The dog is 12 weeks old (has all it's shots) and is lethargic, vomitting and has diarrhea.
I believe he was exposed to an area were the virus was a few weeks ago, but he wasn't exposed to a dog with parvo. He was first exposed to the area on Thursday (6 days ago).

Is this DEFINATLEY parvo, or are there other options?

Couldn't have had all the shots to young

If the dog was in the area it is very likely to have parvo/

you should definetely check up with your vet. I had a 3 month old rot that died 2 days ago of parvo. monday it just started to where it wouldn't come to us when we called it or play, or eat, or drink. we took it to the doctor and he told us it had tape-worms and that it could be easily fixed. the next morning he called me and said that "piggy" the rot had parvo. It's not the disease that cuases them to die or act the way it does, its just dehydration and starvation. I would seriously go and get it checked out. I wish I would've before piggy died.
hope that helps. good luck.

please take your dog to your local vet asap. so that the tests can be done. please?

It does sound like Parvo, but Corona has the very same symptoms. It could also be Cocci, or Giardia.or Salmonella…only a poop smear at the vet's can diagnose for certain..

It sounds like Parvo, but it could also have a severe worm infestation, bacterial infestation (like giardia or coccidia), or HGE (hemorrhageic gastroentritis)… all of these will KILL your pup if they are not treated.

You need to get your dog to the vet TODAY and have it properly diagnosed. Remember to take a sample of its "poop" with you for testing.

does his or her diarrhea have blood in it? are you sure its not been poised?

please dont let your dog suffer with this, he needs to go to the vet today, sometimes if they catch it early on they can save them. it does sound like parvo, but it could be distemper, hook worms, and there are several other diseases that are curable if caught early. so please take him to the vet

Your puppy has not completed the vaccination schedule. It's highly likely that since he was in an area where Parvo was that he's contracted this deadly virus. You need to take him to the vet IMMEDIATELY.

Get the dog tested asap!!!!! if it has parvo everything you own needs to be disinfected. There are treatments for parvo but they are expensive and not guaranteed