Horse + LA Infectious dz (NAVDF Layne, Rosenkrantz) Flashcards
“Summer rash”
“Saddle sores”
“Sweating eczema”
Staphylococcal folliculitis
More common in summer; in areas that tack rubs
What can owners do to minimize risk of Staph infection
Rinse/bathe horses after being worked
Most common Staphylococcus species in horse pyodera
S. aureus
Staph species you may find in horse pyoderma
*S. aureus
*S pseudintermedius
*S hyicus hyicus
*S delphini
Staph species on healthy horse skin
CoNS
*S xylosus
*S lentus
*S epidermidiis
*S hemolyticus
*S capitis
*S sciuri
Most common MRSA lineages in horses
CC398 is increasing prevalence –> from equine hospitals!
(also common in swine)
CC8 is decreasing prevalence
T or F: humans with MRSA often have CC398 (equine hospital type)
False. Rarely causes infections in humans
T or F: Epidermic human MRSA from human hospitals has been found to cause nosocomial infections in horses (ST22, ST225)
True
Risk factors for MRSA in horses
*Hospitalization
*Preventative penicillin use
*Ceftiofur
*Aminoglycosides
*Exposure to previously colonized horses
*Antibiotics within 30 days
*Admission to neonatal ICU, hospital
Main antibiotic used for MRSA in horses
TMS, then doxycycline
Main antibiotics for MSSA in horses
Procaine penicillin, gentamicin, ceftoifur, cephalexin, chloramphenicol, rifampin
T or F: empiric enrofloxacin is a fair choice for horse pyoderma
False. Likely to induce resistance, MRSA
Most common species of Staphylococcal pyoderma in food animals
S aureus
Staphylococcus isolated from goat skin
S aureus
S hemolyticus
S warneri
S epidermidis
S chromogenes
S caprae
S hyicus
Staphylococcus isolated from cow skin
S aureus
S chromogenes
S hyicus
Staphylococcus isolated from sheep skin
S aureus
S xylosus
S epidermidis
Staphylococcus isolated from pig skin
S aureus
S hyicus
S chromogenes
S sciuri
What bacteria are considered normal commensals in most food animals
S aureus
S hyicus
Most common colonization sites of staphylococcus in food animals
Udders, tears, nasal/oral/perineal mucous membranes
Primary causes for secondary bacterial infections in food animals
*Stress from parturition/lactation
*Poor nutrition
*Overcrowding
*Transport
*Poor hygiene
*Coarse feed or bedding
*External, Internal parasitism
*Systemic illness
Which food animal more commonly develops impetigo
Dairy cows– as lesions are most common on tears/udder.
Milking equipment, lack of sanitization = predisposing factors
Predisposing factors for impetigo Staph pyoderma in dairy cows
Milking equipment, lack of sanitization
Where is impetigo staph pyoderma most common on the body of large animals
Teats/udders
Can impetigo on teats lead to mammillitis or mastitis?
Debatable
Where is folliculitis most common on farm animals
Anywhere, but sparsely haired regions are more common
-Periocular
-Muzzle
-Ventral abdomen
-Medial thighs
“Udder rot”
“Udder cleft dermatitis”
“Flexural, udder seborrhea”
“Necrotic dermatitis”
Udder dermatitis 2’ Fusobacterium, Trueperella, Treponemes»_space; Staphylococcus
NOT usually 2’ Staphylococcus, but clinically overlaps with Staph intertrigo.
Are small or large animal veterinary staff more likely to be nasal carriers of MRSA
Large animal
T or F: food animals are a reservoir of MRSA for human infection
True.
Zoonosis to hand dermatitis on dairy workers, skin wounds on pig farmers
What is the Sequence Type of MRSA that is associated with swine»_space; calves, chicken, dogs, horses, pigs, rats, humans
ST 398
Relatively non-host specific
Topical therapies for superficial, local pyoderma in food animals
*Chlorhexidine
*Povidone-iodine
Concern with systemic antibiotics in food animals
Legal issues if going into food supply
Base on C&S if you are going to do this
Other name for “Greasy pig disease”
Exudative epidermitis
Age of pigs with EE
Suckling or recently weaned pigs. Age 4 days to 6 weeks
T or F: Most cases of EE are severe
False. Usually mild. But CAN have extensive morbidity/mortality
Body regions on piglets where EE begins
Axillae, groin
Reddish/copper skin discoloration w/ thin scales
Then pustules on lips, nose, tongue, coronary band
Progresses to widespread greasy brown exudate w/oral erosions and ulcers
Clinical lesions of exudative epidermitis in piglets, advanced disease
*Widespread greasy brown exudate
*Oral erosions and ulcers
*Coronary band, heel erosions/ulcers
What sign of acantholysis will be present on abdominal skin
Positive Nikolsky sign
What non-cutaneous sign can be caused by Staphylococcus hyicus in pigs
Septic arthritis
Cause of death from exudative epidermitis in piglets
Anorexia, dehydration
Lesions are PAINFUL (not pruritic. Not pyrexic)
Exfoliative toxins that cause exudative epidermitis
*Exh A, B, C, D
*SHETA, SHETB
Target of Exh A, B, C, D & SHETA, SHETB
DSG-1
–> acantholytic kertinocytes
Digest it DSG-1. Similar to Scalded Skin Syndrome in humans
T or F: Staphylococcus hyicus is a commensal in pig skin
True.
