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PubMed2002

Climate change and skin cancer.

Depletion of the ozone layer and climate change by the increasing greenhouse effect are distinctly different processes. It is becoming quite clear, however, that the two global environmental problems are interlinked in several ways [D. L. Albritton, P. J Aucamp, G. Mégie, R. T. Watson, Scientific Assessment of Ozone Depletion, 1998, World Meteorological Organization, Global Ozone Research and Monitoring Project, Report No. 44 (WMO, Geneva, 1998)]. In the present analysis we deal with the possibility of such an interlinkage within one effect on human health, namely, skin cancer. The increase in the incidence of skin cancer is one of the most extensively studied effects of increasing ultraviolet radiation by ozone depletion (F. R. de Gruijl, Skin cancer and solar radiation, Eur. J Cancer, 1999, 35, 2003-2009). We wondered if this impact could also be influenced by increasing environmental temperatures. Here we show that it is likely that such an influence will occur. For the same reason, it is likely that the baseline incidence of skin cancer will be augmented by rising temperatures, which may become significant in magnitude.

Animals↗
PubMed2005

Environmental health implications of global climate change.

This paper reviews the background that has led to the now almost-universally held opinion in the scientific community that global climate change is occurring and is inescapably linked with anthropogenic activity. The potential implications to human health are considerable and very diverse. These include, for example, the increased direct impacts of heat and of rises in sea level, exacerbated air and water-borne harmful agents, and--associated with all the preceding--the emergence of environmental refugees. Vector-borne diseases, in particular those associated with blood-sucking arthropods such as mosquitoes, may be significantly impacted, including redistribution of some of those diseases to areas not previously affected. Responses to possible impending environmental and public health crises must involve political and socio-economic considerations, adding even greater complexity to what is already a difficult challenge. In some areas, adjustments to national and international public health practices and policies may be effective, at least in the short and medium terms. But in others, more drastic measures will be required. Environmental monitoring, in its widest sense, will play a significant role in the future management of the problem.

Climate↗
PubMed1998

Mechanical ventilation protects one-storey single-dwelling houses against increased air humidity, domestic mite allergens and indoor pollutants in a cold climatic region.

BACKGROUND: Poor ventilation in modern, highly insulated housing is an important factor in promoting indoor humidity levels to exceed 7 g/kg in cold climatic regions. OBJECTIVE: To investigate the ventilation rate in houses with different ventilation systems in relation to indoor air humidity, domestic mite allergen levels and volatile organic compounds (VOC). METHODS: Measurements were performed regarding ventilation rate, indoor temperature, air humidity, mattress mite allergen concentrations using enzyme-linked immunosorbent assay and total indoor VOC in 59 similarly constructed one-storey single-dwelling houses. In 22 of the houses, a mechanical supply and exhaust ventilation were installed after construction. RESULTS: In only five of the houses with mechanical supply and exhaust ventilation the air exchange rate per hour (ACH) was below 0. 5 compared with 24 of the 29 houses with natural ventilation (OR = 0. 06, CI 95% 0.01-0.2). None of the 23 houses with an ACH >/= 0.5 had an absolute indoor humidity (AIH) of 7 g/kg air or more, compared with 10 of the 36 houses with an ACH < 0.5 (P = 0.01 ). In none of the 23 houses with an ACH >/= 0.5 were concentrations of mite allergen exceeding 2 microg/g of dust found, compared with six of the 36 houses (17%) with an ACH below 0.5 (P = 0.04). Further, 10 of the 34 houses with a total VOC exceeding 200 microg/m3 had mite allergen in mattress dust exceeding 0.5 microg/g, compared with one of the 22 houses with VOC < 200 microg/m3 (P = 0.04). CONCLUSION: The study shows that in modern, highly insulated, one-storey single-dwelling houses in cold temperate regions, mechanical ventilation increases the possibility of reaching an ACH of >/= 5 which protects against indoor humidity levels contributing to mite survival as well as high levels of indoor air pollutants in winter.

Air Pollution, Indoor↗
PubMed1998

Use of climatic data and satellite imagery to model the abundance of Culicoides imicola, the vector of African horse sickness virus, in Morocco.

