Dermatophytosis

Question 1

What is the likely organism implicated if calves present with dermatophytosis (ringworm)?

Answer 1

Trichophyton verrucosum

Question 2

What is the likely organism implicated if horses present with dermatophytosis (ringworm)?

Answer 2

Trichophyton equinum

Question 3

What is the likely organism implicated if cats present with dermatophytosis (ringworm)?

Answer 3

Microsporum canis

Question 4

How does dermatophytosis typically present?

Answer 4

• Patchy (focal/multifocal) alopecia/broken hairs
• Scale
• Crust
• ± Erythema
• ± Pruritus
• Occasionally furunculosis
• Lesions frequently occur at the site of abrasion

Question 5

Which animals does dermatophytosis typically affect? What is notable about this disease?

Answer 5

• Affects young/naïve animals in particular
• Very common, highly transmissible (direct and indirect)
• Zoonotic!

Question 6

How severe is dermatophytosis in calves?

Answer 6

• Generally its effect is not severe
• It may cause ill-thrifter hide damage if pruritic

Question 7

What is important to remember about horses with dermatophytosis?

Answer 7

Competition animals are subject to restrictions and are unable to compete

Question 8

What are the treatment/control options for calves with dermatophytosis?

Answer 8

• Isolation is often ineffective due to spores in the environment
• Often not treated if mild: natural immunity developing and UV exposure can resolve clinical signs (may take 4-9months)
  
  • The animals remain a source of infection in the mean time
• Emphasise improving underlying health and turnout for UV exposure
• Treatment if required: enilconazole rinses (may appear ineffective as you aren’t treating the whole animal)

Question 8

How to prevent ringworm in calves?

Answer 8

• Best preventative = optimising general health
• Routine good environmental hygiene
• Can vaccinate: Bovilis Ringvac = attenuated non-pathogenic strain from 2 weeks of age if needed

Question 9

What are the challenges with treatment/control of ringworm?

Answer 9

• Arthrospores may remain active in the environment for years
• Animals may remain mycologically infected after appearing grossly cured

Question 10

What are the treatment/control measures needed for equine ringworm?

Answer 10

• Isolate
• Environmental/fomite cleaning: remove organic matter and use suitable disinfectant
• Use enilconazole rinse on the animal for 3 days. Remove crusts and treat the whole horse/the wide surrounding area
• Can use chlorhexidine/miconazole shampoo off-label
• If untreated, will last 1-3 months if the animal has a good immune system

Question 11

How should you prevent equine ringworm?

Answer 11

• Routine good hygiene
• Avoid sharing fomites (tack, rugs, grooming equipment, buckets)

Question 12

What are the challenges of treating ringworm in a cattery/rescue environment?

Answer 12

• Resources (physical/financial) may not be available for treatment
• Multiple animals are often housed together
• Treatment of feral cats is not practical
• There is an ongoing risk from new entries to the shelter

Question 13

How to prevent ringworm in a cattery/rescue setting?

Answer 13

• Continue screening measures for new entries
• Routine good environmental hygiene

Question 14

How to treat a cat with ringworm?

Answer 14

• Daily treatment with anti fungal drug e.g. itraconazole
• Repeated application of anti fungal wash e.g. miconazole
• Ongoing environmental cleaning
• Ongoing monitoring of treatment

To prevent spread to others, house affected cats long-term in a dedicated treatment area.