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43 Cards in this Set
- Front
- Back
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What is the causative agent of Lumpy Jaw? |
Actinomyces bovis (and Actinomyces viscosus) |
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Describe the lesion caused by Actinomyces bovis. |
Localized pyogranulomatous infection, usually in the jaw. Causes proliferation of connective tissue, usually with several abscesses. Also causes osteomyelitis. |
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Describe the pathogenesis of Actinomyces bovis. |
Bacterium gains entry via a break in the oral mucosa, usually by trauma from sharp items in feed, dental disease, or tooth eruption. Invasion > granulomatous abscesses > osteomyelitis NO spread to regional LNs |
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What are the clinical signs of actinomycosis? |
Hard, immovable, bony mass (Usually on the horizontal ramus of the mandible) Early: painless Progression: becomes painful, due to misaligned teeth and difficult mastication Loss of body condition Swelling may break and discharge (sticky honey fluid with sulfur granules) |
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What are some differential diagnoses for a swollen jaw on a cow? |
Wooden tongue Abscess/foreign body Osteomyelitis (other organisms) Tooth root abscess Fracture Tumour |
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How do you diagnose actinomycosis? |
Smear of exudate (gram-positive club-shaped rods and colonies) (Difficult to culture) |
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How can you treat actinomycosis? What's the prognosis? |
Tx: Sodium iodide IV with concurrent antibacterial therapy (penicillin, LA oxytetra) Note: don't treat late preg cows! Prog: depends on chronicity and extent. Moderate/good prognosis to arrest progression, but unlikely to resolve lesion (the bone is all holey!) |
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How can you control actinomycosis? |
Avoid mucosal trauma If outbreak, examine forage or pasture for traumatic items > softer diet |
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What causes Wooden Tongue? |
Actinobacillus lignieresii |
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Describe the pathogenesis of Actinobacillus lignieresii. |
Gains entry via a break in the mucosa (usually trauma, foreign material, teeth) Results in granulomatous abscesses Often spread to regional lymph nodes (unlike Actinomycosis). |
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What are the clinical signs of Wooden Tongue? |
1. Glossal actinobacillosis (most common) - dysorexia, salivation, chewing, difficult prehension, swollen, hard tongue 2. Cutaneous actinobacillosis - swellings on external nares, cheeks, skin, eyelids, etc 3. Lymphadenitis - enlargement of the submaxillary, parotid, or retropharyngeal nodes |
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How can you diagnose actinobacillosis? |
Smear of exudate - gram negative club-like rosettes Full thickness excision biopsy - will see multiple abscesses in the deep dermis with distinct club-rosette Bacterial culture |
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How can you treat actinobacillosis? What's the prognosis? |
Prognosis is good if treated on time, and usually permanent. Tx: sodium iodide IV with concurrent antibacterial therapy (streptomycin, LA oxytetra, sulfonamide) |
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What are some differences between lumpy jaw and wooden tongue? |
Regional lymph node involvement (yes in WT, no in LJ) Response to tx (permanent in WT, lesions remain in LJ) Gram staining (WT = g-, LJ = g+) Organism (obviously) (WT = Actinobacillus lignieresii, LJ = Actinomyces bovis) Location of lesion (sometimes) (WT usually tongue, if on jaw it is moveable masses. LJ is immobile masses on jaw.) |
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What is the most common organism causing ringworm in cattle? |
Trychophyton verrucosum (Also often T. mentagrophytes) |
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Describe the epidemiology of ringworm. |
Zoonotic - affects all species Contagious via direct and indirect contact, so can have an "outbreak" Nutritional status of host plays a role Common in young animals in an indoors group (eg post-weaned calves) Fungal spores can remain viable for years |
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Describe the pathogenesis of ringworm. |
Fungus attacks keratinized tissues, usually the stratum corneum and hair fiber. Results in exudation and alopecia. |
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What are the clinical signs of ringworm? |
Heavy, grey-white crust raised above the skin Roughly circular lesions (2-3cm or larger) Non-pruritic Usually on head, neck, perineum |
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What's your main (broad) differential for ringworm? How can you diagnose ringworm? |
Ddx: sarcoptic, chorioptic, or psoroptic mange (but they'll be pruritic!) Dx: See spore and mycelia in skin scraping or fungal culture (often not done in cattle) |
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How can you treat ringworm? |
Spontaneous recovery in 2-4 months (questionable efficacy) debridement; copper, iodine, other solutions (do not recommend systemic treatment) |
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How can you control and prevent ringworm? |
