Swine Skin Disease (PDF)

December 5, 2024 Swine skin disease Dorothy Debbie [email protected] 607-253-4017 C4 111 Vet Medical Center PollEv.com/dorothydebbie -or...

December 5, 2024 Swine skin disease Dorothy Debbie [email protected] 607-253-4017 C4 111 Vet Medical Center PollEv.com/dorothydebbie -or- text DOROTHYDEBBIE to 22333  Outline Characteristics microscopic appearance growth response to oxygen reservoir transmission Disease description Pathogenic mechanisms Diagnosis Treatment and Prevention Online pathology vignette  Learning Objectives 1. List common outcomes of infections in pigs by Staphylococcus hyicus, Erysipelothrix rhusiopathiae, and Microsporum nanum. 2. Describe how different virulence factors produced by these organisms: a. contribute to their ability to infect the host. b. contribute to damage resulting in disease. 3. List the samples needed for accurate diagnosis and any tests beyond standard culture methods needed for identification of these organisms. 4. List any issues relating to treatment of greasy pig, erysipelas, and ringworm in pigs. 5. Describe the main strategies to prevent greasy pig, erysipelas, and ringworm in pigs. *Note: Learning objectives generally describe the minimum knowledge needed to pass the course.  Staphylococcus hyicus Gram positive, facultative anaerobe, coccus, in clusters Part of the normal microbiota - skin, mucous membranes Transmission - direct or indirect contact Greasy pig disease, exudative epidermitis young pigs reddish or copper colored skin thin brown scales develop then become dark and greasy, peel off in scabs anorexia, dehydration, weakness, depression Greasy pig Courtesy Gordon Campbell  S. hyicus pathogenic mechanisms Newborn piglets colonized with bacteria from dam Avoid clearance Antiphagocytic capsule IgG binding protein inhibits opsonization by antibodies Produce toxins  S. hyicus pathogenic mechanisms Newborn piglets colonized with bacteria from dam Avoid clearance Produce toxins Exfoliative toxins cleave porcine desmoglein 1 cause intraepidermal cleavage plane exfoliative toxin cleaves porcine desmoglein 1 intraepidermal normal skin blisters J Dermatol Sc (2008) 49:21-31  S. hyicus pathogenic mechanisms Newborn piglets colonized with bacteria from dam Avoid clearance Produce toxins Exfoliative toxins cleave porcine desmoglein 1 cause intraepidermal cleavage plane outer skin layer lost bacteria spread in epidermis, induce inflammation piglets lose fluids through skin  S. hyicus diagnosis Based on clinical signs Culture of exudates, skin scrapings  S. hyicus treatment and prevention Antibiotic resistance is common Good hygienic practices Autogenous bacterins  Erysipelothrix rhusiopathiae Gram positive, facultative anaerobe, slender bacillus Normal microbiota - gastrointestinal tract, lymphoid tissues Pigs acquire organism by ingestion Erysipelas, diamond skin disease  Diamond skin disease Courtesy Bristol Biomedical Image Archive Courtesy Thomas Divers  Erysipelothrix rhusiopathiae Gram positive, facultative anaerobe, slender bacillus Normal microbiota - gastrointestinal tract, lymphoid tissues Pigs acquire organism by ingestion Erysipelas, diamond skin disease Acute septicemic disease Fever, anorexia, depression, vomiting, skin lesions Subacute disease Chronic disease Arthritis, vegetative endocarditis Zoonotic  E. rhusiopathiae pathogenic mechanisms Bacteria ingested Avoid clearance by host defenses adherence - multiple afimbrial adhesins inhibit complement deposition - capsule, cell surface protein facultative intracellular pathogen Produce neuraminidase  E. rhusiopathiae pathogenic mechanisms Bacteria ingested Avoid clearance by host defenses adherence - multiple afimbrial adhesins inhibit complement deposition - capsule, cell surface protein facultative intracellular pathogen Produce neuraminidase endothelial damage  E. rhusiopathiae diagnosis Culture of blood or skin lesions  E. rhusiopathiae treatment and prevention E. rhusiopathiae is naturally resistant to several antibiotics, penicillins are effective Modified live vaccines, bacterins  Microsporum nanum Obligate aerobic molds Macroconidia, microconidia formed off aerial hyphae in free-living form Arthroconidia in parasitic form Normal microbiota of soil Spread by contact Ringworm, tinea, dermatophytosis  Dermatophytoses Conidia germinate in host, mycelium grows along cornified epithelium, within hair Ectothrix - arthroconidia form on surface of hair Lesions remain superficial Erythema, pustules, scaling, crusting Self-limiting Zoonotic Ringworm lesion Courtesy Gordon Campbell  Dermatophyte pathogenic mechanisms Conidia enter through breaks in skin Adaptation to host environment adhere to stratum corneum germinate thermotolerance produce spreading factors - keratinases & other proteases Inflammatory response to fungus radiating from site of inoculation leads to characteristic ring-shaped lesion  Dermatophyte pathogenic mechanisms Conidia enter through breaks in skin Adaptation to host environment Inflammatory response to fungus radiating from site of inoculation leads to characteristic ring-shaped lesion  Dermatophyte diagnosis Examination of hairs and scales in mineral oil or treated with KOH for hyphae and arthroconidia Fungal culture – dermatophyte test medium (DTM), up to 3 weeks, characteristic macroconidia From Block IV labs  Dermatophyte treatment and prevention Topical antifungals Good sanitation  Summary Staphylococcus hyicus greasy pig in young piglets exfoliative toxins cause damage to skin leading to loss of outer layers dehydration due to fluid loss through skin Erysipelothrix rhusiopathiae erysipelas, diamond skin disease endothelial damage Microsporum nanum dermatophytes ringworm keratinases & other proteases