Human Mobility and Disease: A Global Challenge

Human mobility increased tremendously during the last century, and masses of travelers, workers, migrants, refugees and displaced persons are moving today all over the planet. The progressive ease of mobility makes business connections between different parts of the world much easier, and has led to a large increase in tourism, which now involves all age groups and social classes in the Western world. As a result, it is estimated that, every year, as many as 50 million people from the industrialized world cross international borders to tropical or subtropical destinations, where they encounter different cultures, social habits and economic standards, and, of the utmost importance, a different microbiological environment. The frequent inconsiderate risky behavior of nonimmune travelers from the Western world may cause serious infections to occur. Risk behaviour for contracting infectious diseases may be related to:(1) alimentation;(2) sexual habits;and to (3) the underrecognition of the vector-borne risk,particularly with regard to malaria.The consumption of contaminated food by the nonimmune Western traveler may lead to gastrointestinal complaints or even systemic diseases, such as hepatitis A and typhoid fever. Besides alimentary education, the effectiveness of which has been questioned, safe and effective vaccines are available which may protect travelers from acquiring hepatitis A and typhoid fever.Casual sexual contacts during short-term travel are frequent,and the risk is even higher in long-term expatriates.Apart from the obvious risk of HIV infection,hepatitis B is a substantial threat, given the high HBsAg prevalence rate in various southern countries.Safe sexual practices should be adopted by travelers,and safe and effective vaccines against hepatitis B are available and should be considered by those traveling to areas that are highly endemic for hepatitis B virus.