Background Antibody to hepatitis E virus (anti-HEV) is prevalent in Western countries, where clinical hepatitis E is rarely reported. The aim of this study was to determine the prevalence of anti-HEV among Danish blood donors and Danish farmers. In addition, we compared the prevalence among 2 sets of serum samples obtained from blood donors 20 years apart. Methods Samples from 291 Danish farmers and 169 blood donors that were collected in 1983 and samples from 461 blood donors that were collected in 2003 were tested for anti-HEV. Relevant information on HEV exposure was collected by self-administered questionnaire. Results Anti-HEV testing was performed on samples after 20 years of storage at −20°C. The prevalence of anti-HEV was 50.4% among farmers and 32.9% among donors in 1983 and 20.6% among donors in 2003 (P < .05). Presence of anti-HEV was significantly correlated with increasing age in all 3 groups (P < .05). Among donors who had serum samples obtained in 2003, age, contact with horses, and the presence of antibody to hepatitis A virus were associated with the presence of anti-HEV in multivariate analysis. Among farmers, only age was independently associated with the presence of anti-HEV. Conclusion Anti-HEV was highly prevalent among Danes but has decreased in prevalence over the past 50 years. Our study supports the hypothesis that HEV infection in Denmark may be an asymptomatic zoonotic infection.

The "anti-atopy" protective effect of a farm childhood could be confirmed in Danish farming students: prevalences of positive SPT, specific and total IgE, allergic symptoms and BHR were lower in those being born or raised on a farm. Past exposure to the farm environment in early childhood may therefore also contribute to a lower risk of atopic sensitization and disease at a later age.

The aim of this study was to assess the prevalence of asthma (selfreported) and relate this to lung function and factors associated with asthma in young farmers.Two hundred and ten female and 1,691 male farming students together with 407 males controls were studied. Each subject underwent a medical interview; forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were recorded using a dry wedge spirometer. Histamine bronchial reactivity was measured using the Yan method. Skin prick testing was performed using inhalant allergens.Nonsmokers had lower prevalence of asthma (5.4±10.8%) than smokers (11.3± 21.0%) (p<0.05). Females reported symptoms of asthma nearly twice as often as males. Sex, smoking and a family history of asthma/allergy were significantly associated with asthma. Controls had higher standardized FEV1 and FVC residuals than male students, both nonsmokers (0.21 and 0.24) versus (-0.06 and -0.05) and smokers (0.29 and 0.33) versus (-0.11 and 0.13) (p<0.032). Bronchial hyperresponsiveness, asthma, siblings with allergy and working with cattle (controls only) were significantly associated with reduced lung function.In conclusion, the prevalence of asthma was significantly related to smoking, female sex, family history of asthma and allergy. Whilst bronchial hyperresponsiveness was associated with reduced lung function and lung function was slightly reduced in the male farming students, there was no association found between occupational farming exposure and either lung symptoms or lung function. Eur Respir J 1999; 13: 31±37. Exposure to fumes and both organic and inorganic dusts represents an occupational hazard in farming. High concentrations of carbon dioxide, hydrogen sulphide and ammonia have been measured inside animal confinement buildings [1±4]. Analyses of the dust have revealed several compounds including animal-derived material such as dander, hair, saliva and urine [5,6], bacteria [7,8], endotoxin [7,9,10], fungi [8,11], spores [9,12] and mites [13,14]. Inhalation of these substances might result in cellular and immunological responses that could lead to lung diseases.The prevalence of asthma in farming populations, studied in the northern part of Europe, has shown a range 2.1± 32% [15±18]. Positive skin prick test [15], pig farming [16] and positive test to both storage and house dust mites [17] have been suggested as risk factors for asthma, and exposure to dusts, animals and fodder yeast have been reported as provoking factors for asthma in the farming population [18].The influence of occupational exposure on lung function in agricultural workers has been studied in farmers working in dairy barns and mainly in swine confinement buildings. Most of the studies have been cross-sectional [19, 21±30] but some longitudinal studies have been published [20,29,32]. Dairy farming has been found to be associated with minor lung function changes both in the UK [19] (forced expiratory volume in one second (FEV1)) and in Finland [20] (forced vital capacity (FVC)). In s...

Occupational endotoxin exposure has a protective effect on allergic sensitisation and hay fever but increases the risk for organic dust toxic syndrome and chronic bronchitis. Endotoxin's protective effects are most clearly observed among agricultural workers.

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The respiratory health of 230 female and 1,734 male farming students (FS) and 407 male rural controls was analyzed. A Torben Sigsgaard is Associate Professor, Charlotte Hjort and Øyvind Omland

Several studies have found an association between the rare Pi-alleles and asthma or bronchial hyperresponsiveness (BHR). This study deals with the effect of Pi-type on BHR among 2,308 young Danish people living in rural areas with a meanSD age of 19.72.4 yrs.Interviews, pulmonary function testing, bronchial histamine provocation and skinprick tests were performed. Serum a 1 -antitrypsin levels were determined and phenotyping was performed by means of isoelectric focusing and the subjects categorized into four groups: 1) MM and MX; 2) MS; 3) MZ; and 4) rare, i.e. SZ, SS and ZZ.Among the farmers, a significant positive trend for sensitization towards house dust mites was found, ranging from 12% in the MM group to 22% in the rare Pi-group. A positive test for trend was found within the Pi-groups in a one-sided test for doctordiagnosed asthma with a peak prevalence of 40% for these symptoms among smokers in the rare Pi-group. On multiple logistic regression analysis, an increased odds ratio (OR) for BHR was found among farming school attendants with the rare Pi-alleles. The OR (95% confidence interval) was 1.71 (0.84±3.49) for MS, 1.93 (1.10±3.39) for MZ and 4.34 (1.19±15.8) for the rare Pi-group. Such a relationship was not found among the conscripts.These results show that a gene/environment interaction may exist between the farming occupation and the rare Pi-alleles, leading to a higher proportion of bronchial hyperresponsiveness related to the rare Pi-alleles in farming school attendants, in contrast to what is found among other young people living in rural areas. Eur Respir J 2000; 16: 50±55. The antiprotease a 1 -antitrypsin (a 1 -AT) has, since 1963, been known to be involved in the pathogenesis of chronic obstructive lung diseases and emphysema [1]. Since then several studies have investigated a possible link between asthma, bronchial hyperresponsiveness (BHR) and Piphenotypes. The most-studied alleles with low a 1 -AT levels are the two most common types, S and Z. COLE et al.[2] and studied the association between a 1 -AT phenotype and pulmonary symptoms in the working population. They found no association with respiratory symptoms, for either S or Z heterozygous persons, whereas, in a study of cotton workers, an increased risk of respiratory symptoms among the MZ heterozygous was found, after control for other factors, i.e. smoking, sex and exposure [4].A history of asthma among close relatives was found to be more common among the heterozygous in one study [5], and, in another study, the odds ratio (OR) for familial atopy was increased among persons with the Pi-MZ phenotype [4].Asthma has been found to be associated with the Z allele in some studies and the S allele in others [5±7]. However, the association between asthma and the S or Z alleles could not be confirmed in other studies. A recent study of a 1 -AT and BHR found the S allele to be associated with hyperresponsiveness [8], indicating that the underlying mechanism for the association with asthma might be inflammation.Allergy measured a...