Indoor survey of moulds and prevalence of mould atopy in Israel.

BACKGROUND: Moulds are ubiquitous indoor as well as outdoor allergens and therefore potential candidates for indoor environmental control measures. However, very few studies have been performed to examine the significance of indoor moulds in allergic diseases and the effectiveness of measures to reduce the quantity of indoor moulds has not been established. OBJECTIVE: To determine the significance and the contribution of moulds to allergic manifestations. METHODS: Prevalence of allergic rhinitis and asthma in 395 members of a rural community were examined by questionnaire and examination of medical files. The atopic status in general and allergy to moulds was determined by skin-prick tests (SPTs) to a panel of aeroallergens including Aspergillus, Penicillium, Alternaria and Cladosporium. A study of indoor mould levels was performed by placing SDA plates in 59 houses. The type of fungi and the number of colonies from each species were recorded. RESULTS: Forty-two subjects, comprising 10.9% of the study group had positive SPT to moulds, 61.9% of those were classified as symptomatic. When taking into account individuals with a borderline positive SPT to moulds, an additional 23 had positive results. Of the 65 mould-positive subjects, 48% were symptomatic and of the 13 who were allergic to moulds alone, only two had allergic symptoms. Viable moulds were recovered from all 59 houses examined. The most common isolated genus was Aspergillus, followed by Penicillium, Alternaria and Cladosporium. Aspergillus was also the most abundant mould in houses. There was no significant correlation between the abundance of moulds, positive SPT to that mould and symptomatology. CONCLUSIONS: Viable moulds are common in houses in temperate climates. Allergy to moulds itself has a low predictive value to development of allergic symptoms, but allergy to moulds in otherwise atopic subjects increases the risk of symptomatic allergic disease.

The importance of the pecan tree pollen in allergic manifestations.

BACKGROUND: Pecan tree pollen is considered to be highly allergenic. However, no specific scientific data about its role in causing allergic diseases are available. OBJECTIVE: To study the role of pecan tree pollen in the development of allergy. METHODS: The presence of pecan tree pollen was determined by weekly and monthly counting of airborne grains. The incidence of pecan tree pollen atopy and clinical manifestations were studied in 395 participants, aged 4-70 years, who comprised 78.2% of the whole eligible population of a rural community. The participants were skin tested for different extracts of allergens, completed detailed questionnaires, and their medical files were evaluated. RESULTS: During May, pecan tree pollen grains comprised 70% of the total airborne grains. A positive skin-prick test (SPT) to pecan was shown by 46 (11.6%) participants, constituting 25.4% of the atopic population. Of those who were found atopic to one or more allergens 50.3% had symptoms, whereas the parallel figure for those atopic to pecan pollen was 76.1% (P < 0.005); 58.7% of the pecan atopic participants had hay fever, 43.5% had asthma, and 31.5% had both hay fever and asthma. Among pecan atopic participants the incidence of hay fever increased with age (P = 0.05), while the incidence of bronchial asthma, as a sole manifestation of allergy, decreased in the > 17-year-old age group (P < 0.01). Of the pecan atopics 65.2% had clinical symptoms coinciding only with the pecan pollen season and an additional 10.9% had perennial symptoms. CONCLUSION: Pecan tree releases highly allergenic pollen grains, which are correlated to the incidence of hay fever in the exposed population. The contribution of pecan tree pollen to the symptoms was highly significant after discounting olive and cypress trees that also pollinate in the spring. In children, the pecan tree constitutes a possible etiologic agent for the development of asthma.