Ferrets (Laboratory) - Pathology

Introduction

Ferrets (Mustela putorius furo) are thought to have been dometicated for over 2000 years and are descended from the wild European Polecat. Despite being domesticated for such a long period, ferrets were only recognised as important in medical research in the 20th century and were only beginning to be used in the 1960s as an important animal model. Ferrets are often utilised in a laboratory setting as they are known to share many anatomical, metabolic and physiological features with humans. Therefore ferrets are often utilised in studies covering a broad subject matter including toxicology, bacteriological and virological studies. Ferrets have also been used as a model for studies into ischemia and ion exchange in the heart, influenza, neurological injury and gastric infections. Ferrets are particularly important in influenza studies as they can be infected with type A and B influenza viruses. According to the US Department of Agriculture Animal Care Report, approximately 17,000 ferrets were used in laboratory studies.

As ferrets are a social, curious and intelligent species, they often require a higher level of husbandry than other species such as hamsters or mice. Laboratory ferrets will require a complex and stimulating environment with enrichments that include tubes and boxes that are able to simulate a burrow. Ferrets have a strong drive to explore and therefore they will investigate all aspects of their enclosure. Enclosures therefore need to be well designed and strong as ferrets will exploit any opportunity to escape.

Strains and Stocks

Most ferrets utilised for laboratory studies are males due to oestrous related health problems associated with females. Female ferrets are induced ovulators and can develop severe hyperoestrous if not mated. Laboratory ferrets are often purchased pre-castrated and 'de-scented' (i.e. anal gland sacculectomy).

Due to the small number of laboratory ferrets compared to species such as mice, there are no specific strains/stocks commonly used. Researchers often request natural wild-type colour patterns (called sable or fitch) which is often in contrast with the various coat colour variations found in domestic populations. Some studies have also utilised albino ferrets.

Physiology

Ferrets are obligate carnivores that typically have a total length of ~50cm (with a ~13cm tail) and weight between 0.7 - 2kg. Ferrets have a natural life span of between 7 - 10 years and males are substantially larger than females, with males up to 2kg and females up to 1.2kg. Ferrets become sexually mature at around 4-6 months and occurs in the first spring after birth.

Ferret gestation is 42 days and litters usually contain between 3-7 young. The litter are usually weaned between 3 - 6 weeks and are totally independant of the parents at 3 months. Females can have up to 3 litters annually.

Ferrets are crepuscular and therefore they spend between 14-18hrs per day asleep and are most active around dawn and dusk. Ferrets have scent glands near their anus which are used for scent marking. Ferrets have also been shown to use urine marking.

Anatomy and Histology

This section has been included to allow familiarisation with the peculiarities of ferret anatomy to provide a context for some of the disease and pathological headings found below. Therefore only anatomical areas with specific features warranting emphasis have been included below;

Diseases

For ease of use, the diseases of ferrets listed below are by body system, or where this is not appropriate in an “Other” category displayed after the body system sections. Those diseases listed below are not exhaustive but rather highlight common diseases encountered with laboratory ferrets.