What testing was done???? The SNAP should *always* be followed by the C6 test, and your vet should inform you of this.
Personally I would treat any new infection aggressively, at the dosage of 10 mg/kg twice a day, for 6 weeks, and monitor bloodwork.
It's not necessarily that the Bernese don't have clinical disease, but that you might not see it until Lyme causes kidney disease. Tick diseases causes silent disease in some cases, and just because we can't see it externally, doesn't mean that something isn't happening inside. Shelties, Goldens, and Labs also share this risk of kidney disesase from both "silent" lyme and also the lyme vaccination.
http://www.cliniciansbrief.com//arti...-mountain-dogs
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A familial glomerulonephritis has been reported in Bernese mountain dogs. Antibodies against Borrelia burgdorferi were found in most of these dogs, raising the concern that glomerular disease in this breed may be related to infection or that the breed may be predisposed to B burgdorferi infection. A study performed in Switzerland examined 160 Bernese mountain dogs and 62 control dogs. All were considered healthy by their owners and had no obvious disease as evaluated by complete blood count, serum biochemical analysis, and urinalysis. Owners were asked questions regarding the dogs' environment, and all dogs in the study were found to live in similar environments in the same areas of Switzerland and were walked in the woods with the same frequency and length of time. ELISA and Western blot analysis found a seroprevalence of 58% in Bernese mountain dogs compared with 15% in control dogs. The presence of antibody against leptospires, history of vaccination against Lyme borreliosis, and hair coat color (fair vs dark) did not influence the results.This study suggests that Bernese mountain dogs are predisposed to B burgdorferi infection. Further study is needed to determine both the biological reasons for this predisposition as well as the clinical consequences.
COMMENTARY: Breed predispositions for tick-borne diseases have been previously recognized. German shepherds are thought to be more seriously affected by Ehrlichia and Siberian husky dogs seem to have more serous disease when infected with Rickettsia ricketsii. Breed predistribution has been speculated before for clinical signs of Lyme disease as well. A study at the University of Pennsylvania teaching hospital found that 37% of the general population and 57% of dogs with polyarthropathy were Lyme-positive. And 57% of lame retrievers compared with 24% of healthy retrievers were seropositive. The reasons for these predispositions are unknown.
Increased prevalence of Borrelia burgdorferi infections in Bernese mountain dogs: A possible breed predisposition. Gerber B, Eichenberger S, Wittenbrink MM, Reusch CE. BMC VETERINARY RESEARCH 3:15, 2007.