*1,2Mba, A. N., and 3Ekwealor, I. A.
1Department of Microbiology and Parasitology, David Umahi Federal University of Health Sciences, Uburu, Ebonyi State, Nigeria
2International Institute for Infectious Diseases, Biosafety and Biosecurity Research, David Umahi Federal University of Health Sciences, Uburu, Ebonyi State, Nigeria.
3Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Awka, Nigeria
*Correspondence to: tonia762013@gmail.com; +2348035082191; ORCID: https://orcid.org/0000–0001–8409–8559
Abstract:
Background: Poultry farm workers, often exposed to fungal-laden environments, are at heightened risk of ocular mycoses, which is a potentially blinding infection that warrants urgent attention and investigation. This study investigates the fungal load and pathogenicity of fungal isolates from ten selected poultry farms in Anambra State, southeast Nigeria, and their potential to cause ocular mycoses in a murine model, simulating occupational exposure.
Methodology: A total of 300 environmental samples (droppings, feed, and litter) from 10 randomly selected poultry farms in 6 local government areas of Anambra State, southeast Nigeria, were examined. Fungal loads were determined, and isolates were characterized macroscopically, microscopically using needle mount and slide culture technique, and genetically using DNA sequencing and Basic Local Alignment Search Tool (BLAST) analysis. Pathogenicity testing of the characterized isolates was conducted in a murine model, wherein 30 albino mice, randomly divided into 6 groups of 5 mice each (with one group as uninfected control), were topically inoculated with 1ml of fungal inoculum (approximately 1×106 spores/ml) directly into the eyes, and monitored twice daily for clinical signs and histopathological changes in the eyes for a period of 10 days. Data analysis was done using ANOVA in SPSS software version 21.0.
Results: The mean fungal loads in the environmental samples significantly differs (p<0.05) between dry and rainy seasons. The mean fungal loads (spore forming unit/g) during the rainy season ranged from 1.5×104 2.0×105 sfu/g in droppings, 1.1×104 – ‘too numerous to count’ (TNTC) in litter samples, and 9.5×103 – 2.10×105 sfu/g in feed samples. The mean fungal loads during the dry season in droppings, litter, and feed samples ranged from 1.2×104 – TNTC, 2.2×104 -9.5×104, and 6.0×103 -1.7×105 sfu/g, respectively. Fifteen genera of fungi were identified, with yeast being the most prevalent during the dry season and Aspergillus species during the rainy season. Pathogenicity testing showed significant differences (p<0.05) between the different fungi-induced ocular lesions in the experimental mice, with Aspergillus tubingensis and Curvularia verruculosa causing the most frequent and severe histopathological changes that included mild to severe erythema, blood congestion, distorted cornea, iris, and ciliary body, and sloughing off of the sclera.
Conclusion: The prevalence of fungi isolates is high in the farms. Due to the pathological changes produced in the eyes of infected experimental mice, ocular exposure to fungi may pose significant health risks to poultry farm workers in Anambra State. This highlights the need for personal protective equipment, improved hygiene practices, proper ventilation, and sanitation in these farms to prevent ocular exposure and potential risks to poultry farm workers.
Keywords: Ocular mycoses, poultry farming, fungal infections, murine model, pathogenicity.
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