Problem: An adult lab-cross presents with a history of inappetence and lethargy. You notice that his weight is down 10 lbs. from his visit 2 months ago. He is dehydrated about 8%, has pale mucous membranes and bruising on his gums and abdomen, and lymph nodes are enlarged. His CBC shows non-regenerative anemia and thrombocytopenia. Your doctor asks you to draw additional blood for a tick panel. What disease is the doctor concerned about?