There's been no change in food. When we first got the cat (6 - 8 wks ago) we know the dogs had 'snacks' from the kitty litter box (can you say gross!), but we stopped that immediately. We are wondering if they might have picked up something through that? The sheltie is mostly okay, but the border is still not good, and it has been 3-4 days in a row this time. She is eating normally.