Research carried out by doctors in the USA have found that despite a majority of swingers not using a condom, STD´s (Sexually transmitted diseases) have a lower incidence in the swinging community than in the general population.
Again it comes down to being honest. If a swinger contracts a STD they will almost always know who they played with to contract it, and who they have played with since. If a person outside the scene catches an infection it is usually as the result of a one night stand with someone picked up when drunk in a bar or club.
Swingers will also alert the people they have played with so that they can all get treated, the casual pick up is often someone who cannot be contacted, and will go on to spread their infection on their next one night stand.
So, if you get infected, don`t be shy, tell the people you have played with that you have picked up an infection and that they should get themselves checked as a precaution.