An allergological study to evaluate allergenicity to Cladosporium, Burkard 7-Day Volumetric Spore Trap and Personal Volumetric air sampler (viable mode) were employed to conduct air sampling for 12 months in three regions of Saudi Arabia. The study was extended for a continuous 3rd year at one site. Skin prick testing (SPT) was also conducted on 605 allergic individuals using commercial extracts of C. herbarum. Cladosporium emerged to be the most prevalent genus in the outdoor environment constituting up to 25% of all fungal spores in the dry region and 37.1 and 41.2% in two coastal cities respectively. Amongst the species C. sphaerospermum, C. macrocarpum, C. cladosporioides and C. herbarum were noted. Maximum hourly concentrations up to 14 x 10(3) m(-3) were recorded in coastal region during winter months. Morning concentrations were higher at both city sites compared to afternoon concentration. SPT result revealed an overall 19.67% positive reactions with majority showing mild reactions.

Airborne Pollen grains and Spores of three different cities viz., Al-Khobar (1987-1988, Abha (1991Abha ( -1992 and Hofuf (1992Hofuf ( -1993 in Saudi Arabia were studied using Burkard Volumetric Seven-Day Spore Trap. The data were analyzed in relation to their allergenic capability and one-year pollen and spore calendars were designed to correlate the patients' symptoms as well as for selection of appropriate allergen extracts for diagnosis and treatment of allergic diseases. Amongst pollen group, Amaranthus viridis, Plantago spp., Chenopodium album, Ricinus communis, Rumex vesicarius, Juniperus spp., Parkinsonia aculeata, Prosopis spp., and Phoenix dactylifera were some of the frequent types. Amongst the fungal spores group Cladosporium, Smuts spores, Colored basidiospores, Alternaria, Ulocladium and Drechslera were the dominant types.

Seasonal and diurnal variations of airborne basidiomycetous spores concentrations (basidiospores, smuts and rust spores) were studied using Burkard Volumetric Spore Traps in three major coastal cities viz., Dammam, Jeddah and Jizan in Saudi Arabia. The distance between the sites was approximately 1600 km from East to West. In addition to numerous airborne deuteromycetous spores identified at all sites, a considerable concentration of basidiomycetous spores were also recorded. The data revealed that basidiospores constituted a maximum of 17% of the total air spora in Jizan, while the maximum for Dammam and Jeddah was 11% each. Spores from smuts constituted the highest percentages of all basidiosmycetous spores ranging between 9-33% and 12-33% respectively in Dammam and Jizan. In Jeddah, it constituted between 14-26%. In contrast, rusts were less frequent at all sites. Maximum concentration of basidiospores showed that at certain months the level reached between 1000-6000 m )3 . The data did not exhibit any seasonal pattern in their maximum appearance. Maximum concentration of smuts were much higher compared to basidiospores and the level fluctuated between 500-4000 m )3 . Rusts were low in concentration (<150 m )3 ). The diurnal pattern of basidiospores concentration for at least one site (Jizan) averaged over the year showed a nocturnal trend consistent with basidiospores active discharge. The other two sites had no such trend. Diel periodicities of smuts and rusts spores did not exhibit any clear pattern. The study suggests that even in coastal regions having the same climatic conditions with a slightly different geography, show variation in basidiospores concentrations.

BACKGROUNDAmaranthus pollen grains are known to be highly allergenic and a potential cause of respiratory allergic diseases. Nevertheless, data on the prevalence of Amaranthus pollen in the environment is limited and almost non-existent for Saudi Arabia.METHODSWe conducted an investigation to record the airborne incidence of A. viridis and other allergenic pollen in Al-Khobar, Dammam, Hail, Jeddah, Jizan, Qassim and Taif, using Burkard Volumetric Samplers. The samplers were operated continuously for one year at each location.RESULTSThe data revealed A. viridis as one of the major components of outdoor airspora, constituting a maximum of 96% of total pollen counts in Hail, followed by Al-Khobar (89%), Jeddah (87%), Qassim (85%), Taif (84%), Dammam (83%) and Jizan (61%). These higher percentages contributed largely to the total weed pollen catch during August to November in all seven regions. In addition, the data also showed that A. viridis pollen were present throughout the year with distinct seasonal variations. The diel periodicities for at least five sites averaged over a year showed mid-day to early evening maxima. The maximum concentration approached 3000/m3 of air in October and 1827/m3 of air in September. The data also exhibited a seasonal pattern in their maximum appearance.CONCLUSIONFurther studies related to biochemical and allergological aspects are needed to confirm the allergenic impact of Amaranthus pollen and sensitization in allergic individuals in the Kingdom of Saudi Arabia.

No abstract