[Outdoor aeroallergens and climate change]. / Les aéroallergènes de l'environnement extérieur et le changement climatique.

INTRODUCTION: Pollen and fungal spore concentrations in outdoor air are partly dependent on atmospheric conditions. Since the climate is changing, there is a growing body of research on the effects of climate change on aeroallergens. The present article provides a rapid review of this literature, highlighting the points of agreement, but also drawing attention to the main mistakes to be avoided. STATE OF ART: For pollen, the prevailing view is that rising temperatures lead to an earlier start to the pollen season, a longer season, increased allergenic potential and higher concentrations. However, there are exceptions: what is true for one taxon, in one place and at one time, can almost never be generalised. For fungal spores, it is even more difficult to state universal rules. PERSPECTIVES: Four priorities can be set for future research: (1) to look for trends only on sufficiently long series and not to neglect possible trend reversals; (2) to give priority to the local scale and the separate consideration of the various pollen and mycological taxa; (3) not to limit oneself to temperature as an element of explanation, but also to consider the other elements of the climate; (4) not to try to explain any evolution in the abundance or seasonality of aeroallergens by climate change alone. CONCLUSIONS: Many more analytical studies giving precedence to observation over reasoning are still required, without any preconceptions, before it is possible to synthesise the impacts of climate change on pollen and, even more so, on fungal spores.

Short-term effects of airborne ragweed pollen on clinical symptoms of hay fever in a panel of 30 patients.

OBJECTIVES: Ragweed, Ambrosia artemisiifolia, is a highly allergenic annual herbaceous plant that is spreading quickly across the globe. Few studies have investigated the relationship between ragweed pollen counts and hay fever symptoms. We investigate the dose-response relationship between ragweed exposure in patients sensitized to ragweed and daily hay fever symptoms. METHOD: A panel study was conducted among 31 adult patients sensitized to A artemisiifolia in France and Switzerland. Rhinitis, conjunctivitis, and bronchial symptoms were recorded daily, as well as daily pollen counts of ragweed, air pollutants, and meteorological data over 2 successive years. Data were analyzed with generalized estimating equation models to quantify effects of ragweed pollen whilst controlling for confounders. RESULTS: The relationship between ragweed pollen and the percentage of patients with nasal, ocular, and bronchial symptoms was linear. For every increase of 10 grains/m3, the odds ratio (OR) (95% confidence interval) for nasal symptoms was, in 2009, 1.18 [1.04-1.35] on weekdays and 1.43 [1.16-1.75] at weekends, and in 2010, 1.04 [1.00-1.07] on weekdays and 1.25 [1.06-1.46] at weekends.The OR for ocular symptoms was 1.32 [1.16-1.56] in 2009 and 1.05 [1.02-1.07] in 2010. Finally, the OR for bronchial symptoms was 1.14 [1.03-1.25] in 2009 and 1.03 [0.97-1.08] in 2010. CONCLUSION: There is a statistically significant linear relationship between ragweed pollen counts and hay fever symptoms. Our study shows that nasal symptoms differ on weekdays and at weekends.

Short-term effects of airborne ragweed pollen on clinical symptoms of hay fever in a panel of 30 patients

