A non-intervention controlled study on the safety of distemper vaccines in ferrets. (Draft version).
Materials and Methods
This was an open, prospective, controlled, non-intervention study on the safety of distemper vaccines in the ferret. The trial was non-intervention, i.e. ferrets entered into the trial were either treated with the CD vaccine used routinely by their veterinary surgeon, or not vaccinated, according to their owner's personal preference, and data was recorded irrespective of treatment administered.
Ferrets owners were invited to enter ferrets into the study, irrespective of vaccination status, by means of articles on web sites, in magazines and ferret club newsletters, and by 'word of mouth'.
Owners who volunteered to enter data for ferrets into the study were asked to record the following demographic and clinical information about each ferret they owned on a simple questionnaire: age (as a range), weight, gender, neutering status, 'type', coat colour, eye colour, vaccination status (not vaccinated, vaccinated previously or first vaccination), and medical/behavioural conditions at entry into the study.
CD vaccines were obtained by veterinary surgeons from their normal supplier. A wide range of CD vaccines were used; details of these, manufacturer, and the number of ferrets treated with each vaccine can be seen in Table 1.
Following vaccination, owners were asked to record the vaccine administered; whether or not the ferret had received this vaccine before, and any adverse changes (medical or behavioural) that occurred in the one month following vaccination.
For non-vaccinated ferrets, owners were asked to record concurrent conditions and treatments, and adverse medical and behavioural changes occurring over a random one month period.
Safety was assessed using the incidence and nature of adverse medical and behavioural changes reported by ferret owners during the one month observation period.
Adverse events were classified by type using a simplified coding scheme based on the British National Formulary 46, September 2003. The adverse events were additionally reviewed on a 'blinded' basis by a veterinary surgeon and designated as either 'serious' or 'not serious'.
Data from the questionnaires was entered into a database using a coded format where appropriate. Since there are no recognised separate breeds, and no clear consensus on classifying ferrets by colour in the UK, any effect of strain on response to CD vaccination, was assessed by allocating ferrets to one of four colour classes using eye colour and coat colour as outlined below:
- Polecat-type, brown eyes, brown coat, no white on body trunk or limbs (colour code PC)
- Coloured 1, brown eyes, white on trunk or legs, brown may also be present on trunk, head or legs, (colour code C1)
- Coloured 2, red eyes, brown and white on trunk or legs (colour code C2)
- Albino, red eyes, white coat (colour code A)