More information

Clinical picture

At the moment a serious increase has been noticed in (very) young ferrets (< 2 years) which suffer from (severe) health issues. The problems in these youngsters manifest as GI-tract- and mid-ear (tympanic cavity)inflammations. Given the nature of these inflammations, it is almost certain an infection we are dealing with. The origin could be bacterial, viral as well as parasitical. During the process of the disease, which mostly shows a chronical course, other organs can become involved.

This infection does not always respond to treatment. Some ferrets have a positive reaction to an antibiotic treatment and seem to recover. Many ferrets live on with permanent damage.


It seems all affected ferrets do have something in common: a raw meat diet from young age on (mostly started in the litter already). A couple of years ago a research on Commercial Raw Minced Meat (KVV) has been done by the University of Utrecht, which showed high amounts of diverse pathological bacteria were present. Equally known is, that one-day-old chicks from commercial industry can be contaminated with a great variety of bacteria. As a result of this knowledge, these two types of raw food presently aren’t used anymore at most shelters and breeders. However, whole prey like rodents, poultry and game have been provided, sometimes in high quantities.
It has become clear that quality of these prey animals, available on the market in The Netherlands has decreased dramatically. Seemingly caused by the (much) higher demand for it, it wasn’t possible to breed enough SPF (Specific Pathogen Free) prey animals anymore, which are usually meant (and bred) for laboratory use. Currently most prey animals are derived from one whole sale centre, which delivers to most sales points in the country (and abroad). A serious amount of the stock of this company origins from mass-production producers abroad, who don’t produce within the strict regulations and rules meant for SPF mice.
We absolutely don’t want to blame or pinpoint any fingers towards any one. We certainly want to investigate our suspicions about the diet being a source of the infection(s).

Our advise would be to be very critical on the food source you are using and be very careful with raw. For now good quality kibble seems to be the safest choice. In case one wants to continue feeding raw, look into where it originates from and be extremely hygienic and thoughtfully in dealing with it; be aware of the risks involved.


Research will be mainly focused on:

  • Ferrets under the age of two years
  • Ferrets which have had raw food at any time of their life. This includes ferrets which are on a kibble diet now, but had raw meat at some time earlier in their life
  • Ferrets with sudden severe or persistent ailments or complaints of GI-trackt and/or mid-ear

It mainly will be the additionally research costs that will be paid for by the workgroup. Ferrets which qualify for the protocol will be divided in three groups:

  1. Ill ferrets of which bacterial/parasitical testing can be done of urine and faeces.
  2. Ill ferrets which are qualified for operation at which biopsies of organs can be taken for tissue- and bacteriological research. The ferret owner will be responsible for the surgery fee, as it is part of regular treatment. Costs for additionally research will be paid by the workgroup.
  3. Ill ferrets which unfortunately do not have options for further treatment and need to be euthanized. These will be send entirely to the laboratory where a necropsy of the total body can be performed. Several organs can be removed for further research and/or bacterial cultivation. The ferret owner is to give permission to perform this necropsy, as it is a radical procedure, besides a very emotional decision to let go of a (young) ferret. Not being able to get any remains of the animal back, is not reserved for all of us.

Do you have or happen to know a ferret, which can be qualified for this research? Please contact the Frettenkliniek (Ferret Clinic). They will be able to explain protocol details in person.

Research and costs

At this moment we focus on tissue, bacterial and parasitical research as the probability of involvement of bacteria is plausible. Viral testing is extremely costly, but won’t be excluded in further research in future. Expenses to have a complete research on a ferret are very high. Besides surgery, euthanasia and additional necropsy at the Frettenkliniek, there will be made use of expertise and service of several (pathological)laboratory among which the University of Utrecht.

To give an indication of average costs: Extended pathological research and cultures of some organs and blood can be as much as € 400-500 per ferret.


Results aren’t guaranteed. One hopes bacteria will be present at several ferrets so conclusions can be made to either find an origin of the problems or a better treatment for the ones affected. There is no guarantee every tested ferret will give actual results, as in the past individual performed tests haven’t always shown a cause either.

We are depending on donations to finance all the needed research. Besides that, collecting enough qualified ferrets sufficing the protocol and conditions takes time.

Update January 2018

We would like to share an update concerning the developments in research on behalf of our workgroup.
Again we want to express our gratitute towards all contributors, old and new. Thanks to your support we are able to finance this research!

In the meantime a number of ferrets have had a thorough examination and we have some first results. We want to share as much as possible with you, but right now sequel research is being done and interpretations with other specialists are being made. Therefore conclusions can't be made yet, but we are heading in the right direction trying to find answers.

