This book can be downloaded and read in iBooks on your Mac or iOS device.
Plague Ship is the 5th installment of the The Oregon Files by Clive Cussler & Jack Du Brul. It is based around a series of violent viral attacks on cruise ships by extremists who want to make half the worlds population sterile.
By far one of the best Si-Fi books, out side of the Dune series. it's a High 5!
Wrong book, iTunes!
The description above is clearly and error, it's describing a Clive Cussler novel, whereas this one is a classic Andre Norton novel, and a good one. For accurate description, see the other copy of it, the one with only one page, but at least they got the author's name right. Bang up job, iTunes.