Alien Plague — Christopher Koehler

Humanity has united under one government and has started to take to the stars. However, FTL is dangerous, expensive, and still slow. So, a probe is sent out to gather samples and bring them back for analysis. Dr Avery Hutton is one of the scientists assisting in analysis back on Earth. But these samples contain something a bit nastier than anything humanity had encountered before. A pathogen, that if not contained, could kill everything on Earth.