Isolate affected animals Clean environment Adequate nutrition (supplement with Vit A) (Vxs available elsewhere) |
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What causes cow warts? |
Bovine papillomavirus Note: 10 different ones identified, each with a different site of predilection (eg esophagus, cutaneous) |
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Describe the epidemiology of bovine papillomavirus. |
Transmission by direct contact or fomite Mostly in young animals (6mo - 2yrs) but risk of teat warts (BPV-1) increases with age |
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What is the pathogenesis seen with papillomatosis? |
Benign hyperproliferative lesions of the epithelium and underlying dermis |
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What are the clinical signs of bovine papillomatosis? |
Grey-white, hairless, dry, raised or pedunculated lesions May have few or a large, coalescing mass of warts |
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How can you diagnose papillomatosis? |
Usually by clinical examination only Can perform biopsy DNA analysis for virus ID |
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How can you treat bovine papillomatosis? What's the prognosis? |
Prognosis is good - usually spontaneously regress. Typically no treatment required; can crush or pinch off. Surgical removal/cryosurgery (esp if on teats or penis) Vaccine available - may speed regression/recovery |
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How can you prevent and control papillomatosis? |
Segregate affected animals Discard/disinfect contaminated equipment Vaccines are available, but depend on virus type |
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What causes pinkeye? What's the other name for pinkeye? |
Moraxella bovis Disease also known as infectious bovine keratoconjunctivitis |
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Describe the epidemiology of infectious bovine keratoconjunctivitis. |
Endemic and/or epidemic Young cattle most susceptible Transmission by flies or fomites Exposure to ultraviolet light or dust results in increased susceptibility |
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Describe the pathogenesis of Moraxella bovis. |
Bacterium attaches to corneal epithelium and causes corneal ulceration via cytotoxins. Corneal ulcer progresses to corneal edema and corneal neovascularization. |
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How can you diagnose Moraxella bovis? |
Fluorescein for corneal ulcer Culture (improve sensitivity by hydrating swab with sterile water) |
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Describe the prognosis and treatment for Moraxella bovis. |
Prognosis: often self-limiting, and prognosis is good if treated on time (less chance of scarring) Tx: systemic treatment is best. Topical not recommended, subconjunctival less effective than systemic. Temporarily suture third eyelid across the globe for several days (tarsorrhaphy) in advanced cases. |
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What drugs can you use to systemically treat for Moraxella bovis? |
Tulathromycin Oxytetracycline Florfenicol |
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How can you control and prevent pinkeye? |
Control the fly population (long-acting insecticides) Provide shade Avoid corneal irritation Segregate affected animals Vx - available, but not necessarily effective |
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What's the other name for cancer eye? What causes it? |
Bovine ocular squamous cell carcinoma Would you believe it's caused by... cancer?!?!? Neoplasm of the conjunctiva or cornea |
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Describe the epidemiology of bovine ocular squamous cell carcinoma. |
One of the most common bovine neoplasms. More common in beef (sunlight exposure) and white-faced cattle with unpigmented faces (especially Herefords). Usually in animals greater than 5yo |
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What are the steps in the pathogenesis of cancer eye? |
1. Plaque 2. Keratoma 3. Papilloma 4. Squamous cell carcinoma Steps 1-3 are nonmalignant. |
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Describe the clinical signs of cancer eye. |
Invasive - involves entire orbit and local soft tissue and bone. Foul-smelling with necrosis. Metastatic - involves nearby lymph node (parotid) and viscera. Occurs later in course of disease. |
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How can you confirm diagnosis of cancer eye? |
Biopsy Can differentiate one of the benign precursors from the malignant carcinoma. |
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What's the prognosis of cancer eye? |
Steps 1-3 (nonmalignant) - up to 80% spontaneously regress. Step 4 (malignant) - rarely regresses; metastasis is unlikely (higher if eyelid), but third eyelid lesions are more likely to aggressively invade orbit and bone. Recurrence after excision is common. |
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How can you treat cancer eye? |
Superficial keratectomy; dissection of tissue with 2-3mm margin. Excision of the lesion (eyelid) Enucleation (more advanced lesions) |
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How can you control and prevent cancer eye? |
Select for animals with periocular pigment. Don't breed affected animals! Moderately heritable. Provide shade. |