African horse sickness (AHS) is a vector-borne, infectious disease of equids caused by African horse sickness virus (AHSV). The only proven field vector of the virus is the biting midge Culicoides imicola. Following a recent epizootic (1989-91) of AHS in Morocco, light traps and automatic weather stations were operated for 2 years at twenty-two sites distributed over much of the country. The annually-averaged mean daily trap catch of C. imicola at these sites was negatively correlated with wind speed, and positively correlated with the average and mean annual minimum NDVI (Normalized Difference Vegetation Index, a remotely sensed measure of vegetation activity). There were no significant correlations between the mean daily trap catch and air temperature, soil temperature, relative humidity, saturation deficit, rainfall, altitude or the mean annual maximum or range of NDVI. The best two-variable model, which combined WindspeedMnAvMn (the average daily minimum wind speed of the least windy month) and NDVImin (the average annual minimum NDVI) as predictors, explained over 50% of the variance in the annually-averaged mean daily trap catch of C. imicola. There was a significant, positive correlation between minimum wind speed at night and the daily mortality rate of adult female C. imicola and it is suggested that the relationship between wind speed and the abundance of C. imicola arises from effects on adult mortality or dispersal. Considering several climatic variables, in North Africa NDVImin was most significantly correlated with total annual rainfall. It is suggested that the relationship between NDVImin and the abundance of C. imicola arises from the impact of soil moisture on both. It is proposed that areas of Morocco with higher levels of soil moisture in late summer or autumn provide more, larger and/or more enduring breeding sites for C. imicola, as well as supporting more photosynthetically active vegetation and hence having higher NDVI.

African Horse Sickness Virus↗
PubMed2002

Seasonal activity patterns of Ixodes pacificus nymphs in relation to climatic conditions.

In western North America, the tick Ixodes pacificus Cooley & Kohls (Acari: Ixodidae) is the primary vector to humans and domestic animals of the disease agents causing Lyme disease and granulocytic ehrlichiosis. We examined the seasonal activity patterns of I. pacificus nymphs over a 4-year period, including the wet and cold El Niño winter/spring of 1998, in a dry oak/madrone woodland, and for one year in a cooler and moister redwood/tanoak woodland in Mendocino County, California. Linear regressions were used to estimate when nymphal densities first exceeded and then fell below 25, 50 and 75% of the recorded yearly peak densities. In oak/madrone woodland, nymphs typically were active by mid-March, reached 50% of their yearly peak densities in early to mid-April, peaked by early May, fell below 50% of their peak densities by early to mid-June, and were absent by late July to mid-August. The lengths of the periods with nymphal densities exceeding 50 and 75% of the recorded yearly peaks in oak/madrone woodland were associated positively with rainfall and negatively with maximum air temperatures during April-May. Moreover, nymphal numbers typically reached 50% of their peak 10-15 days later, remained at levels above 50% of the peak 1.3-1.5 times longer, and started declining 4-6 weeks later under cooler, moister climatic conditions (oak/madrone woodland in 1998 and redwood/tanoak woodland in 2000) relative to warmer, drier conditions (oak/madrone woodland in 2000-2001). In oak/madrone woodland, nymphal densities typically started to decline when mean maximum daily air temperatures exceeded 23 degrees C. Nymphal densities were higher in dry oak/madrone relative to moist redwood/tanoak woodland from mid-March to late May 2000, similar in both habitat types in early June, but higher in redwood/tanoak woodland from late June onwards. We conclude that large-scale studies of the density of I. pacificus nymphs in California need to consider spatial variation in the length of nymphal activity periods and select temporal sampling regimens that yield representative data for all included habitat types.

Animals↗
PubMed2000

High seroprevalence of antibodies to varicella zoster virus in adult women in a tropical climate.

OBJECTIVES: To determine whether the seroprevalence of antibodies to varicella zoster virus (VZV) in adults is similar to that reported in tropical populations elsewhere. METHODS: We measured the seroprevalence of VZV IgG antibodies, using an enzyme immunoassay (EIA) in women attending an antenatal clinic in an urban centre in tropical Australia. RESULTS: The overall seroprevalence of VZV antibodies in 298 women was 92% (95% CI 88-95), with no difference between women who spent their childhoods in the tropics and colleagues. None of the overseas-born women was seronegative. CONCLUSION: The seroprevalence of VZV antibodies in this tropical population in Australia is as high as that reported from temperate regions, suggesting that social and cultural factors and population mobility are more important determinants of age distribution of VZV immunity than tropical climate.

Adolescent↗
PubMed2003

Climatic and social risk factors for Aedes infestation in rural Thailand.

