I have a 2.5 yo lab male who is now going through a second bout of fever (104.5-105.1) and lethargy without any indication of a source. This happened back in December, lasted a few days and then he seemed to be fine. All blood work comes back normal, a short tick, etc.. test came back negative. Seems to be sore (muscles) and seems to be some correlation to a hard workout. However, being sore should not raise white blood cells. Any thoughts/experience?