Spatial Distribution Of Atmospheric Pollen And Fungi Spores And Their Relation To Allergy In Nigeria

ABSTRACT

The socioeconomic burden of pollen and fungi spores allergy are very high in terms of hospitalization, treatment, lethargy, poor concentration and behavioral changes which impact negatively on adults and children. The study of atmospheric pollen and fungal spores in the six geopolitical zones of Nigeria was carried out from June 2011 to May 2012. The aims of the study are to determine the seasonal prevalence of atmospheric pollen and fungal spores, examine the impacts of weather parameters on them and assess their allergenic potentials in mice. Airborne pollen and fungal spores were trapped with Tauber-like pollen traps and subjected to acetolysis, temporary slides were for microscopical examination and identification. Mature anthers which have not undergone anthesis were procured and vaccum dried at 35 oC. Both anthers and cultured fungal spores were subjected to protein extraction using 100 ml of 0.02 M phosphate buffered saline at pH 7.4. The protein content was assayed by Bradford procedures and the extracted proteins were inoculated into mice weekly by subcutaneous and intranasal injections. Blood samples were obtained by retro-orbital bleedings for sera and used for analysis of mice immunoglobulin E using enzyme linked immunoperoxidase assay. Mice were sacrificed at the end of the 5th week, the trachea, bronchi, bronchioles and lungs were subjected to histological staining and examination. Results from this work revealed seasonal variations of atmospheric pollen and fungal spores contents in the six geopolitical zones. They are rainy season, two major seasons of pollen and fungal spores abundance were noted in Southern and North Central zones; rainy seasons were characterized by higher fungal load and late rainy/harmattan season characterized by higher airborne pollen load. The North West and North East zones has one defined season of more allergenic exposure in terms of floral components. Poaceae pollen dominated North West and North East Nigeria during the rainy season and was the most dominant anemophilous pollen recorded in the atmosphere of Nigeria. While there was a clear abundance of entomophilous pollen in Southern zones, anemophilous pollen prevailed over entomophilous in Northern zones. Spores were more abundant in the South than the North. There was a positive correlation between the atmospheric aeroallergens and weather parameter. The pollen grains of anemophilous plants such as Poaceae, Elaeis guineensis, Casuarina equisetifolia, Cyperaceae, known to trigger allergic rhinitis were commonly recorded from the atmosphere of the six studied geopolitical zones. Immunological results using mice revealed an increase in immunoglobulin E levels and infiltration of lymphocytes. Pollen protein of Oreodoxa oleracea induced both intrinsic and extrinsic allergenic reactions which manifested dermatophytic and inflammatory reactions on the skin and within the lung parenchyma respectively. Spore protein of Aspergillus niger, pollen protein of Mariscus ligularis and Terminalia catappa elicited hypertrophy of the mucous gland, over pseudostratification of tracheal epithelium and inflammation within the lung parenchyma respectively. A direct relationship as recorded between allergen protein and immunoglobulin E elicited in some mice. Oreodoxa oleracea pollen protein skewed basophil production, which promoted inflammatory reactions in mice. The results indicated that the production index of pollen and fungi spores are highly sensitive to weather parameters, it also established that pollen and spores protein orchestrate immunological stimulation leading to lymphocyte infiltration and proliferation of other immune cells.