The domestic ferret is highly susceptible to canine distemper virus (CDV). Several available CDV vaccines
have been implicated in causing deleterious side-effects in this species. The purpose of the present study was to assess the safety
and efficacy of Galaxy® D (modified-live CDV vaccine, Schering-Plough Animal Health Inc.) for CDV vaccination in the domestic
Sixteen neutered male ferrets were randomly assigned to one of two treatment groups and either vaccinated
subcutaneously with Galaxy® D (vaccinates) or injected similarly with saline (controls) at 16 and 20 wk of age. Live virus
virulent strain CDV challenge (Synder Hill Strain, NVSL, Ames IO, instilled intranasally and orally) was performed 3 wk after the
second vaccination. Sign development was scored by a study blinded observer, and body weights were collected at regular intervals
throughout the study. Blood serology (serum neutralization, SN) samples were drawn before study, prior to vaccination and
challenge, and at 10, 15, and 21 days after challenge. Blood samples for PCR were drawn 5 days following the first vaccination, and
at 5, 10, 15 and 21 days after challenge.
No significant sign differences were observed in the vaccinates in response to vaccination, whereas,
CDV-induced signs, including weight loss (days 7 and 14, P < 0.0001) were noted in all the controls following challenge.
In response to challenge, vaccinate survival was 100% (8/8); nonvaccinate survival was 0% (0/8). PCR analysis of blood samples 5
days after vaccination detected vaccine strain CDV in one first-time vaccinate (12.5%). Following challenge, CDV was detected by
PCR in the blood of all controls (100%, 8/8) from 5 days until death; in contrast, detection was made in two (25%) vaccinates (two
primers) at 10 days post-challenge. Median SN titers went from 1:2 before the first vaccination, to 1:384 before the second the
vaccination, to 1:2048 before the challenge. Corresponding titers in the controls were 1:2, 1:8, and 1:4. At necropsy, PCR detected
CDV in fresh (all four primers) or formalin-fixed (two primers) tissues (lung, bladder, brain) from infected controls dying of CDV,
and in none of the vaccinates.
Although not approved by the U.S. Department of Agriculture for this application, Galaxy® D given twice
subcutaneously to domestic ferrets starting at 4 mo of age appeared safe and protective against CDV virulent strain challenge. PCR
was a useful method to detect CDV infection from fresh blood and tissue samples, and from formalin fixed tissues.
Partial support was provided by Schering-Plough Animal Health Inc.; we thank Ms. Jane Carmen Jill Steege, and
Rick Heimbichner for expert technical assistance.