Feline and Canine Ringworm
Just
as in humans, ringworm is not a worm
but a fungal disease that infects skin,
hair, and claws by one of the three
types of fungus: Epidermophyton ,
Microsporum, and Trichophyton.
These fungi are found worldwide, and
all domestic animals are susceptible.
Ringworm in cats is the most common
form of ringworm in pets. Second most
common is ringworm carried by rodents
and picked up by curious dogs digging
into rodent burrows. The third form is
a soil fungus.
Ringworm in dogs and cats generally
appears as a red, crusty, rough area of
skin with broken hairs and hair loss
with hardly any itching. Ringworm can,
however, present itself in many ways
which are not typical.
Due to the susceptibility of young
animals, the disease is more common in
puppies and kittens.
How does a dog or cat get
ringworm?
Dogs and cats can pick up
ringworm in several ways:
- Contact with
hair, fur and skin from
infected animals
- Contact with
contaminated bedding, grooming
equipment, toys or
environment
- Contact with
soil containing fungal
organisms
Ringworm is spread by contact with
animals which already have ringworm,
and by touching objects that the
infected animal has touched; such as
bedding, brushes or grooming equipment,
saddles and other tack, furniture,
rugs, etc. Not every animal or human
who touches infected animals or objects
will become infected; the age,
immune status, skin condition and
grooming habits of the animals
influence if the fungus is actually
able to grow and infect.
In animals, the classic Ringworm
lesions are patchy areas of hair loss
and scaliness, usually with very little
inflammation or redness.
Animal/Human transmission of
ringworm
Some ringworm in dogs and
cats can be contagious to people
(zoonotic disease), especially
children. Studies show that in 30
percent to 70 percent of households
where the cat has ringworm, at least
one person will get it. People with the
highest risk for catching ringworm from
their pet are young children who have
never been exposed, the elderly, or
people with a depressed immune
system.
Once a person has been exposed to a
strain of ringworm, most develop
immunity and rarely get the same strain
again. If a person develops ringworm,
your pets should be examined, although
many times the source of infection is
actually another person and not a
pet.
Cat Ringworm
Infected dogs
generally always have a skin lesion at
the site of infection, whereas infected
cats can
carry the fungus and
transmit it without actually having a
skin lesion. In other words, cats can
have the fungus on their coat or
transmit the fungus to other animals
and people and not have any noticeable
lesions themselves.
Diagnosis of pet
ringworm
Diagnosis of ringworm
requires a fungal culture from a sample
of hair plucked from the edge of a
lesion. This can take several days to a
few weeks for growth and a
diagnosis.
Cats that are suspected of carrying the
fungus but have no lesions can be
diagnosed by culturing a sample of the
coat after brushing the cat. An
ultraviolet light can be used to
diagnose about 30% of the ringworm
infections.
Although the disease is considered to
be self limiting in most healthy people
and animals, treatment of infected cats
and dogs is usually recommended to
speed recovery and prevent passing on
the fungus. Most animals will "outgrow"
the Ringworm fungus as their body's
immune system fights it off over the
course of a few weeks.
Old animals, puppies and
kittens
Due to the susceptibility
of young animals, the disease is more
common in puppies and kittens.
Animals that are immunocompromised or
very young or old are less likely to
rid themselves of the condition without
treatment.
To some extent, infection may be
persistent and widespread in longhaired
breeds of cats.
Symptoms of Ringworm in your
pet:
- Lesions, either single or
multiple
- Scaling or crusting
- Patches of hair loss that may
be circular
- Minimal to no itching
- Nodules with ulcers or draining
tracts are rare, but may
occur.
Treatments for Animal
Ringworm
Topical treatments involve
clipping the hair, bathing with
antifungal shampoo and rinses that
decrease transmission immediately. Some
cases may require systemic antifungal
therapy that has been shown to shorten
the course of the disease. A ringworm
vaccine is also available for use in
cats in catteries or multi-cat
households where treatment of
individual cats is difficult. The
anti-fungal drug of choice in dogs is
Ketoconazole and in cats is
Itraconazole. Oral medications are
generally reserved for severe and/or
chronic infections and can be expensive
and with side effects.
Treatment must continue until the
culture results are negative, even
though the animal may look better. Hair
re-grows long before the fungus is
exterminated. In a single-cat
household, treatment can last 3 to 8
weeks and may be needed for longer
periods in a multi-pet household.
- Localized infections may be
treated with topical therapy
alone.
- Systemic antifungal in
combination with topical therapy
should be used for generalized
infections or in dogs with multiple
lesions.
- Thoroughly disinfect and vacuum
the pet's environment.
- All in-contact animals should
be evaluated for possible
infection.
Home Treatment for Ringworm in
pets
Treating your home is also
important. Fungal spores can persist in
your carpet for up to 2 years, so
re-infection is a concern. The more
animals in the house, the longer the
treatment must go on before the
environment is clear. Getting rid of
the hair in the house, kennels and pet
sleeping areas are the best way to rid
the fungus from the environment. This
is why veterinarians recommend clipping
the pet's hair (alert the groomer).
Fungus likes to grow in dark spaces on
hair and debris.
If your pet has ringworm, change the
bag each time you vacuum. The parts of
a bagless vacuum can be soaked in
diluted bleach water between uses. The
only reliable killer of the ringworm
spores is a 1:10 dilution of bleach in
water. Use this with care because it
will stain.
Sunlight and Ringworm
Sunlight
also kills ringworm. Items that cannot
be thrown away can be left in the sun
outside to rid them of ringworm
contamination.