Impacts of Climate Change on Stream Inflows into the Volta Lake

The study examined the impact of climate change on future water availability in the Volta Lake from climate downscaled data using ensemble projections of two Global Climate Models (MPEH5 and HADCM3) and two emission scenarios (A1B and A2) used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. The SWAT hydrological model was calibrated and validated and then used with the downscaled climate change data to assess the impacts of climate change on the inflows to the Lake. Results from the impact assessment showed that future mean annual streamflow into the Volta Lake could increase by about 17 and 16 percent under the A1B and A2 scenarios, respectively. However, streamflow from Geoere, Boromo and Dapola in the Black Volta basin and Nawuni in the White Volta basin could decrease. The projected increase in total annual streamflow in the basin is consistent with the increase in annual rainfall in the basin under both the A1B and A2 scenarios of between 2.0 and 8.0 percent obtained in a separate climate downscaling study. Since streamflow in some of the sub-basins were found to decrease under the climate change scenarios investigated, integrated and prudent management of the basin's water resources would be necessary to ensure sustainability in water use

Designing a combined Liothyronine (LT3), L-thyroxine (LT4) trial in symptomatic hypothyroid subjects on LT4 – the importance of patient selection, choice of LT3 and trial design

Approximately 10%–15% of subjects with hypothyroidism on L-thyroxine (LT4) alone have persistent symptoms affecting their quality of life (QoL). Although the cause is unclear, there is evidence that “tissue T3 lack” may be responsible. If so, combining liothyronine (LT3) with LT4 would be helpful. However, randomized controlled trials (RCT), have not established greater efficacy for the LT3 + LT4 combination in these subjects than for LT4 alone. While the trial design may have been responsible, the use of unphysiological, short-acting LT3 preparations and non-thyroid-specific patient-reported outcome measures (PROMs) may have contributed. We recommend attention to the following aspects of trial design for future RCTs of LT3 + LT4 compared to LT4 alone: (a) Subject selection—(i) measurable symptoms (disadvantages should be recognized); (ii) using a validated thyroid specific PROM such as ThyPRO39 or the Composite scale derived from it; (iii) those taking over 1.2 μg/day or 100 μg/day (for pragmatic reasons) of LT4 defining a population likely without intrinsic thyroid activity who depend on exogenous LT4; (iv) recruiting a preponderance of subjects with autoimmune thyroiditis increasing generalisability; and (v) those with a high symptom load with a greater response to combination therapy e.g. those with the deiodinase 2 polymorphism. (b) The use of physiological LT3 preparations producing pharmacokinetic similarities to T3 profiles in unaffected subjects: two long-acting LT3 preparations are currently available and must be tested in phase 2b/3 RCTs. (c) The superiority of a crossover design in limiting numbers and costs while maintaining statistical power and ensuring that all subjects experienced the investigative medication

Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa

Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25C,the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29C and 34C, about 3C and 7C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 298C and of savannah flies (Ghana) at 308C. Small temperature increases (less than 28C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 338C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13–41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions