Prevalence of sensitization to Tetranychus urticae in greenhouse workers.
BACKGROUND
Tetranychus urticae (TU) is a macroscopic mite which infests a large number of plants of economic interest worldwide. It has recently been described as a cause of occupational allergic disease in greenhouse workers. However, there are no epidemiological data concerning the prevalence of TU allergy in an unselected exposed population.


OBJECTIVE
The aims were to study the prevalence of TU sensitization among greenhouse workers and its relationship to the working environment and to personal factors.


METHODS
We studied 246 consecutive greenhouse workers, recruited directly from the field. A clinical and epidemiological questionnaire, a skin-prick test (SPT) to TU and common allergens and TU-specific IgE (RAST) determinations were performed. Seventy-five healthy volunteers and 152 atopic patients were used as a control group.


RESULTS
The prevalence of a positive SPT to TU was of 25%. Forty-five workers (19%) were TU-allergic, occurring more often in atopic greenhouse workers (P < 0.0001). Seven per cent showed asymptomatic sensitization. The time of exposure to TU was significantly greater in the TU-allergic patients (P < 0.05). The probability of sensitization to TU was 3.7 times greater in exposed than in non-exposed subjects (P < 0.0001).


CONCLUSIONS
In this study, the prevalence of TU sensitization was 25%. There were significant associations with TU allergy and atopy and the time of exposure to TU.
Navarro
A M
AM
Unidad de Alergia, Hospital El Tomillar, Sevilla; Servicio Regional de Inmunología y Alergia, Hospital Virgen Macarena, Sevilla, Spain.
Delgado
J
J
Sanchez
M C
MC
Orta
J C
JC
Martínez
A
A
Palacios
R
R
Martínez
J
J
Conde
J
J
D000328:Adult; D000383:Agriculture; D000818:Animals; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000453:epidemiology* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology*; D009784:Occupational Diseases / Q000453:epidemiology* / Q000276:immunology; D016273:Occupational Exposure; D015995:Prevalence; D011852:Radioallergosorbent Test; D012882:Skin Tests; D011795:Surveys and Questionnaires