On our last trip, our son was so cranky our first day there. We didn't understand why since he had just finished his last round of antibiotics for an ear infection and had been looking forward to visiting the Mouse. By the afternoon, he felt warm, my daughter was complaining of a sore throat, and my chest was getting tight (I have asthma). We took him to the clinic at the MK, and he had a 101.7 temp. We all went to the urgent care. DS had another ear infection (we ended up getting tubes when we got home from vacation), DD had strep, and I had bronchitis. At that time, dh was fine.
We stayed at the hotel the next day rather than hit the parks. DD recovered the quickest. She and I went for walks around the resort outside. DS stayed in the room and watched tv and slept. I still felt a little bad, but we were all fever free before the next morning. We went back to the parks and continued our antibiotics. Dh started slowly declining as our week progressed. By the last day, he went to the urgent care and was diagnosed with a sinus infection. We had intended to make up our missed park day, but we just waved the white flag and went home.
People get sick. In our case, we all had something different, so who knows where we all got it. DS was probably never contagious. Before tubes, he was getting those ear infections because of his skinny eustacian tubes. DD, with strep, was contagious, but she wasn't around anyone but us once we left the urgent care.
I do realize there are people that will show up contagious, whether they realize it or not. Next time, we will just take plenty of vitamins a few weeks before going on our trip. We will also be taking our own camper next time, so I can better control the cleanliness of our sleeping quarters. Hoping hand washing will help with the rest.