There's no barrier that you can put up against a virus. It can just move continuously across countries and across areas. And the answer to that is yes. Anyone who's traveled to the Indian subcontinent or Africa knows that one of the things to be careful about is malaria. As we mentioned, about a million people a year who get it die.
Malaria is transmitted from person to person by a mosquito.
And, until fairly recently, it was not considered a serious threat here. That is changing. Here's ABC's Deborah Amos. It was very unusual. We haven't had it in as far back as our records can say.