What are the odds of Giardia in this case?

[Imajerk]

I was transporting a dog in the back of my car for a rescue, who turns out to have been in the middle of treatments for Giardia. He's been on panacur and last tested positive on Jan 9th.
I stupidly put my own dog in the back of the car on the same bedding. He must have been there for roughly an hour.

Once I found out, I cursed myself for my lack of brains, put him in the back seat ( not the very back like before),
then wiped him with baby wipes. I washed my own hands. I  wiped him down this morning with a combo of hot water and 2% chlorhexidine, then washed all his bedding in same, and sprayed the foam under his mats/beds with rubbing alcohol.

I left a voicemail for my vet on whether to start some Panacur or Metrondiazole or something prophylacticly ( spelling?). My Q is, what are the odds of him catching this Giardia under these circumstances? Also, I hear there is a Vaccine but given all the warnings about vaccines today, is it worth it?

[Imajerk]

Re reading your email. Just to be clear, my dog was not sitting next to the infected dog. The infected dog was on my own dog's mat in the back of my car for about 2 hours, then I dropped him off, then I put my own dog in the back of the car on the same mat and he was there for about an hour.

Just thinking the infected dog could have had dirty kennel feet, and what if my dog got cysts on his fur or body and licked them off? I mean, how commonly is Giardia spread this way?

[Imajerk]

The infected dog I transported came from a kennel situation and I found out later that he has been under a course of treatment for weeks or months or some long time. He was energetic but his spine showed a bit. He needed to gain at least 5 pounds ( this was a rhodesian ridgeback mix). Kennels are notorious for spreading disease and not being great at keeping things sterile enough, so I imagined his load may have been significant. His last fecal done Jan 9th came back positive.

I imagined his paws might have been in a kennel that he constantly pooed in, and might not have been cleaned adequately. If those paws got on my dog's bed and then my dog laid in them, then licked his own feet or body later.......

No direct ingestion of, or exposure to, actual feces or drinking water. All these websites make it sound as if your dog just has to inhale the stuff or be in the area and he/she will get it.

Can't wait for my own vet to get to me. Thanks. How many negative fecals can a person get back in a row before they can relax?

[Aleda M Cheng, D.V.M., C.V.A]

I think that the chances of your dog's catching giardia from a dog who sat next to them for an hour is not very likely.  I would be more concerned if your dog's ingested the infected dog's feces, or stepped in the infected feces and than licked their paws.  

However, it would not hurt to treat your dogs prophylactically  with panacur for a week.