Airborne contaminants and farmers health in swine farms with high and low prevalence of respiratory diseases in pigs

The main purpose of this study was to investigate the relationship between prevalence of respiratory disease in swine and respiratory health of swine farmers. Fourteen farms were selected based on clinical history and slaughtercheck evidence of respiratory problems in pigs. The farms were divided into two groups with either high (n = 7) or low (n = 7) prevalence of respiratory disease in pigs. Airborne dust, endotoxin and peptidoglycan were measured once in farrowing, gestation, nursery and finishing of each farm. Respiratory health of farmers in participating farms was evaluated by questionnaire and pulmonary function test. A mean of 71% of the pigs in high prevalence farms had pneumonic lesions at slaughter, compared with 7% in low prevalence farms. No significant relationship was found between prevalence of respiratory disease in pigs and airborne dust, endotoxin or peptidoglycan. More farmers in high prevalence farms reported chest tightness (p = 0.038). The percentage predicted FEF 25%-75%; was lower (p = 0.046) in farmers working in high prevalence farms. Significant differences disappeared after adjusting for smoking status. Our study suggests that farmers working on farms with a high prevalence for respiratory disease in pigs may have more respiratory problems than farmers working in farms with low prevalence of such diseases.

Effects of exposure to grain dust in Polish farmers: work-related symptoms and immunologic response to microbial antigens associated with dust

Medical examinations were performed in a group of 76 Polish farmers heavily exposed to grain dust during harvesting and threshing, and in a group of 63 healthy urban dwellers not exposed to organic dusts (controls). The examinations included: interview concerning the occurrence of respiratory disorders and work-related symptoms, physical examination, lung function tests, and allergological tests comprising skin prick test with 4 microbial antigens associated with grain dust and agar-gel precipitation test with 12 microbial antigens. As many as 34 farmers (44.7%) reported the occurrence of work-related symptoms during harvesting and threshing. The most common was dry cough reported by 20 individuals (26.3%). Dyspnoea was reported by 15 farmers (19.7%), tiredness by 12 (15.7%), chest tightness by 8 (10.5%), plugging of nose and hoarseness by 5 each (6. 5%). No control subjects reported these work-related symptoms. The mean spirometric values in the examined group of farmers were within the normal range, but a significant post-shift decrease of these values was observed after work with grain. The farmers showed a frequency of the positive early skin reactions to environmental allergens in the range of 10.8 - 45.5%, and a frequency of positive precipitin reactions in range of 3.9 - 40.8%. The control group responded to the majority of allergens with a significantly lower frequency of positive results compared to the farmers. The obtained results showed a high response of grain farmers to inhalant microbial allergens and indicate a potential risk of occupational respiratory diseases (such as allergic alveolitis, asthma, Organic Dust Toxic Syndrome) among this population

Allergic alveolitis among agricultural workers in eastern Poland: a study of twenty cases

The aim of this study was to identify the specific agents which caused extrinsic allergic alveolitis (EAA) in the selected group of 20 agricultural workers from eastern Poland. The microbiological analysis of the samples of plant materials or dusts reported by the patients as causing symptoms has been carried out, followed by allergological tests (inhalation challenge, agar-gel precipitation test, inhibition of leukocyte migration, skin test) with extrinsic microbial antigens. It was found that the causative agents of allergic alveolitis in the examined group of patients were mesophilic, non-branching bacteria associated with grain dust, mostly Pantoea agglomerans (synonyms: Erwinia herbicola, Enterobacter agglomerans) and Arthrobacter globiformis (each in eight cases). The remaining agents were Alcaligenes faecalis (in two cases), and Brevibacterium linens and Staphylococcus epidermidis (in one case each). On the basis of the clinical picture, the bronchoalveolar lavage (BAL) and allergological tests, the diagnosis of the chronic form of the disease was stated in 14 patients and an acute form - in 6 patients. EAA patients demonstrated in the BAL fluid a typical lymphocytic alveolitis both in terms of percentage and absolute number of lymphocytes. Also, the numbers of eosinophils and neutrophils were significantly higher in EAA patients.

Cancer among farmers: a meta-analysis

PURPOSE

We conducted a meta-analysis of 37 studies to assess whether farmers had elevated rates for several cancers, as was concluded in a previous meta-analysis of 21 studies.

