Dog Mites
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Mites in dogs is known generally as Mange and
cause severe irritation in dogs with symptoms of
inflammation, itching and hair loss(炎症，瘙痒和脱毛).
Mites cause their damage by tunneling into the skin
via the hair follicles and oil glands(毛囊和皮脂腺) of
the epidermal layer.
Mites normally live freely in dogs and cats, even
humans, without ever bothering their host(螨虫通常
自由的生活在犬、猫甚至人身上而对宿主的生活不造成影响);
it is only when the immune system of the host
suffers because of any number of circumstances do
the mite begin their process of infestation –
sometimes causing life-threatening conditions.(当宿
主的免疫系统受损时,任意数目的螨虫都可以造成感染,甚至危害
宿主的生命)
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The most frequent types of dog mites
are as follows:
S. scabiei var. canis/Mange mites(犬疥螨)
 Otodectes cynotis/Ear mites(犬耳痒螨)
 Demodex canis(犬蠕形螨)
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Sarcoptes is round in outline and up to
0.4 mm in diameter. Adults have 4 pairs
of short legs, of which the third and
fourth pairs do not project beyond the
margin of the body.
虫体呈圆形，龟状，口器短。背部
生刚毛。
(图1)雄螨在1、2、4对脚有钟形吸
盘，第三对脚各有长刚毛1根。
(图2)雌螨在第1、2对脚上有钟形
吸盘。第3、4
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Its most important
recognition characters
are the numerous
transverse ridges(横嵴)
and triangular scales on
the dorsum, features
possessed not by the
other mange mite of
domestic mammals.
背部有众多的横嵴和三角形的鳞屑
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Sarcoptes mites spend their entire life
on or in the skin. The male and female
copulate(交配) on the skin surface and
the male soon dies off. The female
then burrows into the upper layer of
skin and begins forming tunnels. As
she tunnels along eggs are laid that fill
the tunnels. (雌虫在宿主体表挖掘隧道,并
在里面产卵)
Adult mites feed on the serum(血清)
that oozes into the tunnels from the
surrounding irritated tissue. When the
female mite completes her egg laying
mission she dies at the end of the
tunnel. The eggs(卵) soon hatch to
form larvae(幼虫) and then molt to
become nymphs(成虫). The larvae and
nymphs also feed on serum and skin
debris. When the nymph makes a final
molt to become an adult they return to
the skin surface where they mate and
start the life-cycle over anew.
Incomplete metamorphosis
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Transmission from animal to animal is
thought to be through direct contact(直接
传播). Dog and cats in close contact with
an infected host are succeptible.
Animals can also become infected from
fomites(污染物) e.g. infested pens and
blankets, combs, brushes, collars and any
upholstered surfaces(受到污染的钢笔,毛毯,
梳子,刷子,项圈和软垫的表面).
Young and poorly nourished animals are the
most succeptible to infection.
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Severe, constant itching(严重地,不断地瘙痒) at any time of
year is a classic symptom of sarcoptic mange. Areas with
less hair, such as the earflaps, elbows, hocks(跗关节),
ventral abdomen(腹部), chest, and legs, are affected most
commonly. The mites cause hair loss, a reddened rash, and
yellowish crusts(脱发,红疹,淡黄色的渗出物) to form on the
skin in affected areas.
Typically the ear margins and elbows are affected most
severely. The ear margins tend to have thickened, crusty
material on the tips and yellow scales(增厚,变硬,形成鱼鳞状
黄痂).
The animal may develop a secondary skin infection and
severe scratches from the trauma of constantly
scratching(皮肤的继发感染,严重抓伤). The lymph nodes also
may swell(淋巴结肿大) as a result of mite related
inflammation.
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Diagnosis of sarcoptic mange infection is by deep
skin scraping to find the parasite. Multiple
scrapings are necessary on skin areas without
excoriation(在无损伤部位多次刮取). Deep scrapings
are necessary and should be performed to a depth
where some bleeding occurs(在出血部位深层刮取).
Scrapings should be examined under the
microscope(显微镜下检查), and are best treated
with 10% potash before examination. The presence
of a single mite is sufficient for diagnosis(单个螨虫
足以确诊). However, mites are often absent, even
with multiple skin scrapings.(可先服用治疗螨虫的药
物看有否好转)
A diagnostic clinical sign, although non-specific, is
the pinnal-pedal reflex.
