Humoral nitric oxide levels and antibody immune response of symptomatic and indeterminate Chagas' disease patients to commercial and autochthonous Trypanosoma cruzi antigen.

Abstract

We report here the evaluation of chagasic patients for the presence and/or severity of the disease, antibody to Trypanosoma cruzi, and nitric oxide (NO) serum levels. Serum samples tested by ELISA with autochthonous and commercial antigen revealed that 10% and 7.5% of the individuals were anti-T. cruzi antibody-positive, respectively. Ten of 21 seropositive individuals had no clinical signs, the other 11 cases presented cardiomyopathy and/or mega-gastrointestinal syndromes, and three patients presented a combined form. A statistical difference (P Ͻ 0.001)in antibody titer between asymptomatic and symptomatic patients with autochthonous antigen was detected, and serum NO levels was found to be three times higher in cases than in controls. These results suggest that it is recommended to use a sole source of antigen (autochthonous) for the serodiagnosis of Chagas' disease, and that the pathogenic role of NO in this disease should be evaluated.

Serologic and parasitologic demonstration of Trypanosoma cruzi infections in an urban area of central Mexico: correlation with electrocardiographic alterations.

“…17 More important, an increasing number of clinical cases have been reported in some parts of Mexico not previously considered as chagasic areas, such as the states of Jalisco and Puebla. [18][19][20] These states are in the central part of the country, a considerable distance from the southern areas traditionally considered as chagasic zones.…”

Update on Chagas' disease in Mexico

“…However, a major limitation of many of these studies is that a single serological test was used for diagnosis of infection (immunofluorescence, hemagglutination or ELISA being the most common), even though the WHO recommends the use of at least two methods for an accurate diagnosis. Important methodological differences, particularly in the choice of antigen, 47 also make difficult the comparison of the different studies. The most extensive and homogeneous study performed to date to determine the prevalence of human T. cruzi infection is the National Seroepidemiology Survey of 1987 (ENS, Encuesta Nacional de Seroepidemiología), which confirmed the irregular distribution of Chagas' disease in Mexico, with prevalence of infection ranging from 0.1% in the state of Jalisco up to 5.0% in the state of Chiapas, but also revealed prevalence levels much lower than what had been previously reported in regional studies.…”

“…Very few epidemiological data are available for the incidence of the chronic disease in Mexico. 69 Some isolated cases have been described in different states 47,[49][50][51]69 and, in the past five years, health authorities reported a total of 441 new cases of chronic chagasic cardiomyopathy. 52 As pointed out previously by other authors, 53 the fact that few chronic cases are reported in Mexico despite the endemicity of T. cruzi parasites in vectors and reservoirs and the relatively high seroprevalence in humans may be due to a low virulence of the Mexican strains of T. cruzi, or to the lack of detection of the existing cases.…”

Seroprevalence of human Trypanosoma cruzi infection in diferent geografic zones of Chiapas, Mexico

“…In ELISA the antigen used is from Mexican isolate while IHA uses antigen from Argentina. It has been published that an autochthonous antigen improves serodiagnosis 9 . In Mexico there are few studies regarding the evaluation of diagnostics for Chagas' disease, and one of these was carried out between our Institution (Instituto Nacional de Cardiología) and the National Institute of Epidemiologic Reference (INDRE), showing a good correlation between them (Kappa index above 0.8) 6 .…”