Infection of less virulent Helicobacter pylori strains in asymptomatic healthy individuals in Thailand as a potential contributing factor to the Asian enigma.

In Thailand, gastric cancer incidence is considerably low despite the high prevalence of Helicobacter pylori infection. We investigated the prevalence of H. pylori infection and the genotypes of cagA by using 179 stool specimens obtained from asymptomatic Thai individuals. In this study, the prevalence of H. pylori infection was 43.6%, and the detection rate of cagA-positive strains was 43.5%. In addition, the proportion of the highly virulent East-Asian type of cagA was 7.2%. These results indicate that the low prevalence of cagA-positive H. pylori strain as well as the low prevalence of East-Asian genotype cagA-positive strains may contribute to the low gastric cancer incidence.