EFFECTIVE ISOLATION DISTANCE FOR PREVENTION OF CASSAVA VIRUS INFECTIONS IN UGANDA

Cassava brown streak disease (CBSD) and cassava mosaic disease (CMD) are the major viral diseases of cassava in Uganda. Although isolation distance of \u201c50 m\u201d has been recommended by MAAIF in Uganda for prevention of virus infections in crops, the minimum isolation distance has not been verified for effectiveness in cassava. This study assessed the effective isolation distance for management of viral diseases in cassava. Virus-clean cassava cultivars (NASE 03, NASE 14 and NAROCASS 1) from farmers\u2019 fields were used as field sourced (FS) planting materials. Tissue culture (TC) material of the same cultivars were sourced from the National Crops Resources Research Institute and Makerere University Agricultural Research Institute tissue culture laboratories. Both FS and TC materials were tested at isolation distances of 50, 100, 150 and 250 m for virus prevention. The experiment was laid out in a randomised complete block design and was run for 12 months after planting (MAP). Mean CBSD/CMD prevalence significantly varied (P<0.05) among isolation distances in both FS and TC plants, and the 250 m isolation distance was the most effective in reducing disease prevalence. Across cultivars and planting material category at 12 MAP, the 50 m isolation distance had the highest foliar incidence for CBSD (29.2%) and CMD (16.1%); while severity for CBSD was 1.4 and 1.2 for CMD. At 250 m, all FS and TC plants had CBSD/CMD severity of 1.0 and 0% incidence. These results show that 250 m isolation distance can provide an option to disseminate popular, but CBSD/CMD susceptible cassava cultivars thereby manage CBSD/CMD.La maladie des stries brunes du manioc (CBSD) et la maladie de la mosa\uefque du manioc (CMD) sont les principales maladies virales du manioc en Ouganda. Bien qu\u2019une distance d\u2019isolement de \uab50 m\ubb ait \ue9t\ue9 recommand\ue9e par le MAAIF en Ouganda pour la pr\ue9vention des infections virales dans les cultures, l\u2019efficacit\ue9 minimale de la distance d\u2019isolement n\u2019a pas \ue9t\ue9 v\ue9rifi\ue9e dans le manioc. Cette \ue9tude a \ue9valu\ue9 la distance d\u2019isolement efficace pour la gestion des maladies virales dans le manioc. Des cultivars de manioc sans virus (NASE 03, NASE 14 et NAROCASS 1) provenant des champs des agriculteurs ont \ue9t\ue9 utilis\ue9s comme le source de mat\ue9riel de plantation (FS). Le mat\ue9riel de culture tissulaire (TC) des m\ueames cultivars provenait des laboratoires National Crops Resources Research Institute and Makerere University Agricultural Research Institute tissue culture. Les mat\ue9riaux FS et TC ont \ue9t\ue9 test\ue9s \ue0 des distances d\u2019isolement de 50, 100, 150 et 250 m pour la pr\ue9vention des virus. L\u2019exp\ue9rience a \ue9t\ue9 pr\ue9sent\ue9e dans un bloc complet randomis\ue9 et a \ue9t\ue9 r\ue9alis\ue9e pendant 12 mois apr\ue8s la plantation (MAP). La pr\ue9valence moyenne de CBSD / CMD variait significativement (P <0,05) entre les distances d\u2019isolement dans les plantes FS et TC, et la distance d\u2019isolement de 250 m \ue9tait la plus efficace pour r\ue9duire la pr\ue9valence de la maladie. \uc0 travers les cultivars et la cat\ue9gorie de mat\ue9riel de plantation \ue0 12 MAP, la distance d\u2019isolement de 50 m avait l\u2019incidence foliaire la plus \ue9lev\ue9e pour le CBSD (29,2%) et le CMD (16,1%); tandis que la gravit\ue9 pour CBSD \ue9tait de 1,4 et 1,2 pour CMD. \uc0 250 m, toutes les plantes FS et TC avaient une gravit\ue9 CBSD / CMD de 1,0 et une incidence de 0%. Ces r\ue9sultats montrent qu\u2019une distance d\u2019isolement de 250 m peut fournir une option pour diss\ue9miner des cultivars de manioc sensibles au CBSD / CMD, ce qui permet de g\ue9rer le CBSD / CMD

Exploring the influence of climate change and capital assets on livelihood formations in central region of Uganda

Current research provides less understanding of how climate change affects the livelihood process at a household level. This study explores household’s perceptions of climate change and its implications on livelihood formation process using empirical data from Uganda. Climatic data, household surveys and key-informant interviews from Wakiso and Gomba districts served as data sources for the study analysis. Majority of the respondents observed climate changes in the last 10–20 years and perceived them to have affected their capital assets in the process of forming livelihoods. As a result, households’ livelihoods have diversified and are pursuing livelihood strategies for sustenance. The study underlines the need to access credit conditioned to climate change resilience, access to improved varieties of crops, availing extension services and targeted resources allocations. Incorporating climate change into the planning process at a local level and associated local institutions in order to improve livelihood formation processes of households is recommended.UNISA postdoctoral fellowshiphttps://www.springer.com/journal/106682022-01-19hj2021Geography, Geoinformatics and Meteorolog

