Fallout

The Earthlings are dead. In space, a quarantine is executing.

The armored rescue workers are in no danger. Yet.

It's a tricky thing for a single virus to infect a wide range of different organisms. A transport site that provides an opening in one cell membrane might have evolved in a different species to be completely invulnerable.

It is relatively easy for a single virus to hijack cellular machinery for the construction of other viruses with different targets.

Most of Earth's Animal life fell prey to such payload viruses.

Another nearly trivial option in viral design is genetic therapy. This is especially easy with undeveloped embryos. This an range from a minor tweaking of bacterium to a complete replacement of a genome. Not all tadpoles will become frogs.

Most of the Earth's plant life is already converted. The armored rescue works should detect steadily rising levels of chlorine.

I should stress that I did little work in designing either the organisms or the ecosystem. Nature provided a massive and diverse library of life, and nature will establish a balance over most of the new earth. Only a few species received special protection, to ensure that the ecosystem meets certain quality of service requirements.

There is one payload virus still filtering its way down to the deep sea ecosystems.

In a day or two it will reach the squids.

Then the battle for earth will be over.