I'm an expat from SA lived on the coast for 20 years, I'd imagine that a couple of jabs when you get to SA will sort you out, (not sure what to suggest, cant remember it being a major issue) but it's not that a radical place. The west coast or as us south africans call it "die wes-kus" is very tame, even if the weather and sea can be wild.
You've got more chance of catching something from a dog bite than anything else.
keep those ankles nicely covered and if need be, dont be afraid to fend them off with leg and shoe, those dogs won't let you past them. They run the joint.
PS : You might want to watch out for snakes, they can be very present in South Africa, especially when it's nice and hot. they'll be straight in front of you, lapping up that african sun.
Have a snake anti venom kit does the trick.
Health tips for travellers - SouthAfrica.info
Southern Africa Snakes