Occurrence and Characteristics of Mycotic Agents Isolated from Skin Lesions of Trade Horses and Donkeys in Obollo-Afor, Enugu State, Nigeria

Abstract

This study was conducted to document the occurrence and characteristics of mycotic agents isolated from trade horses and donkeys in Obollo-Afor, Enugu State. A total of 497 horses and 65 donkeys presented for sale at Obollo-Afor horse/donkey market during the wet season (June to August 2014) and dry season (January to March 2015) were examined for skin lesions. For each horse/donkey examined, the location of skin lesion as well as the sex of the animal were recorded. Each skin lesion was disinfected with 70% ethanol and skin scrapings collected. Each sample was inoculated onto the surface of SDA plates containing 0.05mg/ml of chloramphenicol and 0.5mg/ml of cycloheximide. Inoculated plates were incubated at room temperature (27oC) for up to 4 weeks and examined daily for fungal growth. Laboratory identification of the fungal isolates was based on macroscopic and microscopic features. Wet mount preparations of fungal growth were examined for microscopic features of the isolates (presence, shape, arrangement and relative abundance of micro and macroconidia). The cultural and microscopic features of the fungi isolated were compared with those in the reference colour atlas. One hundred and fifty (30.18%) horses and 11 (16.92%) of the donkeys had skin lesions. Forty seven (9.5%) of the 497 horses and 2 (3.1%) of the 65 donkeys examined yielded fungal growth. Of the 150 horses with skin lesions, 87 horses had lesions on the dorsal trunk with 27 (31%) being positive for fungal isolation; 11(52.4%) of the 21 lesions on the head yielded fungal growth. Six (6.9%) of the 18 lesions on the hind limb were positive for fungal isolation while 2 (18.2%) of the 11 lesions on the forelimb yielded fungal growth. Fungal agents were isolated from one of the 3 lesions on the tail of the horses examined. No mycotic agent was isolated from the lesions located on the neck and ear of the horses. Fungi were isolated from 2 (18.2%) of the 11 donkeys with lesions on the dorsal trunk. Out of 97 male horses, 43 (44.3%) were positive for fungal isolation while 4 (7.5%) of the 53 female horses were positive. Fungi were isolated from none of the 8 males and 2 (66.7%) of the 3 female donkeys examined. There was a significant association (P>0.05) between sex and the prevalence of fungal isolation in both animal species. Fungi were isolated from 45 (32.1%) of the 140 horses with lesions observed during the wet season. Of the 10 horses with skin lesions recorded during the dry season, 2 (20%) were positive for fungal isolation. Fungi were isolated from 2 (20%) of the 10 donkeys with lesions observed during the wet season but from none that were observed during the dry season. There was also a significant association (P>0.05) between season and the prevalence of fungal isolation in horses but no significant association (P>0.05) in the donkeys. The fungi genera identified in order of descending rate of isolation were Aspergillus (24.5%), Trichophyton (14.3%), Microsporum (10.2%), Penicillium (8.2%), Curvularia (6.1%), Fusarium (4.1%) and Coccidoides (2%); 22.4% of the fungal isolates (moulds) were not identified. The fungal species identified include: Aspergillus niger (10.2%), Aspergillus fumigatus (8.2%), Aspergillus flavus (6.1%) and Fusarium subglutinans (4.1%). All the seven Trichophyton spp tested were resistant to fluconazole while none of them was resistant to voriconazole and nystatin. All the five isolates of Microsporum spp, 3 of Curvularia, 2 of Fusarium and 12 of Aspergillus were resistant to fluconazole while none of them was resistant to voriconazole and nystatin. The four isolates of Penicillium were all resistant to fluconazole, voriconazole and nystatin. This study revealed that a wide range of fluconazole resistant mycotic agents, covering all ecological groups infect horses and donkeys in the study area, all of them with the potential of being zoonotic. Preventive measures should be put in place by veterinarians and groups to mitigate the spread of the infectious agent.