Diagnosis of tuberculosis in three zoo elephants and a human contact — Oregon, 2013

What is already known on this topic? In North America, approximately 5% of captive Asian elephants are infected with Mycobacterium tuberculosis. Bidirectional spread of M. tuberculosis between elephants and humans has been documented. What is added by this report? Investigation of a tuberculosis (TB) outbreak among three elephants at an Oregon zoo identified multiple close, casual, and spectator contacts. One hundred and eighteen contacts were identified, 96 of these contacts were screened, and seven close contacts (six recent conversions and one earlier positive test) were found to have latent, noninfectious TB. Whole-genome sequencing revealed that one elephant’s M. tuberculosis isolate identically matched the isolate of a person with pleural TB who attended a zoo orientation in 2012. The lack of guidance about how to manage captive, TB-infected elephants complicated the decision-making process for protection of zoo contacts, other animals at the zoo, and the general public. What are the implications for public health practice? Collaboration between public health, veterinary medicine, and occupational health experts could lead to better understanding about associated risks, and could help prevent zoonotic transmission of M. tuberculosis. The development of improved TB screening methods for elephants is needed to prevent exposure to humans with close and prolonged contact.