states didi not permit any estimation of the proportion of every clinical form.

/pdf/morbidade-da-doenca-de-chagas-i-estudo-de-casos-procedentes-13xg5ig4kk.pdf

Morbidade da doença de Chagas: I - Estudo de casos procedentes de vários estados do Brasil, observados no Rio de Janeiro

/pdf/a-follow-up-evaluation-of-chagas-disease-in-two-endemic-3sl2ik9hta.pdf

A follow-up evaluation of Chagas' disease in two endemic areas Brazil

Out of 2484 patients harboring S. mansoni seen in Rio de Janeiro, 1197 had been living permanently out of endemic area frorn one to 30 years, without any possibility of reinfection; 90.1% of these 1197 patients were first seen with, hepato-intestinal schistosomiasis and only 9.9% with hepatosplenic form. 55% of thern still had S. mansoni active infection 6 years or more after they had left the endemic area and 26.5% remained infected for more than 10 years. The patients with intestinal or hepato-intestinal schistosomiasis did not develop the most severe form whether they had been treated or not, and the hepatosplenic patients had a long time to deteriorate.

/pdf/evolutive-pattern-of-schistosomiasis-and-life-span-of-s-u5w8sf7li4.pdf

J. Rodrigues Coura

Papers

Morbidade da Doença de Chagas. IV. Estudo longitudinal de dez anos em Pains e Iguatama, Minas Gerais, Brasil

Morbidade da doença de Chagas. II. Estudos seccionais em quatro áreas de campo no Brasil

Morbidade da doença de Chagas: I - Estudo de casos procedentes de vários estados do Brasil, observados no Rio de Janeiro

A follow-up evaluation of Chagas' disease in two endemic areas Brazil

Evolutive pattern of schistosomiasis and life-span of S. mansoni in patients living in non-endemic area in Brazil