An intense epidemic of dengue haemorrhagic fever in 1998 prompted the Thai government to investigate the feasibility of focalized vector (Aedes aegypti) control programmes. We tested for correlations of three indices of Aedes larval abundance (housing index, container index and Breteau index) against 38 socio-economic and four climatic variables. Availability of public water wells, existence of transport services and proportion of tin houses were positively associated with larval indices. Private water wells, health education, health insurance coverage, thatched houses and use of firewood for cooking were negatively associated. These probably represent both direct effects on breeding sites (private vs. public wells decrease necessity to store water, and health education may encourage breeding site removal), and more general effects of health-related attitudes, housing quality and remoteness from urban areas. Indices were positively associated with daily minimum temperature, an increase in precipitation from the previous month (reflecting the onset of the rainy season) and daily maximum temperatures of approximately 33-34 degrees C. The associations were used to derive statistical models to predict the rank order of larval indices within the study area (Spearman's correlation coefficients = 0.525-0.554). The study provides a rational basis for identifying possible social interventions, and for prioritizing previously unsurveyed villages for further monitoring and focalized vector control.

Aedes↗
PubMed2003

The effect of soil type and climate on hookworm (Necator americanus) distribution in KwaZulu-Natal, South Africa.

We investigated environmental factors influencing the distribution of hookworm infection in KwaZulu-Natal, South Africa. Prevalence data were sourced from previous studies and additional surveys carried out to supplement the database. When geo-referenced the data revealed that higher prevalences are limited to areas below 150 m above sea level, and low prevalences to areas above this altitude. Using univariate analysis we investigated the differences in environmental factors in the two areas. The relationship between hookworm prevalence, altitude and climate-derived variables was assessed using Pearson correlation coefficient, and that of soil type using the t-test. Multivariate analysis was used to determine environmental factors that combine best to provide favourable conditions for hookworm distribution. The results revealed that areas 150 m above sea level, i.e. inland, supported low mean hookworm prevalences (x = 6, n = 21), and were characterized by soils with a clay content of more than 45%, variable temperatures and moderate rainfall. Hookworm prevalence also decreased southwards as temperatures became slightly cooler, rainfall remained more-or-less constant and the coastal plain narrowed. In the multivariate model prevalence was most significantly correlated with the mean daily minimum temperature for January followed by the mean number of rainy days for January. This indicates the importance of summer conditions in the transmission of hookworm infection in KwaZulu-Natal and suggests that transmission may be seasonal.

Adolescent↗
PubMed2003

The effect of climate on the presence of Culicoides imicola in Italy.

A model was developed to classify the Italian territories in relation to their suitability to harbour populations of Culicoides imicola and, as a consequence, also able to sustain a bluetongue (BT) epidemic. Italy was subdivided into 3507 10 x 10 km cells. In 546 cells at least one collection was made. The cell was considered the unit for all subsequent analyses. Culicoides were collected using Onderstepoort-type blacklight traps. Some traps were operated weekly at chosen sites; the remainder were moved almost daily to new sites. Only the results obtained during the peak August-November period were used, to exclude bias caused by the seasonality of C. imicola. Climate data for the period 1999-2001 were obtained from 80 weather stations. Multiple logistic regression was performed using the presence or absence of C. imicola in a specific cell as the dependent variable. Annual means of daily values for minimum temperature and minimum relative humidity, and the mean altitude above sea level, were the independent variables. The probability of occurrence of C. imicola in each grid cell was used to create a prediction map for Italy. The model was able to correctly classify 77.5% of the 546 grid cells in which at least one collection had been made. Culicoides imicola was found frequently through much of Sardinia, in parts of southern Italy, and further north along the Tyrrhenian coast, but was absent from along most of the Adriatic coast, and the internal mainland, and from most of Sicily. Six detailed maps are provided. Also mapped are areas where the probability of the occurrence of C. imicola is lower than 5%. This identification of possible mountainous C. imicola-free areas in central Italy could facilitate safer animal trade and transhumance, even if BT infections in traded animals or moving stock, were to go undetected. Needless to say this depends upon no cool-adapted species of Culicoides being involved in the transmission of BT disease.

Animals↗
PubMedDate not supplied

Influence of climate on donor deferrals.