Some raw fed and ill (young) ferrets have been researched. Inflammations have been found in the gut, gallbladder, liver, pancreas and kidneys. It seems diverse pathogenic bacteria and possibly parasites might be the cause of it. These pathogens are mainly found in raw meat and prey animals. Further research is done with these pathogens, trying to discover an evident proof to be the possible cause of the problems we see with young and (young) adult raw fed ferrets lately. After receiving more results we can try to develop the right treatment, targeted for the specific pathogens. The last part could be difficult, as a great variety of pathogenic bacteria has been found.
Additional research is done with the possibly related mid-ear issues. This process takes much more time, as bones of the skull need to be decalcified.

For now the most important advice towards owners/caretakers of ferrets: Do NOT feed raw meat or prey animals until more knowledge is collected about the pathogens and their possible damage they can cause in health and welfare of ferrets!

Once more we like to appeal to all ferret lovers and owners to help us. Only with your support, we will be able to continue this project. Specially now it seems we are heading in the right direction and additional research is of great value to find answers.

Workgroup Rawfed Ferrets

Dr. Hanneke Roest in behalf of the Frettenkliniek / Ferret Clinic
Marianne Boymans in behalf of Stichting De Fret
Chaimel Lerou in behalf of Stichting Fret & Welzijn
Minka Verheijen-Hermans in behalf of Stichting Fret & Welzijn
Karen Pedro in behalf of Make My Day Ferrets
Rochelle van den Brink in behalf of Ferretry Ainsley
Mette van Eck in behalf of Ferretry Lelibel


23-07 € 45 Nadine Kerroua
15-07 € 25 Helen Willemse and Gwin de Kluys
19-06 € 20 Mother of Miranda Rotteveel
13-06 € 15 Helen Willemse and Gwin de Kluys
09-06 € 200 Stichting de Fret
07-06 € 10 Heidi van Vugt
07-06 € 15 Annabel Lijten
01-06 € 50 Karen Pedro
28-05 € 52 Frettenvraagbaak auction
26-05 € 15 Miranda Rotteveel
24-05 € 25 Melissa Hardam
25-05 € 15 Christina Jamison
20-05 € 1000 De Frettendag
18-05 € 50 Fred Kimpel
15-05 € 10 Ferretry a Winter's Tale
08-05 € 25 Helen Willemse and pension
08-05 € 15 E van Reede
04-04 € 15 Fabienne
04-04 € 20 Ferretry Bunch of colors
04-04 € 5 Marga Zoeteman/Baco Ferretry
25-03 € 200 Daniel Vidal Rubio
21-03 € 500 Dental prosthetic practice Brigitte ten Wolde
21-03 € 500 Brigitte ten Wolde and Raymond Venneman
18-03 € 5 Leroy van Eenige
16-03 € 50 Maribel Brouwer
09-03 € 100 Frettenvraagbaak auction
06-03 € 50 Sietske
03-03 € 15 Gepke Peters
01-03 € 100 Frettenvraagbaak auction
01-03 € 100 Wishing Star family
15-02 € 100 Frettenvraagbaak auction
01-02 € 250 Rob van der Sluis
01-02 € 100 Monique Flippo
30-01 € 25 Janita Hilhorst
21-01 € 15 Germain Verschuren
18-01 € 10 Fam. Driehuis
15-01 € 100 Frettenvraagbaak auction
13-01 € 200
13-01 € 25 Leonie de Kluys
01-01 € 150 Wishing Star family
28-12 € 100 Frettenvraagbaak auction
23-12 € 10 Trea Brouwer
22-12 € 25 Karin en Ruud
22-12 € 150 Jorien
22-12 € 5 Ruth Bell
22-12 € 20 Sanne
21-12 € 15 Eveline Bloks
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20-12 € 5 Heidi
19-12 € 25 Marina de Jong
19-12 € 50 Pieter Breuring
19-12 € 200 Stichting De Fret
19-12 € 100 Yvonne Huysman
19-12 € 200 Mette van Eck / Lelibel
08-12 € 100 Frettenvraagbaak auction
23-11 € 18 Frettenvraagbaak auction

Donations of special value

A special thanks to:
- Karen Pedro of Make My Day Ferrets for her research contributions to the workgroup.
- Chaimel Lerou of Stichting Fret & Welzijn for her financial and research contributions to the workgroup.
- Hanneke Roest of the Frettenkliniek for the enormous amount of time, expertise and collaboration.

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