Infectious disease in shelters and foster homes: ringworm

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Infectious disease in shelters and foster homes
ringworm

• Kate F. Hurley, DVM, MPVM
• Shelter Medicine Program
• Center for Companion Animal Health
• University of California, Davis
• www.sheltermedicine.com

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What is different about managing ringworm in a
population?

• Screening is a big deal a missed lesion can be
  very, very costly
• Treatment has to be effective it must work fast
  and protect the environment
• Confirmation of cure is critical a missed
  fungus can be very, very costly
• Decontamination must be successful future
  exposure of naïve cats is inevitable

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Why does it matter so much?

• Human health risk ethical, P.R. and liability
  issue
• Treatment is relatively expensive, labor
  intensive and prolonged
• Long term contamination can cripple a shelter or
  foster home

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Time costs
Which one is easier to find a home for?
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Time costs
What happens when all the cages are full?
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The bottom line

• We need to keep ringworm from getting in to
  feline populations
• If it gets in, we need to deal with it as rapidly
  and effectively as possible while protecting the
  rest of the population
• We need to keep ringworm from getting out to
  adopters homes

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Who are the players?

• M. canis
• Greater zoonotic potential
• Much more readily spread
• Trichophyton mentagrophytes
• M. gyspeum

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What pre-disposes to ringworm?

• Being a kitten
• Compromised skin
• Trauma, allergies, parasites, matting
• Poor grooming habits
• Long hair, stress, matted hair coat, URI,
  e-collar
• Compromised immune system
• FeLV, FIV, steroids, pregnancy
• High risk environment

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Sitting duck
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Classic presentations
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What else does it look like?

• Focal or multifocal
• Milliary Dermatitis
• Eosinophilic Plaques
• Indolent Lip Ulcers
• Pinnae Alopecia
• Chin acne
• Paronychia
• Stud tail
• Granulomatous lesions

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What else does it look like?

• Over-grooming
• Shedding
• Hair loss
• Pruritus (or not)
• Crusting and Scaling
• Erythema
• Comedones

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Woods lamp
Dang!
Dang!!

• Correct wavelength
• Plug-in, not battery
• Dark room
• Ideally
• 10 minute warm up
• 5 minute exam
• Positive very suspicious
• Watch out for tetracyline, KMR, others
• Negative Not ruled out

Busted!
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Fungal culture why?

• Screening tool
• For all?
• Lesions and high risk?
• Diagnostic tool
• Treatment guidance
• Confirmation of cure
• Confirmation of cleaning

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In-house fungal culture

• Cost effective
• Allows earlier diagnosis
• Allows assessment of degree of infection
• Allows creative culturing of environment

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Fungal culture collection

• Wipe cat with damp cloth to remove coat
  contaminants
• Fresh toothbrush in package
• Pluck 2nd choice for suspect lesions
• At least 30 strokes
• Especially face, inside pinnae, around nail beds,
  lesions
• Swiffer? for environment
• Cut into small sections, wipe until visibly dirty
• Individual labeled baggies if multiple samples
• Avoid heat exposure during transport

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Fungal culture details

• Room temperature media
• Plate style preferred
• Press firmly but not so much that culture is
  disrupted
• Press Swiffer? firmly numerous times
• Incubate at 75º- 85º F in the dark with humidity
  source
• Examine daily until growth or for 21 days
• Most M. canis will grow within 10 days
  tentative negative at that point

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Identification

• False negatives and positives possible with red
  color change
• Tape prep
• Lactophenol blue on slide
• Tape on colony
• Tape on slide
• Resources for microscopic ID

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Definitive diagnosis
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Risk assessment for exposed

• Baseline sanitation level?
• Degree of exposure?
• Evidence of spread?
• Ideally toothbrush culture all at risk
• Pathogen score to identify treatment candidates

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P Score 1 Less than four colonies

