A Shiver not a Whimper (Marath Book 0)

While this book is completely stand alone and the events in it take place in the 'present ' day,( or maybe the day after), they are in the same universe/timeline as the Marath saga, some two thousand years before the events of Marath 1 begin.
The population of the world will be reduced in the space of hours to a few thousand.
When the survivors wake they must learn to survive or die.
And a few days later the towns and cities will not be healthy.
They will be full of the decomposing dead.
There are, perhaps, fifty to a hundred people alive in England.
No one is coming to help them.
And their worst enemy will be themselves.