METHODS

We identified studies from the reference list of the previous meta-analysis and from a MEDLINE search through December 31, 1994. The primary purpose of our analysis was to identify and, if possible, understand the sources of heterogeneity in the literature. Stratified analyses of studies and linear modeling with inverse variance weights were used to assess the impact of study characteristics on results. We calculated summary relative risks as a weighted average of the log relative risks across studies using inverse variance weights. Fixed and random effects models were used as appropriate.

RESULTS

The results for most cancers were markedly heterogeneous by study design and, for fewer cancers, by geographic location, and whether the studies focused on crop and livestock farmers. There was some indication of publication bias due to underreporting of near null or sub null findings. Lip cancer was the only cancer that was clearly elevated among farmers.

CONCLUSIONS

The results do not suggest that farmers have elevated rates of several cancers. However, the known heterogeneity of exposures by type of farming, geographic area, time period, and other factors limits the informativeness of meta-analyses of these studies for assessing potential carcinogenic exposures in agriculture.

Endotoxin exposure as a major determinant of lung function decline in pig farmers

Exposure-response relationships for endotoxin as measured in dust and longitudinal decline in lung function were studied. A cohort of 171 pig farmers was followed over a 3-yr period. Long-term average exposure to dust and endotoxin was determined by personal monitoring in summer and winter, using data on farm characteristics and activities. Mean decline in FEV1 was 73 ml/yr and in FVC 55 ml/ yr. Long-term average exposure to dust was 2.63 mg/m3 (geometric SD [GSD] 1.30), and to endotoxin, 105 ng/m3 (GSD 1.5). Annual decline in FEV1 was significantly associated with endotoxin exposure. An increase in exposure with a factor 2 was associated with an extra decline of FEV1 of 19 ml/yr.

The erythemal ultraviolet exposure for humans in greenhouses

A spectrum evaluator has been employed to evaluate the erythemal exposure in late spring and late summer at three sites and five orientations at each site inside a glass greenhouse with black shadecloth over the glass roof. The maximum in the erythemal irradiance in the greenhouse is not necessarily at noon. Over a day, the maximum erythemal exposure occurred on the eastern side of the greenhouse in the morning and on the western side in the afternoon. The erythemal irradiance on the eastern side in the morning was higher by 26% and 50% for horizontal and vertical surfaces respectively compared with the same site at noon. On the western side the irradiance was higher by 45% and 78% for the horizontal and vertical surfaces respectively compared with the same site at noon. The erythemal irradiance inside the greenhouse does not vary as much during the day as it does outside; for example, for horizontal surfaces, the ratio of the erythemal irradiance outside to the average inside the greenhouse varies from 66 to 112 to 74 for the morning, noon and afternoon periods respectively. Over a 6 h period, the erythemal exposure to the shoulder for a standing posture in the greenhouse was 5 mJ cm-2.

Bronchial hyperresponsiveness and exposure in pig farmers

OBJECTIVE

To study the effect of exposure on bronchial responsiveness in pig farmers.

METHOD

A group of 196 pig farmers were tested for lung function and bronchial responsiveness to histamine in the summer of 1992. To achieve sufficient contrast in respiratory morbidity and exposure, 96 of the farmers were selected because they had chronic respiratory symptoms and the remaining 100 because they were free from any respiratory symptoms. Personal exposure to dust, endotoxins and ammonia was measured during 1 working day in the summer of 1991 and 1 day in the winter of 1992. Data on farm characteristics were gathered in the same period.

RESULTS

After adjusting for age and smoking behaviour, mild bronchial responsiveness, defined as PC10 < or = 16 mg/ml, was associated with the use of quaternary ammonium compounds as disinfectant [prevalence odds ratio (POR) 6.7, 95% confidence interval (CI) 1.4-32.8], use of wood-shavings as bedding (POR 13.3, CI 1.3-136.7), use of automated dry feeding (POR 2.8, CI 1.0-7.8), use of pellets as feeding material (POR 4.8, CI 1.1-21.1) and location of air exhaust via pit or roof in the confinement units (POR 2.7, CI 1.2-6.3). The association with the use of disinfectants other than quaternary ammonium compounds was not significant (POR 2.4, CI 0.7-8.4). No associations between bronchial responsiveness and measured exposure to dust, endotoxins or ammonia were discernible.

CONCLUSION

Protective measures, designed to prevent airway disease in confinement farming, should be based on information about the operational and other characteristics of farms that are related to high exposure and health effects. Specifically, the use of quaternary ammonium compounds as disinfectant, the use of wood-shavings as bedding and the use of automated dry feeding should be discouraged.

