Above-ground biomass and carbon stocks of different land cover types in Mt. Elgon, Eastern Uganda

This research applied selected allometric models to estimate the total above ground biomass (TAGB) and carbon stocks in the different land-use/ land cover (LULC) types in Mt. Elgon National Park, in Eastern Uganda. The LULC types identified for the study were – tropical high forest (THF) - normal, THF- degraded and grasslands. The vegetation in each land cover type was assessed at four levels i.e. the mature trees, poles, saplings and undergrowth. Tree diameter and height of each sampled tree were also measured. In each plot, one sapling was randomly selected, uprooted and sub-samples of the foliage, bole and root components were collected, and their fresh weight was determined in the field. Calculation of the Mean Squared Error (MSE), Prediction Sum of Squares (PRESS) statistic and Predicted R2 values of the selected equations was done to establish the most appropriate equation for biomass and carbon estimation. The TAGB was 652.15t/ha, 55.16t/ha and 41.7t/ha in the THF-Normal, THF-Degraded and Grasslands respectively. The carbon stocks in the THF-normal were 293.65tC ha-1, 25 tC ha-1 in the THF- degraded and 18.76 tC ha-1 in the grasslands. Over 90% of sequestered carbon was lost due to land cover change from THF-Normal to THF-Degraded. This calls for policy makers to urgently come up with interventions to address forest degradation.Joel Buyinza, Susan Balaba Tumwebaze, Justine Namaalwa, Patrick Byakagab

Effectiveness of selected preservatives in protecting ugandan grown eucalyptus grandis wood against termite attack

Termites are one of the major wood destroying agents in the tropics and with the increasing rate of deforestation, there is a need to protect wood from biodegradation in order to extend its service life. In this study the incidence and severity of termite attack on Eucalyptus grandis sapwood treated with CCA, used engine oil and neem extract were investigated. Sixty samples (20 × 20 × 300mm) were prepared from the sapwood at mid-height of the tree of E. grandis and air seasoned for two weeks then treated with the preservatives. An area of 20m by 20m in a pine plantation and 15 plots of 1m by 1m were selected at random. Four samples, one from each treatment, were placed at the corners of the selected plots.Inspection and evaluation of stakes was made by visual assessments after every 30 days for any sign of termite attack for a period of 8 months. The specimens were removed from the ground, damage assessed and returned to the ground. After 4 weeks all the untreated wood samples had been attacked, neem extract treated wood samples were attacked after 17 weeks and used engine oil treated samples after 30 weeks. None of the CCA treated wood samples were attacked by the end of study period. Chi square analysis showed a high association between treatment and incidence as well as between treatment and severity. It was recommended that further research be carried out on neem extract using different concentrations

Trench layering using indole-3-butyric acid and local organic substrate mixtures to enhance rooting and survival of apple rootstocks

