Signalment:  

3-7-year-old Texas Longhorn Bull (Bos texanus)This bull is from an Amish dairy farm with approximately 15 Texas Longhorns. The bulls were bred in Ohio and moved to New York. Currently, they are kept on a separate but nearby pasture from where the diary cattle are kept. The owner feeds "good quality" hay but not ad lib and it is unknown if grain is fed. The owner does not vaccinate the dairy cattle. The bulls vaccination history is unknown. The owner reported that five bulls had died in the previous month. In February of 2008, the referring veterinarian performed a field necropsy on the most recently deceased animals and submitted tissues to Cornell University for histopathological evaluation. Because of ambient conditions, the tissues were partially frozen at the time of necropsy and fixation.

Gross Description:  

The referring veterinarian could not perform a complete field necropsy since the carcasses were partially frozen. Both bulls were in poor body condition with a lack of perirenal and cardiac adipose tissue. Ruminal content consisted of a normal quantity of fiber and some stones. The feces were solid, and a small to moderate number of non-specified parasites were seen on fecal examination. Buccal and lingual ulcers were present in one animal, and the other animal had reddened Peyer's patches.

Histopathologic Description:

Tongue: Skeletal muscle fibers are disrupted by multiple variably sized coalescing nodules composed of central aggregates of hyperesoinophilic, radiating, club-shaped hylanized material (Splendore-Hoeppli material) that often contain moderate numbers of cocco-bacilli and a thin peripheral rim of densely basophilic granular material (mineral) (Fig. 1-1). These nodules are surrounded by concentric layers of degenerate neutrophils admixed with a moderate amount of pale eosinophilic fibrillar material (fibrin) and macrophages with occasional Langerhans type multinucleated giant cells. Dissecting between the remaining myofibers and the inflammatory foci are dense bundles of collagen and regularly arranged fibroblasts admixed with moderate numbers of lymphocytes and plasma cells. The remaining myofibers are often hyperesoinophilic with floccular cytoplasm and lack cross striations (degeneration). There are multiple ulcers of the lingual epithelium and there are several dense intraepithelial aggregates of degenerate neutrophils, acantholytic keratinocytes, and nuclear debris (microabcesses).

Grams stain of the tongue: There are moderate numbers of Gram negative cocco-bacilli within the Splendore-Hoeppli material.

Morphologic Diagnosis:  

Tongue: Severe, multifocal to coalescing, chronic, pyogranulomatous glossitis with Splendore-Hoeppli material, mineralization, intralesional bacteria, fibrosis, ulceration and myonecrosis (-�-�Wooden Tongue)

Lab Results:  

Virus FA results for Bovine Viral Diarrhea virus was negative

Condition:  

Actinobacillus lignieresi

Contributor Comment:  

Wooden tongue, or actinobacillosis, is caused by the bacteria Actinobacillus lignieresii. This bacterium has been isolated in a variety of species. The organism is ubiquitous and causes sporadic disease of primarily of cattle, sheep, and goats. Since the organism is a commensal of the oral cavity in ruminants, development of disease is most frequently associated with damage to the oral mucosa. In cattle, the tongue is the most common site of infection and thought to be associated with their use of the tongue to prehend food. Comparatively, sheep, which use their lips to prehend food, most frequently have lesions associated with their lips and cheeks. The bacterium has also been isolated from the rumen.(6)

Clinically, affected animals present with weight loss and hypersalivation. This is due to the extensive destruction of the tongue and oral tissues. Gross lesions commonly manifest as variably sized, hard, circumscribed nodules that measure up to several millimeters in diameter. These nodules are most commonly found in the tissues and skin of the face, and can progress to form soft abscesses which can fistulate and discharge through the mouth or skin. The discharged purulent material is odorless and contains abundant granules.(6) This infection induces in the tongue a severe fibroblastic response causing it to become large and immobile making chewing and swallowing difficult. This hardening of the tongue is the genesis of the common name of the disease wooden tongue. The formation of granulation tissue within the fibrous connective tissue gives the nodular appearance to these lesions. Additionally, small yellow foci (sulfur granules) can often be seen within the dense granulation tissue. These represent the bacterial colonies within the lesion.

Oral infection with A. lignieresii will commonly spread via lymphatics to local lymph nodes. Infections are less commonly found in the forestomachs, lungs, skin and uterus.(4) Grossly, infected lymph nodes contain yellow-orange granulomatous nodules which frequently project above the normal nodal capsular contour and are surrounded by sclerosing inflammation.(2) Affected lymphatics are diffusely thickened with similar nodules.(2) The most commonly affected lymph nodes are the retropharyngeal and submaxillary nodes.