Objectives: Ragweed, Ambrosia artemisiifolia , is a highly allergenic annual herbaceous plant that is spreading quickly across the globe. Few studies have investigated the relationship between ragweed pollen counts and hay fever symptoms. We investigate the dose-response relationship between ragweed exposure in patients sensitized to ragweed and daily hay fever symptoms. Method: A panel study was conducted among 31 adult patients sensitized to A artemisiifolia in France and Switzerland. Rhinitis, conjunctivitis, and bronchial symptoms were recorded daily, as well as daily pollen counts of ragweed, air pollutants, and meteorological data over 2 successive years. Data were analyzed with generalized estimating equation models to quantify effects of ragweed pollen whilst controlling for confounders. Results: The relationship between ragweed pollen and the percentage of patients with nasal, ocular, and bronchial symptoms was linear. For every increase of 10 grains/m 3 , the odds ratio (OR) (95% confidence interval) for nasal symptoms was, in 2009, 1.18 [1.04-1.35] on weekdays and 1.43 [1.16-1.75] at weekends, and in 2010, 1.04 [1.00-1.07] on weekdays and 1.25 [1.06-1.46] at weekends. The OR for ocular symptoms was 1.32 [1.16-1.56] in 2009 and 1.05 [1.02-1.07] in 2010. Finally, the OR for bronchial symptoms was 1.14 [1.03- 1.25] in 2009 and 1.03 [0.97-1.08] in 2010. Conclusion: There is a statistically significant linear relationship between ragweed pollen counts and hay fever symptoms. Our study shows that nasal symptoms differ on weekdays and at weekends (AU)

Objetivos: La Ambrosia artemisiifolia es una planta herbácea, altamente alergénica, que tiende a extenderse mundialmente muy rápidamente. Muy pocos estudios han investigado la relación de los contajes de polen de ambrosia con la intensidad de los síntomas. En este trabajo hemos documentado la relación dosis/respuesta entre la exposición a ambrosia, en pacientes sensibilizados a este polen, y la intensidad de su sintomatología Métodos: En el estudio se incluyeron 31 pacientes residentes en Francia o Suiza y sensibilizados a Ambrosia artemisiifolia . Durante dos años consecutivos, se registraron diariamente los síntomas oculares, nasales y bronquiales de los pacientes, los niveles de polen de ambrosía, los niveles de contaminantes ambientales junto con los datos. El análisis de los datos se realizó mediante la construcción de modelos de ecuaciones de estimación generalizada, de forma que se pudiera cuantificar los efectos del polen de ambrosia y controlando las variables de confusión. Resultados: La relación entre los recuentos de polen de ambrosía y el porcentaje de pacientes con síntomas nasales, oculares y bronquiales fue linear. Para cada incremento de 10 granos/m 3 , el OR para los síntomas nasales, en el año 2009, fue 1.18 [1.04-1.35] durante los días entre semana, y 1.43 [1.16-1.75] durante el fin de semana, y en 2010, 1.04 [1.00-1.07] durante los días entre semana y 1.25 [1.06-1.46] durante el fin de semana; el OR para los síntomas oculares fue de 1.32 [1.16-1.56] en el 2009 y 1.05 [1.02-1.07] en el 2010; el OR para los síntomas bronquiales fue 1.14 [1.03-1.25] en 2009 y 1.03 [0.97-1.08] en 2010. Conclusión: Hemos demostrado una relación lineal significativa entre los recuentos de polen de ambrosía y los síntomas de la polinosis en los pacientes sensibilizados. Nuestro estudio también demostró que el nivel de molestias difiere entre los días entre semana comparados con los del fin de semana (AU)

[Health impact of exposure to pollens: A review of epidemiological studies]. / Impact sanitaire des pollens : revue des études épidémiologiques.

The aim of this review is to describe the health impact of exposure to pollen based on recently published epidemiological studies. The methodology chapter, describes a review of the literature and outlines important elements of these studies: measurement of exposure to pollens, study types used, study populations and the health indicators related to pollen exposure. In this review, two types of studies have been used to assess the epidemiological evidence of short-term links between pollen exposure and hay fever or asthma. Ecological time-series studies use daily indicators of asthma exacerbations (emergency room admissions or hospitalizations), consultations for rhinitis or conjunctivitis, or anti-allergic drug consumption within general population. Panel studies relate measurements of pollen grain concentrations to nasal, ocular and bronchial symptom severity in a group of subjects sensitized to a specific pollen, monitored during the pollen season. In both cases, the studies show a relationship on a day-to-day basis between health indicators and daily rates of atmospheric pollen collected by a pollen trap. These studies take into account confounding factors, such as air pollution, weather factors and sometimes exposure to outdoor molds. Unlike earlier studies, more and more studies focus on the shape of the dose-response relationship and the lag between pollen exposure and symptoms. Only rarely, individual susceptibility factors, the clinical phenomenon of priming and polysensitization are reported. Thus, ecological time-series studies and panel studies assess respectively the impact of pollen exposure in the general population and in groups of sensitized patients. Using appropriate statistical tools, these studies provide insight into the shape of the dose-response relationship, with a potential threshold below which symptoms are absent, then a linear relationship for nasal, ocular and bronchial symptoms and a plateau where the symptoms do not increase despite the continued increase in pollen.

