4 year old has intermittent fever. Was playing a beach near water and swam in busy pool. At the beach there was a dead Goose. Still had meat on it but decaying. I moved the goose far away. Kids were near water and goose but didn't swim. Earlier that day we were in a well treated pool at a high end club. Lots and lots of kids. 5 kids total in our group. Only the 4 yr old got sick. Ages 8 7 6 5 and 4. 24 hours later he had a fever. We thought hydration since we have a heat spell and r not accustomed yest but their Dad said they drank lots of milk. We gave him lots of water too. Motrin brought fever down for a few hours but it came back. Some stomach pain. No diarrhea. Tears. In body pain. Symptoms improving a bit. What do u think this could be?