It is highly contagious. Antibiotics is the only way to rid of it, unfortunately. You say you are clean tidy people and wash hands frequently. Did you know that putting an unwashed finger in your eyes, nose, and mouth are the ways we get sick? Imagine this scenario for a moment: You walk into a bathroom, wash your hands, open the door with the hands you just washed and touch your eyes. You just introduced a germ into your body, even though you washed your hands, they look clean, you just picked up a germ(s) you cannot see on your seemingly clean hands and infected yourself by touching your eye(s). It's a very common mistake we all make but IF you make yourself aware of what you are doing, you can stop from doing it. When my eyes itch, I put my finger under my shirt and use my shirt to touch my eye(s). If my nose itches, I do the same thing or use the top of wrist to touch my nose. I never put any foreign objects to my lips. Again, it's very easy to do: you are writing something down and you absentmindedly put the pen to your lips. I catch my husband doing this ALL the time and it's no wonder he gets sore throats. Since your whole family is catching strep, you need to be diligent that nobody is drinking from the same cups or sharing food on plates. I have stopped nibbling from my children's plates when they are finished eating and there is something left. I also do not share any cups, straws, bottles of water, etc. with any of my family members. Just because they look healthy doesn't mean they are not carrying something that could make me sick. Disinfect all door knobs on a daily basis until the strep in your family is gone and then make sure your family understands that they must always wash their hands BEFORE they eat. It's a rule in our house whenever we come in from wherever we came from, we always wash our hands. At school, I have hounded my children with the "wash your hands before lunch and snack time" rule. They are hardly sick. Boil or replace tooth brushes once an illness is gone. I no longer keep my toothbrush in the same container as my husband's tooth brush because I discovered that sometimes our brushes touch and there is a way to get sick too. Hand towels in the bathroom: this is a discovery I made: my husband and kiddos have been using the hand towel to dry their faces. When we are sick, we use paper towels more often but use a hand towel for the clean hands.