Aplastic anemia in rural Thailand: its association with grain farming and agricultural pesticide exposure. Aplastic Anemia Study Group

OBJECTIVES

A population-based case-control study was conducted to elucidate the incidence and etiology of aplastic anemia in Thailand.

METHODS

Case patients and hospital control patients were enrolled in three regions from 1989 to 1994; data were collected by interview.

RESULTS

Forty-six percent of 81 case patients and 19% of 295 control patients from Khonkaen were grain farmers (estimated relative risk [RR] = 2.7, 95% confidence interval [CI] = 1.4, 5.2). Sixteen percent of case patients and 6% of control patients used agricultural pesticides (estimated RR = 2.7, 95% CI = 1.1, 6.6). The association with grain farming remained among those not exposed to pesticides. In Songkla, 16% of 43 case patients and 2% of 181 control patients were grain farmers (crude RR estimate = 11, 95% CI = 3.4, 35).

CONCLUSIONS

The relation of aplastic anemia to grain farming may partly explain the high incidence of aplastic anemia in Thailand.

Positive human health effects of dust suppression with canola oil in swine barns

A crossover trial was conducted to evaluate the acute human health effects of a dust control technology in a swine confinement facility. Twenty lifetime nonsmoking male subjects, with no evidence of allergy or asthma and no previous swine barn exposure, participated in the study, which included a laboratory session (baseline), 5-h exposure in a swine room sprinkled with canola oil (treatment) and 5-h exposure in a traditional swine room (control). Mean values of inhalable dust concentrations and endotoxin levels in the control room were significantly greater than those observed in the treatment room. Mean shift changes in FEV1 from preexposure to end of exposure were 1.1% (standard error, 0.63%) on baseline day, -1.9% (0.63%) on treatment day, and -9.9% (1.12%) on control day; the differences in the shift changes were statistically significant. Mean value of methacholine concentration that reduced the FEV1 by 20% (PC20) in bronchoprovocation tests on baseline day was significantly different from that on treatment day (p = 0.04) and that on control day (p < 0.001). Significant increases were also observed in white blood cell counts and nasal lavage cell counts on the control day in comparison with the other two days. Blood neutrophil counts after control room exposure were twice those observed on baseline and after exposure to the treatment room. Significant differences were also observed in IL-1 beta, IL-6, and IL-8 nasal lavage cytokines and in IL-6 serum cytokine. These results suggest that the canola oil dust control method is effective in improving indoor air quality in swine barns and reducing acute health effects in naive healthy subjects.

Is working in greenhouses healthy? Evidence concerning the toxic risks that might affect greenhouse workers

Greenhouses are essentially microcosms aimed at providing physical environments suitable for the survival and growth of plants. Crops grown intensively in greenhouses in Great Britain include cut flowers, pot plants and edible crops such as tomato, lettuce cucumber and celery. The enclosed conditions mean that greenhouse workers are more likely to be exposed to higher levels of plant material, plant pests and plant protection products than general horticulture workers. The potential for ill-health in greenhouse workers is examined with particular reference to Great Britain. The principal potential effects expected include irritancy, asthma, allergic aleveolitis and dermatitis. Although biological control agents are widely used, there were no reports of their having caused ill-health in greenhouse workers. About two people per year are found to have suffered ill-health as a consequence of greenhouse exposure to chemical pesticides in reported pesticides incidents in Great Britain.

[A retrospective analysis of aborted pregnancy in women engaged in agricultural production in controlled areas of Ukraine]

A retrospective analysis was carried out of failure for a woman to be delivered of a child at the natural time in those female workers engaged in agricultural production in controlled territories of Ukraine (Narodichi and Ovruch districts of Zhytomir Province). Data files were studied of 5371 histories of labor (2440 those before and 2931 after the Chernobyl accident) and 525 records of spontaneous abortion (255 those before and 27 after the ChNPP breakdown). There has been found relationship between the frequency of incomplete pregnancies and density of contamination of soil with cesium-137 in certain settlements.

