Bugs to the left of me

Too many to battle, so one resides in me. Like the old Ogden Nash poem, "The Germ":

A mighty creature is the germ,
Though smaller than the pachyderm.
His customary dwelling place
Is deep within the human race.
His childish pride he often pleases
By giving people strange diseases.
Do you, my poppet, feel infirm?
You probably contain a germ.