Zygomycotic lymphadenitis in slaughtered feedlot cattle

J. Ortega, Francisco A Uzal, R. Walker, Hailu Kinde, Santiago S Diab, F. Shahriar, R. Pamma, A. Eigenheer, D. H. Read

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


During the 12 months of 2006, zygomycotic lymphadenitis was diagnosed in 194 of 198 feedlot steers (0.04% of cattle slaughtered during that period) in a California slaughterhouse as part of bovine tuberculosis surveillance. Mesenteric lymph nodes were involved in 190 cases. Affected lymph nodes were enlarged (2 to 42 cm in greatest dimension), firm, and mottled gray-white to yellow with multiple granular or caseocalcareous foci. Histologically, nodal architecture was effaced by necrosis, granulomatous inflammation, and fibrosis. In approximately 20% of the cases, granulomas were mainly restricted to subcapsular sinuses and afferent lymphatic vessels, causing granulomatous lymphangitis. Nonseptate, irregularly branching hyphae with nonparallel walls and bulbous enlargements were common in necrotic areas and within the cytoplasm of multinucleated giant cells. Fungal cultures were performed on 124 affected lymph nodes using 7 media, but no zygomycetes were cultured. Fungal DNA was amplified from 20 lymph nodes. Amplicons from 16 nodes had nearly 100% homology with sequences for Rhizomucor pusillus; 4 amplicons had (> 98%) homology with Absidia corymbifera sequences. Zygomycosis should be considered in the differential diagnosis for granulomatous lymphadenitis in feedlot steers.

Original languageEnglish (US)
Pages (from-to)108-115
Number of pages8
JournalVeterinary Pathology
Issue number1
StatePublished - 2010


  • Absidia corymbifera
  • Bovine
  • Lymphadenitis
  • Mucormycosis
  • Rhizomucor pusillus
  • Zygomycosis

ASJC Scopus subject areas

  • veterinary(all)


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