RESUMO
Antibody prevalence to Toxoplasma gondii among residents of a Pacific coastal region of Oaxaca State, Mexico is among low rates reported worldwide. From 60 small, rural communities, 3229 persons from ages 6 months to over 70 years provided blood specimens that were stored on filter papers. 124 (3.8%) of the eluates were seropositive (positive titer greater than 1:256) in the indirect hemagglutination test, and 43 (1.3%) had titers greater than 1:1024. Seropositive rates increased by age group and females were positive twice as often as males. There was no difference in rates for persons who lived at sea level, compared to those who lived between 600 and 1800 meters. In two small communities in which the number of persons tested were a large percentage of the total population, seropositive rates were 1.0 and 1.9%, respectively. The probable explanation for these low rates is the near absence of cats and paucity of meat in the diet. By contrast, sera tested from 479 persons living about 150 km to the east in the coastal, urban towns of Tehuantepec of Salina Cruz showed positive reactions among 122 (125.5%), and 71 (14.8%) had titers less than 1:1024. These people had a higher standard of living, more meat in their diet, and a few cats.
Assuntos
Anticorpos Antiprotozoários/sangue , Toxoplasma/imunologia , Toxoplasmose/epidemiologia , Adolescente , Adulto , Idoso , Altitude , Animais , Gatos , Criança , Pré-Escolar , Etnicidade , Feminino , Inquéritos Epidemiológicos , Humanos , Lactente , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Prevalência , Toxoplasmose/sangue , Toxoplasmose/imunologiaAssuntos
Doença de Chagas/epidemiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , México , Pessoa de Meia-IdadeRESUMO
A serologic survey was conducted in south-western Mexico to obtain information on human experience with arbovirus infections. Sera were collected from two semitropical areas along the Pacific coast of Oaxaca State, two mountain areas above 1,700 meters and the interior valley at 1,500 meters. Of the 610 sera tested for group A antibody, 4.9 per cent were positive in the hemagglutination-inhibition (HI) test to Venezuelan (VE), 11 per cent to Eastern, and none to Western encephalitis viruses. In neutralization tests the antibody was shown to be probably due to VE virus infections. When sera were screened for group B antibodies in the HI test, 32 per cent were positive with St. Louis encephalitis (SLE), 19 per cent with Ilhéus, and 4 per cent with yellow fever viruses. The pattern of reactions suggested that SLE or an antigenically related virus was responsible for the antibody detected. An unusually high rate was found in a mountain area at 2,000 meters: 41 per cent of 113 persons tested were seropositive to SLE. Of 493 sera screened by complement-fixation test, 6 per cent were positive to Nepuyo, 4 per cent to Patois, and 3 per cent to Tlacotalpan viruses.