Apples ( Malus domestica ) were introduced to enhance nutrition and improve livelihoods of famers in highlands of Uganda. However, adoption and commercialisation of apples is largely constrained by low quality rootstocks due to poor rooting and low survivability. This study determined the effect of organic substrate mixtures (OSM) and indole-3-butyric acid (IBA) on rooting, sprouting and survival characteristics of apple rootstocks propagated by trench layering. Four apple rootstock varieties (M106, M109, MM793 and bitten-felder) were planted in OSM (Site soil as control, TsaOm and TsdOm) then treated with IBA concentrations (IBA-0 ppm, IBA-4000 ppm and IBA-8000 ppm) in a factorial randomised block design with three replications. Results showed significant (P<0.001) variability among rootstocks for all characters. OSM significantly (P<0.01) increased rooting, root numbers and root length while IBA significantly (P<0.01) increased all traits, except rooting. The highest rooting (46.7%), root numbers (23.1) and root length (14.9cm), and sprout length (59.5cm) were obtained in bitten felder under TsaOm + IBA-4000ppm, TsaOm, and TsdOm, respectively. For M106, maximum rooting (28.1%) and root numbers (22.3) were obtained under TsaOm + IBA-8000ppm while root (14.3cm) and sprout (35.2cm) lengths under TsdOm. TsaOm gave the highest root numbers (14.2), root (12.8cm) and sprout (30.7cm) lengths in M109 likewise root (7.8cm) and sprout (38.3cm) lengths in MM793. Logistic regression revealed that rooting, sprout length, and IBA-4000ppm significantly (P<0.01) increased survival of apple rootstocks. The highest survival rates in bitten felder and M106 were 52.4% and 51.7% under TsdOm + IBA-4000 ppm and TsdOm + IBA-8000 ppm respectively; likewise 49.5% in M109 and 51.7% in MM793 both treated with IBA-8000 ppm. The results demonstrate that trench layering with OSM and IBA improves rooting and survival of apple rootstocks which might improve farmers\u2019 access to quality apple planting material.Les pommes ( Malus domestica ) \ue9taient introduites pour renforcer la nutrition et am\ue9liorer le niveau de vie des producteurs dans les r\ue9gions montagneuses d\u2019Ouganda. Toutefois, l\u2019adoption et la commercialisation des pommes sont largement limit\ue9es par la faible qualit\ue9 des porte-greffes \ue0 cause du pauvre enracinement et la faible capacit\ue9 de survie. Cette \ue9tude visait \ue0 d\ue9terminer l\u2019effet des m\ue9langes du substrat organique (OSM) et l\u2019acide indole-3-butyrique (IBA) sur l\u2019enracinement, la germination et les caract\ue9ristiques de survie des porte-greffes de la pomme propag\ue9e par le marcottage de tranch\ue9e. Quatre portes greffes des vari\ue9t\ue9s de pomme (M106, M109, MM793 et bitten-felder) \ue9taient plant\ue9es dans l\u2019OSM (site de sol servant de contr\uf4le, TsaOm et TSdOm) et trait\ue9e avec diff\ue9rentes concentrations de l\u2019IBA (IBA-0 ppm, IBA-4000 ppm et IBA-8000 ppm) dans un design factoriel \ue0 blocks compl\ue8tement al\ue9atoires avec trois r\ue9plications. Les r\ue9sultats ont montr\ue9 de variabilit\ue9 significative (P<0,001) entre les porte-greffes des vari\ue9t\ue9s pour tous les caract\ue8res. OSM significativement (P<0.01) a fait accro\ueetre l\u2019enracinement, le nombre de racines et la longueur de la racine; alors que IBA a augment\ue9 significativement (P<0.001) tous les traits, sauf l\u2019enracinement. Les plus grandes valeurs des caract\ue8res \ue0 savoir\ua0; l\u2019enracinement (46,7%), le nombre de racines (23,1), la longueur des racines (14,9 cm), et la longueur des pousses (59,5cm) \ue9taient obtenues sur bitten felder sous TsaOm + IBA-4000ppm, TsaOm, et TsdOm, respectivement. Pour M106, les valeurs maximales de l\u2019enracinement (28,1%) et de nombre de racines (22.3) \ue9taient obtenues sous TsaOm + IBA-8000ppm alors que les valeurs maximales de la longueur des racines (14,3 cm) et des pousses (35,2 cm) sous TsdOM. TsaOm ont donn\ue9 le plus grand nombre de racines (14,2), la plus grande longueur des racines (12,8 cm) et de pousses (30,7 cm) dans M109 pareillement \ue0 la longueur des racines (7,8 cm) et de pousses (38,3 cm) dans MM793. La r\ue9gression logistique a r\ue9v\ue9l\ue9 que l\u2019enracinement, la longueur de la pousse et IBA-400ppm ont augment\ue9 significativement (P<0,01) la survie des porte-greffes de la pomme. Les plus forts taux de survies sur le bitten felder et M106 \ue9taient 52,4% et 51,7% sous TsdOm+IBA-4000 ppm et TsdOm+IBA-8000 ppm, respectivement\ua0; de m\ueame 49,5% ont \ue9t\ue9 obtenus sur M109 et 51,7% sur MM793 tous trait\ue9s avec IBA-8000 ppm. Les r\ue9sultats ont d\ue9montr\ue9 que le marcottage de tranch\ue9e avec OSM et IBA am\ue9liore l\u2019racinement et la survie des porte-greffes qui pourrait am\ue9liorer l\u2019acc\ue8s des producteurs \ue0 des mat\ue9riels de plantation de pomme de qualit\ue9

Intermittent preventive treatment with dihydroartemisinin-piperaquine in Ugandan schoolchildren selects for Plasmodium falciparum transporter polymorphisms that modify drug sensitivity.

