This vet is suffering from Q fever, which commonly presents with fever, elecated liver enzymes, throbocytopenia and lung infiltrates. The gram stain and culture appear to be negative because coxiella is an intracellular bacteria. He is at high risk for this infection from the inhalation of the bacteria during farm animal delivery.

Q fever Coxiella burnetii, no arthropod vector. Spores inhaled as aerosols from cattle/sheep amniotic fluid. Presents with headache, cough, influenza-like symptoms, pneumonia, possibly in combination with hepatitis. Common cause of culture ⊝ endocarditis. Q fever is caused by a Quite Complicated Bug because it has no rash or vector and its causative organism can survive outside in its endospore form. Not in the Rickettsia genus, but closely related.