As if getting sick abroad weren't bad enough, add to that the possibility of being quarantined or placed in isolation when you come home by the Centers for Disease Control and Prevention. ("Quarantine" refers to the separation of people who have been exposed to an infectious disease and might be contagious. "Isolation" is the separation of people who already exhibit symptoms.)

In the 1970s, with most major infectious diseases under control, the number of quarantine stations at U.S. ports of entry dwindled from more than 50 to just eight. And procedures for reporting individuals who were ill prior to entering the U.S. were generally given short shrift. But that has changed due to terrorist attacks, the outbreak of SARS (severe acute respiratory syndrome) and the spread of avian flu.

More recently, there was the case of lawyer Andrew Speaker, who not only made several airline flights abroad after being diagnosed with a multi-drug-resistant form of tuberculosis but also managed to return to the U.S. without being detained. Today, the CDC has increased the number of its port-of-entry quarantine stations to 20 and is getting more serious about denying entry into the U.S. to individuals (American citizens included) who exhibit symptoms of such diseases as cholera, diphtheria, infectious tuberculosis, yellow fever, SARS and any form of flu that might result in a pandemic. In fact, the law requires all aircraft crews to report individuals with symptoms of such diseases to the quarantine officer at the port of entry or other appropriate medical authorities.