RESUMO
A systematic, house-based serological survey for Trypanosoma cruzi seroreactivity was conducted in three contiguous communities in Olopa municipality, Chiquimula Department, Guatemala. Blood samples from a total of 292 individuals in 63 households were examined by enzyme-linked immunosorbent assay. The seropositive rate ranged from 0% to 20.8% for the three communities, with a mean of 15.1%. Log-linear models showed that seroprevalence was significantly related to age (P < 0.005) but not to sex. However, when the age group with the lowest prevalence (1-9 years) was excluded from the analysis, age was not a significant factor (P = 0.55). Data from a stratified sample collected at the same time were combined with those of the systematic sample to analyze the relationship between seropositivity and possible explanatory variables. Log-linear models, based on 586 individuals in 129 households from the two surveys, revealed a significant positive association between seropositivity and thatched roofs (P = 0.01).
Assuntos
Doença de Chagas/epidemiologia , Animais , Doença de Chagas/microbiologia , Métodos Epidemiológicos , Feminino , Guatemala/epidemiologia , Humanos , Masculino , População Rural , Estudos de Amostragem , Estudos Soroepidemiológicos , Trypanosoma cruziRESUMO
People infected with Trypanosoma cruzi remain so for life, yet only 30-40% of these individuals develop characteristic chagasic cardiomyopathies. Similarly, when infected with the Brazilian strain of T. cruzi, DBA/2 mice develop severe cardiac damage while B10.D2 mice do not. To better understand the immunological parameters that may be involved in the disease process, we have used this murine model (DBA/2 vs B10.D2) and compared the changes in cytokine production during the course of infection with T cruzi. Concanavalin A (Con A) stimulation of spleen cells harvested during the acute phase (day 30) resulted in similarly high levels of IFN-gamma in both mouse strains. However, the amount of IFN-gamma in supernatants from cultures of B10.D2 spleen cells initiated during the chronic phase (day 72) was at subacute levels, whereas secretion by chronic DBA/2 spleen cells remained high. In addition, Con A-stimulated spleen cells from acute DBA/2 mice produced approximately twice as much IL-10 and significantly more IL-4 than cells from B10.D2 mice. IL-4 secretion remained low by cells from chronic B10.D2 mice, but when using cells from chronic DBA/2 mice, levels continued to increase beyond the already high levels secreted by cells harvested during the acute phase. Proliferative responses to Con A stimulation by spleen cells from DBA/2 mice were significantly higher than those from B10.D2 mice in both the acute and chronic phases. These data suggest that enhanced responses in DBA/2 mice, which may be related to a higher parasite burden, a lack of down-regulation, and/or the onset of autoimmune phenomena, correlate with the more severe cardiomyopathy seen in pathopermissive mice.
Assuntos
Doença de Chagas/imunologia , Citocinas/fisiologia , Modelos Animais de Doenças , Animais , Interferon gama , Interleucina-10 , Interleucina-4 , Camundongos , Camundongos Endogâmicos DBARESUMO
People infected with Trypanosoma cruzi remain so for life, yet only 30-40 percent of these individuals develop characteristic chagasic cardiomyopathies. Similarly, when infected with the Brazilian strain of T. cruzi, DBA/2 mice develop severe cardiac damage while B10.D2 mice do not. To better understand the immunological parameters that may be involved in the disease process, we have used this murine model (DBA/2 vs B10.D2) and compared to changes in cytokine production during the course of infection with T. cruzi. Concanavalin A (Con A) stimulation of spleen cells harvested during the acute phase (day 30) resulted in similarly high levels of IFN-gamma in both mouse strains. However, the amount of IFN-gamma in supernatants from cultures of B10.D2 spleen cells initiated during the chronic phase (day 72) was at subacute levels, whereas secretion by chronic DBA/2 spleen cells remained high. In addition, Con A-stimulated spleen cells from acute DBA/2 mice produced approximately twice as much IL-10 and significantly more IL-4 than cells from B10.D2 mice. IL-4 secretion remained low by cells from chronic B10.D2 mice, but when using cells from chronic DBA/2 mice, levels continued to increase beyond the already high levels secreted by cells harvested during the acute phase. Proliferative responses to Con A stimulation by spleen cells from DBA/2 mice were significantly higher than those from B10.D2 mice in both the acute and chronic phases. These data suggest that enhanced responses in DBA/2 mice, which may be related to a higher parasite burden, a lack of down-regulation, and/or the onset of autoimmune phenomena, correlate with the more severe cardiomyopathy seen in pathopermissive mice.
Assuntos
Camundongos , Animais , Doença de Chagas/imunologia , Doença de Chagas/fisiopatologia , Citocinas/fisiologia , Modelos Animais de Doenças , Interferon gama , Interleucina-10 , Interleucina-4 , Camundongos Endogâmicos DBARESUMO
Sera from 9,254 individuals that presented at one of three outpatient clinics in Quito, Ecuador were assayed by indirect hemagglutination for the presence of antibodies reactive with antigens from Taenia solium cysts. Immunoblot analysis of 81 selected sera with IHA titers ranging from 0 to 1,028 showed that a titer of > or = 32 was suggestive of exposure to the parasite. Nine percent (9%) of the 9,254 patients had titers of 32 or greater. Of 3,503 sera from one clinic, which included sera from food handlers undergoing yearly physicals, 390 (11%) were positive. In addition, a correlation with age was seen in some, but not all, populations. In situations where age-related effects were noted, the highest incidence was seen in the youngest (0-20 years) and in the oldest (51-60 years) group. Thus, a resurgence of infection after a period of lower prevalence may be developing. Overall, this study shows that cysticercosis is relatively common and potentially a serious health problem in this region.
Assuntos
Anticorpos Anti-Helmínticos/sangue , Cisticercose/diagnóstico , Taenia/imunologia , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Equador , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Pacientes AmbulatoriaisRESUMO
Chagas' disease is a serious health problem for the population of South and Central America. Blood transfusion is the second most common way in which this disease is transmitted. Several studies have reported finding Trypanosoma cruzi-infected blood in blood banks in endemic areas. Serum samples were taken from the Red Cross blood bank in Quito, a nonendemic and vector free zone of Ecuador, in December 1992 and May 1993 and analyzed by enzyme-linked immunosorbent assay using crude epimastigote extract from the Brazil strain of T. cruzi. Of 162 samples examined in December 1992, 12.1%, 13.9%, and 74% were seropositive, indeterminate, and seronegative, respectively. Of 173 samples taken in May 1993, 6.2%, 17.9%, 75.9% were seropositive, indeterminate, and seronegative, respectively. Western blot analysis of these sera using sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 7.5% gels separated T. cruzi epimastigote antigen proteins, and revealed a reaction with a 205-kD doublet antigen with most of the seropositive samples. These results indicate the necessity for long-term screening of blood bank donors to reduce the risk of transfusion transmission of the disease even in areas of endemic countries where the vector is not present.