Ferrets and children
Ferrets can make good pets for some children, but usually do not make good pets for very young children. Important considerations include assessing potential danger to a human child by a pet ferret, and potential danger to a pet ferret by a human child, either deliberately or by neglect. Ferrets are capable of delivering a bite almost as strong as a domestic cat. Like all other domesticated animals, they should never be left unsupervised near infants or very young children. There have been rare cases where ferrets have severely injured babies but nearly all such incidents involved neglect, abuse, or roughhousing that the ferret likely perceived as an attack, and some of the animals involved were ferret-polecat hybrid crosses. Given that young children and ferrets can be both excitable and prone to rough play, interaction between ferrets and children must always be closely supervised for the protection of both. With regard to the danger of potential pet ferret attacks as contrasted to attacks from other pet species, statistics would imply that the danger is probably overstated. In the United States, a government study by the California Department of Health Services on national pet attack statistics found 452 reported incidents of ferret bites during the ten year period 1978–87. By comparison, pet dogs accounted for an estimated 585,000 injuries that required medical attention in the year 1986 alone, with the total number of pet dogs in the United States in 1996 estimated at 55,000,000and the total number of pet ferrets in the United States in 1996 estimated at 800,000. Adjusting for the proportionate ratio of dogs to ferrets in the United States of 68 to 1, dog bites occurred 5 times more frequently than ferret bites.

Other uses of ferrets
Ferrets have been used to run wires and cables through large conduits. Event organizers in London used ferrets to run TV and sound cables for both the wedding of Charles, Prince of Wales to Lady Diana Spencer, and for the "Party in the Park" concert held in Greenwich Park on Millennium Eve. One ferret, Freddie, was even registered as an electrician's assistant with the New Zealand Electrical Workers Union.
Because they share many anatomical and physiological features with humans, ferrets are extensively used as experimental subjects in biomedical research, in fields such as virology, reproductive physiology, anatomy, endocrinology and neuroscience.

Ferret biology and health concerns
Ferrets do not require frequent bathing, which may remove natural oils in the ferrets coat that prevent dry skin. However, most ferrets are not averse to water. Ferrets also need their nails clipped about once a month, and usually shed twice a year in the spring and fall.
Like many other carnivores, ferrets have scent glands near their anuses, the secretions from which are used in scent marking. It has been reported that ferrets can recognize individuals from these anal gland secretions, as well as the sex of unfamiliar individuals. Ferrets may also use urine marking for sex and individual recognitions.
As with skunks, ferrets can release their anal gland secretions when startled or scared, but the smell dissipates rapidly. Most pet ferrets in the US are sold descented, with their anal glands removed. In many other parts of the world, including the UK and other European countries, descenting is considered an unnecessary mutilation.
Males, if not neutered, are extremely musky. It is considered preferable to delay neutering until sexual maturity has been reached, at approximately six to eight months old, after the full descent of the testicles. Neutering the male will reduce the smell to almost nothing. The same applies for females, but spaying them is also important for their own health. Unless they are going to be used for breeding purposes, female ferrets will go into extended heat and a female that will not mate, without medical intervention, can die of aplastic anemia. It is possible to use a vasectomised male to take a female out of heat.
Many domestic ferrets are known to suffer from several distinct health problems. Among the most common are cancers affecting the adrenal glands, pancreas, and lymphatic system. Certain health problems have been linked to ferrets being neutered before sexual maturity was reached, and because of this some owners now choose to use implants instead of having the ferret neutered too early. Some owners even choose not to have their ferret neutered at all but use longer working implants instead. Certain colors of ferret may also carry a genetic defect known as Waardenburg syndrome.

Foot Rot
A common ailment which is fatal in ferrets is foot rot (cage rot). Foot rot is a form of fungal infection which attacks the feet and is sometimes found to affect the tail. It initially appears as a small, yellow, scab-like infection. If untreated, it can cover the feet. In worse cases, almost the entire body. Foot rot is normally caused by poor cage hygiene, ie. feces accumulation.

Adrenal disease
Adrenal disease, a growth of the adrenal glands that can be either hyperplasia or cancer, is most often diagnosed by signs like unusual hair loss, increased aggression, constant grooming of owner or other ferrets as well as themselves, difficulty urinating (caused by an enlarged prostate) or defecating, or agitation when urinating, and (in the case of females) an enlarged vulva. Signs of an enlarged prostate should be considered an emergency; even if the growth is benign, it can still cause a hormonal imbalance which can have devastating effects on the ferret's health.
Treatment options include surgery to excise the affected glands, melatonin implants, which treat the symptoms but not the disease itself, and/or hormone therapy. The causes of adrenal disease are as yet uncertain, but speculated triggers include unnatural light cycles, diets based around processed ferret foods, and prepubescent neutering. It has also been suggested that there may be a hereditary component to adrenal disease.
Adrenal disease is usually detected during the spring or fall, as it affects the hormones that make the fur grow. When affected ferrets shed their winter coat, the fur does not grow back. The hair loss pattern is usually very specific for adrenal disease. It begins at the base of the tail and then continues up the back. Ferrets treated for adrenal disease may suffer temporary but severe hair loss as their bodies recover.