Abrasions/trauma or co-infection with Porcine Circovirus type 2 or porcine parvovirus may predispose piglet to EE
Predisposing factors of piglets to EE
*Abrasions/trauma
*Co-infection with Porcine Circovirus type 2 or porcine parvovirus
Reportable vesicular lesions in pigs DDx
*Foot and mouth disease
*Swine vesicular disease
*Vesicular stomatitis
*Vesicular exanthema
Which antibiotics are Staphylococcus hyicus commonly resistant to
*Ceftiofur (71%)
*Penicillin G (97%)
How is exudative epidermitis best managed
Prevention: hygiene husbandry, no crowding, needle teeth
Treatment: Topical and systemic help. Use C&S
Erysipelothrix rhusiopathiae (shape, gram, O2)
Gram positive
Facultative anaerobic
Rod
Where in the body is Erysipelothrix rhusiopathiae a commensal bacteria on many mammals
Oral, tonsillar
(Outdoor, unvaccinated pigs»_space; dog, marine mammals)
3 forms of Erysipelothrix rhusiopathiae
1) Subacute = classic diamond skin disease
-Erythematous papules, wheals on throat, neck, pinnae, abdomen, thighs –> rhomboid plaques –> necrotic in center
2) Acute = fever, lameness, anorexia + purpural skin discoloration of jowls, abdomen, pinnae, legs
3) Chronic = ulceration, necrosis of pinnae, tail, feet
Clinical lesions of classic diamond skin disease
-Erythematous papules, wheals on throat, neck, pinnae, abdomen, thighs –> rhomboid plaques –> necrotic in center
Erysipelothrix rhusiopathiae
Differential for Erysipelothrix rhusiopathiae
Actinobacillus suis
What is the issue with culturing Erysipelothrix rhusiopathiae
It is slow growing– so may need PCR
Treatment for Erysipelothrix rhusiopathiae
Ampicillin, amoxicillin
FQs in small animals
T or F: Erysipelothrix rhusiopathiae is zoonotic
TRUE
Human infections are minor, self limiting. Bright red/purple swellings on hands/fingers where they touched the animal
How to prevent Erysipelothrix rhusiopathiae
Commercial vaccine available
Dermatophilus congolensis (shape, gram, O2)
Gram positive
Facultative anaerobe cocci actinomycete
TWO MORPHOLOGIES!
1) Filamentous hyphae
2) Motile zoospores
How do Dermatophilus congolensis hyphae branch
Both transverse and longitudinal separation –> packets of coccoid cells, aka Railroad tracks!
What is the infectious stage of Dermatophilus congolensis
Ovoid Zoospores!!