Occupational allergy in saffron workers

Sensitization to the flower of saffron, a plant commonly grown in Spain for commercial purposes, and its clinical significance as an occupational allergen were studied. The prick test and RAST, with saffron pollen, stamen, and pistil extracts, were used to evaluate the cutaneous and specific antibody responses in the studied population. Provocation tests in patients with clinical findings were used to verify the implication of saffron components in these symptoms. Fifty saffron workers were evaluated. Three of them were sensitized to saffron pollen and stamen proteins, giving prick and RAST positive values. One patient presented asthma, showing a positive bronchial provocation test, and two patients rhinoconjunctivitis, showing positive conjunctival provocation tests. Of a general allergic population of 237, 10 patients also presented cutaneous test and IgE positive to saffron. Saffron allergens (from pollen and stamens) were characterized by SDS-PAGE immunoblotting. A relevant allergen of 15.5 kDa with profilinic nature was detected and further purified by high-resolution gel filtration chromatography. No allergenic components were demonstrated in pistils. Cross-reactivity of saffron extracts was evaluated by RAST inhibition with respect to other pollen species commonly causing sensitization in the same area of study. A significant degree of cross-reactivity was demonstrated between saffron and Lolium, Salsola, or Olea. The identification of the protein components involved in the cross-reactions was investigated by blot inhibition.

Occupational type I allergy to Christmas cactus (Schlumbergera)

The study aimed to determine whether occupational contact urticaria and symptoms of mucous membranes, reported by five workers in a cactus nursery, were due to IgE-mediated allergy to Schlumbergera cacti. The five persons had positive skin prick tests to the plants as is and positive histamine-release tests, and in three of them specific IgE to the cacti could be demonstrated by Maxisorp RAST and immunoblotting. Four of the patients were atopic, and the fifth had a positive skin prick test to cat dander, indicating latent atopy. Skin prick tests with cacti were negative in most atopic volunteers, and all had negative histamine-release tests. The results suggest a true IgE-mediated allergy to the cacti, and both genetic predisposition and close contact with the plants at work seem to be important factors in the emergence of this new occupational allergy.

Actinic keratosis: a case of sun damage in the tropics

Sun damaged to the skin in the tropics is not an uncommon event. There is need for a high index of suspicion especially in patients with outdoor occupations. Prompt diagnosis and therapy will prevent progression to a cancerous state. We report a case of cutaneous horns secondary to actinic keratosis, a pre-cancerous condition relatively uncommon in Black skin. The importance of histological support in its diagnosis cannot be over-emphasized.

The role of endotoxin in grain dust exposure and airway obstruction

Grain dust exposure is a common cause of respiratory symptoms in grain workers, feed mill employees, and farmers. Many of these workers develop wheezing and acute and chronic bronchitis symptoms, which can be associated with obstructive changes on pulmonary function testing. It has recently been demonstrated that grain dust exposure causes neutrophilic airways inflammation and systemic symptoms related to release of interleukin-1, tumor necrosis factor, interleukin-6, and other mediators of inflammation. Although grain dust is a heterogenous substance, endotoxin has received the greatest amount of attention as a possible cause of the airway inflammation that occurs after grain dust exposure. Although endotoxin undoubtedly causes a portion of the changes seen after grain dust exposure, it is becoming clear that other substances play a role as well.

Meta-analyses of prostate cancer and farming

Articles published in peer-reviewed journals between January 1983 and June 1994 were reviewed for inclusion in a meta-analysis designed to estimate the relative risk of prostate cancer in farmers. Three analyses were performed: (1) an analysis including all articles written during the specified time period that listed an estimate of the relative risk of prostate cancer in farmers: (2) an analysis that included only retrospective studies; and (3) an analysis that included only studies reporting a standardized mortality ratio. Positive associations between prostate cancer and farming were found by the analysis including all studies and the analysis limited to the retrospective studies. No association was found with the analysis that included only studies reporting a standard mortality ratio. The most plausible explanation for the positive association between prostate cancer and farming is exposure to hormonally active agricultural chemicals.

[The epidemiological characteristics of brucellosis in the primary health care district of Sierra de Cádiz]

OBJECTIVES

To find the incidence of brucellosis, and analyse its epidemiological characteristics and the evolution of the cases recorded in the Sierra de Cádiz Primary Care (PC) Area during 1992.

DESIGN

A prospective longitudinal incidence analysis, with a nested study of cases and controls.

SETTING

Sierra de Cádiz PC Area.

PATIENTS AND OTHER PARTICIPANTS

CASES

members of the cohort who developed the disease.

CONTROLS

sample of members of the cohort free of Brucellosis paired for age, gender and town of origin.

MEASUREMENTS AND MAIN RESULTS

Incidence was 52.39 per 100,000, 66.27 and 38.20 per 100,000 in men and women, respectively. Highest incidence was at between 15 and 49 years of age (67.70 per 100,000). CASES in the Spring predominated (chi 2 = 16.77, gl = 3, p < 0.05). The most affected professional group was farmers/herders (RR = 4.59, CI 95%, 2.05-10.26).

