Prostitutes are rife in DAR and AIDS is rampant there.....so rubber up if you dare to touch anything....
As unstable load says...it's an on going debate...
I was always advised not to take anything as it would mask the symptoms, but instead, take a self test kit with and the anti-venom pills in case...
I got it in DRC while working there. We had a full time medic with us at all times, so no real worries.... Started showing the symptoms, spoke to him about it, he did a self test which turned up negative (I have now learned that a neg does not necessarily mean you don't have it...!) but because of the symptoms, he suggested taking the drugs and having a few days off.... After about 3 days resting up, sweating it out, I was A OK and back up for work...
So, my advice, don't waste your money on the pre-meds, get a self test kit, know the symptoms, and if they start showing, take the few days off and pop the good pills...
Get down to a travel clinic and speak to them about what drugs are best for Tanzania.....
Tanzania is a great country with lots of good people who are not as bribe orientated as their brothers on the west coast...