Abstract
Canine distemper virus (CDV) infections have occurred sporadically in captive tigers (Panthera tigris) over the past 25 years, with outbreaks occurring recently at sanctuaries.1,2 Additionally, CDV infections have been documented in wild Amur tigers (Panthera tigris altaica), which are critically endangered.3,4 To date, there has been no cogent study of the safety and efficacy of CDV vaccines in tigers. Seven tigers were vaccinated with a 1 ml dose of a recombinant canary pox-vectored CDV vaccine (Recombitek C3, Merial Limited, Duluth, GA, USA). These tigers received a second 2 ml dose of the vaccine SC four to six weeks later. CDV serology (serum neutralization) was performed at weeks zero, four, and nine. No tigers had detectable antibodies at weeks zero and four, and only two tigers had low (1:16 and 1:32) antibody titers at week nine. Eight different tigers were then vaccinated with a modified-live CDV vaccine (Nobivac DP, Merck Animal Health, Madison, NJ, USA) at time zero and around six months. Serology was performed on these tigers prior to vaccination and at three weeks, prior to the six-month booster vaccination, and two- to three-weeks post-booster vaccination. Seven of eight tigers in the Nobivac group had no detectable titers prior to vaccination, and all animals three-weeks post-vaccination had titers >128. At six months all tigers still had detectable titers. All but two at two-weeks post-booster showed an increase to >128. To date, no adverse effects have been observed following use of either vaccine.
Acknowledgments
The authors thank the staff of Tiger Haven for their assistance and care of the animals.
Literature Cited
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