Bacterial and fungal skin diseases

Question 1

What are some examples of mechanical skin defences?

Answer 1

keratinocytes, keratin layer, continuous renewal

Question 2

What are some examples of chemical skin defences?

Answer 2

antimicrobial compounds

Question 3

What are the two different things that can activate the innate immune system?

Answer 3

PAMPS and DAMPS

Question 4

What are PAMPS?

Answer 4

pathogen associated molecular patterns
(petidoglycan fragments, proteins, nucleic acids, cell wall lipids, carbs)

Question 5

What are DAMPS?

Answer 5

damage-associated molecular patterns such as-
stress-induced proteins
nuclear proteins

Question 6

What are some disease types associated with skin infections?

Answer 6

• Pruritis
• alopecia
• scaling
• pyoderma
• Erosions, Ulcers, Pigment Disorders, nodules and tumours, sinus tracts

Question 7

How does alopecia occur?

Answer 7

Bacteria colonise/ infect a hair follicle
The infection triggers an innate and adaptive immune response
* folliculitis
* damage to hair shafts
* atrophy

Question 8

What is pyoderma commonly caused by?

Answer 8

Staphylococci, Streptococci

Question 9

What are the two different types of pyoderma

Answer 9

Superficial and Deep

Question 10

What are some examples of deep pyoderma?

Answer 10

• subcut abscess
• cellulitis
• necrotising fascitis

Question 11

What are the two different types of staphyloccus?

Answer 11

• Coagulase negative
• Coagulase positive

Question 12

What are the key features of Group A streptococci

Answer 12

Aerobic/ Faculative anaerobic
Beta Haemolytic
Gram +
Catalase -
Oxidase +

Question 13

What are the key features of Erysipelothrix rhusiopathiae?

Answer 13

• Gram-Positive, Catalase Negative, Rod Shaped, Non-Spore forming,
• Produces H2S
• non-haemolytic

Question 14

Where is Erysipelothrix rhusiopathiae present?

Answer 14

It is present in tonsilar tissues and then shed in faeces

Question 15

What are the symptoms of Erysipelothrix rhusiopathiae?

Answer 15

Febrile episodes, diamond skin, painful joints, lethargy, distress
it is well detected in the acute phase but not so much in the chronic phase

Question 16

What is the first stage of a foot-rot infection?

Answer 16

• Begins with fusobacterium necrophorum
• this is a gram-negative rod shaped strict anerobe
• enters the foot through breakage or weakness of the skin surrounding the hoof

Question 17

What is the second stage of the two-step foot rot infection?

Answer 17

Dichelobacter nodosus
Gram-negative anerobe
Can be treated with antibiotics
initiates invasion of the hoof matrix

Question 18

What does the development of foot-rot lesions in production animals depend on?

Answer 18

• The presence of D.nodosus
• host susceptability
• environmental factors
• predisposing infection with any other bacteria between the claws

Question 19

What is Trychopython spp.

Answer 19

Common soil dermatophillic fungus
Rarely causes infection in man or animals
Readily isolated from the soil by hair-baiting
Cigar-shaped

Question 20

What is Microsporum Canis?

Answer 20

• Macronidia are abundant and thick-walled with many septa
• they are often hooked or curved at the end
• They are small and clavate

Question 21

What is the most common cattle dermatophyte?

Answer 21

Trichophyton verrucosum

Question 22

What are the clincial signs of Dermatophytosis in calves?

Answer 22

• nonpruritic lesions
• generalized skin disease may develop
• Lesions are characteristically discrete, scaling patches of hair loss with
  gray-white crust formation

Question 23

What are the most common causes of dermatophytes in dogs?

Answer 23

• Microsporum canis
• M. gypseum
• Trichophyton
  mentagrophytes

Question 24

What dermatophyte is always in cats?

Answer 24

• Microsporum canis

Question 25

What are the clinical signs of dermatophytes in dogs and cats?

Answer 25

* Dogs- alopecia, scaly patches, broken hair, * Cats- focal alopecia, scaling, crusting around the ears, face or extremities

Question 26

What are the primary dermatophytes in horses

Answer 26

Trichophyton equinum and T. mentagrophytes

Question 27

What are the clinical signs of dermatophytes in horses?

Answer 27

alopecia, erythema, scaling and crusting especially around the saddle

Question 28

What are the common dermatophytes of pigs?

Answer 28

usually Microsporum nanum, often asymptomatic, not zoonotic

Question 29

What are the common dermatophytes in sheep/ goats?

Answer 29

M. canis, M. gypseum, T. verrucosum

Question 30

What two things determine the severity of ringworm/ dermatophytes?

Answer 30

* Strains or species of fungus involved * Sensitivity of the host to a particular pathogenic fungus

Question 31

What are some of the treatments of dermatophytes?

Answer 31

* hair plucks/ coat brushing * fungal hyphae * antifungals * Dip or shampoo * hair clipping

Question 32

What causes deep necrotising fascitis?

Answer 32

Streptococcus canis

Question 33

What causes the strep A pathology?

Answer 33

* Toxin and aggresin production * Hyaluronidase * Erythogenic toxin * DNAse * Exotoxins

Question 34

How would you treat Erysipelothrix rhusiopathiae?

Answer 34

Penicillin or Tetracycline

Question 35

Where is fusobacterium necrophorum usually found?

Answer 35

Found in the environment and the alimentary tract

Question 36

How does fusobacterium necrophorum enter the foot?

Answer 36

Through breakness or weakness of the skin surrounding the hoof

Question 37

What is trychopython spp?

Answer 37

* Common soil dermatophillic fungus * rarely causes infection in man or animals * readily isolated from the soil by hair baiting * Cigar-shaped macroconidia with smooth ends

Question 38

What are microsporum canis?

Answer 38

* abundant, thick-walled, with many septa * hooked or curved at the ends * small and clavate

Question 39

What is the most common dermatophye of cattle?

Answer 39

Trichophyton verrucosum

Question 40

What does trichophyton verrycosum in cows cause?

Answer 40

* nonpruritic lesions * generalised skin disease may develop * lesions are characteristically discrete, scaling patches of hair loss with gray-white crust formation

Question 41

How would you treat trichophyton verrycosum in cows?

Answer 41

Topical treatment and a vaccination

Question 42

What are the clinical signs of a dermatophyte in dogs?

Answer 42

* alopecia, scaly patches * regional or generalised folliculitis

Question 43

What are the clinical signs of a dermatophyte in cats?

Answer 43

* Focal alopecia, scaling * Crusting around the ears, face or extremities

Question 44

What are the clinical signs of dermatophytes in horses?

Answer 44

One or more patches of alopecia/ erythema, especially in the saddle and girth areas transmission via direct contact and grooming equiment

Question 45

How would you diagnose a dermatophyte?

Answer 45

* Hair plucks, Coat-Brushing, UV lamp * Looking for hyphal fungae

Question 46

How could you treat a dermatophyte?

Answer 46

* Antifungals * Dips/ Shampoo * Cliping of hair * Keeping animals in isolation * Can be zoonotic

Question 47

What are the usual clinical signs of malassezia?

Answer 47

* Erythema, Pruritis * Alopecia * It is usually secondary to an underlying disease

Question 48

What causes sporotrichosis?

Answer 48

Sporothrix schenckii

Question 49

What are the three most common portals of entry for an environmental fungal organism?

Answer 49

* Primary mycoses -> respiratory portal * Subccut -> inculated skin * Cutaneous and superficial -> contamination of the skins surface