Helicobacter pylori serostatus in backpackers following travel to tropical countries

The mode of transmission of Helicobacter pylori is unknown. The seroprevalence of H. pylori and the rate of transmission of feco-oral pathogens in developing countries are both high. Long-term travelers to these regions, who come from developed countries are thus potentially at increased risk of an infection with this bacterium. We studied the H. pylori serology status before and after travel of 104 backpackers who traveled to tropical countries; 76 medical students who did not leave Israel served as controls. Southeast Asia (70%) and South America (24%) were the major destinations, but the area of travel had no effect on the seroconversion rate. The total time spent abroad was 53 person-years. Thirty six of the travelers and 30 controls were positive at the outset. Seropositivity at entry was significantly associated with being a Sepharadic Jew or having a parent with a peptic ulcer disease. The majority of travelers (86.5%) and controls (92.1%) did not change their serostatus. Four travelers seroconverted, but 10 seroreverted, while three controls seroconverted, and three others seroreverted. No significant association with gastroenteritis was found. Serostatus may have been affected by mefloquine use because none of the four seroconverters, but eight of 10 seroreverters used it as malaria prophylaxis. In vitro studies demonstrated that mefloquine has anti-H. pylori activity. Feco-oral transmission is apparently not an important route of transmission of this organism among travelers.