Upper limit on the photon fraction in highest-energy cosmic rays from AGASA data.

A new method to derive an upper limit on photon primaries from small data sets of air showers is developed which accounts for shower properties varying with the primary energy and arrival direction. Applying this method to the highest-energy showers recorded by the AGASA experiment, an upper limit on the photon fraction of 51% (67%) at a confidence level of 90% (95%) for primary energies above 1.25 x 10(20) eV is set. This new limit on the photon fraction above the Greisen-Zatsepin-Kuzmin cutoff energy constrains the -burst model of the origin of highest-energy cosmic rays.

The potential role of rodents in the enzootic cycle of Rift Valley fever virus in Senegal.

Wild rodents (214) of fourteen species were trapped at seven sites in Senegal. Arvicanthis niloticus and Mastomys erythroleucus were among the most frequently collected species (77.2% of total capture). All rodents were examined for the presence of anti-Rift Valley fever virus (RVFV) antibody; the prevalence over all sampled species was 3.8%, varying widely with respect to species and location. Four of 14 species of rodents were found to have anti-RVFV antibodies: Rattus rattus (one positive of two tested) Mastomys huberti (13.5%), A. niloticus (4.3%), and M. erthroleucus (2.4%). The highest prevalence of anti-RVFV antibody was recorded within the enzootic area of the Senegal River delta, at Richard Toll (9.6%). A. niloticus and M. erythroleucus and a strain of laboratory-bred mice were experimentally inoculated with two strains of RVFV and examined for viremia, illness, seroconversion and mortality. A. niloticus and M. erythroleucus demonstrated a limited resistance to infection, thus potentially allowing for the replication of virus in these animals and making these species possible candidates as hosts in the maintenance cycle of RVFV in nature.

Prevalence of asthma and respiratory symptoms in dairy farmers in the French province of the Doubs.

With the aim of determining whether dairy farming is associated with an excess of asthma and respiratory symptoms, we compared the respiratory status in a sample of dairy farmers (n = 265) and a control group of nonexposed subjects (n = 149). The study protocol comprised a questionnaire, spirometry, and a bronchodilatation test (400 micrograms salbutamol powder), and an allergological evaluation: serum total IgE level, Phadiatop test, and skin prick tests (SPT) for seven inhalant allergens. Cumulative prevalences of self-reported asthma and of current asthma were respectively 5.3% and 1.5% in farmers, and respectively 3.4% and 1.3% in control subjects (both NS). Prevalences of all the respiratory symptoms studied were higher in farmers, with statistically significant differences after adjusting for age, sex, and smoking, for wheezing ever (OR: 2.7, p < 0.05), wheezing within the last year (OR: 5.2, p < 0.025), usual morning cough (OR: 5, p < 10(-)3), usual morning phlegm (OR: 11.3, p < 10(-)4), and chronic bronchitis (OR: 11.8, p < 0.01). The effect of exposure on these symptoms was more pronounced than, or of the same magnitude as that of smoking. Smoking and exposure had an additive effect except for chronic cough for which a positive interaction was observed (p = 0.05). Mean FEV1/VC (percentage of predicted) was statistically negatively correlated to dairy farming (p < 0.025) after adjusting for confounders. Bronchial obstruction was reversible in about 10% of subjects in both groups. In conclusion, this study mainly demonstrated an excess of respiratory symptoms in dairy farmers which is weak and nonsignificant for asthma, and high for cough, phlegm, and chronic bronchitis. It also suggested that the combined effect of farming and smoking was synergistic on chronic cough.

[Respective influence of occupational and personal factors on respiratory function in dairy farmers]. / Influence respective des facteurs professionnels et personnels sur la fonction respiratoire en milieu agricole de production laitière.

Occupational and individual factors influencing respiratory function were analysed in a sample of dairy farmers. The study protocol included a medical questionnaire, an occupational questionnaire, spirometry and allergological tests (skin prick tests for a panel of inhalant allergens, serum total IgE level and Phadiatop (CAP System). Two hundred and forty-five farmers were studied (140 men, 105 women with an average age of 45.9 (11.3) years, 35 were smokers, 27 ex-smokers and 183 non-smokers). A multiple linear regression model was used to analyse the correlations between respiratory function and the different independent variables. There was a statistically significant negative correlations between smoking (expressed in pack-years) and all the respiratory function parameters (p < 0.01). Respiratory function was significantly impaired in farmers working on traditional farms (p < 0.05 for VC and for FEV1), and the respiratory function values increased proportionally with the modernisation of the farms (notably using an artificial barn drying system for hay and a ventilation system for the cow byres). No significant relationship between respiratory function and quantitative indicators of exposure (size of farm, amount of livestock, quantity of hay handled during professional lifetime) or indicators of IgE-mediated allergy was observed. In conclusion, this study suggests that traditional work conditions in farms which have little mechanisation are, along with tobacco, the determining factors for the respiratory function impairment in dairy farmers.

[Prevalence of immediate allergy to respiratory allergens in fodder farmers in Doubs]. / Prévalence de l'allergie immédiate aux pneumallergènes chez les agriculteurs fourragers du Doubs.

The Doubs is a damp, semi-mountainous fodder farming department in which occupational respiratory diseases (including asthma) are common in farmers. We studied the prevalence of IgE-mediated allergy (total IgE, Phadiatop and skin prick tests) in a group of 265 exclusive dairy farmers of both sexes of the department and in a control group of non exposed, administrative workers living in the same area. Skin prick tests were: Dermatophagoides pteronyssinus, Acarus siro, cat hair, cow danders, grass pollens, betullacea pollens (trees from the East of France), and hay extracts from the Doubs. Total IgE were higher than 180 KUI/l in 26 (9.9%) farmers and in 15 (10.5%) controls (NS). Phadiatop was positive in 41 (15.7%) farmers and in 27 (19%) controls (NS). Prevalence of positive skin prick tests (at least one) in farmers and controls was respectively 36% and 40% (NS). Farmers were more frequently sensitized to hay extracts (OR = 1.7), cow danders (OR = 1.3) and less frequently to cat hair (OR = 0.63) than controls but the differences were not statistically significant. In conclusion, this study fails to give evidence of a risk of IgE-mediated allergy to work-related and other common inhalation allergens in dairy farmers the Doubs.

[Ossified bronchial neuroendocrine tumors: 3 cases]. / Tumeurs neuro-endocrines bronchiques ossifiées: trois observations.

Large calcium deposits can occur in neuroendocrine tumours of the bronchi and have been observed more frequently with the development of tomodensitometry which is now used for the diagnosis of calcified lung tumours including neuroendocrine tumours. The knowledge of such calcified images should not however mask the possibility of a malignant tumour.