①Clipping the hair from the affected area.(患部剪毛)
②An anti-seborrheic shampoo that breaks down and
removes crusts, skin oil, and debris.(除去污垢和痂皮)
③ Debride and swab with parasiticidals dip e.g.
Selamectin,Amtiraz, Dipterex.(局部涂擦杀螨药的油剂)
④ Medication:
 Ivermectin/Doramectin 0.2-0.4mg/kg sc/im.
⑤All animals and objects that have come into contact
with a dog should be washed thoroughly and
disinfected.(所有与犬只有接触的动物和物品都应该彻底
清洁和消毒)
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Comprehensive prevention:
The best way to prevent transmission is to
avoid any contact with animals or the
environment of any animal that may be carrying
scabies(避免接触任何可能带有疥螨的动物及环境).
All boarding facilities, grooming equipment(剪毛
器械), and bedding materials(垫料) should be
washed thoroughly and disinfected on a regular
basis(定期彻底清洁和消毒).
Parasiticidal pet collar(除虫项圈)
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Otodectes is elliptical with conical mouthpart.
The epimeres(上段) extending from the bases of
legs I and II are joined. The male has broad bowlshaped ambulacra(钟形吸盘) borne on very short
unsegmented pedicels(不分节的腹柄) on all the legs,
but only legs I and II of the female have pedicels
and amulacra. Legs III of the female terminate in
two long setae and legs IV are reduced.
虫体呈椭圆形，口器长，呈圆锥
状，脚比较长。
雄螨第1、2、3对脚有钟形吸盘，
第4对脚短小。
雌螨第1、2、4对脚有钟形吸盘，
第3对脚有2条长刚毛。第四
对足不发达。
Male Otodectes cynotis
Female Otodectes cynotis
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The life cycle of Otodectes is similar to that of all
other mites, i.e. development from egg to adult via
a larval and two nymphal stages. Development time
is about 3 weeks.
Otodectes larvae feed for 3 to 10 days, rest for a
short time and then molt to become a
protonymph(一期若虫). This nymphal stage is rather
short and leads to the telonymph(二期若虫); once
the female reaches this stage copulation occurs
with an adult male mite(二期若虫交配). Fertilization
only occurs, however, after the female telonymph
has molted to become an adult female(成虫受精).
The life span of adult mites is about 2 months. (成
虫大约有两个月的寿命)
Incomplete metamorphosis
Infective routes: Contagious infection
 Young animals are most susceptible to
infestation and, as the mites are highly
contagious and not host-specific(高度传
染性和无特定宿主), all in-contact animals
should be presumed to be infected.
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Head shaking.
Scratching the ears (there may be sores around
the ears as a result of scratching) .
Reddish-brown to black discharge (crusts and
cerumen) in the ears that resemble coffee
grounds.(红棕色,黑色像咖啡渣滓样的渗出物,痂和
耳垢)
A characteristic otitis externa of parasitic
origin.(寄生虫引起的外耳炎)
Odour(气味)
Sometimes there seem to be no observable
signs of ear mites.
Accumulation of
exsudate and
cerumen in auditory
canal(耳垢和分泌物
的沉积)
Sometimes lesions
may spreads to
other areas of the
head or the rest of
the body(病变的扩
散)
A diagnosis of ear is usually made by one
of the following methods:
①Direct visualization of the mites with
an otoscope.(检耳镜直接观察法)
②Microscopic examination of the
cerumenous debris from an infected ear
canal.(显微镜下观察感染耳道取出的耳垢)
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① Instillation of Paraffin oil to the ear and then rub(向
耳内滴入石蜡油)
② Debride and swab with Parasiticidals dip e.g.
Selamectin,Amtiraz,Permethrin. (局部涂擦杀螨药的油剂)
③Medication:
 Ivermectin/Doramectin 0.2-0.4mg/kg sc/im.
④ Use antibiotics when secondary bacterial
infections.(继发性细菌感染时,应配合抗生素治疗)
Comprehensive prevention:
 The best way to prevent is thus to keep
your pets indoors.(减少外出)
 To avoid any contact with itching and
ectillotic animals.(避免与有脱毛和瘙痒症
状的动物接触)
 Parasiticidal pet collar(除虫项圈)
 Periodic deworming(定期驱虫)
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Demodex are easily recognised by
their annulate(环状的), vermiform
(‘worm-like’) shape(蠕虫状), and is a
white, oblong(长形的) mite. Adult
female mites measure 300 µm and
the males about 250 µm. The
capitulum(头部口器) is horseshoelike with clearly visible mandibles.
