RESUMO
BACKGROUND: In 1999, an extensive study among bell pepper growers showed a prevalence of 53.8% work-related symptoms and 35.4% sensitisation to bell pepper pollen. Experiments with bees to remove pollen from bell pepper flowers have been done for a few years. OBJECTIVES: It was the aim of this study to investigate whether bees can reduce the pollen exposure in bell pepper greenhouses and whether this reduction results in a decrease in allergic complaints in the greenhouse workers. METHODS: Eighteen greenhouses were selected for the study. In each greenhouse, pollen exposure was estimated. In 6 and 3 of the greenhouses, high, respectively low, numbers of honeybees were placed throughout the pollen season of the sweet bell pepper plant. Nine greenhouses without honeybees were used as control. At baseline, as well as after 4 and 8 months, nasal symptoms assessed with a visual analogue score and lung function parameters were used as outcome measure. RESULTS: Forty-four of the 133 employees invited reported work-related symptoms. High numbers of bees reduced the pollen amount in a dose-dependent way to 18% of the baseline exposure. A significant trend relationship between the visual analogue scale in nasal symptoms and the number of colonies of bees was seen. CONCLUSIONS: The interference of bees in bell pepper greenhouses significantly reduces the pollen amount. This reduction is associated with less work-related rhinitis symptoms in allergic greenhouse workers. This intervention study supports the hypothesis that allergic work-related complaints of greenhouse workers, sensitised to bell pepper pollen, are caused by occupational exposure to this pollen in the greenhouse.