Our last maintenance gardener, Omer, lost his father to a snake bite. Happened in one of the villages so probably too remote to get to a hospital on time for the anti-venom jab.
I've not been bitten by any snake although I used to catch grass snakes in Nairobi when I was a teenager. But I was spiked in the finger by a lion fish in Malindi and the pain was unbearable - had to have pain killing jabs- but fortunately unaffected by the 'poison'.
So, if you are bitten by a viper/adder, which has either the markings mentioned previously or the darker zig zag markings - get to the hospital without delay because although the venom will, generally, only kill the aged or weak, the pain will be severe.