Many illnesses mimic Parvo. I came across a great site called Parvo Puppy, Here is what they say.... IS IT REALLY PARVO? ~ There are many diseases that can mimic parvo. Some of these diseases are viral, some bacterial, others are worms or protozoan. Here is a partial listing of diseases that mimic parvovirus: 1. Campylobacter aka "Campy" or Campylobacteriosis Jejuni Parvo or is it Campylobacter? 2. Coccidiosis aka "Cocci" or Coccidia (single celled organism - protozoa) 3. Coronavirus 4. Distemper aka Hardpad Disease (exhibits upper respiratory symptoms) 5. Giardiasis aka Giardia (single celled organism - protozoa (trophozoites) 6. Food Poisoning (i.e., salmonella) 7. Poisoning (non-food; i.e., antifreeze, drugs - i.e., wormers) 8. Intestinal Blockage (i.e. From consuming foreign objects) 9. Worm Infestation (roundworms, hookworms, whipworms, tapeworms) 10. Dysbiosis (aka Leaky Gut Syndrome) 11. Irritable Bowel Syndrome (IBS), Inflammatory Bowel Disease (IBD), Colitis 12. Ebola virus 13. Dog Show Crud (Bacterial Overgrowth) 14. Leptospirosis (Bacterial infection) 15. Infectious canine hepatitis (virus) 16. Hemorrhagic Gastroenteritis (HGE) 17. Heliobacter Infection (Bacteria) 18. Addison's disease (Hypoadrenocorticism) 19. Pet food poisoning