Detecting changes in surface water area of Lake Kyoga sub-basin using remotely sensed imagery in a changing climate

Detection of changes in Earth surface features, for example lakes, is important for understanding the relationships between human and natural phenomena in order to manage better the increasingly scarce natural resources. This work presents a procedure of using Modified Normalised Difference Water Index (MNDWI) to detect fluctuations of Lake surface-water area and relate it to a changing climate. The study used radiometrically and geometrically rectified Landsat images for 1986, 1995 and 2010 encompassing the Kyoga Basin lakes of Uganda, in order to investigate the changes in surface-water area between the respective years. The Standard Precipitation Index (SPI) and Drought Severity Index (DSI) are applied to show the relationship between variability of surface-water area and climate parameters. The present analysis reveals that surface-water area fluctuation is linked to rainfall variability. In particular, Lake Kyoga sub-basin lakes experienced an increase in surface-water area in 2010 compared to 1986. This work has important implications to water resources management for Lake Kyoga and could be vital to water resource managers across Ugandan lakes.http://link.springer.com/journal/7042016-09-30hb2016Geography, Geoinformatics and Meteorolog

Predictors and outcome of surgical repair of obstetric fistula at a regional referral hospital, Mbarara, western Uganda

<p>Abstract</p> <p>Background</p> <p>Obstetric fistula although virtually eliminated in high income countries, still remains a prevalent and debilitating condition in many parts of the developing world. It occurs in areas where access to care at childbirth is limited, or of poor quality and where few hospitals offer the necessary corrective surgery.</p> <p>Methods</p> <p>This was a prospective observational study where all women who attended Mbarara Regional Referral Hospital in western Uganda with obstetric fistula during the study period were assessed pre-operatively for social demographics, fistula characteristics, classification and outcomes after surgery. Assessment for fistula closure and stress incontinence after surgery was done using a dye test before discharge</p> <p>Results</p> <p>Of the 77 women who were recruited in this study, 60 (77.9%) had successful closure of their fistulae. Unsuccessful fistula closure was significantly associated with large fistula size (Odds Ratio 6 95% Confidential interval 1.46-24.63), circumferential fistulae (Odds ratio 9.33 95% Confidential interval 2.23-39.12) and moderate to severe vaginal scarring (Odds ratio 12.24 95% Confidential interval 1.52-98.30). Vaginal scarring was the only factor independently associated with unsuccessful fistula repair (Odds ratio 10 95% confidential interval 1.12-100.57). Residual stress incontinence after successful fistula closure was associated with type IIb fistulae (Odds ratio 5.56 95% Confidential interval 1.34-23.02), circumferential fistulae (Odds ratio 10.5 95% Confidential interval 1.39-79.13) and previous unsuccessful fistula repair (Odds ratio 4.8 95% Confidential interval 1.27-18.11). Independent predictors for residual stress incontinence after successful fistula closure were urethral involvement (Odds Ratio 4.024 95% Confidential interval 2.77-5.83) and previous unsuccessful fistula repair (Odds ratio 38.69 95% Confidential interval 2.13-703.88).</p> <p>Conclusions</p> <p>This study demonstrated that large fistula size, circumferential fistulae and marked vaginal scarring are predictors for unsuccessful fistula repair while predictors for residual stress incontinence after successful fistula closure were urethral involvement, circumferential fistulae and previous unsuccessful fistula repair.</p

CT Scan Screening for Lung Cancer: Risk Factors for Nodules and Malignancy in a High-Risk Urban Cohort

Low-dose computed tomography (CT) for lung cancer screening can reduce lung cancer mortality. The National Lung Screening Trial reported a 20% reduction in lung cancer mortality in high-risk smokers. However, CT scanning is extremely sensitive and detects non-calcified nodules (NCNs) in 24-50% of subjects, suggesting an unacceptably high false-positive rate. We hypothesized that by reviewing demographic, clinical and nodule characteristics, we could identify risk factors associated with the presence of nodules on screening CT, and with the probability that a NCN was malignant.We performed a longitudinal lung cancer biomarker discovery trial (NYU LCBC) that included low-dose CT-screening of high-risk individuals over 50 years of age, with more than 20 pack-year smoking histories, living in an urban setting, and with a potential for asbestos exposure. We used case-control studies to identify risk factors associated with the presence of nodules (n=625) versus no nodules (n=557), and lung cancer patients (n=30) versus benign nodules (n=128).The NYU LCBC followed 1182 study subjects prospectively over a 10-year period. We found 52% to have NCNs >4 mm on their baseline screen. Most of the nodules were stable, and 9.7% of solid and 26.2% of sub-solid nodules resolved. We diagnosed 30 lung cancers, 26 stage I. Three patients had synchronous primary lung cancers or multifocal disease. Thus, there were 33 lung cancers: 10 incident, and 23 prevalent. A sub-group of the prevalent group were stable for a prolonged period prior to diagnosis. These were all stage I at diagnosis and 12/13 were adenocarcinomas.NCNs are common among CT-screened high-risk subjects and can often be managed conservatively. Risk factors for malignancy included increasing age, size and number of nodules, reduced FEV1 and FVC, and increased pack-years smoking. A sub-group of screen-detected cancers are slow-growing and may contribute to over-diagnosis and lead-time biases

