Canine Mange: Demodex and Sarcoptic
Mites live on
all mammals, including humans, year round,
24/7 and cause no damage unless there is a
weak or weakened immune system in its host.
It may
surprise you to know that demodectic mites (photo)
of various species live on the bodies of
virtually every adult dog and most human
beings, without causing any harm or
irritation. These small (0.25 mm)
'alligator-like' mites live inside of the
hair follicles (i.e., the pore within the
skin through which the hair shaft comes
through), hence the name follicular mange.
In humans, the mites usually are found in
the skin, eyelids, and the creases of the
nose.
Normally, the
immune system fights off the mites
naturally, but if weakened, Demodectic Mange
is the result and is not normally
contagious. Because the mites prefer
to live in or near the bases of hair
follicles, they cause damage as they disturb
the natural environment of the follicle,
causing hair to fall out and then continue
to nip at the skin once the hair has gone.
The demodectic
mite spends its entire life on the dog. Eggs
are laid by a pregnant female, hatch, and
then mature from larvae to nymphs to adults.
The life cycle is believed to take 20-35
days.
How is Demodex canis transmitted?
The mites are transferred directly from the
mother to the puppies within the first week
of life. Transmission of the mites is by
direct contact only. That is, the mother and
puppy must be physically touching, as the
parasite cannot survive off of the animal.
This is important because it means the
kennel or bedding area does not become
contaminated and therefore the environment
need not be treated.
In the
localized form, Demodex usually shows itself
in puppies and depends upon the breed as to
exact age you can anticipate its arrival.
For example, a Pug puppy hood is quite long
and they may not fully develop until they
are as much as two years of age so demodex
can present itself between the ages of 6 and
18 months; Labs mature even slower so you
can see it develop up to the age of three
years or more. Generally the smaller
the breed, the earlier it will show in
puppies.
Adult dogs can
have Demodex also and it has been diagnosed
due to a massive change in a dog's
environment. Because of this, it is
also theorized that stress may be a cause of
Demodectic Mange as well. While this does
make sense, and is logical enough, it’s
important to note that this is more the
effect of stress on the dogs’ immune system
than it is stress itself. Stress can lower a
dogs ability to fight off disease and
illness, just as it does in people, but it’s
the lowering of the immune system itself
that leads to the mites doing their damage.
Older dogs diagnosed with Demodectic Mange
should be screened for certain other
diseases such as Cushing's disease,
hypothyroidism, cancer, and heartworm
disease.
Symptoms of
Demodectic Mange: The symptoms of
Demodectic Mange are actually easy to spot.
It shows itself in dime sized bald patches
on your pet, usually found near the base of
the ear opening, above the eyes, the belly,
paws and sometimes elsewhere. It is believed
these areas are concentrated where the pups
come into contact with the mother while
nursing. These bald patches, in Generalized
Demodex leave the skin appearing as a
reddish color, which is where Demodex got an
alternative name called "Red Mange". Other
symptoms can accompany Demodectic Mange such
as listlessness, loss of appetite and other
illnesses, depending upon the type of
Demodectic Mange your pup is suffering from.
-
Localized Demodectic Mange:
The
localized form of Demodex shows itself as
one or a few bald spots in the "usual
places" mentioned above.
-
Generalized Demodectic Mange:
The generalized form of
Demodex shows itself in a greater number
of bald spots, as it worsens and spreads,
and is often accompanied by other
secondary infections of the skin and
perhaps elsewhere.
Sarcoptic
Mange
Sarcoptic and
Demodex are very hard to tell apart and it
is best to get your pet to the vet for a
proper diagnosis - Sarcoptic is contagious (photo)
and can be transferred to humans, unlike
normal Demodex. Because the mite in
Sarcoptic Mange deliberately burrows into
the skin to lay its eggs, it MUCH more
serious than Demodex for all the secondary
infections it causes. Treatment for
each condition is also different, so again -
see your vet for a proper diagnosis right
away!
The contagious
situation is due partly to the fact that pus
may drain from the exposed skin of a dog
suffering with mange. Tiny mites may be
found in the pus and be passed on to a new
host. When this occurs, the mites burrow
into the skin of the new host, leading to
the loss of hair and reddish scales on the
exposed skin. While Demodetic mites
cannot live off of its host, the mites which
cause Sarcoptic Mange can, making the
treatment for this health issue much harder
to control and eradicate.
At normal room
temperature in a home, Sarcoptic mites will
live from 2 to 6 days (and up to 22 days in
a cool, moist environment such as high air
conditioning temperatures). Because of the
mite's ability to survive off the host, dogs
can become infected without ever coming into
direct contact with an infected animal as
well.
Along with the loss of hair and the
development of the red hue on the surface of
the skin, dog mange also can cause the
development of pimples in the infected area.
Dry patches of skin may also develop,
eventually becoming thicker in texture than
the surrounding areas. The dog will also
often develop scaling around the mouth,
eyes, and the front legs as the condition
continues to worsen.
Symptoms of
Sarcoptic Mange:
The symptoms
are varied, but usually include hair loss
and severe itching especially on the elbows,
ears, armpits, hocks, chest, and ventral
abdomen (belly). The mites prefer to live on
areas of the skin that have less hair. As
the infection worsens it can spread over the
entire body.
The type of mite that has invaded the skin
often determines the exact course of
treatment for dog mange. Sarcoptic mites are
round shaped while demodectic mites are
elongated and have an appearance that is
somewhat like that of a cigar.
Sarcoptic mites are very hard to see, even
under a microscope and the type of manage is
generally diagnosed based more upon the area
on the dog's body that has begun balding and
their reactions than by actually being seen
in a scraping by a vet. In both cases,
the mites move around under the surface of
the skin and create an itching sensation
that is almost unbearable for the host.
While
increasing vitamin E intake in the diet does
not help the actual mange, it does
accelerate the rate of healing and is
generally recommended by most vets.
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