Exotic imported travel-related infections in Japan.

Human social and economic activities as well as changes in the global environment are responsible for outbreaks of emerging and re-emerging infectious diseases. We have encountered 5 cases of asymptomatic schistosomiasis in Japanese travelers who were exposed to cercariae-contaminated freshwater in east Africa. Because all 5 travelers showed normal results upon their return medical examination, Schistosoma, which is not indigenous to Japan, was unfortunately not suspected as the causative agent of this chronic and silent infection. In addition, in 2008, we experienced 2 Japanese cases in an exotic and local pandemic of human trichinellosis which was associated with eating raw soft-shelled turtles in Taiwan. The cause of this emerging pandemic can be attributed to the traditional custom of eating raw soft-shelled turtles. It is important for all travelers to understand that anyone at anytime can be exposed to the threat of a pandemic; therefore, the first step for all travelers is to be aware of worldwide endemicity and keep up to date on the infectious diseases that are prevalent. Concurrently, it is important to identify the presence of slowly and silently expanding infectious diseases and establish surveillance systems to detect not only serious emerging infectious diseases but also chronic and silent infections.