From the moment they leave the security of their accustomed environment, travelers are at risk. (1)____ arise not just from s trange diseases they meet on their travels but from other factors too: seemingly uninspiring home (2)____ such as safe water (3)____, sanitation and public hygiene controls, legal safety standards for motor vehicles and road (4)____, are easily taken for granted, but simply do not exist in many countries. Environmental factors such as arduous conditions, (5)____ climate, and high altitude may constitute a danger; and so may travelers’ own behavior, free from the (6)____ of the daily routine, and determined to have a good time with scant (7)____ for the consequences. When illness or injury occur abroad, travelers are again at a disadvantage – from (8)____ to communicate with a doctor on account of language or cultural difficulties, or being unable to find a doctor owing to (9)____ of the (10)____ medical system. There may be a complete (11)____ of skilled medical care, or of medical facilities of a (12)____ acceptable to travelers from technologically sophisticated countries. When symptoms of an illness (13)____ abroad do not appear until after return home a final hazard becomes apparent: the symptoms may be (14)____, may pass (15)____, and the correct diagnosis may not be considered until it is too late.