Babies and bugs

Babies weak immune systems let good bacteria in 

As any new parent knows, infants are notoriously susceptible to bacterial infections. A study now suggests that the body engineers this vulnerability deliberately, allowing beneficial microbes to colonize the baby’s gut, skin, mouth and lungs. Learning to manipulate this system could lead to treatments for infections in newborns, and perhaps even improve the way babies are vaccinated.

n the womb, a fetus is sterile. But from the moment that a baby travels down the birth canal, bacteria and fungi begin their colonization. How the immune system tolerates this sudden influx of invaders has been a mystery.

I wonder, from where do babies born via caesarian pick up their useful bugs.   Must look around for that information later...

Update:  an answer? -

In vaginally-born babies, the bacteria destined for the gut microbiota originate primarily in the maternal birth canal and rectum. Once these bacteria are swallowed by the newborn, they travel through the stomach and colonize the upper and lower intestine, a complicated process that evolves rapidly.

Infants born by cesarean section—particularly cesareans performed before labor begins—don’t encounter the bacteria of the birth canal and maternal rectum. (If a cesarean is performed during labor the infant may be exposed to these bacteria, but to a lesser degree than in vaginal birth.) Instead, bacteria from the skin and hospital environment quickly populate the bowel. As a result, the bacteria inhabiting the lower intestine following a cesarean birth can differ significantly from those found in the vaginally-born baby.