Smoking cessation opportunities in severe mental illness (tobacco intensive motivational and estimate risk — TIMER—): study protocol for a randomized controlled trial

There is an increased risk of premature death in people with severe mental illness (SMI). Respiratory disorders and cardiovascular disease are leading causes of increased mortality rates in these patients, and tobacco consumption remains the most preventable risk factor involved. Developing new tools to motivate patients towards cessation of smoking is a high priority. Information on the motivational value of giving the lung age and prevention opportunities is unknown in this high-risk population. In the context of community care, screening and early detection of lung damage could potentially be used, together with mobile technology, in order to produce a prevention message, which may provide patients with SMI with a better chance of quitting smoking.This study receives funding by the Spanish Ministry of Economy, Industry and Competitiveness, Instituto Carlos III (FIS PI16/00802)

Quantifying HIV transmission flow between high-prevalence hotspots and surrounding communities: a population-based study in Rakai, Uganda

Background International and global organisations advocate targeting interventions to areas of high HIV prevalence (ie, hotspots). To better understand the potential benefits of geo-targeted control, we assessed the extent to which HIV hotspots along Lake Victoria sustain transmission in neighbouring populations in south-central Uganda. Methods We did a population-based survey in Rakai, Uganda, using data from the Rakai Community Cohort Study. The study surveyed all individuals aged 15–49 years in four high-prevalence Lake Victoria fishing communities and 36 neighbouring inland communities. Viral RNA was deep sequenced from participants infected with HIV who were antiretroviral therapy-naive during the observation period. Phylogenetic analysis was used to infer partial HIV transmission networks, including direction of transmission. Reconstructed networks were interpreted through data for current residence and migration history. HIV transmission flows within and between high-prevalence and low-prevalence areas were quantified adjusting for incomplete sampling of the population. Findings Between Aug 10, 2011, and Jan 30, 2015, data were collected for the Rakai Community Cohort Study. 25 882 individuals participated, including an estimated 75·7% of the lakeside population and 16·2% of the inland population in the Rakai region of Uganda. 5142 participants were HIV-positive (2703 [13·7%] in inland and 2439 [40·1%] in fishing communities). 3878 (75·4%) people who were HIV-positive did not report antiretroviral therapy use, of whom 2652 (68·4%) had virus deep-sequenced at sufficient quality for phylogenetic analysis. 446 transmission networks were reconstructed, including 293 linked pairs with inferred direction of transmission. Adjusting for incomplete sampling, an estimated 5·7% (95% credibility interval 4·4–7·3) of transmissions occurred within lakeside areas, 89·2% (86·0–91·8) within inland areas, 1·3% (0·6–2·6) from lakeside to inland areas, and 3·7% (2·3–5·8) from inland to lakeside areas. Interpretation Cross-community HIV transmissions between Lake Victoria hotspots and surrounding inland populations are infrequent and when they occur, virus more commonly flows into rather than out of hotspots. This result suggests that targeted interventions to these hotspots will not alone control the epidemic in inland populations, where most transmissions occur. Thus, geographical targeting of high prevalence areas might not be effective for broader epidemic control depending on underlying epidemic dynamics. Funding The Bill & Melinda Gates Foundation, the National Institute of Allergy and Infectious Diseases, the National Institute of Mental Health, the National Institute of Child Health and Development, the Division of Intramural Research of the National Institute for Allergy and Infectious Diseases, the World Bank, the Doris Duke Charitable Foundation, the Johns Hopkins University Center for AIDS Research, and the President's Emergency Plan for AIDS Relief through the Centers for Disease Control and Prevention

Inferring HIV-1 transmission networks and sources of epidemic spread in Africa with deep-sequence phylogenetic analysis

To prevent new infections with human immunodeficiency virus type 1 (HIV-1) in sub-Saharan Africa, UNAIDS recommends targeting interventions to populations that are at high risk of acquiring and passing on the virus. Yet it is often unclear who and where these ‘source’ populations are. Here we demonstrate how viral deep-sequencing can be used to reconstruct HIV-1 transmission networks and to infer the direction of transmission in these networks. We are able to deep-sequence virus from a large population-based sample of infected individuals in Rakai District, Uganda, reconstruct partial transmission networks, and infer the direction of transmission within them at an estimated error rate of 16.3% [8.8–28.3%]. With this error rate, deep-sequence phylogenetics cannot be used against individuals in legal contexts, but is sufficiently low for population-level inferences into the sources of epidemic spread. The technique presents new opportunities for characterizing source populations and for targeting of HIV-1 prevention interventions in Africa