[Methods of studying airborne pollen and pollen calendars]. / Méthodes d'étude des pollens atmosphériques et calendriers polliniques.

INTRODUCTION: Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnosis, treatment and prevention, as well as for biomedical and biological research. Many aero-biological studies have been conducted all over the world to ascertain aerial concentrations and seasonality of pollen grains. BACKGROUND: Monitoring of airborne biological particles is carried out by various gravimetric, impaction, and suction sampling devices. The Hirst trap, later modified to Burkard(®) or Lanzoni(®) traps, is the most widely used sampler. Counting and identifying pollen grains is then performed under optical microscopy. Based on differences in airborne pollen recorded over several years of observation, pollen calendars have been drawn up as aids to allergy diagnosis and management but they could be replaced advantageously by allergy-risk calendars. Pollen counts also provide valuable information about the geographical origin of pollen grains. VIEWPOINTS: Since the identifying and counting of pollen grains in ambient air samples is still a demanding and time-consuming task, there is an increasing interest in the automation of pollen monitoring. Furthermore, the divergence sometimes observed between clinical observations and pollen counts provides an incentive to collect aero-allergens directly. Lastly, pollen monitoring could be improved through the use of personal bioaerosol samplers. CONCLUSIONS: Great progress has been made in aerobiology for over a century, but much remains to be accomplished, particularly in relation with the standardization of methods.

[Climate change and pollination]. / Changement climatique et pollinisation.

INTRODUCTION: There is growing evidence to support an increase in air temperature over recent decades, with significant effects on aeroallergens such as pollen. It is generally accepted that the trend will continue, and become even more pronounced in the future. BACKGROUND: Global climate change is already affecting, and will continue to affect, with earlier floral initiation, the timing of the production of allergenic pollen. In addition, a warmer climate might lead to a longer pollen season and more days with high pollen counts. It could also increase the allergen content of pollens, and result in extension of plant species towards the poles and higher altitudes. Finally, rising levels of atmospheric CO2 are likely to reinforce these trends. VIEWPOINT: These predictions are subject to uncertainties that may lead to outcomes that differ materially from what is expected. Understanding the magnitude and direction of the changes affecting pollinisation is critical in order to quantify the future allergic disease burden and model the impacts of different climate change scenarios. CONCLUSIONS: Climate change influences the production, distribution, dispersion and allergenicity of anemophilous pollen and the growth and distribution of weeds, grasses and trees that produce it. These changes in aeroallergens and subsequent human exposure could affect the prevalence and severity of allergic disorders. There is, therefore, an important public health issue that requires development and implementation of appropriate response strategies without delay.

Has allergenic pollen an impact on non-allergic diseases?

Recent observations suggest that pollen do not only interacts with the human immune system to elicit an allergic response in susceptible individuals. It would have a much broader impact on human health. This applies more especially, yet not exclusively, to three groups of diseases: non-allergic respiratory conditions, cardio- and cerebrovascular accidents, and psychiatric disorders including suicide and suicide attempt. At present, the reasons for these unexpected connections are only hypothetical, and require further exploration in larger samples, but there is perhaps a multitude of them. One must therefore favour a holistic approach of pollen and its impact on human health.

Forecasting the onset of an allergic risk to poaceae in Nancy and Strasbourg (France) with different methods.

