RESUMO
In a multicenter study, hepatitis A virus (HAV) seroprevalence was surveyed in six countries in Latin America in which in 12,000 subjects were stratified for age. The highest rates of seroprevalence were recorded in the Dominican Republic (89.0%) and Mexico (81.0%), with lower rates in Brazil (64.7%), Chile (58.1%), Venezuela (55.7%), and Argentina (55.0%). The seroprevalence of HAV in children between 1 and 5 years of age was less than 50%, except in the Dominican Republic. In the 5-10-year-old age group, seroprevalence rates have also decreased compared with previous reports. This suggests that the epidemiology is shifting from high to intermediate endemicity, with the population susceptible to HAV infection shifting from children to adolescents and adults. Furthermore, data from Brazil, Argentina, and Mexico show that HAV seroprevalence is significantly lower in people living in medium and high socioeconomic conditions. This study suggests the need for appropriate vaccination programs to be implemented targeting children, adolescents, and adults, particularly in higher socioeconomic groups.
Assuntos
Hepatite A/epidemiologia , Hepatovirus/imunologia , Adolescente , Adulto , Distribuição por Idade , Criança , Pré-Escolar , Estudos Transversais , Feminino , Anticorpos Anti-Hepatite A , Anticorpos Anti-Hepatite/sangue , Humanos , Técnicas Imunoenzimáticas , Lactente , América Latina/epidemiologia , Masculino , Estudos Soroepidemiológicos , Distribuição por Sexo , Classe SocialRESUMO
Using an indirect immunofluorescence assay on stool samples, we found a 6.4% prevalence of cryptosporidiosis among 403 children less than five years of age with acute diarrhea in Mexico City over a one-year period. The prevalence was highest (11.4%) during the rainy summer months. Most Cryptosporidium parvum cases occurred in infants less than one year of age. Cryptosporidium parvum was more common in malnourished children (P < 0.05) and in nonbreast-fed infants less than six months of age (P < 0.01). Neither dwelling characteristics nor the presence of domestic animals at home were associated with C. parvum infection. Enteropathogenic bacteria were found in 26.8% of the children; Escherichia coli, Salmonella, and Shigella being the most frequently identified. None of 100 serum samples tested showed antibodies against human immunodeficiency virus. When compared with immunofluorescence, the acid-fast technique showed a sensitivity of 76.9% and a specificity of 98.9%, with a predictive positive value of 83.3%. It was concluded that 1) monoclonal antibody-based immunofluorescence is a better diagnostic tool than the acid-fast technique, 2) the prevalence of cryptosporidiosis in this population was similar to that of other developing countries, 3) clinical manifestations were nonspecific, and 4) C. parvum was more common in malnourished children and in nonbreast-fed infants.