• Probable environmental contamination
• Careful exam
• Repeat culture
• Lime sulfur dip
• Probably okay to place for adoption while
  awaiting second culture results

Dust Mop Syndrome
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P score 2 4-9 colonies

• Super careful visual and Woods lamp exam
• Inside pinnae, face, chin, tail, top and bottom
  of feet
• If suspect lesions, treat as infected
• If not, re-culture, dip and go as with P score
  of 1
• Hold until 2nd culture negative to be extra
  careful

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P score 3 initiate treatment for sure
RATS!
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Lime sulfur dip

• Top priority in order to reduce environmental
  contamination
• Sufficient as sole treatment in many cases
• Optimally, combine with systemic

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Lime sulfur details

• Use 8 concentration
• Twice weekly if at all possible
• Okay in pregnant and nursing cats, kittens gt 2-3
  weeks old
• Wipe nursing moms, keep kittens warm
• E-collar afterward may not be necessary

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Lime sulfur application

• Do not pre-wet
• Pesticide sprayer
• Powder first, then water
• Keep close to cat
• Or, hold by feet and dunk
• Sponge dip on face, nose and ears

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The prophylactic dunk
For my own good, you say?
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Systemic treatment

• Speeds recovery in all
• Itraconazole drug of choice
• Fluconazole 2nd choice (10 mgs/kg)
• Terbinafine (Lamasil?) works but is costly and
  may require higher than published dose
• Higher risk and/or less effective Griseofulvin
  and ketoconazole

Especially important for generalized ringworm or
immunosuppressed
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Itraconazole

• Get compounded, divide into capsules, or mix into
  food or butter
• OK in kittens gt 3 weeks
• Remember to adjust dose as kittens grow
• Avoid in pregnant queens
• Adverse effects GI, hepatoxicity

100 mg capsules being split into 4 25 mg capsules
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To clip or not to clip?

• Usually not necessary may temporarily worsen
  lesions
• Consider in nursing moms, long haired, unkempt,
  unable to groom, or coat that is unmanageable
  after dipping
• Be careful to avoid clipper burn
• Bag hair and dont use the surgery clippers!

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Some things not to use

• Ineffective
• Lufenuron
• Chlorhexidine alone
• Locally applied topical ointments
• Potentially toxic
• Ketoconazole in cats
• Not legal
• Enilconazole

Alas, not the magic bullet
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Verifying cure

• Effective treatment fungal cure prior to
  clinical cure
• Ineffective treatment clinical cure prior to
  fungal cure
• Bottom line need to verify fungal cure
• 3 consecutive negative cultures, one week apart
  (can use only 2 if treat with lime sulfur plus
  itraconazole)
• Begin after week one of treatment

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Infection control during treatment

• Immediate dip to reduce risk
• In home, limit access until 2 weeks treatment
• Isolation and cat-hair control
• Separate clothing, supplies
• Daily bedding wash in hot water, bleach, dryer
• Written directions in shelter

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What kills ringworm?

• Bleach 110
• Clean surface
• Repeated twice
• High heat (gt 110º F)
• Commercial steam cleaner
• Commercial dish washer
• Dryer
• Hot car
• Dry environment and sunlight helps

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What doesnt kill ringworm?

• Chlorhexidine
• Quaternary ammonium compounds
• Potassium peroxymonosulfate (Trifectant?,
  Virkon-S?)
• Povidone-iodine
• Time

Whats on your exam tables?
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Environmental cure 5 Ds

• Diagnose
• Recognize and treat infected and carrier animals
  and humans
• Discard
• Toss heavily exposed items
• Debulk
• Careful mechanical cleaning
• Disinfect
• Bleach 1.5 cups per gallon
• Document
• Environmental culture

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Thank you!
And many thanks to the Shelter Medicine
Dermatology Project, a partnership between the
Dane County Humane Society and the University of
Wisconsin - School of Veterinary Medicine
Dermatology Research Laboratory