Insulinoma
Ferrets may suffer from insulinoma, a cancer of the pancreas. The growth of cancerous nodules on the lobes of the pancreas sometimes, but not always, leads to an increase in the production of insulin, which regulates the rate at which the ferret's body metabolizes blood glucose. Too much insulin will cause blood sugar to drop, resulting in lethargy, seizures, and ultimately death. Symptoms of an insulinoma attack include episodes of lethargy, drooling, pawing or foaming at the mouth, high pitched screams, staring "blankly" into space, and seizures.
Like adrenal cancer, the exact cause of insulinoma is unknown. It is speculated that the diets of domestic ferrets are too far removed from the natural diets of their polecat ancestors, and include too much sugar or simple carbohydrates.
Treatment for insulinoma may include surgical excision of the cancerous lobes, pharmaceutical treatment with steroids that suppress the production of insulin, supplemental changes in diet (most often poultry-based baby food), or a combination thereof. Unfortunately, the growth of the tumors cannot always be completely stopped, and the ferret will sometimes suffer a recurrence of symptoms. In an insulinoma attack, a temporary remedy to stabilize the ferret is any kind of a sugary syrup, such as corn syrup or honey.

Lymphoma
Lymphoma/lymphosarcoma is the most common malignancy in ferrets. Ferret lymphosarcoma occurs in two forms -- juvenile lymphosarcoma, a fast-growing type that affects ferrets younger than two years, and adult lymphosarcoma, a slower growing form that affects ferrets four to seven years old.
In juvenile ferret lymphosarcoma, large, immature lymphocytes (lymphoblasts) rapidly invade the thymus or the organs of the abdominal cavity, particularly the liver and spleen. In adult ferret lymphosarcoma, the lymph nodes in the limbs and abdominal cavity become swollen early on due to invasion by small, mature lymphocytes. Invasion of organs, such as the liver, kidney, lungs, and spleen, occurs later on, and the disease may be far advanced before symptoms are noticeable.
As in humans, ferret lymphosarcoma can be treated surgically, with radiation therapy, chemotherapy or a combination thereof. The long-term prognosis is rarely bright, however, and this treatment is intended to improve quality of life with the disease.

Viral diseases
Epizootic catarrhal enteritis (ECE)
ECE, a viral disease that first appeared in the northeastern US in 1994, is an inflammation of the mucous membranes in the intestine. The disease manifests itself as severe diarrhea (often of a bright green color), loss of appetite, and severe weight loss. The virus can be passed via fluids and indirectly between humans. Although it was often fatal when first discovered, ECE is less of a threat today, with the right supportive care, that usually includes hospitalization with intravenous fluids. The virus is especially threatening to older ferrets and requires immediate attention.

Aleutian disease virus (ADV)
Aleutian Disease Virus (ADV) is a parvovirus discovered among mink in the Aleutian Islands in the early 20th century. In ferrets, the virus affects the immune system and many internal organs, particularly the kidneys. There is no cure or vaccine for the disease, and ferrets may carry the virus for months or years without any external symptoms. As a result, some ferret organizations and shelters recommend that owners test their pets for the virus regularly, separating them from other ferrets if they test positive.

Canine distemper
Canine distemper (CD) is an extremely contagious virus that is almost always fatal. Being strict indoor pets does not necessarily protect ferrets, as owners may bring the virus home on their clothes or their shoes. The only protection against the virus is vaccination, but that is not without controversy as there have been reports, particularly from the USA, of ferrets going into anaphylactic shock after being vaccinated against CD.

Influenza virus isolation using ferrets
Ferrets have served as a good experimental animal models in the study of influenza virus. Smith, Andrews, Laidlaw (1933) inoculated ferrets intra-nasally with human naso-pharyngeal washes, which produced a form of influenza that spread to other cage mates. The human influenza virus (Influenza type A) was transmitted from an infected ferret to a junior investigator, from whom it was subsequently re-isolated.

Waardenburg-like coloring
Ferrets with a white stripe on their face or a fully white head, primarily blazes, badgers, and pandas, almost certainly carry a congenital defect which shares some similarities to Waardenburg syndrome. This causes, among other things, a cranial deformation in the womb which broadens the skull, white face markings, and also partial or total deafness. It is estimated as many as 75% of ferrets with these Waardenburg-like colorings are deaf. Beyond that, the cranial deformation also causes a higher instance of stillborn ferret kits, and occasionally cleft palates. Because of this, many breeders will not breed Waardenburg-patterned ferrets.