Contribution of ambient ozone to changes in Scots pine defoliation. Step II of Lithuanian studies.
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This study aimed to explore if changes in peak ozone (O3) concentrations may reinforce the phytotoxic effects of air concentration of acidifying compounds and their deposition, as well as unfavorable climatic factors on pine crown defoliation. Forty-eight pine stands with more than 8000 sample pine trees have been monitored annually. The impact of sulfur dioxide (SO2) on pine defoliation was found to be the most significant. The impacts of peak O3 concentrations, acid deposition, and amount of precipitation were considerably lower, whereas the impact of air temperature, the least. Contribution of peak O3 concentrations to the integrated impact of acid deposition and amount of precipitation on pine defoliation was most significant, whereas the contribution to the impact of acidifying air compounds, mainly SO2, was the least. No synergetic effect between peak O3 concentrations and high temperature during vegetation period was detected. (+info)
Effect of meteorological factors on clinical malaria risk among children: an assessment using village-based meteorological stations and community-based parasitological survey.
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BACKGROUND: Temperature, rainfall and humidity have been widely associated with the dynamics of malaria vector population and, therefore, with spread of the disease. However, at the local scale, there is a lack of a systematic quantification of the effect of these factors on malaria transmission. Further, most attempts to quantify this effect are based on proxy meteorological data acquired from satellites or interpolated from a different scale. This has led to controversies about the contribution of climate change to malaria transmission risk among others. Our study addresses the original question of relating meteorological factors measured at the local scale with malaria infection, using data collected at the same time and scale. METHODS: 676 children (6-59 months) were selected randomly from three ecologically different sites (urban and rural). During weekly home visits between December 1, 2003, and November 30, 2004, fieldworkers tested children with fever for clinical malaria. They also collected data on possible confounders monthly. Digital meteorological stations measured ambient temperature, humidity, and rainfall in each site. Logistic regression was used to estimate the risk of clinical malaria given the previous month's meteorological conditions. RESULTS: The overall incidence of clinical malaria over the study period was 1.07 episodes per child. Meteorological factors were associated with clinical malaria with mean temperature having the largest effect. CONCLUSION: Temperature was the best predictor for clinical malaria among children under five. A systematic measurement of local temperature through ground stations and integration of such data in the routine health information system could support assessment of malaria transmission risk at the district level for well-targeted control efforts. (+info)
Alternaria alternata prevalence in cereal grains and soybean seeds from Entre Rios, Argentina.
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A mycological survey was carried out at Entre Rios province, Argentina, on sorghum grain, maize, rice, soybean seeds and on freshly harvested and stored wheat. The isolation frequencies and relative densities of species belonging to genera Alternaria, Aspergillus, Fusarium, Penicillium and other fungi were calculated. Alternaria alternata was the major fungal species isolated from sorghum, rice, soybean seeds and on freshly harvested wheat, and a low incidence of Fusarium species was observed on the same substrates. In maize the major fungal species isolated was Fusarium verticillioides. The high incidence levels of A. alternata observed,suggest that it may be necessary to determine, among other mycotoxins, if Alternaria toxins occur in these commodities. (+info)
Airborne allergenic pollen in natural areas: Hornachuelos Natural Park, Cordoba, southern Spain.
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The present study shows the results of monitoring the atmospheric pollen in the atmosphere of an area of natural vegetation, the Hornachuelos Natural Park, Cordoba, southern Spain, during a six years (1998-2003). Special attention was paid in the seasonal and intra-diurnal characteristics of airborne allergenic pollen. During this period, 31 pollen types were described, some of them rare in aerobiological analysis. High concentrations of allergenic pollen from entomophilous species and from areas at a long distance were found. Significant differences between pollen spectrum and pollen concentration of the natural study area and the surrounding cities were detected. Intra-diurnal pattern from trees surrounding the trap presented a clear peak at midday/afternoon. Pollen from taxa comprising many species and from species at far locations showed a smoother intra-diurnal pattern. The correlation with meteorological parameters was positive with maximum and mean temperatures, and negative with humidity and rainfall. (+info)
Relationship between daily suicide counts and temperature in England and Wales.
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BACKGROUND: Seasonal fluctuation in suicide has been observed in many populations. High temperature may contribute to this, but the effect of short-term fluctuations in temperature on suicide rates has not been studied. AIMS: To assess the relationship between daily temperature and daily suicide counts in England and Wales between 1 January 1993 and 31 December 2003 and to establish whether heatwaves are associated with increased mortality from suicide. METHOD: Time-series regression analysis was used to explore and quantify the relationship between daily suicide counts and daily temperature. The impact of two heatwaves on suicide was estimated. RESULTS: No spring or summer peak in suicide was found. Above 18 degrees C, each 1 degrees C increase in mean temperature was associated with a 3.8 and 5.0% rise in suicide and violent suicide respectively. Suicide increased by 46.9% during the 1995 heatwave, whereas no change was seen during the 2003 heat wave. CONCLUSIONS: There is increased risk of suicide during hot weather. (+info)
Role of meteorological factors in duodenal ulcer seasonality: a nation-wide, population-based study.