Pollens of Poaceae are among the most allergenic pollen in Europe with pollen of birch. It is therefore useful to elaborate models to help pollen allergy sufferers. The objective of this study was to construct forecast models that could predict the first day characterized by a certain level of allergic risk called here the Starting Date of the Allergic Risk (SDAR). Models result from four forecast methods (three summing and one multiple regression analysis) used in the literature. They were applied on Nancy and Strasbourg from 1988 to 2005 and were tested on 2006. Mean Absolute Error and Actual forecast ability test are the parameters used to choose best models, assess and compare their accuracy. It was found, on the whole, that all the models presented a good forecast accuracy which was equivalent. They were all reliable and were used in order to forecast the SDAR in 2006 with contrasting results in forecasting precision.

Prospective survey of indoor fungal contamination in hospital during a period of building construction.

An 18-month survey of indoor fungal contamination was conducted in one haematology unit during a period of construction work. Air was sampled with a portable Air System Impactor and surfaces with contact Sabouraud plates. During this survey the mean concentration of viable fungi in air was 4.2 cfu/m(3) and that for surfaces was 1.7 cfu/plate. At the beginning of construction work, there were increases in airborne fungal spores (from 3.0 to 9.8 cfu/m(3)) in the unit, but concentrations did not exceed 10 cfu/m(3) during the 18-month period. The most frequently recovered airborne fungi were Penicillium spp. (27-38%), Aspergillus spp. (25%) and Bjerkandera adusta, a basidiomycete identified with molecular tools (7-12%). Blastomycetes accounted for more than 50% of the fungal flora on surfaces. Investigating the impact of a new air-treatment system (mobile Plasmair units), there were significant reductions in fungal contamination for the Plasmer -treated rooms, and in these rooms we observed the same level of fungal load whether construction work was in progress or not.

Short-term effects of ozone air pollution on ischaemic stroke occurrence: a case-crossover analysis from a 10-year population-based study in Dijon, France.

OBJECTIVE: To evaluate the association between air pollutants and the occurrence of acute stroke from 10-year population-based study. METHODS: The daily stroke count was obtained from Dijon Stroke Register between March 1994 and December 2004. The register recorded all first-ever strokes among residents of Dijon (150,000 inhabitants) in France, using standard diagnostic criteria. Pollutant concentrations (SO2, CO, NO2, O3 and PM10) were measured hourly. A bi-directional case-crossover design was used to examine the association between air pollutant and stroke onset. The conditional logistic regression model included the meteorological parameters (temperature, relative humidity), influenza epidemics and holidays. RESULTS: The authors collected 493 large artery infarcts, 397 small artery infarcts, 530 cardio-embolic infarcts, 67 undeterminate infarcts, 371 transient ischaemic attacks and 220 haemorrhagic strokes. For single-pollutant model and for a 10 mg/m(3) increase of O3 exposure, a positive association was observed only in men, over 40 years of age, between ischaemic stroke occurrence and O3 levels with 1-day lag, (OR 1.133, 95% CI 1.052 to 1.220) and 0-day lag (OR 1.058, 95% CI 0.987 to 1.134). No significant associations were found for haemorrhagic stroke. In two-pollutant models, the effects of O3 remained significant after each of the other pollutants were included in the model, in particular with PM10. A significant association was observed for ischaemic strokes of large arteries (p = 0.02) and for transient ischaemic attacks (p = 0.01). Moreover, the authors found an exposure-response relations between O3 exposure and ischaemic stroke (test for trend, p = 0.01). An increase in association in men with several cardiovascular risk factors (smoker, dyslipidemia and hypertension) was also observed. CONCLUSION: These observational data argue for an association between ischaemic stroke occurrence and O3 pollution levels; these results still need to be confirmed by other studies.

Forecasting the onset of an allergic risk to poaceae in Nancy and Strasbourg (France) with different methods.