Dihydroartemisinin-piperaquine (DP) offers prolonged protection against malaria, but its impact on Plasmodium falciparum drug sensitivity is uncertain. In a trial of intermittent preventive treatment in schoolchildren in Tororo, Uganda, in 2011 to 2012, monthly DP for 1 year decreased the incidence of malaria by 96% compared to placebo; DP once per school term offered protection primarily during the first month after therapy. To assess the impact of DP on selection of drug resistance, we compared the prevalence of key polymorphisms in isolates that emerged at different intervals after treatment with DP. Blood obtained monthly and at each episode of fever was assessed for P. falciparum parasitemia by microscopy. Samples from 160 symptomatic and 650 asymptomatic episodes of parasitemia were assessed at 4 loci (N86Y, Y184F, and D1246Y in pfmdr1 and K76T in pfcrt) that modulate sensitivity to aminoquinoline antimalarials, utilizing a ligase detection reaction-fluorescent microsphere assay. For pfmdr1 N86Y and pfcrt K76T, but not the other studied polymorphisms, the prevalences of mutant genotypes were significantly greater in children who had received DP within the past 30 days than in those not treated within 60 days (86Y, 18.0% versus 8.3% [P = 0.03]; 76T, 96.0% versus 86.1% [P = 0.05]), suggesting selective pressure of DP. Full sequencing of pfcrt in a subset of samples did not identify additional polymorphisms selected by DP. In summary, parasites that emerged soon after treatment with DP were more likely than parasites not under drug pressure to harbor pfmdr1 and pfcrt polymorphisms associated with decreased sensitivity to aminoquinoline antimalarials. (This study has been registered at ClinicalTrials.gov under no. NCT01231880.)

Changing antimalarial drug resistance patterns identified by surveillance at three sites in Uganda.

: We assessed Plasmodium falciparum drug resistance markers in parasites collected in 2012, 2013, and 2015 at 3 sites in Uganda. The prevalence and frequency of parasites with mutations in putative transporters previously associated with resistance to aminoquinolines, but increased sensitivity to lumefantrine (pfcrt 76T; pfmdr1 86Y and 1246Y), decreased markedly at all sites. Antifolate resistance mutations were common, with apparent emergence of mutations (pfdhfr 164L; pfdhps 581G) associated with high-level resistance. K13 mutations linked to artemisinin resistance were uncommon and did not increase over time. Changing malaria treatment practices have been accompanied by profound changes in markers of resistance.<br/

Modelling rotavirus concentrations in rivers: Assessing Uganda's present and future microbial water quality

Faecal pathogens can be introduced into surface water through open defecation, illegal disposal and inadequate treatment of faecal sludge and wastewater. Despite sanitation improvements, poor countries are progressing slowly towards the United Nation's Sustainable Development Goal 6 by 2030. Sanitation-associated pathogenic contamination of surface waters impacted by future population growth, urbanization and climate change receive limited attention. Therefore, a model simulating human rotavirus river inputs and concentrations was developed combining population density, sanitation coverage, rotavirus incidence, wastewater treatment and environmental survival data, and applied to Uganda. Complementary surface runoff and river discharge data were used to produce spatially explicit rotavirus outputs for the year 2015 and for two scenarios in 2050. Urban open defecation contributed 87%, sewers 9% and illegal faecal sludge disposal 3% to the annual 15.6 log10 rotavirus river inputs in 2015. Monthly concentrations fell between -3.7 (Q5) and 2.6 (Q95) log10 particles per litre, with 1.0 and 2.0 median and mean log10 particles per litre, respectively. Spatially explicit outputs on 0.0833 × 0.0833° grids revealed hotspots as densely populated urban areas. Future population growth, urbanization and poor sanitation were stronger drivers of rotavirus concentrations in rivers than climate change. The model and scenario analysis can be applied to other locations

Як уникнути підйому рівня води?

East Africa’s Lake Victoria provides resources and services to millions of people on the lake’s shores and abroad. In particular, the lake’s fisheries are an important source of protein, employment, and international economic connections for the whole region. Nonetheless, stock dynamics are poorly understood and currently unpredictable. Furthermore, fishery dynamics are intricately connected to other supporting services of the lake as well as to lakeshore societies and economies. Much research has been carried out piecemeal on different aspects of Lake Victoria’s system; e.g., societies, biodiversity, fisheries, and eutrophication. However, to disentangle drivers and dynamics of change in this complex system, we need to put these pieces together and analyze the system as a whole. We did so by first building a qualitative model of the lake’s social-ecological system. We then investigated the model system through a qualitative loop analysis, and finally examined effects of changes on the system state and structure. The model and its contextual analysis allowed us to investigate system-wide chain reactions resulting from disturbances. Importantly, we built a tool that can be used to analyze the cascading effects of management options and establish the requirements for their success. We found that high connectedness of the system at the exploitation level, through fisheries having multiple target stocks, can increase the stocks’ vulnerability to exploitation but reduce society’s vulnerability to variability in individual stocks. We describe how there are multiple pathways to any change in the system, which makes it difficult to identify the root cause of changes but also broadens the management toolkit. Also, we illustrate how nutrient enrichment is not a self-regulating process, and that explicit management is necessary to halt or reverse eutrophication. This model is simple and usable to assess system-wide effects of management policies, and can serve as a paving stone for future quantitative analyses of system dynamics at local scales