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BACKGROUND: Understanding disease seasonality can provide guidance for future biomedical research. OBJECTIVE: To examine whether meteorological factors and calendar months impact duodenal ulcer (DU) exacerbations. DESIGN: We conducted a retrospective time series analysis of population-based claims data. PARTICIPANTS: DU inpatients (1997-2003; all endoscopy confirmed) from Taiwan, a small island nation, n = 160,510. Inpatient admission was used as a proxy for exacerbation because 98.5% of cases had hemorrhage or perforation or both. MEASUREMENTS: We used multivariate autoregressive integrated moving average (ARIMA) modeling to examine if DU admissions/100,000 was associated with calendar month, ambient temperature, relative humidity, rainfall, atmospheric pressure, and sunshine hours, controlling for available DU-relevant comorbidities. RESULTS: DU admissions increased with age. ARIMA modeling showed a February (Chinese New Year-related) trough in all age groups (all p < 0.001; adjusted for meteorological variables and comorbidities), consistent with a February dip in all-cause admissions. Among 35-49 and 50+ age groups, DU admissions were negatively associated with temperature (both p < 0.05; model R2 = 0.875 and 0.920, respectively), representing a winter peak and summer trough. Among the < or = 19 age group, sunshine hours and rainfall are positively associated with DU admissions (both p < 0.001; R2 = 0.565), representing a summer peak. CONCLUSION: Meteorological variables are associated with DU exacerbations, although the potential role of nonsteroidal anti-inflammatory drug (NSAID) use because of seasonal acute respiratory illness cannot be ruled out. We recommend in-depth studies using chart reviews of DU patients admitted during peak and trough (incidence) months to clarify whether meteorological factors or the associated seasonal peaks of respiratory and other illnesses involving NSAID use are responsible for the observed seasonality. (+info)
How human practices have affected vector-borne diseases in the past: a study of malaria transmission in Alpine valleys.
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BACKGROUND: Malaria was endemic in the Rhone-Alpes area of eastern France in the 19th century and life expectancy was particularly shortened in Alpine valleys. This study was designed to determine how the disease affected people in the area and to identify the factors influencing malaria transmission. METHODS: Demographic data of the 19th century were collected from death registers of eight villages of the flood-plain of the river Isere. Correlations were performed between these demographic data and reconstructed meteorological data. Archive documents from medical practitioners gave information on symptoms of ill people. Engineer reports provided information on the hydraulic project developments in the Isere valley. RESULTS: Description of fevers was highly suggestive of endemic malaria transmission in the parishes neighbouring the river Isere. The current status of anopheline mosquitoes in the area supports this hypothesis. Mean temperature and precipitation were poorly correlated with demographic data, whereas the chronology of hydrological events correlated with fluctuations in death rates in the parishes. CONCLUSION: Nowadays, most of the river development projects involve the creation of wet areas, enabling controlled flooding events. Flood-flow risk and the re-emergence of vector-borne diseases would probably be influenced by the climate change. The message is not to forget that human disturbance of any functioning hydrosystem has often been linked to malaria transmission in the past. (+info)
Seasonal variation in the incidence of preeclampsia and eclampsia in tropical climatic conditions.
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BACKGROUND: Observational studies have demonstrated various correlations between hypertensive disorders of pregnancy and different weather parameters. We aim to study if a correlation exists between the incidence of eclampsia and pre-eclampsia and various weather parameters in the tropical coastal city of Mumbai which has the distinction of having relatively uniform meteorological variables all throughout the year, except for the monsoon season. METHODS: We retrospectively analysed data from a large maternity centre in Mumbai, India over a period of 36 months from March 1993 to February 1996, recording the incidence of preeclampsia and eclampsia. Meteorological data was acquired from the regional meteorological centre recording the monthly average temperature, humidity, barometric pressure and rainfall during the study period. Study period was then divided into two climate conditions: monsoon season (June to August) and dry season September to May. The incidence of preeclampsia and eclampsia and the meteorological differences between the two seasons were compared. RESULTS: Over a 36-month period, a total of 29562 deliveries were recorded, of which 1238 patients developed preeclampsia (4.18%) and 34 developed eclampsia (0.11%). The incidence of preeclampsia did not differ between the monsoon and the dry season (4.3% vs. 4.15%, p = 0.5). The incidence of eclampsia was significantly higher in the monsoon (0.2% vs. 0.08%, p = 0.01). The monsoon was significantly cooler (median maximum temperature 30.7 degrees C vs. 32.3 degrees C, p = 0.01), more humid (median relative humidity 85% vs. 70%, p = 0.0008), and received higher rainfall (median 504.9 mm vs. 0.3 mm, p = 0.0002) than the rest of the year. The median barometric pressure (1005 mb) during the monsoon season was significantly lower than the rest of the year (1012 mb, p < 0.0001). CONCLUSION: In the tropical climate of Mumbai, the incidence of eclampsia is significantly higher in monsoon, when the weather is cooler and humid with a lower barometric pressure than the rest of the year. This effect is not seen with preeclampsia. This strengthens the association of low temperature and high humidity with triggering of eclampsia. (+info)