Two of the highest rates of HIV in the world right there Pal.
Cheap as chips I would imagine as both economies are royally fucked, so the chances of any of the prossies using condoms with the locals is probably close to zero, if they can get them they probably cant afford the rubbers. Combination of high HIV infection rates and local cultures who hate using condoms gives a massive risk factor.
Mutare is on the border with Mozambique and a thoroughfare for trade
Take your own, extra strength ones and use them even for oral.
If anything breaks, you should take a course of anti virals when you get home.
I lived in Zim, but pre-punting days.