Chronic means its ongoing over a long period of time, while progressing slowly, and not a new infection.

With tick carried diseases the doxycycline does a good job of eliminating the infection but if damage was done such as arthritic changes to joints that won't be undone.

Asymptomatic means there are no symptoms of the problem other than that it showed up on a test. That is good!

So do the meds and he is likely going to be fine just as your vet said.

You can read about tick diseases here

http://www.mirage-samoyeds.com/tick.htm

Hope this helps you!

If the chronic disease had symptoms I'd be concerned about those. But as he is asymptomatic that means there is nothing seen that the tick disease is doing to him.

Many dogs get a tick carried disease and their immune system fights it. In the tick disease FAQ listed above the sub acute (ie no symptoms) phase is listed as this

"SUB-ACUTE (SUB-CLINICAL):

Untreated, the disease may move into the sub-clinical phase. The dog's body weight normalizes and laboratory abnormalities may be quite subtle. Thrombocytopenia (low platelets) may or may not be present. This phase of disease can last for months or years as long as the dog is not subjected to something that causes undue stress. The parasite is essentially living with the host in stasis; not overpowering the dogs immune system. "

So treating it and resolving it before any visible disease is triggered may work fine.

Of course you can't know how the future will turn out. If you are enjoying him and all is going well will it be worth it to have time with him? That is always the question when you adopt.

Sorry about the delay in replying had to cope offline with a broken hot water heater repair guy!

Chronic is one thing. Asymptomatic is another.

Chronic means what I said above. I think the word was maybe not used correctly in the terms you were given it.

Yes I know a fair amount about greyhound health due to local track rescuers that I know.

here is one article directly on tick diseases and greyhounds

http://www.geocities.com/bo_freddy/ticks.html

They discuss treatment as being successful.

For them chronic means final stage of illness where the dog is very ill and dies - which is not what you have described.

I find one must always be fatalistic with animals - they do not live as long as we do and we always lose them too soon no matter how long we have them. You have to know there is heartbreak coming unless your pet is a long lived tortoise or another long lived creature.

As I've adopted many senior dogs I've always found it worth having known them no matter how long we have together.

I would suggest you go back to the rescue and get the exact medical results to make sure you are comfortable with the adoption.

No one can predict what will happen in the future with health on any pet.

I do doublt that the rescue would adopt out a dog that was in end stages of fatal illness.