Recurring tickbite fever

[Ursh]

Hi!

I am desperate for some advise on for my dog. I have a 16 week old female beagle pup. About 10 days after we got her (at 8 weeks) she beame lethargic and did not want to eat. We took her to local vet who diagnosed her with tickbite fever. He gave her what I think was blue Trypan as he said she was too young for the more serious injection and so to buy her time. After 2 weeks she went back for Diminizine injection. She seem to respond well in the first week however week 2 after the injection I noticed signs that she lost her appetite and was lethargic. She went back to vet and he did blood smear to find there was still some of the parasite in her blood. He then did the blue Trypan again as because she is so little he did not want to inject her again. A week or so later he tried DiproPrionate. Again she seem to respond well but at her check up a week later there were still traces of the parasite in her blood smear..less than 2%..
Again he did the blue Trypan to control the spread and a week later he injected her with both ones mentioned before. This was 2 weeks ago. We returned today to the vet where he again did a blood smear and found there to still be traces of the parasite in her blood.. Again very little..
My vet is trying to reach out to specialists he knows for advise and I thought I would try post here for some advice.

Thanks
Ursh