Klima wandel und Malaria

Goal and Scope

The coastal zones of Lower Saxony (Germany) are former malaria regions. Malaria had finally become extinct in the early 1950s, and subsequently related scientific investigations declined. But from that time until nowadays, the vector in the form of Anopheles mosquitoes has still been present in Lower Saxony. Thus, the question arises, whether a new autochthon transmission could take place due to the monthly mean temperatures of the recent years. Answering this question was one goal of the investigation at hand. Another one was to examine the spatial and temporal structure of potential transmissions in respect to the predicted increase of the air temperatures according to the IPCC scenarios.

Methods

Current information about anophelines and their characteristics within Germany, such as details on historical incidences, breeding preferences, longevity or distribution of the respective species, were collected by literature research. Further, measurement and incidence data had to be collected and processed: temperature values were provided by the Deutscher Wetterdienst (DWD), and recent findings of Anopheles were supplied by the former Niedersächsisches Landesamt für Ökologie (NLÖ) as a data bank. Then temperature maps were calculated for the three periods (1947–1960, 1961–1990, 1985–2004) by means of Kriging. To model areas at risk, the transmission potential for a new vivax malaria spread in respect to temperature was computed using the Basic Reproduction Rate (R₀) formula. It provides the average number of secondary infections produced when a single infected individual is introduced into a potential host population in which each member is susceptible.

Results

The computations corroborate a climate warming between the 30-years interval from 1961 to 1990 and the period from 1985 to 2004. According to the rise of the air temperature as predicted by the IPCC scenarios, the spatial pattern of potential malaria outbreak was calculated for 2020, 2060 an 2100. To this end, for each of these years a best-case-scenario with the lowest reasonable temperature increases (+0.3°C, +0.9°C, +1.4°C) and a worst-case-scenario implying the highest plausible temperature rise (+0.9°C, +3.3°C, +5.8°C) were assumed. While in 2020 the maximum duration of the transmission risk is estimated to last four months, in 2100 the vivax transmission will be likely from May until October.

Discussion

Correlated with the higher monthly mean temperature values, the risk of a vivax transmission is increasing as temperature is the determining variable of the mathematical model. Therefore Lower Saxony is at risk of a new outbreak of vivax malaria assuming no other risk factors are of relevance.

Conclusions

The study could demonstrate that most parts of the country lie within a transmission zone with a duration of two months. The areas containing the highest risk with a transmission length of three months are located around Nordhorn and Hameln, and within the rectangle of Celle, Hannover, Helmstedt and Wolfsburg. These areas match with recent Anopheles larvae finding by the NLÖ, thus, only the pathogen is lacking for a successful transmission. And as Germany is not an endemic malaria zone, the pathogen can enter the country most likely by infected people or imported mosquitoes that transport it in their guts.

Recommendations and Perspectives

The results should be understood as a request for more comprehensive investigations in that field. This would be an essential basis for a successful risk monitoring and precautionary management. Although the chances of a new endemic malaria disease in Germany seem to be considerably low today, it would be better to be prepared than to be suddenly faced with the unexpected.     

Buoyancy and turbulence-driven atmospheric circulation over urban areas

In the buoyancy and turbulence-driven atmospheric circulations (BTDAC) that occur over urban areas where the approach means wind speeds are very low (less than turbulent fluctuations and typically < 3 m/sec), the surface temperatures are significantly higher than those in the external rural areas, and the atmosphere above the mixing layer is stably stratified. In this paper, the mechanisms of BTDAC formation are studied through laboratory experiments and modelling, with additional low-level inflow from external rural areas and a divergent outflow in the opposite direction in the upper part of the mixed layer. Strong turbulent plumes in the central region mix the flow between lower and higher levels up to the inversion height. There are shear-driven turbulent eddies and weaker buoyant plumes around the periphery of the urban area. As the approach flow is very weak, the recirculating streamlines within the dome restrict the ventilation, and the dispersion of pollution emitted from sources below the inversion height leading to a rise in the mean concentration. Low-level air entrained from rural areas can, however, improve ventilation and lower this concentration. This trend can also be improved if the recirculating structure of the BTDAC flow pattern over urban areas breaks down as a result of the surface temperature distribution not being symmetrical, or as the approach wind speed increases to a level comparable with the mean velocity of circulation, or (except near the equator) the urban area is large enough that the Coriolis acceleration is significant.     

Developmental changes of nasal and oral calls in the goitred gazelle <Emphasis Type="Italic">Gazella subgutturosa</Emphasis>, a nonhuman mammal with a sexually dimorphic and descended larynx

In goitred gazelles (Gazella subgutturosa), sexual dimorphism of larynx size and position is reminiscent of the case in humans, suggesting shared features of vocal ontogenesis in both species. This study investigates the ontogeny of nasal and oral calls in 23 (10 male and 13 female) individually identified goitred gazelles from shortly after birth up to adolescence. The fundamental frequency (f0) and formants were measured as the acoustic correlates of the developing sexual dimorphism. Settings for LPC analysis of formants were based on anatomical dissections of 5 specimens. Along ontogenesis, compared to females, male f0 was consistently lower both in oral and nasal calls and male formants were lower in oral calls, whereas the first two formants of nasal calls did not differ between sexes. In goitred gazelles, significant sex differences in f0 and formants appeared as early as the second week of life, while in humans they emerge only before puberty. This result suggests different pathways of vocal ontogenesis in the goitred gazelles and in humans.     

Life cycle assessment of energy from waste via anaerobic digestion: A UK case study

Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO₂ and total SO₂ saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded.