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Biotin Deficiency

Raw egg white contains an enzyme which destroys biotin in the ration. Experiments show with25 to 30 percent of the ration as raw egg whites, this condition will develop. Newborn foxes will show the deficiency if the females are deficient.

Symptoms take a number of weeks to develop (up to 12 or 15). They include fur loss over body and tail. The fur color becomes gray, especially around the muzzle. Eye infections may develop along with leg weakness. Eggs are an excellent source of high quality protein provided they are cooked, thus destroying the harmful enzyme.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.
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Ringworm (Dermatomycoses)

This is the only fungus infection of importance in foxes. This can become a problem on large farms with  ranchers raising mink in Canada reporting major problems. Symptoms would be crusts and hair loss, especially around the face. However, any part of the body can be involved in severe infections. The usual cause is Trichophyton species.

Cats are a major non-symptomatic carrier. Elimination of cats can control or prevent exposure.

Diagnosis would be by skin scrapings and laboratory culture. The most effective treatment is griseofulvin by mouth. The dosage varies byt 10-20 mgm. per kgm. of body weight works well. Other treatments applied to the skin are less effective.

Sanitation aids prevention as spores survive in the environment for a long time.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service. Updated 8/16/12 by Hugh Hildebrandt DVM, Medford Veterinary Clinic.
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Pseudorabies

This is an important disease in countries such as Russia. It is a brain infection but it is not present in Canada. Infection is by feeding contaminated slaughter house products, especially from pigs.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.
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Rabies

Foxes are quite susceptible to this virus infection of the nervous system. Wild foxes play an important role in the spread of this disease when it is present. However, there appears to be little risk to ranch foxes so vaccination would not be necessary.

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Fox Encephalitis (Canine Virus Hepatitis)

This disease is present in the dog population of Nova Scotia. Reports on this disease in foxes suggest the hepatitis or liver form is also seen frequently.

One severe outbreak in Norway involved 2,700 foxes ina few days. Symptoms were lack of interest, not eating, vomiting, diarrhea, convulsions and jaundice. About 620 animals died acutely and another 30 developed chronic signs. These included fluid under the skin, especially of head and legs.

Inclusion body in liver cell due to infectious canine hepatitis

Figure VI. Inclusion body (arrow) in liver cell due to infectious canine hepatitis magnified 2,400 times.

Diagnosis is by finding typical virus “inclusion bodies” in liver cell nuclei under the microscope. (see Figure VI). Blood samples can also be used to determined enchephalitis in non-vaccinated animals.

Once present on a ranch, the virus can survive for a long time (up to three years). This is especially true if weather is cool and it is protected in dirt or feces.

The same virus will also cause encephalitis or brain infection in foxes. Symptoms relate to this site of infection and fits would be seen.

Prevention is by vaccination. Some dog vaccines are for both distemper and hepatitis. While more costly, they should be used. One hepatitis shot provides protection for the life of most animals.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service. Updated 8/16/12 by Hugh Hildebrandt DVM, Medford Veterinary Clinic.
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Distemper

This is a highly infectious disease. It can attack susceptible foxes of any age. The same virus causes distemper in mink, dogs, raccoons, weasels, ferrets and skunks. Cat distemper is a different disease and is not contagious to foxes.

Normal fox lung

Figure III. Normal fox lung magnified 130 times.

 

Distemper lung showing pneumonia

Figure IV. Distemper lung showing pneumonia magnified 130 times.

The virus is spread by coughing and sneezing or by contaminated equipment, etc. It is killed by heat (40C), sunlight or disinfectants. Freezing temperatures and dirt will let the virus live for some time.

Symptoms of disease occur at least two weeks after exposure. Eyes begin to water, become crusted and stick shut. Thenose is crusted and sometimes foot pads are swollen. The coat is rough and animals often have diarrhea. Animals almost never survive the disease and treatment is of little value.

Prevention is by vaccination. Adults which have been vaccinated pass antibodies to young via milk. These will last for eight to ten weeks. If present, they interfere with vaccination. Therefore, young should not be vaccinated until they are eight to ten weeks of age. A booster vaccination of all animals kept for breeding is suggested for late fall or early winter.

Distemper inclusion bodies in urinary bladder cells

Figure V. Distemper inclusion bodies (arrow) in urinary bladder cells magnified 500 times.

Several types of vaccine are available. The cheapest here is the mink product combined with botulinism and virus enteritis. The latter is of no concern to fox ranchers, but would not harm animals. Vaccine used for dogs is available containing both distemper and hepatitis. It is more costly but should be seriously considered (see Hepatitis article). Research indicates the aerosol (air) vaccine used for mink distemper will also work on foxes.

If distemper is suspected on an unvaccinated ranch, one must act quickly. Sick or dead animals should be sent to a veterinarian or laboratory for diagnosis (see Figure IV and Figure V). Vaccination should start immediately working towards sick animals. If a fox is sick or incubating the disease, vaccination will not help.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.
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Tubercolosis

This disease has been reported in apparently healthy adult blue foxes. The symptoms were high infertility, abortions and stillbirths. The tuberculin test was given using the eyelids of animals. Any with positive swelling were killed. The bacteria was found in liver and gut lymph nodes using special tests. Following elimination of the disease, production returned to normal.

This is unlikely to be a major problem today in Nova Scotia as there are few sources of infection.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.

 

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Salmonellosis

Outbreaks of Salmonella typhimurium have been reported in foxes between five and thirteen weeks of age. Main signs were of infection of the nervous system due to septicemia. Response to treatment using combined sulphonamides and furazolidone was excellent.

Salmonella can also cause abortion in vixens and early death of young. Foxes, especially under stress, appear very susceptible to this bacteria.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.
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Listeriosis

One outbreak of nervous listeriosis resembling distemper has been reported in foxes. Most were about four week of age. Symptoms included weakness, loss of appetite, tremors, neck rigidity and salivation. Death took place after seven to eleven days of illness.Antibiotics were of very limited value. The suspected source of infection was abottoir offal.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.
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Colibacillosis

It is a common bacteria of the intestinal tract. Certain strains or serotypes are harmful to new-born animals. Two types of disease may be seen. Gastroenteritis, or stomach or gut inflammation, is common. The main symptoms are diarrhea, loss of body fluids and rapid death. The second type of disease is septicemia or blood poisoning (see figure at right). This infection is often obtained via the navel at birth. Infection, especially of the brain, followed by rapid death is seen.

Treatment would be with selected antibiotics and electrolyte fluids. Sanitation is important to reduce the level of contamination of nestboxes.

Normal brain and meninges

Figure I. Normal brain and meninges (arrow) magnified 130 times.

Infected meninges due to septicemia or blood poisoning

Figure II. Infected meninges (arrow) due to septicemia or blood poisoning magnified 50 times.

Fox Diseases. Novia Scotia Dept. of Agriculture and Marketing Livestock Service.