The purpose of this study was to ascertain the cause for seasonal variations of donor deferral. Deferred donors and monthly temperatures from 1981 to 1984 were tallied and analyzed. Temperatures were categorized at 10-degree intervals from 15 degrees F to 75 degrees F. Donors failing the hemoglobin screening then underwent a microhematocrit evaluation. Of the 65,531 donors seen at this blood center, 4537 were deferred, for an annual deferral rate of 6.7 to 7.2 percent (p less than 0.1). Deferrals for low hematocrit were significantly higher for both sexes at and above 45 degrees F. Similar experiences were also observed in 79,563 donors who came to the bloodmobiles over 19 months in 1983 and 1984. The percentages of deferrals at the blood center for low hematocrit in 1984 were 1.22, 2.6, and 3.5 for men and 6.7, 11.3, and 13.2 for the women at monthly average temperatures of 15.1 to 45 degrees F, 45.1 to 65 degrees F, and 65.1 to 75 degrees F, respectively. These differences of deferral rates are significant (p less than 0.05-0.001). Although other personal demographics remained constant, more of the donors deferred in this study had also been deferred in the past. The climatic changes had a significant effect on the blood composition that resulted in the deferral of blood donors with a borderline low hematocrit.

Adaptation, Physiological↗
PubMedDate not supplied

Towards a lower prevalence of Oestrus ovis infections in sheep in a temperate climate (south west France).

Oestrus ovis larvae are obligatory parasites of the nasal and sinus cavities of sheep and goats. In the temperate climate of western Europe, fly attacks occur between May and October and the first stage larvae arrest their development within the host between October and February. Oestrosis clinical signs such as nasal discharge and sneezing are well known by sheep breeders in southwest France. According to veterinarian recommendations, most of them treat their animals with long lasting fasciolicides once a year at least, mainly during the fly activity period and at the beginning of the hypobiotic period (when the parasitic population is only constituted of larvae). The consequences of these therapeutic programs were analysed in a local slaughterhouse by larval counts. Both prevalence and intensities of O. ovis infections decreased between 1989-1991 (before the use of systematic treatments) and 1996-1998 (after the spread of these treatments). The use of systematic treatments during the fly activity period and the beginning of the hypobiotic period seems to be very efficient in O. ovis control and could theoretically lead to a possible 'eradication' program as with cattle hypodermosis. Nevertheless the presence of parasites in apparently healthy goats, the possibility for a fly generation to develop before the first treatment in July-August and the succession of several fly generations all around the year in southern Mediterranean and tropical countries will maintain O. ovis infections. Furthermore, there are increased concerns about drug residues on consumer health and environment and this is the basis for the prospect of alternative strategies in O. ovis control.

Abattoirs↗
PubMed2001

The role of outdoor air pollution and climatic changes on the rising trends in respiratory allergy.

Evidence suggests that allergic respiratory diseases such as hay fever and bronchial asthma have become more common world-wide in the last two decades, and the reasons for this increase are still largely unknown. A major responsible factor could be outdoor air pollution, derived from cars and other vehicles. Studies have demonstrated that urbanization and high levels of vehicle emissions and westernized lifestyle is correlated with the increasing frequency of pollen-induced respiratory allergy. People who live in urban areas tend to be more affected by pollen-induced respiratory allergy than those from of rural areas. Pollen allergy has been one of the most frequent models used to study the interrelationship between air pollution and respiratory allergic diseases. Pollen grains or plant-derived paucimicronic components carry allergens that can produce allergic symptoms. They may also interact with air pollution (particulate matter, ozone) in producing these effects. There is evidence that air pollutants may promote airway sensitization by modulating the allergenicity of airborne allergens. Furthermore, airway mucosal damage and impaired mucociliary clearance induced by air pollution may facilitate the access of inhaled allergens to the cells of the immune system. In addition, vegetation reacts with air pollution and environmental conditions and influence the plant allergenicity. Several factors influence this interaction, including type of air pollutants, plant species, nutrient balance, climatic factors, degree of airway sensitization and hyperresponsiveness of exposed subjects.

Air Pollution↗
PubMed2005

Beech leaf colonization by the endophyte Apiognomonia errabunda dramatically depends on light exposure and climatic conditions.

