title: Health effects of selected microbiological control agents. A 3-year follow-up study.
abstract: OBJECTIVE
  Microbiological control agents (MBCA) are widely used in greenhouses, replacing chemical pesticides. The presented study aims to describe health effects of exposure to three types commonly used: Bacillus thuringiensis, Verticillium lecanii, and Trichoderma harzenianum covering seven different products in greenhouse workers with emphasis on sensitization and respiratory effects.
  
  
  METHODS
  579 persons aged 17-67 years culturing ornamental flowers were included. They were followed for three years with annual examinations including interview about exposure and symptoms, lung function, including bronchial (histamine) challenge test, and blood samples. Direct and indirect exposure for each person and year was estimated by information from respondents and employers. IgE in serum against the 7 products of MCBA was analyzed using an enzyme immunoassay technique.
  
  
  RESULTS
  65%, 40%, and 78% were exposed to B. thuringiensis, V. lecanii, and T. harzenianum, respectively, while 6, 3 and 3% were handling the products. IgE against B. thuringiensis was seen in 53% of the samples and with prevalence rate ratios among exposed increasing from 1.20 (CI95%:1.01-1.42) to 1.43 (CI95%:1.09-1.87) over the 3-year period. There was no relation between exposure to any MBCA and neither prevalence nor incidence of respiratory symptoms and there was no effect on lung function or bronchial responsiveness.
  
  
  CONCLUSIONS
  Use of B. thuringiensis in greenhouses may give rise to sensitization while no effect on the occurrence of respiratory symptoms or lung function was observed. The persons had a relatively long exposure. Therefore, a healthy worker effect may have influenced the results.
authors: Department of Occupational and Environmental Medicine, Odense University Hospital, Odense, Denmark. jesper.baelum@ouh.regionsyddanmark.dk
authors: Jesper
authors: J
authors: Baelum
authors: Preben
authors: P
authors: Larsen
authors: Gert
authors: G
authors: Doekes
authors: Torben
authors: T
authors: Sigsgaard
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000382:Agricultural Workers' Diseases / Q000453:epidemiology* / Q000382:microbiology; D001413:Bacillus thuringiensis / Q000302:isolation & purification; D061046:Biological Control Agents; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D051639:Gardening; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D015989:Healthy Worker Effect; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D009181:Mycoses / Q000453:epidemiology* / Q000382:microbiology; D016273:Occupational Exposure; D012129:Respiratory Function Tests; D011795:Surveys and Questionnaires; D014242:Trichoderma / Q000302:isolation & purification; D020172:Verticillium / Q000302:isolation & purification; D055815:Young Adult
chemical_list: D061046:Biological Control Agents; D007073:Immunoglobulin E