First report of Dermatophilus congolensis infection in native Omani cattle.

Skin lesions were reported in a group of quarantined Omani native cattle for exportation purpose during January 2018. The skin lesions were reported in 17 animals out of 140 and were scattered over the head, neck, back and perineal region of the animals. Lesions varied from paint-brush matted hairs to wart-like lesions that are up to 2 cm in diameter. Skin scraping samples were obtained from the living animals and were directly stained with gram stain. Histologically, there was severe multifocal exudative dermatitis with hyperkeratosis. Dermis was infiltrated with neutrophils, mononuclear cells, and numerous branching filaments coccoid bodies. Bacterial culture on sheep blood agar revealed gray to white, beta hemolytic, raised and irregularly shaped colonies. Gram staining showed gram positive branching filaments with both transverse and longitudinal fragments formed from packs of coccoid cells confined with Dermatophilus congolensis . Animals were treated successfully with 3 doses of intra muscular injection of long-acting oxytetracycline with topical application of antibiotic spray. To the best of our knowledge, this is the first report of dermatophilosis in Omani cattle.