The San Diego Zoo Safari Park walk-through aviary of rainbow lorikeets (Trichoglossus haematodus) has a history of morbidity and mortality caused by Salmonella enterica ser. Typhimurium. A three-month-long epornitic in 2014 affected 15 birds (21%) with high case mortality (53%) and sporadic cases over the next year. All 57 birds were evaluated, and those with clinical signs or laboratory evidence of disease were individually treated. Monocyte count, fecal PCR, and Salmonella titers were most effective at diagnosing subclinical disease and monitoring response to treatment (enrofloxacin 20 mg/kg PO, SID for 21 days). Serology was also used to monitor response to vaccination with an inactivated Salmonella spp. bacterin.a In 2017, all aviary birds (n=51) received the first dose subcutaneously and a second dose orally after four weeks. Serology prior to vaccination showed resolution of previously high titers from infection in most birds. Post-vaccine, opportunistic titers were measured to evaluate response to vaccination and to develop an effective vaccine protocol. While humoral immune response post vaccination has been inconsistent, no adverse reactions were noted. Early intervention and streamlined intervention protocols have reduced death due to salmonellosis, which has been the cause of death in only one individual (4%) since 2015. Husbandry staff also changed feeder design and heightened vigilance to hygiene and bird behavior. Since implementation of targeted flock surveillance and husbandry modifications to minimize disease risk and maximize early intervention, salmonellosis morbidity and mortality have been drastically reduced.
a. Infectious Disease Laboratory, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
Special thanks to Dr. Spencer Kehoe for his early work on this outbreak and its followup, and to Dr. Bran Ritchie for his invaluable work to develop the vaccine and consult on multiple aspects of this management. The staff at the Wildlife Disease Laboratory and the San Diego Zoo Safari Park Veterinary Services and bird department (veterinarians, registered veterinary technicians, hospital keepers, and bird keepers) deserve significant recognition for their dogged pursuit of answers and dedicated treatment and work on these cases.