Allergen sensitization linked to climate and age, not to intermittent-persistent rhinitis in a cross-sectional cohort study in the (sub)tropics

Background: Allergen exposure leads to allergen sensitization in susceptible individuals and this might influence allergic rhinitis (AR) phenotype expression. We investigated whether sensitization patterns vary in a country with subtropical and tropical regions and if sensitization patterns relate to AR phenotypes or age. Methods: In a national, cross-sectional study AR patients (2-70 y) seen by allergists underwent blinded skin prick testing with a panel of 18 allergens and completed a validated questionnaire on AR phenotypes. Results: 628 patients were recruited. The major sensitizing allergen was house dust mite (HDM) (56%), followed by Bermuda grass (26%), ash (24%), oak (23%) and mesquite (21%) pollen, cat (22%) and cockroach (21%). Patients living in the tropical region were almost exclusively sensitized to HDM (87%). In the central agricultural zones sensitization is primarily to grass and tree pollen. Nationwide, most study subjects had perennial (82.2%), intermittent (56.5%) and moderate-severe (84.7%) AR. Sensitization was not related to the intermittent-persistent AR classification or to AR severity; seasonal AR was associated with tree (p < 0.05) and grass pollen sensitization (p < 0.01). HDM sensitization was more frequent in children (0-11 y) and adolescents (12-17 y) (subtropical region: p < 0.0005; tropical region p < 0.05), but pollen sensitization becomes more important in the adult patients visiting allergists (Adults vs children + adolescents for tree pollen: p < 0.0001, weeds: p < 0.0005). Conclusions: In a country with (sub)tropical climate zones SPT sensitization patterns varied according to climatological zones; they were different from those found in Europe, HDM sensitization far outweighing pollen allergies and Bermuda grass and Ash pollen being the main grass and tree allergens, respectively. Pollen sensitization was related to SAR, but no relation between sensitization and intermittent-persistent AR or AR severity could be detected. Sensitization patterns vary with age (child HDM, adult pollen). Clinical implications of our findings are dual: only a few allergens –some region specific- cover the majority of sensitizations in (sub)tropical climate zones. This is of major importance for allergen manufacturers and immunotherapy planning. Secondly, patient selection in clinical trials should be based on the intermittent-persistent and severity classifications, rather than on the seasonal-perennial AR subtypes, especially when conducted in (sub)tropical countries

Bioinoculantes y abonos orgánicos en la producción de maíz forrajero

Abstract Introduction The forage production in the Comarca Lagunera is intensive, so there is not enough time that allows the soil to recover. Silage corn crop in this region is second in importance with respect to the harvested area; that is why it is essential to search for strategies to recover the quality of the soils without affecting the yield. Method The production of silage corn was evaluated with the hybrid P3258W, from Pioneer. A commercial bio-inoculant was applied to the soil at doses of 0, 20 and 40 l ha-1, in combination with seven sources of fertilizer: vermicompost at 5 and 10 t ha-1, dairy cow manure in 80 t ha-1, inorganic fertilizer (191-75-30 NPK), and a commercial organic fertilizer at doses of 2.5 and 5 l ha-1 and the control. The experimental design was in randomized blocks, and the treatments in a split-plot arrangement, where the main plot was the bio-inoculant and the subplot was the source of fertilization. The variables evaluated were fresh and dry forage yield, plant height at harvest; soil samples taken after the harvest were evaluated for: organic matter, pH, electrical conductivity, inorganic nitrogen and phosphorus. In plant samples taken at harvest, total nitrogen and phosphorus were determined. Results There was significant differences in yield with respect to the fertilizer source and the best treatment was manure applied at a dose of 80 t ha-1. In the characteristics of the soil: organic matter, nitrogen and phosphorus showed significant differences among doses of soil bio-innoculant and among fertilizer sources. For plant nitrogen, differences were significant among doses of bio-inoculant and among fertilizer sources. In the case of plant phosphorus, the analysis showed a significant interaction among doses of bio-inoculant and fertilizer sources. Conclusion The production of silage corn can be carried out using bio-inoculants and organic fertilizers without affecting the yield and improving the content of organic matter, nitrogen phosphorus in the soil.Resumen Introducción La producción de forrajes en la Comarca Lagunera se realiza de forma intensiva, por lo que no hay un intervalo de tiempo que le permita al suelo recuperarse. El cultivo de maíz forrajero en esta región es el segundo en importancia, por lo que es imprescindible buscar estrategias que nos permitan recuperar la calidad de los suelos sin que el rendimiento se vea afectado. Método Se evaluó la producción de maíz forrajero con el híbrido P3258W de Pioneer. Se usó un bioinoculante comercial para suelo con dosis de 0, 20 y 40 l ha-1, en combinación con siete fuentes de fertilizante: vermicompost en 5 y 10 t ha-1, estiércol de bovino lechero en 80 t ha-1, fertilizante inorgánico (191-75-30 de NPK), un fertilizante comercial orgánico a dosis de 2.5 y 5 l ha-1 y el testigo. El diseño experimental fue en bloques al azar, con arreglo de tratamientos en parcelas divididas, donde la parcela mayor fue el bioinoculante y la parcela menor la fuente de fertilización. Las variables que se evaluaron fueron rendimiento de forraje verde y seco, altura de planta a la cosecha; antes y después de la cosecha se evaluó en muestras de suelo: materia orgánica, pH, conductividad eléctrica, nitrógeno inorgánico y fósforo. En muestras de planta tomadas en la cosecha se determinó nitrógeno y fósforo totales. Resultados Hubo diferencia significativa en cuanto al rendimiento respecto a la fuente de fertilizante y el mejor tratamiento fue donde se aplicó estiércol a una dosis de 80 t ha-1. En las características del suelo: materia orgánica, nitrógeno y fósforo se observaron diferencias significativas entre dosis de bioinoculante del suelo y entre fuentes de fertilizante. Para el nitrógeno en planta, las diferencias fueron significativas entre dosis de bioinoculante del suelo y entre fuentes de fertilizante. En la concentración de fósforo en planta, el análisis mostró una interacción significativa entre dosis de bioinoculante del suelo y fuentes de fertilizante. Conclusión Se puede llevar a cabo la producción de maíz forrajero utilizando bioinoculantes y abonos orgánicos sin que el rendimiento se vea afectado y se favorece el contenido de materia orgánica, nitrógeno y fósforo en el suelo