A 23-Year-Old Man Who Has Recently Started Working on a Sheep

A 23-year-old man who has recently started working on a sheep farm in Nova Scotia develops pneumonia shortly after helping with lambing. His cough produces little sputum, and a saline-induced sputum sample shows no predominant organism either with Gram stain or with acid-fast stain. It is established that he acquired the pneumonia from parturition products from the sheep. Which agent is most likely to be the cause of his pneumonia?

A) Rickettsia akari
B) Rickettsia typhi
C) Rickettsia rickettsii
D) Coxiella burnetii
E) Anaplasma phagocytophilum