Seroprevalence to Trypanosoma cruzi in rural communities of the state of Querétaro (Mexico): statistical evaluation of tests.

OBJECTIVES: The detection of anti-Trypanosoma cruzi antibodies has become one of the priorities of the clinical establishments in the health sector, due both to the increase in positive cases found in transfusion centres as well as to the appearance of patients with characteristic Chagas cardiopathies that seek emergency treatment in the main hospitals of Querétaro (Mexico). DESIGN AND METHODS: The present study seeks to establish for the first time the infection level of Trypanosoma cruzi, in the rural communities of this state and implement the preventive measures necessary to control and/or eradicate this infection. A transversal study was conducted, examining seriologically 1029 blood samples of the inhabitants of rural areas of the state of Querétaro, to detect anti-Trypanosoma cruzi antibodies. RESULTS: The indirect serological diagnostic tests were indirect hemagglutination, enzymo-immunoenzymatic absorbent, recombinant ELISA, and indirect immunofluorescence. For the diagnostic evaluation of serological tests used, ELISA was considered the control test. CONCLUSIONS: The first conclusion was that the two tests with the greatest serological reactivity were ELISA and recombinant ELISA, followed by IFA and IHA, respectively, with the final percentage of positives being 6.6%, far above the national mean of seroprevalence in Mexico (1.6%). On the other hand, the sensitivity, specificity, VP+, VP-, percentage of concordance and Kappa index of the recombinant ELISA tests, IFA, and IHA were determined against the control ELISA. It was found that ELISA and recombinant ELISA presented a greater sensitivity level, as well as the highest values for the different parameters studied.

The prevalence of enteropathy due to strongyloidiasis in Puerto Maldonado (Peruvian Amazon).

Human strongyloidiasis is an important health problem in the southeast region of Peruvian Amazon, due to its prevalence and long term morbidity. An epidemiological study was conducted in the Peruvian Amazon area of Puerto Maldonado to determine the prevalence of strongyloidiasis in the population. Stool samples were collected from 1,133 patients at the outpatient department of our clinic. Strongyloidiasis affected 221 examined patients (20%). Prevalence was highest in males, mostly in children and elderly men. People living in urban and marginal urban areas, those coming from outside the region, and Andean people, showed the highest prevalences. Pre-school children were more likely to be parasitized than older children. The most common symptoms were diarrhea (55%), abdominal pain (32%) and cough (53%). One in 7 (13%) affected patients presented with moderate or severe symptoms, including life-threatening complications. Other intestinal parasites were found frequently in patients diagnosed with strongyloidiasis. Improved human waste disposal services are considered to be the main requirement to reduce the high prevalence of this disease.

The prevalence of enteropathy due to strongyloidiasis in Puerto Maldonado (Peruvian Amazon)

Human strongyloidiasis is an important health problem in the southeast region of Peruvian Amazon, due to its prevalence and long term morbidade. An epidemiological study was conducted in the Peruvian Amazon area of Puerto Maldonado to determine the prevalence of strongyloidiasis in the population. Stool samples were collected from 1,133 patients at the outpatient department of our clinic. Strongyloidiasis affected 221 examined patients (20 percent). Prevalence was highest in males, mostly in children and elderly men. People living in urban and marginal urban areas, those coming from outside the region, and Andean people, showed the highest prevalences. Pre-school children were more likely to be parasitized than older children. The most common symptoms were diarrhea (55 percent), abdominal pain (32 percent) and cough (53 percent). One in 7 (13 percent) affected patients presented with moderate or severe symptoms, including life-threatening complications. Other intestinal parasites were found frequently in patients diagnosed with strongyloidiasis. Improved human waste disposal services are considered to be main requirement to reduce the high prevalence of this disease.

Proton nuclear magnetic resonance analysis of metabolic end products of the Bolivia strain of Trypanosoma cruzi and three of its clones.

Proton nuclear magnetic resonance (1H NMR) was used to study the in vivo metabolism of Trypanosoma cruzi, the pathogen causing American trypanosomiasis (Chagas' disease). Three clones were isolated from a strain of T. cruzi (Bolivia strain), The clones I, II and III and the original strain were characterized according to the spectra of their metabolic pathways to test the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. T. cruzi (Bolivia strain) excreted acetate, alanine, glycerol, and succinate as major end products, in the proportion 6:4:2:2. Comparing the spectra of T. cruzi clones with the original Bolivia strain revealed both quantitative, as well as qualitative differences in the metabolites excreted: the clones I and II, as opposed to the Bolivia strain and clone III, excreted significant quantities of ethanol.

Characterization of a Trypanosoma rangeli strain of Colombian origin.

A Colombian strain of Trypanosoma rangeli was characterized by analyzing its behaviour in different axenic and cellular culture, its infection rate and the histopathological lesions produced in experimental animals. Although slight inflammatory infiltrations were shown in different histopathological sections, no pseudocysts could be observed. Grace's insect medium is better than liver infusion tryptose or artificial triatomine urine supplemented with proline when studying T. rangeli metacyclogenesis, with a peak of 32% trypomastigotes. High infection rates were found in VERO and J774 cells. Because of its 100% infectivity rates and adequacy of parasitemia levels, C23 strain is a suitable model of T. rangeli biology study.

Morphological and morphometric variability of three clones of Trypanosoma cruzi and the strain of origin (Bolivia).

Knowing the great diversity of medical and biological properties of Trypanosoma cruzi, the causal agent of Chagas' disease, we quantified the morphological parameters that typify the different forms of three clones of T. cruzi and their original strain, Bolivia, in comparison among themselves and with strain Bolivia, attempting to provide additional data concerning the clonal biological behaviour of this parasite. Blood forms morphology was quantified using a computerized image analysis (Videoplan/Kontron) and statistical analysis was determined using ANOVA-1 Test. Large number of quantitative differences among slender, broad, and stout forms were found. The comparison of clones I, II and III with their mother strain, leads to the emergence of significant differences in at least 12 parameters out of the 16 we studied. When clones were compared among themselves, the differences decreased. Variations of the percentages of the three kinds of clones were found along the acute infection. These data are the first step in correlating the morphological and pathogenic characteristics of the parasite.

Biological comparison between three clones of Trypanosoma cruzi and the strain of origin (Bolivia) with reference to clonal evolution studies.

After isolating three clones of Trypanosoma cruzi (Bolivia), we first characterized them according to parasitaemia, pleomorphism and virulence, and then histopathologically. The study's interest lies on the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. Data obtained from the studies of parasitaemia, pleomorphism and virulence showed no differences between the groups studied. As a final point, the histopathological study shows us a muscular tissue tropism both in clones and in their mother strain (Bolivia). In this paper, we conclude that Bolivia strain and clones isolated from it, pertaining to the same major clone share similar biological properties.

The application of the statistical study in the morphometric characterization of a Colombian strain of Trypanosoma cruzi.

After morphological and histopathological characterization, the Cali strain of T. cruzi isolated from a patient in Cali (Colombia), was also submitted to a morphometrical characterization. For this we estimated 16 cellular parameters in 30 samples of each evolutive form of T. cruzi in blood in NNN medium through planimetry by the IBAS-1 (Image Basic Analytic System). This morphometrical study was completed with a statistical one through the application of the variance (ANOVA-1). This made it possible to evidence a great number of significant differences between the slender, broad and stout forms and also between the short and large epimastigotes from the NNN medium. These data have a real interest for classifying some features of the biological cycle of T. cruzi as well as the future development of diagnosis techniques or therapeutical and prophylactic experiments.