Where did you hear that???? Flies rule in Andalucia in the Summer and harvest time, especially inland where it's drier and hotter. The harvest also disturbs hundreds of snakes every year, as well as other creatures. Nobody dies. Life goes on.
If you have a fly 'problem' go North a bit. In fairness, it's about keeping them out of the house with mosquiteras for the windows and doors. Outside the home, you are in their territory!!!

I've been bitten/stung by every insect that has the capability & I live north of Alicante! But don't worry because I AM still around despite their efforts after many years.Swings & roundabouts really because at least you won't get chilblains!

Oh I am sor sorry but in my mind I now see swarms of flies everywhere, seriously been here 15 years, Spain is hot we get flies and other insects, as above use netting for the house and fly swatters if needed outside,

Lived here 18 years and never been bothered but don't know about the Almeria region. Obviously, some areas will attract them - animal grazing areas etc.