Ozone and light effects on endophytic colonization by Apiognomonia errabunda of adult beech trees (Fagus sylvatica) and their putative mediation by internal defence compounds were studied at the Kranzberg Forest free-air ozone fumigation site. A. errabunda colonization was quantified by "real-time PCR" (QPCR). A. errabunda-specific primers allowed detection without interference by DNA from European beech and several species of common genera of plant pathogenic fungi, such as Mycosphaerella, Alternaria, Botrytis, and Fusarium. Colonization levels of sun and shade leaves of European beech trees exposed either to ambient or twice ambient ozone regimes were determined. Colonization was significantly higher in shade compared to sun leaves. Ozone exhibited a marginally inhibitory effect on fungal colonization only in young leaves in 2002. The hot and dry summer of 2003 reduced fungal colonization dramatically, being more pronounced than ozone treatment or sun exposure. Levels of soluble and cell wall-bound phenolic compounds were approximately twice as high in sun than in shade leaves. Acylated flavonol 3- O-glycosides with putatively high UV-B shielding effect were very low in shade canopy leaves. Ozone had only a minor influence on secondary metabolites in sun leaves. It slightly increased kaempferol 3- O-glucoside levels exclusively in shade leaves. The frequently prominent hydroxycinnamic acid derivative, chlorogenic acid, was tested for its growth inhibiting activity against Apiognomonia and showed an IC50 of approximately 8 mM. Appearance of Apiognomonia-related necroses strongly correlated with the occurrence of the stress metabolite, 3,3',4,4'-tetramethoxybiphenyl. Infection success of Apiognomonia was highly dependent on light exposure, presumably affected by the endogenous levels of constitutive phenolic compounds. Ozone exerted only minor modulating effects, whereas climatic factors, such as pronounced heat periods and drought, were dramatically overriding.

Ascomycota↗
PubMed2005

[The non-tropical pyomyositis--a rare disease in the moderate climate zone].

Pyomyositis is in the moderate climate zone a rare and acute bacterial infection of the skeletal muscles without an obvious origin of infection. Initial symptoms contain muscle pain and localized swelling and tension. As different causes are taken into account first, the diagnosis of a pyomyositis is often delayed. We report on three cases of pyomyositis and discuss diagnosis and therapy against the background of the available and recent literature.

Abscess↗
PubMed2004

Evidence for a significant urbanization effect on climate in China.

China has experienced rapid urbanization and dramatic economic growth since its reform process started in late 1978. In this article, we present evidence for a significant urbanization effect on climate based on analysis of impacts of land-use changes on surface temperature in southeast China, where rapid urbanization has occurred. Our estimated warming of mean surface temperature of 0.05 degrees C per decade attributable to urbanization is much larger than previous estimates for other periods and locations. The spatial pattern and magnitude of our estimate are consistent with those of urbanization characterized by changes in the percentage of urban population and in satellite-measured greenness.

Biomass↗
PubMed2005

Climatically driven macroevolutionary patterns in the size of marine diatoms over the Cenozoic.

Numerous taxonomic groups exhibit an evolutionary trajectory in cell or body size. The size structure of marine phytoplankton communities strongly affects food web structure and organic carbon export into the ocean interior, yet macroevolutionary patterns in the size structure of phytoplankton communities have not been previously investigated. We constructed a database of the size of the silica frustule of the dominant fossilized marine planktonic diatom species over the Cenozoic. We found that the minimum and maximum sizes of the diatom frustule have expanded in concert with increasing species diversity. In contrast, the mean area of the diatom frustule is highly correlated with oceanic temperature gradients inferred from the delta18O of foraminiferal calcite, consistent with the hypothesis that climatically induced changes in oceanic mixing have altered nutrient availability in the euphotic zone and driven macroevolutionary shifts in the size of marine pelagic diatoms through the Cenozoic.

Animals↗
PubMed2005

Climate-driven regime shifts in the biological communities of arctic lakes.

Fifty-five paleolimnological records from lakes in the circumpolar Arctic reveal widespread species changes and ecological reorganizations in algae and invertebrate communities since approximately anno Domini 1850. The remoteness of these sites, coupled with the ecological characteristics of taxa involved, indicate that changes are primarily driven by climate warming through lengthening of the summer growing season and related limnological changes. The widespread distribution and similar character of these changes indicate that the opportunity to study arctic ecosystems unaffected by human influences may have disappeared.

Animals↗
PubMed2005

Satellite-observed photosynthetic trends across boreal North America associated with climate and fire disturbance.

We analyzed trends in a time series of photosynthetic activity across boreal North America over 22 years (1981 through 2003). Nearly 15% of the region displayed significant trends, of which just over half involved temperature-related increases in growing season length and photosynthetic intensity, mostly in tundra. In contrast, forest areas unaffected by fire during the study period declined in photosynthetic activity and showed no systematic change in growing season length. Stochastic changes across the time series were predominantly associated with a frequent and increasing fire disturbance regime. These trends have implications for the direction of feedbacks to the climate system and emphasize the importance of longer term synoptic observations of arctic and boreal biomes.

Arctic Regions↗