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Immunoblotting with trypomastigote excreted-secreted antigens (TESA blot) of Trypanosoma cruzi was evaluated as a method for diagnosis of chronic and acute phases as well as congenital (in newborn children) Chagas' disease. Serum samples from acute-phase and congenital infections were considered to be positive when they reacted with ladder-like bands of 130- to 200-kDa antigens, recognized by immunoglobulin M (IgM) and IgG antibodies, while IgG from chronic-phase sera recognized a broad band antigen of 150 to 160 kDa. Nonchagasic sera were not reactive to these antigens. The study was carried out on 512 patients, 111 of whom were nonchagasic but included cases of leishmaniasis or other pathologies, and 401 chagasic patients. The latter group comprised 361 chronic cases, 36 acute cases, and 4 congenital cases in newborn children. Among the chronic cases, 256 were from areas in which T. cruzi is endemic but which differed widely in the pathogenic expression of T. cruzi infection and in parasitemia levels. These patients at the same time showed a broad range of low, medium, and high reactivity to conventional enzyme-linked immunosorbent assays and indirect immunofluorescence serotests for Chagas' disease. For these reasons they may better represent the universe of chagasic patients than would a sample of highly reactive sera obtained from chagasic patients in a single area endemic for T. cruzi. All acute and congenital cases showed positivity in the IgM and IgG TESA blots, while chronic cases were 100% positive for IgG antibodies. In nonchagasic sera, including 30 cases of visceral and muco-cutaneous leishmaniasis, the specificity index was 1.000, and no cross-reactions were observed. The TESA blot thus seems to be useful as a sensitive and specific diagnostic assay in cases of suspected acute or congenital T. cruzi infection and as a general confirmatory test for conventional Chagas' disease serology.

This study consists of a broad review on what is known and what should be improved regarding knowledge of Chagas disease, not only through analysis on the main studies published on the topics discussed, but to a large extent based on experience of this subject, acquired over the past 50 years (1961-2011). Among the subjects covered, we highlight the pathogenesis and evolution of infection by Trypanosoma cruzi, drugs in use and new strategies for treating Chagas disease; the serological tests for the diagnosis and the controls of cure the infection; the regional variations in prevalence, morbidity and response to treatment of the disease; the importance of metacyclogenesis of T. cruzi in different species of triatomines and its capacity to transmit Chagas infection; the risks of adaptation of wild triatomines to human dwellings; the morbidity and need for a surveillance and control program for Chagas disease in the Amazon region and the need to prioritize initiatives for controlling Chagas disease in Latin America and Mexico and in non-endemic countries, which is today a major international dilemma. Finally, we raise the need for to create a new initiative for controlling Chagas disease in the Gran Chaco, which involves parts of Argentina, Bolivia and Paraguay.

No abstract

The pathogenesis and evolutive pattern of Chagas disease suggests that the chronic phase should be more widely treated in order to (i)

In order to assay the triatomine infestation and domiciliation in the ruralIn the state of Ceará, the presence of triatomines has been known for a long time, as Alencar (1987) has shown in a research that compiled former surveys carried throughout the state. Alencar et al. (1976) have demonstrated that vectors have not been found in only 9 out of the 141 municipal districts that comprise the geographic division of the whole state of Ceará. The authors have cited the semi-domestic Triatoma brasiliensis as being a primary transmitting species and with larger distribution in that state, found in 91.5% houses of municipal districts, many times with high Trypanosoma cruzi infection indexes. Triatoma pseudomaculata, which is believed less domestic, was found in 68.8% of the municipal districts, with an average infection index of 4.2%. In the distribution ranking, the third species in Ceará was Panstrongylus megistus, displaying a variable infection index; this species was found in 61.7% of the municipal districts. Rhodnius nasutus, with an average of 1% infection index, was found in 17.7% of the municipal districts; Panstrongylus lutzi was found in 18.4% of the municipal districts, presenting an average of 17.9% of infection indexes (Alencar et al. 1976).The objective of the present work was to determine infestation indexes, colonization, and density of triatomines in domiciliary units (DUs) that include intradomicile, peridomicile, and ecotopes found in wild habitats of the four localities that belong to the rural area of Jaguaruana municipality, Ceará, Brazil, formerly considered to be highly infested by these vectors. The indexes were determined by relating them with variables such as type of house's wall type and number of peridomiciliary annexes. The authors have also determined the indexes of natural T. cruzi infection in triatomines captured in each studied habitat and ecotopes.

RESUMO ABSTRACTIntroduction. A seroepidemiological and clinical study was conducted on 152 autochthonous individuals living in the district of Barcelos, State of Amazonas, to evaluate the seroprevalence of Chagas infection and morbidity of Chagas disease. Methods. The serological tests used were indirect immunofluorescence, conventional and recombinant ELISA and immunoblot (Tesa-blot). Thirty-eight patients were considered seropositive; 31 were considered serodoubtful; and 83 were considered seronegative. The 38 seropositive cases were paired with 38 seronegative controls of the same age and sex, and underwent epidemiological and clinical evaluations, electrocardiograms and echocardiograms. Twenty-nine pairs underwent radiological examinations of the esophagus. Results. Seropositivity was 19.9 times more frequent among workers gathering plant materials from the forests and 10.4 times more frequent among piassaba gatherers. Eighty six point seven percent of the seropositive individuals recognized the genus Rhodnius as the local vector, while only 34.2% of the seronegative individuals recognized this. The EKG was abnormal in 36.8% of the seropositive individuals and in 21.5% of the seronegative individuals, while the echocardiogram showed abnormalities in 31.6% of the seropositive and 18.4% of the seronegative individuals. Precordialgia and palpitation were more frequent among the seropositive individuals. Clinical evaluation on the digestive system and X-ray on the esophagus did not show significant abnormalities. Conclusions.

Com o objetivo de avaliar a situação epidemiológica da infecção chagásica no Estado do Piauí e sua relação com idade, gênero, transfusão de sangue e aborto espontâneo, foi realizado, de agosto a dezembro de 2002, um inquérito sorológico com o exame de uma amostra aleatória simples de 36.399 moradores da área rural. A infecção chagásica foi definida pelo teste de imunofluorescência indireta para anticorpos antiTrypanosoma cruzi em amostra de sangue coletada em papel de filtro. A soroprevalência total foi de 1,9%, variando de 0,1% em menores de 5 anos a 6,6% em maiores de 79 anos; foi significativamente maior nas mulheres (2,1%), analfabetos (4,1%), receptores de sangue (3,3%) e nas mulheres com abortamento espontâneo (5,4%). Esses dados ao serem comparados com os obtidos durante o inquérito sorológico nacional (1975-1980) mostraram significativa queda da soroprevalência da infecção chagásica no Estado do Piauí (4% para 1,9%), indicando a eficácia das medidas de controle vetorial implementadas no período 1975-2002.