This article is from the WeChat public account: Nature-Research , the title picture comes from: Figure Worm
Apart from the cells that make up our body, there are trillions of microbes in our body. These microorganisms include not only beneficial bacteria that help the intestines digest, but also bacteria that parasitize our skin, mouth, and vagina. In addition to bacteria, there are various viruses, fungi and archaea in the human body.
When did microbial colonization begin? Most scientists believe that we were exposed to bacteria for the first time at birth, and that before birth, the fetus developed in a sterile environment; however, some recent studies have found that placenta and amniotic fluid surrounding the fetus contain bacterial DNA. Bacteria are also present in the first fetus after birth.