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.
The 1st precept is a training rule to refrain from killing 'breathing' things.
The Pali is: &quot;Panatipata veramani sikkhapadam samadiyami&quot;, where the word &quot;pana&quot; means &quot;life&quot; or 'breath&quot;, such as in the term &quot;ana-pana-sati&quot;.
The 1st precept does not apply to bacteria because they do not breathe.

Strictly speaking, bacteria do not “breathe” as humans and other animals do, but they must still engage in the act of cellular
respiration. Cellular respiration is the method by which cells convert
chemicals into energy that the cell needs to stay alive.
Bacteria

As for mosquitoes, the probability of contracting malaria or dengue fever is very low. I lived in Thailand for 9 years and had dengue fever only once. I can contract dengue fever where I have lived for the last 10 years &amp; have never got it (although one friend did). When I lived in Thailand, there was a period of a few years when hundreds of mosquitoes would bite my feet when I was meditating at sunset. I never got dengue fever or malaria during this period. I felt very free when my mind became accustomed to not worrying about &amp; fearing mosquitoes.
Not killing mosquitoes is beneficial for cultivating metta (loving-kindness), fearlessness &amp; freedom. However, that said, killing mosquitoes is not particularly bad karma. When I first visited Thailand &amp; learned meditation, I did not care about killing mosquitoes &amp; killing a mosquito never affected my samatha (calmness; concentration) meditation. This is because killing a mosquito is kammically a natural act. The mosquito wants to steal our blood &amp; can (possibly) kill us. This is why the kammic results (vipaka) of killing a mosquito are trifling (insignificant).
Most people have killed many mosquitoes &amp; remain mentally normal. Their minds do not become deranged (crazy). Where as the majority of soldiers that kill in war are often mentally affected for life in a negative way. Some ex-soldiers become mentally deranged &amp; even commit suicide. (Here, an ex-soldier must learn to forgive themselves!) This shows the difference between killing many mosquitoes &amp; killing just one or even many human being/s. Kammic consequences (vipaka) follow the law of nature.
The Buddha taught &quot;kamma is intention&quot; (AN 6.63). A mosquito killed with the intention of avoiding malaria or dengue fever is not an unwholesome intention. However, it is still an intention rooted in fear, attachment &amp; a lack of liberation.
For example, to kill a mosquito so it does not bite a small baby or child is probably good karma. If it was known you let mosquitoes bite your small baby, many people would criticize you. You would be blamed &amp; censured for being a bad parent. The government may take your child away from you.
Personally, I would not worry too much about it since not killing mosquitoes is a higher level of dhamma practise. The Buddha did not make strict rules for monks about killing mosquitoes or even about killing animals (for food) for laypeople.

And which is intolerant practice? There is the case where a certain individual doesn't tolerate cold, heat, hunger, &amp; thirst; the touch of
flies, mosquitoes, wind, sun &amp; reptiles; ill-spoken, unwelcome words;
&amp; bodily feelings that, when they arise, are painful, racking, sharp,
piercing, disagreeable, displeasing &amp; menacing to life. This is called
intolerant practice.
And which is tolerant practice? There is the case where a certain individual tolerates cold, heat, hunger, &amp; thirst; the touch of flies,
mosquitoes, wind, sun &amp; reptiles; ill-spoken, unwelcome words; &amp;
bodily feelings that, when they arise, are painful, racking, sharp,
piercing, disagreeable, displeasing &amp; menacing to life. This is called
tolerant practice.
Khama Sutta