Pollen of Poaceae is among the most allergenic pollen in Europe with pollen of birch. It is therefore useful to elaborate models to help pollen allergy sufferers. The objective of this study was to construct forecast models that could predict the first day characterized by a certain level of allergic risk called here the Starting Date of the Allergic Risk (SDAR). Models result from four forecast methods (three summing and one multiple regression analysis) used in the literature. They were applied on Nancy and Strasbourg from 1988 to 2005 and were tested on 2006. Mean Absolute Error and Actual forecast ability test are the parameters used to choose best models, assess and compare their accuracy. It was found, on the whole, that all the models presented a good forecast accuracy which was equivalent. They were all reliable and were used in order to forecast the SDAR in 2006 with contrasting results in forecasting precision.

Reduced fungal contamination of the indoor environment with the Plasmair system (Airinspace).

Aspergillus spp. and other moulds cause life-threatening opportunistic infections in immunocompromised patients. Indoor contamination and construction work that liberate fungal spores are a major source of nosocomial aspergillosis. Dijon hospital is a tertiary care institution in northeast France undergoing construction work beside high-risk clinical units. To determine the impact of this activity, a surveillance programme was implemented one year before building work began in order to establish baseline levels of contamination. Air and surface fungal contamination in adult and paediatric haematology units were prospectively examined following use, or not, of a new air-treatment system with mobile Plasmair units (Airinspace). There were significant reductions in overall fungal contamination for the Plasmair treated rooms for air and surface samples in both clinical units. Plasmair treatment also significantly reduced A. fumigatus in the air. These data suggest that Plasmair units may provide an efficient method of reducing indoor fungal contamination in hospitals.

[How to predict the date of the start of the pollination of a plant from the meteorological data: the example of ragweed at Lyon]. / Comment prévoir la date de début de pollinisation d'une plante a partir des données météorologiques: l'exemple de l'ambroisie a Lyon.

The pollen of Ambrosia, highly allergenic, can be found in high quantities in the French regions of Burgundy, Auvergne and mostly a great part of the Rhône-Alpes region. The aim of this study was to establish some forecast models of the Starting Date of the Pollen season (SDP) of Ambrosia, in order to provide early information to allergists and allergic people. The pollen data came from the Hirst trap set up in Lyon since 1987 by the RNSA, and the meteorological data for the same period were provided by Météo-France. Two models were used, a sum of daily average temperatures and a multiple regression on all the 10-day period meteorological data. The results were quite accurate, except for 2003 with the temperature sums, probably because of very special meteorological conditions. So the models will have to be updated in this way.

[Seasonal variation in strokes incidence and the influence of the meteorological conditions]. / Variation saisonnière des accidents vasculaires cérébraux et influence des conditions météorologiques.

The aim of this paper was to study the seasonal and Monthly distribution of different subtypes of strokes, and also the influence of the most usual meteorological factors on their incidence. The study, based on the population-based data of the Dijon register of stroke (France), involved 3287 patients with a cerebrovascular event during the Years 1985-1998. The seasonal distribution pointed out a summer decrease for all stroke subtypes. The cerebrovascular risk was the highest in autumn for small artery atheroma infarcts and for cerebral infarcts and, among these later, for cardioembolic infarcts and large artery atheroma infarcts, as well as for subarachnoid hemorrhages and for the total number of strokes. It was followed by spring (total number of strokes, small artery atheroma infarcts, cerebral infarcts) and/or winter (subarachnoid hemorrhages, cerebral infarcts, cardioembolic infarcts and large artery atheroma infarcts). For intracerebral hemorrhages, the risk peaked in spring and secondly in autumn. But the difference from one season to another was significant only for total number of strokes, cerebral infarcts and, among the later, for cardioembolic infarcts and large artery atheroma infarcts. As regards the Monthly distribution, the difference between Months was significant only for the total number of strokes and cerebral infarcts, with a minimum from July to September and a maximum in October for the later. Correlations with meteorological data were found for the total number of strokes, cerebral infarcts, cardioembolic infarcts, large artery atheroma infarcts and small artery atheroma infarcts. They showed an influence of temperature and relative humidity of the day of stroke or of the one to five days before. Correlations with wind speed, duration of sunshine or snow, even if less frequent, could also be found. Such results sometimes differ from those of some earlier studies, for which the climate and the risk factors were not the same, showing that regional epidemiological studies are necessary in order to determine the relations between seasons, meteorological factors and strokes.

