Slinky, mischievous, and intelligent, ferrets are members of the weasel family that love to play and socialize. Like humans and many other animal species, ferrets can be infected by various coronaviruses, including SARS-CoV-2, the cause of COVID-19. However, the coronavirus most likely to strike your pet ferret is ferret enteric coronavirus, (FRECV) which causes an illness commonly called green slime disease, but properly termed epizootic catarrhal enteritis.
This infection results in profuse diarrhea, which is often a bright green color and has a seed-like texture. Ferrets of any age can become sick with green slime disease, but symptoms are likely to be more severe in seniors. The ill ferret can become dehydrated and lose its appetite. Luckily, most ferrets recover, but epizootic catarrhal enteritis is quite contagious and easily spread amongst ferrets in close proximity, such as at a pet show or in a pet store.
Ferrets can also become infected with ferret systemic coronavirus, (FRSCV) which also typically causes diarrhea and weight loss.
What Is Coronavirus?
The coronavirus family includes many different viruses capable of causing disease in a wide variety of animals, including humans, cats, dogs, camels, pigs, bats, ferrets, and many others. Typically, diseases caused by coronaviruses cause either respiratory or gastrointestinal symptoms, such as cough or diarrhea. There are three coronaviruses in particular that can sicken your ferret.
Ferret Enteric Coronavirus (FRECV)
The form of coronavirus that most commonly affects ferrets, ferret enteric coronavirus, causes a disease called epizootic catarrhal enteritis (ECE). It's more commonly called green slime or green poop disease, however, due to the green diarrhea that's its chief symptom. ECE starts with liver inflammation that then spreads into the intestines, causing the death of cells lining the intestinal tract.
Ferrets with green slime disease often develop severe diarrhea that tends to have blood in it or look green, slimy, and even fluorescent due to the damage it causes to the intestines. This diarrhea is also seen alongside lethargy and dehydration that results in sunken eyes and skin tenting. Some ferrets don't show any signs of illness, however, but are still able to spread the virus to other ferrets.
The pathogen behind COVID-19, Sars-CoV-19 can cause a mild cough and fever, but in general, ferrets do not appear to become seriously ill from COVID-19. While there is still some uncertainty, it appears that ferrets can catch COVID-19 from humans, but are very unlikely to transmit it to their owner. Still, if you have tested positive for COVID-19, have someone else care for your ferret until you recover.
Ferret Systemic Coronavirus (FRSCV)
The third type of coronavirus that may affect a ferret is one that mimics feline peritonitis and is referred to as ferret systemic coronavirus or FRSCV. This is not a common type, but if a ferret contracts it, it is usually a young animal and it may experience weight loss, anorexia, diarrhea, and an intestinal mass in the abdomen. FRSCV is progressive and usually leads to the death of the ferret within two months.
Symptoms of Coronavirus in Ferrets
Illnesses caused by coronaviruses can cause your ferret to become very ill with diarrhea, weight loss, and lack of appetite, can give it a cough, or can cause no symptoms at all. But should your pet ferret show any signs of illness, it's always best to consult with your veterinarian. The following are symptoms to watch for.
If your ferret catches green slime disease, it might begin to show symptoms within two or three days, although the virus is believed to survive in infected feces for as long as six months. The first signs of illness are usually loss of appetite, vomiting, and then green diarrhea. Note that green diarrhea is not exclusive to green slime disease, however.
A very ill ferret will eventually lose weight, develop dehydration, and become lethargic. Most ferrets do not become this ill, however.
Ferrets with other forms of coronavirus disease can also have diarrhea or might have a cough and a fever.
Causes of Coronavirus
Coronaviruses are ball-like viruses covered with small "spikes" of protein. The word "corona" comes from the Latin word for crown, as the spikes give the virus a somewhat crown-like appearance. The viruses uses the spikes to attach to healthy cells inside their host, whether that be a ferret, human, or some other animal. Once attached, the virus injects its own genetic material into the healthy host cell, overriding the host cell's own genetic information. This means that the once-healthy host cells turn into "breeding centers" for more coronaviruses, instead of dividing into their own type of cell. Thus the infection spreads through the ferret or other infected animal.
Diagnosing Coronavirus in Ferrets
Diagnosis of green slime is typically made by analyzing liver enzyme levels, stool character, and observations of other symptoms. Electron microscopy of the stool may show the virus but this is not commonly performed. Your veterinarian may also order a complete blood count to see if the ferret has elevated white blood cells, which indicates some type of infection.
Diagnosis of COVID-19 in ferrets is made based on exposure history to an infected ferret or person and a fever, but coughing may or may not be present. A special test called a RealPCR test will confirm the diagnosis but other respiratory diseases like influenza should be ruled out first.
Ferret systemic coronavirus is diagnosed based on symptoms, as well as blood tests showing anemia and abnormal results for kidney or liver function.
Treatment of coronavirus depends on the symptoms involved. There is no direct cure for any of the illnesses this virus causes in ferrets, but supportive treatment can help your ferret recover sooner, or keep it comfortable during the progression of ferret systemic coronavirus.
Typically, your veterinarian will order fluids delivered subcutaneously if your ferret is dehydrated. A bland diet often tempts ferrets who have lost their appetites to eat and is easy on their digestive systems. Anti-inflammatories might be used to help relieve intestinal inflammation. If your ferret has ferret systemic coronavirus, the vet may also recommend treatment with steroids, which will not cure the disease but may extend your ferret's survival time.
Prognosis for Ferrets With Coronavirus
Most ferrets with green slime disease or COVID-19 will recover, although senior ferrets are at higher risk of succumbing to the infection. However, ferret systemic coronavirus is a progressive disease that leads to the death of the animal, usually within two months.
How to Prevent Coronavirus
The best way you can truly prevent coronavirus from occurring in your ferret is to keep it away from other ferrets or from other people who may have spent time around ferrets of their own. This, of course, can be difficult since not all people and ferrets show symptoms, but it will greatly decrease the likelihood of your ferret catching a coronavirus.
New ferrets being introduced into a household that already has ferrets should be kept separated from the preexisting ferrets for a couple of weeks to watch for any symptoms of coronavirus or other diseases. You should also wash your hands in between handling your own ferret and any others to prevent transmitting the virus or other diseases.
Is Ferret Coronavirus Contagious to Other Animals?
Ferret enteric coronavirus and ferret systemic coronavirus are highly contagious between ferrets, as well as the closely related mink. These two viruses do not infect other species of animals, however.
Peet, S. & Truex, S. Epizootic Catarrhal Enteritis. Winter Park Veterinary Hospital.
COVID-19 and Your Pet Ferret. Red Bank Veterinary Hospital.
Schoemaker N, & van Zeeland YRA. Infectious Diseases of Ferrets. Merck Veterinary Manual.
Coronaviruses in Domestic Species. American Veterinary Medical Association.