“Rain rot”
“Rain scald”
“Mud fever”
“Lumpy wool”
“Strawberry foot rot”
“Strerothricosis”
Causative agent
Dermatophilus congolensis
Strawberry foot rot can also be Parapox virus in sheep
Transmission of Dermatophilus congolensis
Infected crusts in the environment
Also insect bites
Climate that facilitates Dermatophilus congolensis
Warm, humid environments
Animals most likely to be affected by Dermatophilus congolensis
*Horses
*Cattle
*Sheep
*Goats
*Camelids
LESS likely to affect swine (housed inside)
Clinical lesions of Dermatophilus congolensis
“Paintbrush crusts”: large crusts containing exudated matted hairs with thick purulent green underlying debris
Tufted papules, pustules
If severe: Edema, fever, lymphadenopathy
How to get a cytology sample of dry Dermatophilus congolensis
*Soak crust in saline, mince with a scalpel, spread on a slide and let it dry
Concern with culturing Dermatophilus congolensis
*Needs carbon dioxide
*Slow growth
Treatment Dermatophilus congolensis
*Move to dry pasture, or shelter from rain
*Remove crusts (careful of environmental contamination)
*Topical: lime sulfur, chlorhexidine
*TMS, penicillins
T or F: Dermatophilus congolensis is zoonotic
TRUE
Lesions on humans’ hands, arms. Painful erythematous papules/nodules
Causes of abscesses in large animals
*Corynebacterium pseudotuberculosis
*Actinomyces bovis
*Actinobacillus ligieresii
*Atypical mycobacteria
*Truperella pyogenic
*Nocardia
*Streptococcus
*Fusobacterium
Corynebacterium pseudotuberculosis (shape, gram, O2)
Gram positive
Facultative anaerobe
Coccoid, club, or rod shapes (single or clusters)
Few in number
Cause of caseous lymphadenitis in small ruminants and cattle
Corynebacterium pseudotuberculosis
Cause of ulcerative lymphangitis in small ruminants, cattle, horses
Corynebacterium pseudotuberculosis
Clinical signs of Corynebacterium pseudotuberculosis
SC nodules, granulomas, draining abscesses
Occur at site of wound, fly strike, moisture
Vector of Corynebacterium pseudotuberculosis
Fly strike, wound, excess moisture
Cause of “Lumpy Jaw”
Actinomyces bovis
Cause of Actinomyces bovis
Oral trauma –> firm swelling over mandible
Clinical signs of Actinomyces bovis
Nodule over mandible –> ulcerates, drains
May contain “sulfur granules” = white/yellow granules
Which ruminant bacteria can cause white/yellow sulfur granules
Actinomyces bovis (Lumpy jaw)
Also Actinobacillus lignieressi (wooden tongue)
Actinomyces bovis (shape, gram, O2)
Gram positive
Anaerobe!
Filaments, V/Y/T forms
Diagnosis of Actinomyces bovis
Anaerobic culture for a long time (slow growth)
Histopath of Actinomyces bovis
Splendore-Hoeppli (brightly eosinophilic aggregates in a capsule) with internal mycelial fragments, rosette of peripheral club-shaped structures. Held together by protein-polysaccharide capsule (prevents phagocytosis)
Causative agent of “Wooden Tongue”
Actinobacillus lignieresii
T or F: Actinobacillus lignieresii is an oral/rumen commensal
True
What is the most common clinical presentation of Actinobacillus lignieresii
Firm, ulcerated nodules/abscesses in the mouth, jaw, neck
Discharge “sulfur granules”
Actinobacillus lignieresii (shape, gram)
Gram negative
Coccobacillus, rod
Where do atypical mycobacteria come from
Environment
Infection is rare
Cause of atypical mycobacterial infection
Traumatic incolulation, host immunocompromise
Which species of mycobacteria can infect large animals
M kansaii
M ulcerans
Clinical lesions of atypical mycobacteria in food animals
SC nodules
Ulcerative lymphangitis
Swollen limb
Corded lymphatics
Diagnosis of atypical mycobacteria
Acid fast rods on cytology or histopath
Difficult to culture. PCR is good
+ on tuberculin test if affected
“Farcy” causative agent
Mycobacteria senegalese
In Africa, Asia, S America.
Systemic organ infection –> death
Most common dermatophyte in sheep, goats, cows, camelids
Trichophyton verrucosum
Most common dermatophyte in pigs
Nannizzia nanum (previously M nanum)
What needs to be added to DTM for Trichophyton verrucosum
Thiamine (100%), inositol (80%)
What needs to be added to DTM for Tricophyton equinum
Niacin
Who is this
Nannizia nanum (pigs)
T or F: dermatophyte vaccine exists for cows outside the USA
True
But disease usually self-limiting in 3-4 months for healthy cpws
Causative organism for Contagious Viral Pustular Dermatitis
Parapoxvirus
Orf
Contagious echthyma
Farmyard Pox
Species affected by Orf (parapoxvirus)
Sheep, goats, camelids
Age of animals affected by Orf (parapoxvirus)
Young. 2-4 months old
Self limiting. High morbidity, low mortality
How does Orf (parapoxvirus) spread
From skin abrasions on mouth
To teats when nursing
T or F: Orf (Parapoxvirus) is zoonotic
True
(Also, Pseudopox in cows causes Milkers Nodules. Orf looks similar. Depends on if contact is sheep vs cow!)
Cause for feline cowpox
“Cowpox”
Orthopoxvirus
Endemic in Europe, Asia
Reservoir for Cowpox
Rodents. Cats contract this from hunting rodents near cow farms. Resolves w/o treatment within 2 months.
