I have a 5 month old large breed puppy. Got him at 8 weeks. No issues. Got his vaccination...no issues. Went for follow up vaccination and dr recommended Leptospirosis vaccine. Since he was sniffing everything (at the time) while on walks, I decided it might be a good idea. 2 1/2 hours after vaccine and Leptospirosis shot he started having very bad diarrhea...to the point he couldn't even make it outside. Once diarrhea started I paid even closer attention to him on walks and made sure he did not pick anything up. Gave him plain white rice he got better. Then added kibble slowly to rice and back to diarrhea again. Switched his food to better quality. He has even put on healthy weight. Growing nicely. Diarrhea still present though. He is eating fine. Drinking fine. Absolutely no lethargy. No blood. No vomiting. Always walked on a leash so I keep a very close eye on him. Called vet and they tested stool. No parasites. "Happy and healthy puppy". They ended up giving him meds metro...which helped with the diarrhea. As soon as pills were done, back to overnight diarrhea again. He does not get into garbage. Not picking anything up outside. No milkbones. No rawhide. His food is quality brand. Absolutely no human food. Has anyone had this happen? I see lots of stories here that are similar but noone posts how it turned out or what was the problem. Any advice would be appreciated. Thank you!