[The French Airborne Pollen Network: current situation and prospects for improvement]. / Le réseau français de surveillance aéropollinique: situation présente et perspectives d'optimisation.

The french network of aeropalynology includes traps very close together and vast areas without any trap as well. A study was launched in order to optimise this network, without the number of traps increasing too much. Five criteria are successively reviewed to rationalise the spatial cover. Equi-distance of sites has to be balanced by the number of concerned people. But the need for having long time series is incentive to delete only as a last resort the traps which are reliable for a long time. Moreover, apart from the general network, some local or regional features make indispensable a trap in such-and-such a place (health resort), or justify a higher density of traps in such-and-such an area (the Rhône-Alpes concerning ragweed, the Mediterranean South concerning cypress).

[Evolution of eosinophilia during the pollen season among the general population: a way of determining new sensitiziations]. / Evolution de l'eosinophilie au cours de la saison pollinique dans la population generale: un outil pour determiner de nouvelles sensibilisations.

The purpose of this paper was to verify the effect of pollen peaks on blood eosinophilia in an all and sundry population, including allergic as well as non-allergic subjects, so that we can open up new horizons in the understanding and prevention of pollinosis. Daily eosinophilia counts of hospital patients were measured at the time of a blood checkup (1996-1998), and divided into six classes. Those data were compared to daily pollen counts of twelve taxa, coming from the Hirst trap of Dijon (France). An eosinophilia increase occurred when hazel, hornebeam, birch, oak, grasses, ragweed and plantain were present in high concentration. In other cases, only simultaneous presence of several taxa seemed to play a part, because of cross-reactivity or polysensitization. Lastly, Cupressaceae-Taxaceae and ragweed were seen as increasing eosinophilia in seemingly non allergic people. The analysis of eosinophilia in the general population was able to reveal potential allergic patients and potential allergic diseases.

[Tropical climate pathology]. / La climatopathologie tropicale.

In addition to being a determinant factor for the development of infectious and parasitic diseases, tropical weather conditions can have harmful effects for the human organism different from those of temperate climates. Adverse effects can result from aggressive environmental factors such as ultraviolet radiation, extreme heat, abrupt changes in temperature, and tropical storms. In weather-sensitive subjects, exposure to tropical conditions increases the risk of acute reactions including ischemic heart disease, asthma attacks, and kidney stones. Adverse effects can be enhanced by suddenness of change in climate as underlined by the stress experienced by air travelers. In practice it is important to recognize that different tropical climates have different effects on health. Intertropical climates range from dry and rainy areas to plains and mountain areas. Knowledge of the concepts of climatopathology is necessary to advise patients on the choice of destination and the most favorable period for travel.

Weather conditions and cerebrospinal meningitis in Benin (Gulf of Guinea, West Africa).

Over a 28-year period cerebrospinal meningitis, in sporadic as well as epidemic situations, mainly affected the Beninese territory from November to March, April or sometimes May. On the average, the acme occurred in February-March. A regression analysis confirmed that 14 to 34.5% of the temporal variability of the disease was due to the northern trade wind (harmattan) and a low absolute humidity in the northern areas, which constitute the main epidemiological pole of the country. On the contrary, cerebrospinal meningitis and climate turned out to be fully independent one from the other in the southernmost areas, where the harmattan is seldom experienced although the meningitis belt is at the present time spreading southwards. But the case-fatality ratio was especially high in the coastal region and during the off season, i.e. when endemic meningitis predominantly affected small children aged under one year. In any way, the climate-meningitis relationship proved to be weaker than is sometimes assumed, perhaps because this relationship is partly overshadowed by both anthropic effects (vaccination campaigns) and latency before disease outbreak.