Rarely causes disease in cattle. DOES cause disease in cats!, humans
Causative agent for teat fibropapilloma in cows
BPV-1
Causative agent for head/neck/shoulder fibropapilloma in cows
BPV-2
Causative agent for “atypical warts”. Flat. Do not regress. In cows
BPV-3
Causative agent for “Rice grain” warts on teats in cows. All ages. Do not regress
BPV-5
Causative agent for for branching warts on teats that leave ulcers underneath in cows
BPV-6
What is unique about BPV-4 and Brackenfern
Infection of brackenfern plant interacts with BPV-4, resulting in urinary cancer!
2 forms of ovine papillomavirus: age and body distribution for each
1) Filiform squamous papilloma: young sheep. lower legs
2) Fibropapillomavirus: Adult sheep. Face, pinnae, legs, teats.
Which ruminants are predisposed to Trichophyton verrucosum
-Indoor animals
-“Show” animals. “Club lamb fungus” bc 4H lambs get it more; handled more!
Colloquial names for Actinomyces vs Actinobacillus in cows
Actinomyces (gram +): lumpy jaw
Actinobacillus (gram -): wooden tongue
Which type of immune response can be detrimental to clearance of BOTH pythium and Leishmania
Th2
Where are the viral inclusions for Papillomavirus
Intracytoplasmic
(Also for herpes)
3 Oncogenes for Papillomavirus (and how they affect the immune system)
E5:
-Downregulate MHC cl I (immune evasion)
-Decreased gap junctions (KC separate from neighbors)
-Interacts with PDGF (more mitosis)
E6:
-Downregulate p53 (which usually holds cell cycle in G1-S)
E7:
-Cell transformation, pRb phosphorylation
Which Papillomavirus gene is the target of the SA vaccine
L1 (Capsid structure)
Causative agent of Equine Sarcoids
BPV1
BPV2
Causative agent of Feline Sarcoids
BPV14
Horses most likely to develop Dermatophytosis
Young or immunosuppressed
Hot, moist, humid environments
Season where Dermatophytosis is more common in horses
Fall/winter
Body region of Malassezia dermatitis in horses
*Caudal intermammary
*Tail head
*Prepuce
Most common Malassezia sp in Equines
*Malassezia furfur
*M slooffiae
*M obtusa
*M globosa
*M restricta
Swinepox vector
Haematopinus suis: ventrum, thighs, udder, teat, vulva
Mosquito: face, pinnae, dorsum
Bovine leukemia virus clinical signs
70% = asymptomatic
1-5% develop B cell lymphoma
Many have immunosuppression
Many have reduced milk production
EHV3 disease
Herpes Coital Exanthema
Ulcers –> smooth, white scars
Avoid breeding until clear (~3 weeks)
Cow with respiratory signs and pustular vulvovaginitis
BHV1
Infectious pustular vulvovaginitis or balanoposthitis
Are antivirals (acyclovir, famcyclovir) virocidal or virostatic
Virostatic
Only disinfectants are virocidal
MOA of acyclovir
Nucleoside analog. Replaces GTP in DNA synthesis
Herpesvirus specific
Adverse effects of acyclovir
Hepatotoxic, nephrotoxic (if pre-existing renal dz), bone marrow suppression
Cow
Causative agent?
Rice grain warts
BPV5
Cow
Causative agent?
BPV2
Neck, neck, shoulder fibropapilloma in young cows
Cow
Causative agent?
BPV3
Atypical warts. Any location, any age
Do not spontaneously regress
Cow
Causative agent?
BPV6
Conical papillomas on tears
Clinical signs of BPV 1
Fibropapilloma on teats, penis of young cows
What mediates regression of papillomavirus
T cell mediated
Antibodies help prevent recurrence, but do not clear active infection
Causative agent of equine aural plaques
Papillomavirus
Dyoita PV or Dyorho PV
(NOT the usual delta papillomavirus)
Benign, insect vector
Location of EcPV1 papillomas
Face, legs in young horses
Location of EcPV2 papillomas
Genital
Often progress to SCC
Equine sarcoid vector
Black fly vector
Equine sarcoid predisposed breeds
Quarter horse
Arabian
Appaloosa
Risk factor for equine sarcoid
Certain ELA haplotypes
Vesicular stomatitis vector
Insects: Black fly, Culicoides, Sandfly
Vesicular stomatitis clinical signs
Ulcers, vesicle –> lips, coronary band, teats
Equids»_space; bovine, camelid > Others
Risk factor for vesicular stomatitis
Close to H2O
(Insect vector)
T or F: Vesicular stomatitis is reportable
True. Can’t be clinically distinguished from Foot and Mouth disease
Zoonotic!
