A non-intervention controlled study on the safety of distemper vaccines in ferrets. (Draft version).
Results
Three hundred and forty seven questionnaires were completed for ferrets in the UK and Republic of Ireland, and one questionnaire was completed for a ferret based in Norway. Two hundred and fifty three of the questionnaires provided medical and behavioural observations in the month following administration of CD vaccine. The remaining 113 questionnaires contained medical and behavioural observations over a random one month period for ferrets that had never been vaccinated against CD.
Evaluation of demographic data for the vaccinated and non-vaccinated ferrets showed that although there was a greater percentage of males compared with females in both treatment groups, there was no significant difference between the two treatment groups in sexual status (neutered or intact), colour, weight or housing status (indoors or outside). Although there was a greater percentage of kits (aged less than 6 months) in the vaccinated group the percentage of ferrets aged up to one year was similar for the vaccinated group (24.7%) and the non-vaccinated group (26.6%).
The percentage of ferrets experiencing each class of adverse event apart from lethargy/sleepiness/tiredness was less than 2% for both vaccinated and non-vaccinated ferrets. Lethargy/sleepiness/tiredness was reported for a greater percentage of vaccinated ferrets (12.3%) compared with non-vaccinated ferrets (1.8%).
| Table 4. Number (%) of Ferrets Experiencing Adverse Events During the One Month Observation Period | ||
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| Study Group |
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| Adverse event | Vaccinated N=235 |
Non-vaccinated N=113 |
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| Ferrets experiencing adverse events: n (%) | ||
| Injection site problems (allergy, rash, irritation) | 3 (1.3%) | 0 (0.0%) |
| Felt different | 1 (0.4%) | 0 (0.0%) |
| Aggression/increased aggression | 4 (1.7%) | 0 (0.0%) |
| Lethargy/sleepiness/tiredness | 29 (12.3%) | 2 (1.8%) |
| Loss of appetite | 1 (0.4%) | 0 (0.0%) |
| Infection, bacterial | 2 (0.9%) | 1 (0.9%) |
| Infection, viral | 1 (0.4%) | 0 (0.0%) |
| Tumor, unspecified | 1 (0.4%) | 0 (0.0%) |
| Obesity/weight gain | 3 (1.3%) | 0 (0.0%) |
| Physical abnormality | 1 (0.4%) | 0 (0.0%) |
| Gait problems/limb weakness | 1 (0.4%) | 0 (0.0%) |
| Ear mites | 1 (0.4%) | 0 (0.0%) |
| Operation | 1 (0.4%) | 2 (1.8%) |
| Wounds/injuries | 1 (0.4%) | 0 (0.0%) |
| Death | 1 (0.4%) | 0 (0.0%) |
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Serious adverse events:
All adverse events were reviewed by a veterinary surgeon and designated as either serious or non-serious. Two non-vaccinated ferrets (1.8%) experienced adverse events that were regarded as serious during the one month observation period:
- Ferret 368, a 6 year old neutered albino male housed outside, collapsed. Sleepiness was also noted. Insulinoma was subsequently diagnosed.
- Ferret 400, a 2 year old neutered albino male housed outdoors, developed lethargy and a swollen abdomen. The ferret was diagnosed as having a heart condition, underwent a splenectomy and recovered.
Serious adverse events occurred in four vaccinated ferrets (1.7%) during the one month post-vaccination observation period:
- Ferret 167, a 1 - 2 year old neutered albino ferret housed indoors, had a congenital deformity to the hind limbs. Following vaccination with an unknown dog CD vaccine she became 'very ill and nearly died' and 'depressed'. She avoided putting weight on her hind limbs and her gait worsened. The attending veterinary surgeon proposed that she might have developed canine distemper but this diagnosis was not verified using diagnostic tests. Two further ferrets vaccinated using the same vial of vaccine didn't not experience any problems following vaccination.,/li>
- Ferret 172, a neutered polecat-type ferret aged between 6 months to one year and housed indoors, experienced lethargy and slight limb weakness that continued for several days following vaccination, for the first time, with Vanguard DA2Pi.
- Ferret 178, a 5 year old neutered coloured female was found dead 2 weeks after vaccination with Nobivac DH. The only symptoms observed by the owner were 'she felt different the day before she died'.
- Ferret 313, a 19 month old neutered polecat-type female housed outdoors, had surgery to remove a foreign body from her stomach following vaccination with Nobivac DHPPi
Injection site problems:
Three ferrets (1.3%) experienced problems at or close to the injection site that were possibly or probably related to vaccination. All three were vaccinated for the first time:
- Ferret 246, a 10 month old year neutered albino male housed indoors, developed a large blister at the injection site that scabbed following vaccination with Eurican DHPPi.
- Ferret 298, a 1 year old neutered red eyed coloured female housed outdoors, experienced irritation at the time of the injection with Nobivac DH, as evidenced by biting, squeaking and leaping.
- Ferret 209, a 6 months old polecat-type intact male housed indoors, experienced a small rash down his back. The attending vet felt that it was likely that the rash was caused by biting by a male sibling but did not rule out a vaccine-related cause.