Histologically, these nodular lesions consist of multiple pyogranulomas surrounding aggregates of Gram negative cocco-bacilli embedded in homogenous eosinophilic material. The hypereosinophilic material along with the bacteria forms the club-shaped microcolonies which is characteristic of this disease.(6) These formations are thought to be associated with immune complex deposition.(2) Surrounding the central area of bacteria is a band of inflammatory cells composed predominantly of neutrophils with macrophages and occasional giant cells. The external layer of the pyogranuloma consists of a dense layer of fibrous connective tissue containing variable numbers of lymphocytes and plasma cells. These lesions are often concurrently infected with Actinomyces pyogenes, Streptococcus spp., and Pseudomonas aeruginosa.(4)

A. lignieresii has been isolated from laboratory rodents associated with middle ear infections and conjunctivitis (5) and from healthy and diseased horses.(3) There is one report of the bacteria being isolated from a horse with an enlarged tongue.(1) In swine it is seen as granulomas or abscesses of the teats associated with wounds from the sharp teeth of suckling piglets. In horses this bacteria infrequently causes lower airway disease and abscess.(4)

The most important differential diagnoses for actinobacillosis include Actinomyces bovis, Staphylococcus aureus (botryomycosis) and Mycobacterium bovis. A. bovis also contains sulfur granules within discharge. However, infections with this agent tend to be associated with infection of bone, in particular the mandible.(4) In addition, A. bovis is a Gram positive filamentous organism, and this infection does not consistently spread to local lymph nodes. Botryomycosis classically has chronic granulomas with centers of numerous Gram positive cocci embedded in a homogenous matrix and the purulent material associated with this infection has botryomycotic granules.(4)

JPC Diagnosis:  

Tongue: Glossitis, pyogranulomatous, multifocal to coalescing, severe with Splendore-Hoeppli material, fibrosis, myocyte degeneration, necrosis, and loss

Conference Comment:  

The contributor provided an excellent review of this entity. 

Splendore-Hoeppli material is intensely eosinophilic, club-shaped material that radiates around certain fungi, bacteria, parasites and biologically inert substances such as suture. The material is generally composed of antigen-antibody complexes, debris and fibrin.(7) The most common infections and conditions that result in the Splendore-Hoeppli phenomenon include botryomycosis, Nocardia sp., Actinomyces sp., and feline dermatophytic pseudomycetomas.(7) It has also been reported with Pythium insidiosum, Sporothrix schenckii, Candida albicans, Aspergillus sp., and zygomycetes such as Conidiobolus sp. and Basidiobolus sp., Coccidioides immitis, nematodes, schistosomiasis, and hypereosinophilic syndrome.(7)

The presence of the Splendore-Hoeppli material led to a discussion of antigen-antibody complexes. Deposition of immune complexes causes tissue damage primarily by activation of the complement cascade and activation of neutrophils and macrophages through their Fc receptors.(8) Immune complexes also cause platelet aggregation and activation of Hageman factor which lead to microthombi formation and kinin activation. Activated complement produces chemotactic factors such as C5a which recruits macrophages and neutrophils, and anaphylatoxins such as C3a and C5a which increase vascular permeability.(8) The leukocytes are activated by binding of their C3b and Fc receptors by the immune complexes. Activated leukocytes release prostaglandins, chemotactic substances, oxygen free radicals, and lysosomal enzymes that include proteases capable of digesting collagen.(8)

References:

1. Baum KH, Shin SJ, Rebhun WC, Patten VH: Isolation of Actinobacillus lignieresii from a horse with an enlarged tongue. Journal of the American Veterinary Association, 185:792-793, 1984
2. Brown CC, Baker DC, Barker IK: Alimentary system. In: Pathology of Domestic Animals, ed. Maxie MG, 5th ed., vol. 2, pp. 20-21. Elsevier Saunders, Philadelphia, PA, 2007
3. Christensen H, Bisgaard M, Angen, O, Olsen JE: Final classification of Bisgaard taxon 9 as Actinobacillus arthritidis sp. nov. and recognition of a novel genomospecies for equine strains of Actinobacillus lignieresii. International Journal of Systematic and Evolutionary Microbiology 52:1239-1246, 2002
4. Henton MM, Van Der Lugt JJ: Actinobacillus Infections in Infectious Diseases of Livestock, eds. Coetzer JAW, Tustin, RC, 2nd ed., vol. 3, pp. 1648-1651 Oxford University Press, Cape Town South Africa, 2004
5. Lentsch RH, Wagner JE: Isolation of Actinobacillus lignieresii and Actinobacillus equuli from Laboratory Rodents. Journal of Clinical Microbiology 2:351-354, 1980
6. Rycroft AN, Garside LH: Actinobacillus species and their role in disease. The Veterinary Journal 159:18-36, 2000
7. Hussein MR: Mucocutaneous Splendore-Hoeppli phenomenon. Journal of Cutaneous Pathology 35:979-988, 2008
8. Abbas AK: Diseases of immunity. In: Pathological Basis of Disease, eds. Kumar V, Abbas AK, Fausto N, 7th ed., pp. 213-214. Elsevier Saunders, Philadelphia, PA, 2005

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1-1. Tongue, ox.

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