Transcript Psoroptes communis(痒螨)

Psoroptes communis(痒螨)
Presenter:王燕
 Members：
程家玲，蒋皓敏，刘静，宋子嫦
From Class 3
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Introduction
Species of the genus
Psoroptes (痒螨
属)(Acari:Psoroptedae) are
astigmatid,obligatory
ectoparasites that cause
various forms of psoroptic
mange in mammalian host
including
sheep,cattle,Goats,hoses
and rabbits . One of the
primary distinguishing
features of the genus is the
Presence of relatively
long,jointes pretarsi.
Introduction:
The most well known and clinically important occurrence of this
mite is on sheep ,and the causative agent was described and first
given the name Sarcoptes ovis by Hering in 1838,but later assigned
to the genus Psoroptes .Following the initial description from
sheep ,as many as nine species of Psoroptes mite were
proposed,each distinguished from the others mainly by the different
mamalian hosts they infest.However,because of the morphological
similarity between mites found on different host species ,a number
of early authors believed that populations on different hosts
belonged to a single species synonomised initially as Dematokoptes
communis by Furstenberg in 1861 and subsequently as Psoroptes
communis.Host-derived populations were referred th as
P.communis with varietal names such as ovis of bovis
appended,depending on the host species from which they were
obtained.(Raillet,1893;Stockman&Berry,1913;Shilston,1915)
Morphology
Morphology:
Distinguish beween male and female
The male tritonymph（三期若虫） is
singigicantly larger than the protonymph
（一期若虫）and has five pairs of
metapodosomal setae（刚毛） rather than
three.In addition ,male tritonymphs have
two pairs of cuticular pits on the central
metapodosoma（后足体） rather than the
single pair of the protonymph .The female
protonymph can be distinguished from the
male nymphal stages and the female
tritonymph.
Morphology of larval stage
protonymph of Psoroptes(Male)
protonymph of Psoroptes(female)
Distinguish beween male and female
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Both female nymphal stages possess
dorsoposterior tubercles（结核结节） ,but the
potonymph is significantly smaller than the
tritonymph .In addition,the protonymph
possesses three pairs of metapodosomal setae
rather than five,one pair of cuticular pits rather
than two ,and a pulvillus on leg IV which is the
absent in the female tritonymph.The presence of
dorsoposterior tubercles enables the female
nymphs the be distinguished easily from the
males.By contrast,distinguishing between the
nymphal stages of the same sex relies on the
identification of both the number of
metapodosomal setae （刚毛）and cuticular
pits .These descriptions are used to produce a
key,which allows the various stages of both sexes
to be distingushed.
tritonymph of Psoroptes
adult of Psoroptes
Lesions（病变）
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Intense itch
Inflammation and thickening and
trichomadesis of skin
Emaciation
Life cycle
The female lays about 90
eggs during her lifetime of
4-6 weeks,and
development from the
egg,through the larval and
nymphal stages to mature
adult,takes about ten
days.the greater
pathogenicity of this mite
is attributable to the fact
that unlike most nonburrowing mites,it has
piercing and chewing
mouthparts which can
severely damage the skin.
symptoms
1、intense itch(剧痒）
The most common signs are scratching of the
ears,whining（哀鸣), rubbing(磨蹭） of the face,
scars behind the ears from scratching, shaking of
the head
2、Inflammation and thickening and
trichomadesis of skin(皮肤发炎、增厚和患部脱毛）
Reddish-brown to black discharge (crusts 痂皮
and cerumen) in the ears that resemble coffee
grounds沉积物
Bleeding from the ear
Odour（臭气）
3、Emaciation(消瘦)由于发痒病蓄终日烦躁不安影响采食和休息
Diagnosed
Diagnosis is based on clinical symptoms as
described above.初步诊断
Final diagnosis :
1、direct examination of the ears with a
magnifying glass.
Diagnosed
2、microscopic examination of the ear
discharge
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Superficial scraping
it is used to collect scale or crust（痂皮） for the detection of the parasites
that normally inhabit the stratum corneum(角质层）。
Deep scraping
this technique is used to demonstrate follicular mites
It is also important to scrape the skin until true capillary bleeding is elicited.
The obtained material was placed on a
microscope slide（载玻片）, covered with a
coverslips（盖玻片）, and examined under a
microscopy .
Epidemiology
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Psoroptes communis is a widespread
（世界性分布） endoparasites (外寄生
虫）.
Animals can be infected by direct
contact(直接接触） or indirect contact
with a infected host.
Definite host:a variety of animals,
including swine ,cattle ,goat ,horse ,
poultry ,cats and dogs ,etc.
Treatment
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Clean the dirt（污垢） and crusta (痂皮）
with warm soup water first.
大环内酯类杀虫剂(Macrolides insecticide)。
如用伊维菌素(Ivermectin)或多拉菌素(Doramectin)进行
皮下或肌肉注射。
甲脒杀虫剂类（Formamidine insecticide）。如
用双甲脒(Amitraz) 进行药浴或涂擦。
有机磷类杀虫剂（Organophosphorus
insecticide）。如敌百虫(Dipterex)、巴胺磷
(Propetamphos)、地亚农(Diazinon)等进行药浴，涂擦或
喷洒环境。
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拟除虫菊酯类杀虫剂（Pyrethroid insectide）
。如溴氰菊酯(Deltamethrin)、戊酸氰菊酯等药浴或涂
擦。
伊维菌素（Ivermectin).
Prevention
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Improvement of management
,especially keep the site dry and
aired.
Kill the acarus(螨虫）of the
environment by spraying the
acaricide (杀螨剂）periodically（定期）
.
Don’t let the healthy animals contact
with the carrying or infected animals
directly.