Psoroptes communisPsoroptes communis(( 痒螨痒螨 ))

Presenter:Presenter: 王燕王燕 MembersMembers ：： 程家玲，蒋皓敏，刘静，宋子嫦程家玲，蒋皓敏，刘静，宋子嫦From Class 3From Class 3

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)

MorphologyMorphology

MorphologyMorphology::

Distinguish beween male and femaleDistinguish 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 stageMorphology of larval stage

protonymph of protonymph of Psoroptes(Male)Psoroptes(Male)

protonymph of protonymph of Psoroptes(female)Psoroptes(female)

Distinguish beween male and female Distinguish beween male and female

Both female nymphal stages possess Both female nymphal stages possess dorsoposterior tuberclesdorsoposterior tubercles （结核结节） （结核结节） ,but the ,but the potonymph is significantly smaller than the potonymph is significantly smaller than the tritonymph .In addition,the protonymph possesses tritonymph .In addition,the protonymph possesses three pairs of metapodosomal setae rather than three pairs of metapodosomal setae rather than five,one pair of cuticular pits rather than two ,and five,one pair of cuticular pits rather than two ,and a pulvillus on leg IV which is the absent in the a pulvillus on leg IV which is the absent in the female tritonymph.The presence of dorsoposterior female tritonymph.The presence of dorsoposterior tubercles enables the female nymphs the be tubercles enables the female nymphs the be distinguished easily from the males.By distinguished easily from the males.By contrast,distinguishing between the nymphal contrast,distinguishing between the nymphal stages of the same sex relies on the identification stages of the same sex relies on the identification of both the number of metapodosomal setae of both the number of metapodosomal setae （刚（刚毛）毛） and cuticular pits .These descriptions are used and cuticular pits .These descriptions are used to produce a key,which allows the various stages to produce a key,which allows the various stages of both sexes to be distingushed.of both sexes to be distingushed.

tritonymph of tritonymph of PsoroptesPsoroptes

adult of adult of PsoroptesPsoroptes

LesionsLesions （病变）（病变） Intense itchIntense itch Inflammation and thickening and Inflammation and thickening and

trichomadesis of skintrichomadesis of skin EmaciationEmaciation

Life cycleLife cycle

The female lays about 90 The female lays about 90 eggs during her lifetime of eggs during her lifetime of 4-6 weeks,and 4-6 weeks,and development from the development from the egg,through the larval and egg,through the larval and nymphal stages to mature nymphal stages to mature adult,takes about ten adult,takes about ten days.the greater days.the greater pathogenicity of this mite pathogenicity of this mite is attributable to the fact is attributable to the fact that unlike most non-that unlike most non-burrowing mites,it has burrowing mites,it has piercing and chewing piercing and chewing mouthparts which can mouthparts which can severely damage the skin.severely damage the skin.

symptomssymptoms

11 、、 intense itch(intense itch( 剧痒）剧痒） The most common signs are scratching of the The most common signs are scratching of the

ears,whiningears,whining （哀鸣（哀鸣 ), rubbing(), rubbing( 磨蹭） 磨蹭） of the face, of the face, scars behind the ears from scratching, shaking of scars behind the ears from scratching, shaking of the head the head

22 、、 Inflammation and thickening and Inflammation and thickening and trichomadesis of skin(trichomadesis of skin( 皮肤发炎、增厚和患部脱毛）皮肤发炎、增厚和患部脱毛）

Reddish-brown to black discharge (crusts Reddish-brown to black discharge (crusts 痂皮痂皮 and and cerumen) in the ears that resemble coffee groundscerumen) in the ears that resemble coffee grounds沉积物 沉积物

Bleeding from the ear Bleeding from the ear OdourOdour （臭气） （臭气） 33 、、 Emaciation(Emaciation( 消瘦消瘦 )) 由于发痒病蓄终日烦躁不安影响采食和休息由于发痒病蓄终日烦躁不安影响采食和休息

DiagnosedDiagnosed

Diagnosis is based on clinical symptoms as Diagnosis is based on clinical symptoms as described above.described above. 初步诊断初步诊断

Final diagnosis :Final diagnosis :

11 、、 direct examination of the ears with a direct examination of the ears with a magnifying glassmagnifying glass. .

