My body has been taken over by a virus that has turned it into a croaky, spluttering, snot factory!
The Girl With All the Gifts by M. R. Carey.
The basic premise is that spooky real life fungus, Ophiocordyceps unilateralis aka The Zombie Fungus, which parasitises ants, suddenly crosses the species barrier and infects humans.
In real life, carpenter ants foraging on the forest floor get infected with spores. The spores produce an enzyme which melts the insects tough exoskeleton. Once inside the spore germinates and hyphae invade the ant's brain. This causes a behavioural change. Ants stop foraging on the forest floor and transporting food back to their treetop nests. They climb down the tree until temperature and humidity are just right for the fungus to thrive, typically about 30 cm from the forest floor. They then bite into the underside of a leaf and hang there by their jaws. The fungus slowly kills the ant by digesting its internal organs. When it matures a mushroom grows out of the ant's head. The mushroom then releases thousands of spores, which create a zone of about about 1 square metre in which more ants will become infected and repeat the cycle.
The Girl With All the Gifts is not quite a zombie story, but finds a relatively plausible way to have zombie-like characters that are not supernatural. The target audience is young adults, so the book is not too gruesome, though some of the scenes are quite grim and horrific. The author does a very interesting riff on the premise. The characters are engaging. Their responses to the situations they find themselves in make the reader think. The twist that wraps up the story is ingenious and given the alternative, quite satisfying. There is no deus ex machina to spoil the ending, no miracles or out of place magic.
This is naturalistic imaginative fiction at its best. It ought to defy the crippling genre pigeon holes that can limit readership, but probably won't, which is a shame.