Head lice. Yuck, right? But there are a few things we want you to know about these little parasites:  They’re far more common than you think, you could be infested without realising it and they present absolutely no health risk at all.  But, they’re undeniably gross.  So what do you do when your kids come home with lice in their hair?  What do you say when the school calls to say that they’ve found nits, or lice eggs, in your kid’s hair and you must fetch them immediately, to avoid infecting other children? The fact is, they’re difficult to remove successfully.  You need your child to sit still while the fine-toothed comb tugs at their hair for up to an hour, and then you need to repeat this process every few days for as long as it takes to catch all of the newly hatched louse nymphs, and it only takes one louse from another child’s head to re-infect the head you’ve worked so hard to clear.  In the podcast we discuss how infection happens, what the medical risk is, and the immense frustration of watching your freshly cleared children get re-infected minutes later when they play with a friend! Corrections: Stuff we got wrong about lice To answer some questions we asked ourselves while recording: Yes, lice are insects, and no they are not hermaphrodites – you get male and female lice.  I also stated that live eggs are flat against the scalp, but this is only half-true.  They are laid and attached to a single hair, flush with the scalp, but as the hair grows, the egg moves up with it.  Since eggs take up to nine days to hatch, they could be as far as 6mm from the scalp and still not have hatched yet.  The newly hatched louse is about the size of a pinhead and quite hard to see.  They molt a few times, before reaching adult size (a little bigger than a sesame seed) after seven days.  They live another 30 days before dying of old age, but can lay up to eight eggs per day.  Incidentally, they cannot live off of your head: they need your body heat and your blood – a louse left on a pillow or in clothing will die of starvation within a day or two, and probably be pretty torpid for most of that time.