Abstract
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A. Caseonecrotic bronchopneumonia
Mycoplasma bovis infection causes otitis media, caseonecrotic bronchopneumonia, polyarthritis, meningitis, keratoconjunctivitis, mastitis, and endocarditis in cattle. The lung lesions consist of a core of karyorrhectic debris surrounded by neutrophils, macrophages, lymphocytes, and fewer plasma cells (Figure 1). The natural source and route of infection are colostrum, milk, semen, intrauterine, or direct contact with infected individuals. In animals with compatible lesions, diagnosis can be based on microbial culture; however, because of the time-consuming and fastidious growth requirements, polymerase chain reaction, or immunohistochemistry are often preferred. This case was confirmed by bacterial culture of the lungs and tympanic bullae.
Reference:
Dudek K, Nicholas RAJ, Szacawa E, et al. Mycoplasma bovis infections-occurrence, diagnosis and control. Pathogens. 2020;
Contributor: Tatiane Terumi Negrão Watanabe, North Carolina State University
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C. Actinobacillus lignieresii
Actinobacillosis, also called wooden tongue, is caused by Actinobacillus lignieresii. A. lignieresii is part of the normal oral flora of cattle, sheep, and pigs. Entry of this bacterium into the glossal connective tissue usually occurs through traumatic erosions especially of the lingual groove. Many reports link erosions to coarse feed or grass awns. Grossly, the tongue is swollen and firm. On cut surface, minute nodular yellow to red “sulfur granules” are classically present. Microscopically, the tongue contains multifocal pyogranulomas centered on cores formed by gram-negative coccobacilli surrounded by Splendore-Hoeppli material (Figure 2). A. lignieresii may also cause lymphangitis and regional lymphadenitis.
Reference:
Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals (Vol. 2). 6th ed. St. Louis, MO: Elsevier; 2016:18–19.
Contributor: Kaylin McNulty, Mississippi State University
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C. High mountain disease
Histologic features of high mountain disease include hypertrophy of the tunica media, expansion of the tunica adventitia, and consequent pulmonary vessel narrowing. Pathophysiologically, hypoxia leads to pulmonary vasoconstriction in an attempt to shunt blood to aerated lung which chronically causes architectural changes to pulmonary vessels, pulmonary hypertension, and right ventricular hypertrophy. Right-sided heart failure often follows, with subsequent hepatic congestion and increased systemic venous hydrostatic pressure. Clinically, affected cattle exhibit jugular vein distention, dependent edema, lethargy, and cavitary effusions. Mitigation of this disease in herds at high elevations is accomplished through selective breeding and culling based on pulmonary arterial pressure testing.
Reference:
Robinson WF, Robinson NA. Cardiovascular system. In: Maxie MG. ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals (Vol. 3). 6th ed. St. Louis, MO: Elsevier; 2016:66.
Contributor: Alaina Kuehr, Colorado State University
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C. Sarcocystic myositis
Gross lesions of eosinophilic myositis, usually identified at the time of slaughter, are multifocal to diffuse green to gray-green discolorations of muscles with the involvement of a single or a group of striated muscles. Histologically, numerous eosinophils separate adjacent endomysial sheaths and perimysial trabeculae. Sometimes, a degenerative cyst of Sarcocystis sp. in the center of the lesion confirms the cause (Figure 4). Toxic and nutritional myopathies have multifocal to diffuse pale gross lesions, with histologic macrophage infiltration and, in the latter, mineralization and bilateral symmetry. Immune-mediated myositis histologically has lymphocytic infiltrate and visible muscle atrophy.
Reference:
Cooper BJ, Valentine BA. Muscle and tendon. In: Maxie MG. ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals (Vol. 1). 6th ed. St. Louis, MO: Elsevier; 2016:214–237.
Contributor: Šimun Naletilić, Croatian Veterinary Institute
Veterinary Pathology invites submission of exceptional gross or microscopic images for consideration as an Image Challenge, along with a multiple-choice question and answer. For details, see the Instructions to Authors on the journal website.
