psoroptes communis( 痒螨 ) presenter: 王燕 presenter: 王燕 members ： members ：...
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Introduction Species of the genus Psoroptes ()(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:Distinguish beween male and female The male tritonymph is singigicantly larger than the protonymph and has five pairs of metapodosomal setae rather than three.In addition ,male tritonymphs have two pairs of cuticular pits on the central metapodosoma 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 Both female nymphal stages possess dorsoposterior tubercles ,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 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
LesionsIntense itchInflammation and thickening and trichomadesis of skinEmaciation
Life cycleThe 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 non-burrowing mites,it has piercing and chewing mouthparts which can severely damage the skin.
symptoms1intense itch( The most common signs are scratching of the ears,whining), rubbing( of the face, scars behind the ears from scratching, shaking of the head
2Inflammation and thickening and trichomadesis of skin( Reddish-brown to black discharge (crusts and cerumen) in the ears that resemble coffee grounds Bleeding from the ear Odour 3Emaciation()
DiagnosedDiagnosis is based on clinical symptoms as described above. Final diagnosis :1direct examination of the ears with a magnifying glass.
Diagnosed2microscopic examination of the ear dischargeSuperficial scraping it is used to collect scale or crust for the detection of the parasites that normally inhabit the stratum corneum(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, covered with a coverslips, and examined under a microscopy .
Psoroptes communis is a widespread endoparasites (.Animals can be infected by direct contact( or indirect contact with a infected host.Definite host:a variety of animals, including swine ,cattle ,goat ,horse , poultry ,cats and dogs ,etc.
TreatmentClean the dirt and crusta (with warm soup water first.(Macrolides insecticide)(Ivermectin)(Doramectin) Formamidine insecticide(Amitraz) Organophosphorus insecticide(Dipterex)(Propetamphos)(Diazinon)Pyrethroid insectide(Deltamethrin)Ivermectin).
Prevention Improvement of management ,especially keep the site dry and aired.Kill the acarus(of the environment by spraying the acaricide (periodically.Dont let the healthy animals contact with the carrying or infected animals directly.