An atypical case of respiratory actinobacillosis in a cow

Surgical treatment of bovine nasal granuloma and an allergological exploration

Nasal granuloma in cattle results from inflammation within, and attendant proliferation of, the nasal mucosa possibly in response to an allergic response. However, the relationship between nasal granuloma and allergies remains unclear. Furthermore, severe cases have a poor prognosis because there is currently no effective treatment. Herein, we report three cases of nasal granuloma with severe stertorous breathing that were treated surgically. We also conducted an allergological exploration. Following surgical removal clinical signs did not recur in two of the three cases; however, stertorous breathing persisted in one case, and the cow was sacrificed 4 months later. A histopathological examination revealed that all nasal granulomas featured varying infiltrations of macrophages eosinophils, mast cells, and lymphocytes. The number of mast cells and the proportion of these cells that had degranulated were significantly higher in the granulomas than in normal nasal mucosae. In addition, serum histamine levels were higher in nasal granuloma cases than in normal cows, although serum immunoglobulin E levels were similar, and lymphocyte infiltration in the submucosal layer suggested type I and type IV allergies. Collectively, the results indicate the efficacy of complete surgical curettage for the treatment of allergic nasal granuloma in cattle. Further studies are required to identify the causes and risk factors of allergic nasal granuloma in cows.

Diverse strains of Actinobacillus lignieresii isolated from clinically affected cattle in a geographically restricted area

OBJECTIVE

To investigate whether an outbreak of Actinobacillus lignieresii was caused by one or multiple strains.

METHODS

Nine isolates of A. lignieresii were obtained from the lymph nodes of 15 affected cattle from two farms to determine whether a single strain was involved. An enterobacterial repetitive insertion consensus sequence (ERIC) PCR was used for genotyping, and the repeats-in-toxin genes were analysed by PCR and sequencing.

RESULTS

Isolates from the two farms belonged to two and three genotypes, with a total of four genotypes detected. Genes of the apxICABD operons of some strains had deletions in the apxIA (~697 bp) and in the apxID (~187 bp) genes. The toxin gene deletions and the ERIC PCR patterns suggested the involvement of different A. lignieresii genotypes.

CONCLUSION

There was no evidence that a unique genotype was associated with actinobacillosis on the two farms, confirming that this disease was associated with other contributing factors.

Natural lymphatic ("atypical") actinobacillosis in cattle caused by Actinobacillus lignieresii

Bovine actinobacillosis is typically characterized by pyogranulomatous glossitis (wooden tongue). The involvement of other tissues, generally the skin or lymph nodes, has been regarded as atypical or cutaneous. We describe herein 2 outbreaks of actinobacillosis affecting primarily the lymph nodes of the head and neck. The disease affected 40 of 540 lactating cows in a dairy herd, and 5 of 335 two-y-old steers in a beef herd. Multiple or single, occasionally ulcerated nodules were observed in the region of the mandible, neck, and shoulder, including the parotid, submandibular, retropharyngeal, and prescapular lymph nodes. The histologic lesions were multifocal pyogranulomatous lymphadenitis, dermatitis, and cellulitis with Splendore-Hoeppli material. One steer had an exophytic pyogranuloma in the gingiva and another died because of ruminal tympany secondary to oropharyngeal and esophageal obstruction by a pyogranulomatous mass. Actinobacillus lignieresii was isolated from the lesions and identified by amplification, sequencing, and analysis of the 16S ribosomal (r)DNA gene. Seven of 8 cows recovered after treatment with sodium iodide. Lymphatic actinobacillosis is a frequent disease in Uruguay, southern Brazil, and Argentina. Morbidity is 1-50%; mortality is <1%. A. lignieresii apparently penetrates the intact oral and pharyngeal mucosa, infecting primarily the regional lymph nodes. Later, lesions may extend to the subcutaneous tissue and the skin, causing ulceration. Affected cattle with draining pyogranulomas contaminate the environment, favoring disease transmission, and should be treated with sodium iodide or antibiotics and isolated from the herd in order to control the disease.

Multifocal suppurative granuloma caused by Actinobacillus lignieresii in the peritoneum of a beef steer

An imported crossbred Angus beef steer aged eight to twelve months died suddenly on the eighth day of a quarantine period in Japan. Gross examination showed the peritoneum and mesentery consisted of numerous nodules of various sizes. Histological examination revealed chronic suppurative granulomatous peritonitis with eosinophilic rosettes surrounding colonies of Gram-negative bacilli. The bacteria isolated from the nodules were confirmed to be Actinobacillus lignieresii based on the results of 16S rRNA gene sequencing and immunohistochemistry. Antibiotic sensitivity testing showed that the isolate was resistant to penicillin. Thus, a diagnosis of atypical actinobacillosis caused by A. lignieresii was made.