Tularemia is a rare
zoonotic disease found worldwide. The agent responsible for disease, Francisella tularensis, is one of the most highly infectious pathogens known, one that is capable of causing life-threatening illness with inhalation of <50 organisms. High infectivity explains concerns of its use in bioterrorism. This case describes a 4-year-old male neutered Australian shepherd presented for evaluation of hyporexia and
fever. Physical examination revealed marked enlargement of the right superficial cervical lymph node.
Tularemia lymphadenitis was diagnosed by lymph node aspiration cytology and culture. Public health officials were advised of the isolation of this zoonotic pathogen, and contact tracing was instituted. Seven individuals associated with the aspiration event were screened for
tularemia and treated with prophylactic
ciprofloxacin. All were negative, and none became sick. The dog was treated with
doxycycline for 3 weeks, and clinical signs and physical examination abnormalities were resolved fully. The owner, a solid organ transplant recipient, was also screened for disease and received prophylactic
doxycycline due to a history of shared exposure. The owner remained well throughout the course of his dog's disease and has heightened awareness of potential
zoonoses. This case highlights the importance of animals as a sentinel for human health threats and for coordination of human and veterinary care.