Microsporumcanis
Microsporumcanisisafungalspeciesthatcausesnumerousformsofdisease.Itispartofagroupof
fungiknownasDermatophytes.Thoughmostlywellknownforringworminpetsandotheranimals,itis
alsoknowntoinfecthumans.Thisfactmakesthispathogenbothanthrophilicandzoophilicinnature.
Microsporumcanisisacommunicablepathogen.
Mycology
Microsporumcanisispartofafamilyoffungiknownasdermatophytes.Microscopically,ithasmulticelledsporesknownasmacroconidiawithroughthickwalls.Macroconidiaarecharacteristicallyspindle
shapedwith5-15cells.Onaculturemediumitgrowswhiteandcottonywithayellowperimeteranda
brightyelloworangeunderside.Itcanbefoundinavarietyofenvironmentsandsurviveforupto15
months.Itfeedsonthekeratinontheouterlayersofskin,hairandnails.Thenaturalreservoirof
Microsporumcanisisincatsanddogs.
ClinicalSigns
InfectionsinanimalsduetoMicrosporumcanismanifestasRingwormandcancauseascaly,
crustedrashthatmayappearasround,redpatchesontheskin.Othersymptomsandsignsofringworm
include:
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Patchesofhairloss
Scalingonthescalp
Itching
Blister-likelesions
EpidemiologyofTransmission
ThemainreservoirforMicrosporumcanisarecatsanddogs;however,itcanalsobetransmittedto
humansthroughdirectandindirectcontactwithanimalsandfomitessuchascombs,brushes,hats,
furniture,linensetc.Thegreatestriskfactorforacquiringinfectioniscontactwithdamagedcellson
skin,hairandnails.Microsporumcaniscaninfectallmammals.
TreatmentandControl
Treatmentofringwormdependsontheseverityoftheinfection.Aveterinarianmayprescribea
medicatedshampoo,ointmentoradiptokillthefungus.Insomecases,oralmedicationsarenecessary
tocureringworm.Inseverecases,itmaybenecessarytouseatopicalandoraltreatment,inadditionto
clippingawaythefur.Oncetreatmentbegins,lesionsshouldbegintohealinaboutonetothreeweeks.
Inorderpreventthespreadofinfectionviatheenvironmentorcontaminatedfomites,anEPAorHealth
Canadaapproveddisinfectantwithafungicidalclaimwillbeeffectiveatinactivatingfungalspores.
Directcontactwithinfectedanimalsandrelatedfomitesshouldbeminimized.Ifcontactwithinfected
areasofskinorinfectedanimalsisunavoidable,washhandsimmediatelyafterexposure.Wash/change
beddingasfrequentlyaspossibleasshedskinmayalsospreadinfection.Assoonasinfectionis
suspectedseekmedicalattention.
References
Ringworm,MedicineNet.com(2015).http://www.medicinenet.com/ringworm/article.htm
RingwormInfectionsinDogs,WebMD.http://pets.webmd.com/dogs/ringworm-infection-dogs
PreventionofFungalInfection.http://www.slideshare.net/icsp/prevention-of-fungal-infections
TheDermatophytes.ClinicalMicrobiologyReviews,p.240-259,vol.8,No.2Apr.1995.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC172857/pdf/080240.pdf
CDC-FungalDiseases.http://www.cdc.gov/fungal/
Epidermophytonfloccosum,Microsporumspp.,Trichophytonspp.http://www.phacaspc.gc.ca/labbio/res/psds-ftss/epidermophyton-eng.php
Microsporumcanis.
http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Dermatophytes/Microsporum/Micr
osporum_canis.html