DiagnosedDiagnosed

22 、、 microscopic examination of the ear microscopic examination of the ear dischargedischarge

Superficial scrapingSuperficial scraping

it is used to collect scale or crustit is used to collect scale or crust （痂皮） （痂皮） for the detection of the for the detection of the

parasites that normally inhabit the stratum corneum(parasites that normally inhabit the stratum corneum( 角质层）。角质层）。 Deep scrapingDeep scraping this technique is used to demonstrate follicular mitesthis technique is used to demonstrate follicular mites It is also important to scrape the skin until true capillary bleeding is elicited.It is also important to scrape the skin until true capillary bleeding is elicited.

The obtained material was placed on a The obtained material was placed on a microscope slidemicroscope slide （载玻片）（载玻片） , covered with a , covered with a coverslipscoverslips （盖玻片）（盖玻片） , and examined under a , and examined under a microscopy .microscopy .

EpidemiologyEpidemiology

Psoroptes communis is a widespreadPsoroptes communis is a widespread（世界性分布） （世界性分布） endoparasites (endoparasites ( 外寄生外寄生虫）虫） ..

Animals can be infected by direct Animals can be infected by direct contact(contact( 直接接触） 直接接触） or indirect or indirect contact with a infected host.contact with a infected host.

Definite host:a variety of animals, Definite host:a variety of animals, including swine ,cattle ,goat ,horse , including swine ,cattle ,goat ,horse , poultry ,cats and dogs ,etc.poultry ,cats and dogs ,etc.

TreatmentTreatment Clean the dirtClean the dirt （污垢） （污垢） and crusta (and crusta ( 痂痂

皮）皮） with warm soup water first.with warm soup water first. 大环内酯类杀虫剂大环内酯类杀虫剂 (Macrolides insecticide)(Macrolides insecticide) 。。如如

用伊维菌素用伊维菌素 (Ivermectin)(Ivermectin) 或多拉菌素或多拉菌素 (Doramectin)(Doramectin) 进行进行皮下或肌肉注射。皮下或肌肉注射。

甲脒杀虫剂类（甲脒杀虫剂类（ Formamidine insecticideFormamidine insecticide ）。）。如用双甲脒如用双甲脒 (Amitraz) (Amitraz) 进行药浴或涂擦。进行药浴或涂擦。

有机磷类杀虫剂（有机磷类杀虫剂（ Organophosphorus Organophosphorus insecticideinsecticide ）。）。如敌百虫如敌百虫 (Dipterex)(Dipterex) 、巴胺磷、巴胺磷(Propetamphos)(Propetamphos) 、地亚农、地亚农 (Diazinon)(Diazinon) 等进行药浴，涂擦等进行药浴，涂擦或喷洒环境。或喷洒环境。

拟除虫菊酯类杀虫剂（拟除虫菊酯类杀虫剂（ Pyrethroid insectidePyrethroid insectide ）。）。如溴氰菊酯如溴氰菊酯 (Deltamethrin)(Deltamethrin) 、戊酸氰菊酯等药浴或涂擦。、戊酸氰菊酯等药浴或涂擦。

伊维菌素（伊维菌素（ Ivermectin).Ivermectin).

Prevention Prevention

Improvement of Improvement of management ,especially keep the site management ,especially keep the site dry and aired.dry and aired.

Kill the acarus(Kill the acarus( 螨虫）螨虫） of the of the environment by spraying the acaricide environment by spraying the acaricide (( 杀螨剂）杀螨剂） periodicallyperiodically （定期）（定期） ..

Don’t let the healthy animals contact Don’t let the healthy animals contact with the carrying or infected animals with the carrying or infected animals directlydirectly..