Mortality among workers in an Italian cigarette factory.
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A cohort study was conducted to evaluate the mortality pattern among female and male workers in a cigarette factory. The study followed 972 female workers and 761 male workers with at least 6 months of cumulative employment from 1 January 1962 through 1 July 1996. Among women, mortality from all causes of death [standardized mortality ratio (SMR) = 0.9; 95% confidence interval (CI) = 0.8-1.1] and mortality from all malignant neoplasms (SMR = 1.1; CI = 0.9-1.3) were consistent with reference rates. Male workers had a significantly reduced overall mortality (SMR = 0.8; CI = 0.7-0.9), while mortality from all malignant neoplasms was as expected (SMR = 0.9; CI = 0.7-1.0). Among female workers the frequencies of deaths from diseases of nervous system (SMR = 2.0; CI = 1.1-3.4) and from non-Hodgkin's lymphoma (NHL) (SMR = 2.7; CI = 1.0-5.6) were elevated at a statistically significant level. No association between duration of employment and diseases of nervous system was observed. A higher risk for NHL, based on three deaths, was reported among female workers with 15 or more years of employment (SMR = 8.1; CI = 2.2-21.0). Although based on small numbers, the excess of NHL here reported suggests that potential exposure to foliar residues of pesticides should be thoroughly considered in tobacco manufacturing. (+info)
Use of Beauveria bassiana to control northern fowl mites (Ornithonyssus sylviarum) on roosters in an agricultural research facility.
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Treatment of Northern fowl mite (Ornithonyssus sylviarum) infestation on poultry in research facilities can be challenging. The mite has a rapid reproductive cycle (egg to adult in 5 to 7 d), and chemical treatments can be toxic to birds, personnel, and the environment. In addition, antimite treatment may interfere with experimental research designs. The current study evaluated the efficacy of topical application of an entomopathogenic fungus, Beauveria bassiana, in the treatment of a naturally occurring infestation of Northern fowl mites in pen-housed roosters (n = 14; age, 18 mo). Two groups of 7 roosters each were used in 2 experiments: Beauveria (30 mL, 2.9 x 10(10) spores per bird) compared with water (30 mL, control), and Beauveria compared with the common topical organophosphate agent tetrachlorvinphos-dichlorvos (30 mL). We also assessed a higher dose of Beauveria (300 mL, 2.9 x 10(11) spores per bird) in the 7 birds that were not exposed to tetrachlorvinphos-dichlorvos. Beauveria reduced mite levels relative to the control group but did not outperform tetrachlorvinphos-dichlorvos when used at an equal volume and frequency. Increasing the volume and frequency of Beauveria application improved outcomes such that visual inspection failed to detect any mites. The results presented here suggest that, when applied in sufficient doses, Beauveria effectively reduces mites on poultry and can be an important part of an integrated pest management program. Additional research is needed to document the most effective dose, frequency, and location of B. bassiana application to control Northern fowl mites in poultry. (+info)
Dual effects of tetrachlorvinphos on procaine toxicity and procainesterase activity in rats.
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The effect of tetrachlorvinphos (TCVP) on liver procainesterase (PROCase) and procaine toxicity was studied in rats. TCVP is an organophosphate with an inducible effect on drug metabolizing enzymes. A single oral dose of 500 mg/kg of TCVP caused a remarkable decrease in PROCase (40% of control) 24 hr later and increased the motality after injection of procaine (250 mg/kg, i.p.) from 54% to 87%. Conversely, it was observed that PROCase elevated to 140% of the control and mortality decreased from 54% to 25% on day 3. With repeated administration of TCVP (500 mg/kg/day) for 5 days, the PROCase activity that was inhibited on day 1 was gradually restored to normal levels by 5 days and the mortality altered to 25%. The inducible effect on PROCase was examined using desmethyl-TCVP, a metabolite of TCVP without inhibitory effect on the enzyme; PROCase activity was enhanced to 1.6-fold of the control and procaine concentration in the brain was reduced to 30% of the control, accompanied with no death of rats after procaine injection. Electrophoresis of the solubilized liver microsomal fraction confirmed the inducible effect of TCVP on PROCase; microsomal protein from the TCVP-treated rat was more deeply stained than that from the control, and the PROCase activity of two anodic bands increased in the TCVP-treated microsomes. These results indicate that TCVP has a dual action on PROCase, inducible and inhibitory, and that the direct inhibitory effect of TCVP might mask the increased amount of the enzyme induced by repeated administration of TCVP. The dual effect of TCVP on PROCase would cause the change in procaine toxicity. (+info)
Use of insecticide-impregnated ear tags for the control of face flies and horn-flies on pastured cattle.
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Three studies were conducted to evaluate the effectiveness of insecticide-impregnated ear tags in controlling face flies, Musca autumnalis DeGeer, and horn flies, Haematobia irritans (Linn.), on pastured beef cattle. In one 16-week trial, polyvinyl chloride (PVC) ear tags treated with stirofos (Rabon) insecticide reduced horn fly numbers by 79% (P less than .05) and face fly numbers by 30% (P less than .05). Coumaphos (Co-Ral) insecticide dust bags used in a separate herd produced an 86% (P less than .05) reduction in horn flies and an 18% (P less than .05) reduction in face flies. In the second study, 5 and 10% permethrin (Atroban), PVC-treated ear tags in a one-piece design were tested. In this 11 week trial, horn fly control averaged 95% (P less than .05) with the 10% tag and 77% (P less than .05) with the 5% tag. Face fly control averaged 49% (P less than .05) for 8 weeks with the 10% permethrin tag. No significant face fly control was achieved with the 5% permethrin tag. In a herd treated with coumaphos dust bags, horn fly control averaged 93% (P less than .05) and face fly control averaged 34% (P less than .05). The third study tested 5 and 10% permethrin, PVC-treated ear tags in a two-piece design and two-piece 5% permethrin-treated ear tags in a polyurethane matrix. Fourteen-week horn fly control averaged 88% (P less than .05) with the 10% PVC-treated tag, 83% (P less than .05) with the 5% PVC-treated tag, 71% (P less than .05) with the 5% polyurethane-treated tag and 74% (P less than .05) with coumaphos dust bags. Face fly control averaged less than 50% (P greater than .05) throughout the trial with all treatments. (+info)