CONCLUSIONS

The Sierra de Cádiz is an area with endemic brucellosis, especially in the districts of Olvera and Ubrique. Its work-related character is clear, in spite of the digestive tract being the main transmission path.

Cancer mortality among rice growers in Novara Province, northern Italy

Some excess of non-Hodgkin lymphomas (NHL) and soft tissue sarcomas (STS) was reported in the literature among agricultural workers, mainly in relation to exposure to phenoxyacids and chlorophenols. In this study, information was analyzed for a cohort of rice growers that comprised 1,493 subjects, and for a follow-up that was more than 99% complete with regard to both traced subjects and known causes of deaths. A total of 960 subjects (65%) died during the observation period (1957-1992). Lower than expected standardized mortality ratios (SMRs) were found for all causes, for cardiovascular diseases (especially ischemic heart disease) and for all cancers. Slightly increased SMRs were found for some cancer sites (oral cavity, esophagus, liver, intestines, pancreas, bladder, STS, and NHL), although none of these was statistically significant in the overall analysis. An excess risk of close to statistical significance was found for NHL among workers with longer exposure during the period when phenoxyacid herbicide was in use (1950-1992). Thus, a prolonged follow-up is advisable. At present the study should be evaluated in the context of the data set suggesting a tendency toward an increased risk of NHL among farmers.

Association between female infertility and agricultural work history

Lifetime industrial and occupational histories of women with a medically-confirmed diagnosis of infertility (n = 281) were compared to a group of postpartum women (n = 216) for risks of infertility. Controlling for age of first pregnancy or self-report of infertility, date of outcome, cigarette use, and employment in other types of industries, women were at increased risk of infertility if they had worked in industries associated with agriculture (OR = 7.0, 95% CI 2.3-20.8; cases = 11.7%, controls = 1.9%). Among the occupations in which women worked prior to outcome, only those in agriculture were at significantly elevated risk (adj. OR = 11.3, CI 2.6-48.8; cases = 10.0%, controls = 0.9%). Among those who resided on a farm, the risk of infertility was significantly increased (adj. OR = 1.8, CI 1.2-2.7; cases = 37.4%, controls = 25.8%) although yearly duration of farm residence was not (adj. OR = 0.99, CI 0.95-1.03). Farm residence did not alter the OR seen in agricultural industries or occupations. The risk of being diagnosed with an ovulatory or tubal factor increased 4-16-fold among those who had worked in agricultural industries or occupations. These data suggest that, as has been established in men, agriculturally-related exposures may be a significant risk for infertility in women.

Cow hair allergen (Bos d 2) content in house dust: correlation with sensitization in farmers with cow hair asthma

Farmers (N = 45) suffering from occupational cow hair asthma were visited at home to evaluate the concentration of cow hair major allergen Bos d 2 in the house dust and to correlate these results with measures of avoidance, degree of sensitization, clinical symptoms, and lung function. Bos d 2 was determined by rocket immunoelectrophoresis. In dust of tiles and linoleum Bos d 2 was difficult to detect, whereas dust samples of carpets often contained high concentrations of the allergen (50-520 micrograms/g fine dust). Bos d 2 levels were significantly higher when barn and living quarters were in the same building. Concentrations of cow hair-specific IgE were correlated with concentrations of Bos d 2 in house dust samples. A concentration of 20-29 micrograms Bos d 2 per gram of house dust could be established as threshold value for relevant IgE sensitization. Avoiding the barn is not a sufficient avoidance measure for cow hair asthmatics if the partner continues cattle farming. Cessation of cattle farming and avoiding the former barn results in a marked reduction in Bos d 2 concentration in living quarters, a decreased degree of sensitization, and a reduced symptom score. Farmers with cow hair asthma should avoid cattle and thoroughly clean all carpets in the living quarters to avoid continuous cow allergen exposure.

Headaches and neck pain in farmers

The prevalence of headache and neck pain in farmers was determined by use of a questionnaire. Information about activities which increased the symptoms and about the treatments sought was also recorded. Results showed that 77.7% of farmers experienced neck pain and 79.2% experienced headache. Driving a tractor was the activity which was most frequently described as increasing symptoms in both conditions. While driving a tractor, farmers are exposed to whole-body vibration and assume a rotated neck posture. The contribution of these factors to the development of headache and neck pain is discussed.