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    • Our results showed that the occurrence

    2018-10-25

    Our results showed that the occurrence of T. verrucosum pathogens was higher in cattle, followed by in sheep, and finally in goats. Accordingly, cattle could be considered as the main host for the circulation of T. verrucosum, playing an important role in the epidemiology of this dermatophytosis. Baxter and Rush-Munro stated that T. verrucosum pathogens were isolated from sheep and goats. Whereas the presence of sheep and/or goats with cattle may enhance the transmission of this pathogen, current results indicated that sheep could be considered more important in spreading the pathogen compared to goats. T. verrucosum is the main cause of ringworm in cattle worldwide and creates fasudil lesions in bovine species and humans. This mycosis may circulate between different species of ruminants, increasing the risk of the disease in exposed animals and/or humans. However, cattle are still considered the main reservoir of T. verrucosum. Furthermore, gathering of cattle with sheep and/or goats during rearing increases the threat of the occurrence of T. verrucosum in cattle significantly compared to the threat in cattle that were raised as a single species. In addition, inside mixed ruminant housing, the risk of contagion is increased due to backyard overcrowding and close contact with contaminated objects such as mangers and walls in addition to the diseased cases. In mixed backyards, small ruminants are set free and not tied, so they can move freely between the cattle and to different sections of the backyard due to their relatively small size. Furthermore, small ruminants chewing on feeds may provide the moisture that is needed to nurture the fungus and allow it to live in pens for prolonged periods. Also, the use of topping rams in breeding between different backyards may aid in the spreading of the disease. The risk of T. verrucosum was also increased significantly in humans in contact with mixed species of cattle, sheep, and goats, in comparison with those in contact with cattle reared as a single species. T. verrucosum pathogens may be transmitted to healthy humans through contact with diseased animals, producing inflammatory lesions in the exposed areas of the skin. This indicates an important association between T. verrucosum occurrence in the examined cattle and humans which was affected by the presence of mixed species of small ruminants. Our results indicated that the occurrence rate of T. verrucosum was increased in calves in all the examined groups. Aghamirian and Ghiasian recorded a high proportion of dermatophytoses in calves younger than 12 months. The pH value of the skin reduces with age; young animals are at greater risk due to the high pH of their skin in addition to their weak immunity. Calves are more sensitive to any stress and do not adapt well to environmental changes (heat stress and high humidity), prolonged transportation, and/or changes in diet. In addition, the present study pointed out the presence of unilateral lesions of tinea barbae on one side of the face and/or neck of humans that might turn toward the flank of the animal during the milking process. This might be a potential zoonotic pathway of T. verrucosum pathogens during contact between cattle and humans. Sabota et al found five cases of tinea barbae in human milkers due to T. verrucosum; all lesions were unilateral in the part of the face or neck that was rubbed against the cow during the course of milking. The results of this study pointed out the absence of tinea capitis or tinea pedis in the examined humans. Inversely, a previous study showed that one tinea cruris, six tinea corporis, two tinea pedis, one tinea unguium, and four tinea capitis cases in humans involved in dairy activities were positive for T. verrucosum. They isolated different dermatophyte species and strains from the examined patients, indicating that the reported occurrences of tinea capitis and tinea pedis may be due to the presence of mixed species and strains of tinea. In addition, the severity of the strain may affect the occurrence of a disease and its symptoms. Trichophyton rubrum, Trichophyton mentagrophytes var. interdigitalis, Epidermophyton floccosum, and Trichophyton tonsurans are the etiological pathogens responsible for tinea pedis. Therefore, T. verrucosum is not a common causative agent for tinea pedis. In addition, tinea capitis occurred only in children of school age, whereas adults and the elderly were rarely infected. Humans that tested positive were adults and elderly people, who were involved in rearing ruminants. Our results indicated a higher positivity of T. verrucosum pathogens in human males than in human females. In addition, in Australia, T. verrucosum was isolated from cases of tinea corporis, tinea faciei, and tinea capitis (17 males and 9 females).