An epidemiological survey on cattle ringworm in major dairy farms of Mashhad city, Eastern Iran

Background and Objectives: Cattle dermatophytosis (syn. cattle ringworm), an important skin infection, has received major consideration not only for economical losses in the animal breeding industry but also in regards to its zoonotic transmission to humans. For effective control measures, it is important to determine the disease prevalence in cattle herds. Materials and Methods: To determine ringworm prevalence, a total number of 3,540 cattle in different age groups at three major farms of Mashhad including Kenebist (KB) in the east, Mazraeh Nemooneh (MN) in the south, and Moghoofat Malek (MM) in the north-east were examined. Skin scrapings were prepared from all animals clinically suspected to have dermatophytosis. The samples were examined microscopically for fungal elements (hyphae and/or arthrospores) by adding potassium hydroxide (KOH) to samples. To isolate the etiologic dermatophytes, all samples were cultured on selective agar for pathogenic fungi medium for 4 weeks at room temperature. Results: Among 684 suspected cases (19.3%) selected from a total number of 3,540 cattle based on clinical signs, 604 cases (88.3%) were KOH positive in direct microscopy, while 490 cases (71.6%) were culture positive on selective agar for pathogenic fungi (SAPF) medium. The most frequent dermatophyte isolated was Trichophyton verrucosum (495 isolates accounting for 99% of total isolates) which was obtained from all culture positive cases except five cases (1.0%) infected with another dermatophyte named Trichophyton mentagrophytes. Conclusion: This work is the first comprehensive study on cattle ringworm in Iran. With respect to the high prevalence of cattle ringworm, particularly in young animals reported in the present study, effective management programs such as vaccination and improved hygiene are necessary for disease control in the herds.