Hexahydroquinolines are antimalarial candidates with potent blood-stage and transmission-blocking activity

Hexahydroquinolines are antimalarial candidates with potent blood-stage and transmission-blocking activityAntimalarial compounds with dual therapeutic and transmission-blocking activity are desired as high-value partners for combination therapies. Here, we report the identification and characterization of hexahydroquinolines (HHQs) that show low nanomolar potency against both pathogenic and transmissible intra-erythrocytic forms of the malaria parasite Plasmodium falciparum. This activity translates into potent transmission-blocking potential, as shown by in vitro male gamete formation assays and reduced oocyst infection and prevalence in Anopheles mosquitoes. In vivo studies illustrated the ability of lead HHQs to suppress Plasmodium berghei blood-stage parasite proliferation. Resistance selection studies, confirmed by CRISPR-Cas9-based gene editing, identified the digestive vacuole membrane-spanning transporter PfMDR1 (P. falciparum multidrug resistance gene-1) as a determinant of parasite resistance to HHQs. Haemoglobin and haem fractionation assays suggest a mode of action that results in reduced haemozoin levels and might involve inhibition of host haemoglobin uptake into intra-erythrocytic parasites. Furthermore, parasites resistant to HHQs displayed increased susceptibility to several first-line antimalarial drugs, including lumefantrine, confirming that HHQs have a different mode of action to other antimalarials drugs for which PfMDR1 is known to confer resistance. This work evokes therapeutic strategies that combine opposing selective pressures on this parasite transporter as an approach to countering the emergence and transmission of multidrug-resistant P. falciparum malaria.The authors thank T.T. Diagana (Novartis Institute for Tropical Diseases, Singapore) for provision of the compounds, the Red Cross (Australia and the USA) for the provision of human blood for cell cultures, and G. Stevenson for assistance with the triaging of compounds following screening. The authors acknowledge the Bill and Melinda Gates Foundation (grant OPP1040399 to D.A.F. and V.M.A. and grant OPP1054480 to E.A.W. and D.A.F.), the National Institutes of Health (grant R01 AI103058 to E.A.W. and D.A.F., grant R01 AI50234 to D.A.F, and R01 AI110329 to T.J.E.), the Australian Research Council (LP120200557 to V.M.A.) and the Medicines for Malaria Venture for their continued support. P.E.F. and M.I.V. are supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER).info:eu-repo/semantics/publishedVersio

Malaria incidence in Myanmar 2005–2014: steady but fragile progress towards elimination

Abstract Background There has been an impressive recent reduction in the global incidence of malaria, but the development of artemisinin resistance in the Greater Mekong Region threatens this progress. Increasing artemisinin resistance is particularly important in Myanmar, as it is the country in the Greater Mekong Region with the greatest malaria burden. If malaria is to be eliminated in the region, it is essential to define the spatial and temporal epidemiology of the disease in Myanmar to inform control strategies optimally. Results Between the years 2005 and 2014 there was an 81.1 % decline in the reported annual incidence of malaria in Myanmar (1341.8 cases per 100,000 population to 253.3 cases per 100,000 population). In the same period, there was a 93.5 % decline in reported annual mortality from malaria (3.79 deaths per 100,000 population to 0.25 deaths per 100,000 population) and a 87.2 % decline in the proportion of hospitalizations due to malaria (7.8 to 1.0 %). Chin State had the highest reported malaria incidence and mortality at the end of the study period, although socio-economic and geographical factors appear a more likely explanation for this finding than artemisinin resistance. The reduced malaria burden coincided with significant upscaling of disease control measures by the national government with support from international partners. These programmes included the training and deployment of over 40,000 community health care workers, the coverage of over 60 % of the at-risk population with insecticide-treated bed nets and significant efforts to improve access to artemesinin-based combination treatment. Beyond these malaria-specific programmes, increased general investment in the health sector, changing population demographics and deforestation are also likely to have contributed to the decline in malaria incidence seen over this time. Conclusions There has been a dramatic fall in the burden of malaria in Myanmar since 2005. However, with the rise of artemisinin resistance, continued political, financial and scientific commitment is required if the ambitious goal of malaria elimination in the country is to be realized