The cuticula of the body resembles
transverse wrinkles. Four pairs of
stump-like legs end with 2 claw-like
structures.
虫体长形，呈蠕虫状，分头、胸、腹
三部。
背腹扁平，头部口器呈马蹄形，胸部
有四对粗短的脚，腹部有横皱纹。
Incomplete metamorphosis
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Demodex mites spend their entire
life on the skin of dogs, where they
reside in the hair follicles(毛囊) and,
rarely, the sebaceous glands(皮脂腺).
The developmental cycle starts with
the larvae hatching from the
fusiform(梭形的) eggs. The sixlegged larvae(六足幼虫) moult(蜕皮)
to become the eight-legged first
nymphal stage(八足一期若虫). This is
followed by a second nymphal stage,
which in turn moults to give rise to
the final adult stage.
The whole life cycle is completed in about 3 weeks. All stages of
the mite can be found in the hair follicles, as well as the lymphatic
system, bloodstream, and other bodily organs.
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The mites are transferred directly from the
mother to the puppies within the first week
of life.(主要感染方式)
Transmission of the mites is by direct
contact only(直接传播). That is, the mother
and puppy must be physically touching, as the
parasite cannot survive off of the animal(无法
在动物体外生存).
Most puppies are immune to the mite‘s
effects and display no clinical signs or lesions.
A few are not immune and it is these puppies
that develop full-blown cases of mange.(大多
数不表现出临床症状)
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Demodicosis has two forms:
FORM #1: LOCALIZED(局部型):
Localized demodicosis occurs
as isolated scaly bald
patches(局灶性的脱毛,脱屑),
usually on the dog‘s face,
creating a polka-dot
appearance(圆点状).
Localized demodicosis is considered a common
puppyhood ailment and approximately 90% of
cases resolve with no treatment of any kind(不
需治疗常可自愈).
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FORM #2: GENERALIZED(全身型)
The entire dog is affected with
patchy fur, skin infections, bald,
scaly skin.(皮肤感染,脱毛,脱屑)
Sometimes large patches of
affected skin are present,
sometimes multiple “polka dots” of
lesions cover the dog, and
sometimes the entire body is
involved.
The secondary bacterial infections make this a
very itchy and often smelly skin disease(细菌继发
感染导致非常瘙痒和皮肤有恶臭).
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The standard method for diagnosis of infection
with Demodex mites is microscopic examination of
deep skin scrapings and detection of mites(显微镜下
刮屑检查). Another option is to examine plucked
hair for the presence of mites.(拔毛检查)
To perform a skin scraping, the skin should be
squeezed(刮屑前挤压皮肤), thus expelling the mites
from the depths of the hair follicles to the surface.
Demodex mites are present in the skin of healthy
dogs and a single mite found in a scraping may be
consistent with a diagnosis of healthy skin. (健康的
皮肤上发现蠕形螨也是正常的)
Skin scrapings from several areas are necessary to
confirm infestation. (多部位刮屑取样)
①Debride and swab with hydrogen peroxide(双氧水洗擦)
②Use parasiticidals dip e.g.
Selamectin,Amtiraz,Permethrin. (涂擦杀螨药的油剂)
③Medication:
 Ivermectin/Doramectin 0.2-0.4mg/kg sc/im.
④Dexamethasone/Chlortrimeton may be used when
itching seriously.
⑤Skin infections are usually present in these cases and
antibiotics will likely be necessary.(抗生素的应用)
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Females should be spayed as soon as the disease is
controlled. Also, predisposition to demodicosis is
hereditary and should not be passed on.(对全身型蠕形螨病
的母犬不宜留作种用)
The dog should be fed a reputable brand of dog food so as
to avoid any nutritionally related problems. (避免营养问题)
Keep up the pet‘s vaccinations.(疫苗接种)
The mites themselves cause suppression of the immune
system so the pet needs every advantage to stay healthy.
(提高抵抗力保持健康)
It is very important that cortisone type medications such
as prednisone NOT be used in these cases as they will tip
the immune balance in favor of the mite.(可的松类的药物会
导致免疫平衡失调)