Yung sudden change sa environment can be stressful sa mga dogs, dapat sana hindi mo muna pinabakunahan. Ang tamang practice is to acclimatize newly acquired animals to its new surroundings first. Observation na rin yan just incase na yung nabili mo is may sakit pala.(about 3-7days). Stressed na nga sa bagong lugar, dinagdagan mo pa ng another stressor (vaccine)
Also, since may history ka ng parvo, you should have been informed NOT to bring in a new puppy so soon (specialy if wala pa immunizations) Its possible na na-infect yang aso mo (if at 3mos of age eh wala pang mga bakuna). Ang parvo kasi is very stable. it can last for years sa isang area without a host. Meaning, nung dinala mo sa inyo yung aso baka na contaminate ( add to that the "stress factor", which could weaken the immune system). Incubation period is about 3-7days. Ibig sabihin nyan mag sisimula mag pakita ng symptoms yung aso mo 3-7 days after infection which is pasok sa history mo. (monday mo kinuha, friday na ngayon). Alam mo nmn na siguro a clinical signs ng parvo ( innappetence, weakness, vomiting, diarrhea).
For now keep your dog Hydrated (oral dextrose w/electrolytes). Pag na observe mo na nag suka yung aso, go to a vet ASAP.