Shouldn't I kill even mosquitoes that bite me by first precept?

By first precept I shouldn't kill even a mosquito it bite me but when as by 7th precept I can listen music for therapy If things fall into such circumstances like this mosquito biting can lead me to malaria or dengue. Also I've to ask if I can consume yogurt when it's made with help of bacterias they are also living being. I don't mean I'm trying to find breaking precepts,but I stopped killing them really.