Disease In Uganda Research Articles

Morphological Identification of Phytophthora A Causal Organism of Pineapple Heart Rot Disease in Uganda

Pineapple (Ananas comosus L. Merr) is an economic horticultural crop in Uganda. However, pineapple production is currently being threatened by the latest outbreak of pineapple heart rot disease in Uganda. Yet, information on pineapple heart rot disease causal pathogen is unknown. Therefore, the objective of this study was to identify the pathogen causing pineapple heart rot disease (PHRD) in Uganda. Samples of pineapple leaves with symptoms of PHRD were collected from four districts of Masaka, Luwero, Mukono and Kayunga. Pathogen isolation was done using corn meal agar (CMA) amended with Pimaricin, Ampicillin, Rifampicin Pentachloronitrobenzene, Hymexazol and Benomyl (PARPHB). Macro- and micro- morphological characteristics of the isolates were assessed using Potato dextrose agar (PDA) and V8 media, respectively. Pathogenicity of the isolates was tested using healthy pineapple plants based on Koch’s postulate. The results showed a significant difference (P0.05) in the growth rates, hyphae diameter and asexual structure dimensions of the isolates. Isolates were characterized by a dense rosette and stoloniferous mycelial growth pattern in PDA media. Although, sporangia were non-caduceus, terminal, papillate and mostly ovoid, obpyriform and limoniform sporangia (32-56μm) with a mean length/breadth ratio of 1.32:1μm were observed. Chlamydospores were spherical and thick-walled (25-42µm diameter) while Sporangiophores branching was sympodial. Based on the morphological characteristics of isolates, it was concluded that Phytophthora nicotianae is the species causing pineapple heart rot disease in Uganda. This study therefore represents the first comprehensive information in Uganda. However, molecular identification of the pathogen is recommended to confirm the genetic identity of the species.

Identification of common bean genotypes with dual leaf and pod resistance to common bacterial blight disease in Uganda

Common Bacterial Blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscans (Xapf), is a serious disease that affects common bean production worldwide. In Uganda, it is the most severe and widely occurring bacterial disease, causing significant yield losses in common bean. Although various sources of resistance have been developed around the world, none of the varieties grown in Uganda is known to be resistant. The objective of this study was to identify lines with combined leaf and pod resistance for introgression into locally adapted but susceptible Ugandan genotypes. A total of 132 common bean accessions was evaluated in a screenhouse and under field conditions, in an 11x12 alpha lattice design. Genotypes were inoculated with a local isolate in a screenhouse; while the plants were left to undergo natural infestation in field. Results indicated significant differences (P<0.001) in genotypic reactions against the CBB disease, with a range of disease scores of 2.2 - 7.8 on leaves and 2.6 - 7.1 on pods (1-9 CIAT disease scale), suggesting high genetic variability among the tested germplasm. Relatively low correlation (r = 0.39) was observed between leaf and pod reactions, suggesting differential expression of CBB resistance in these two plant organs. Overall, four genotypes, NE2-14-8, NE17-14-29, NE14-09-78 and VAX3, consistently showed resistance in both screenhouse and field evaluations, leaf and pod inoculations and at all sampling stages. These genotypes were, therefore, identified for transferring CBB resistance into Ugandan susceptible market class bean varieties. Key words: CBB, Phaseolus vulgaris , Xanthomonas axonopodis

A mathematical model for the dynamics and MCMC analysis of tomato bacterial wilt disease

In this paper, we formulate and analyze a mathematical model to investigate the transmission dynamics of tomato bacterial wilt disease (TBWD) in Mukono district, Uganda. We derive the basic reproduction number [Formula: see text] and prove the existence of a disease-free equilibrium point which is globally stable if [Formula: see text] and an endemic equilibrium which exists if [Formula: see text]. Model parameters are estimated using the Markov Chain Monte Carlo (MCMC) methods and robustness tested. The model parameters were observed to be identifiable. Numerical simulations show that soil solarization and sensitization of farmers can help to eliminate the disease in Uganda. A modified tomato bacterial wilt model with control terms is formulated.

A pre-post intervention study of pulmonary rehabilitation for adults with post-tuberculosis lung disease in Uganda.

SettingThe study was conducted at Mulago Hospital, Kampala, Uganda.ObjectiveAs chronic respiratory disease (CRD) is a huge, growing burden in Africa, with few available treatments, we aimed to design and evaluate a culturally appropriate pulmonary rehabilitation (PR) program in Uganda for people with post-tuberculosis lung disorder (p-TBLD).DesignIn a pre–post intervention study, a 6-week, twice-weekly PR program was designed for people with p-TBLD. Outcome measures included recruitment, retention, the Clinical COPD Questionnaire (CCQ), tests of exercise capacity, and biometrics. Given this was a developmental study, no formal statistical significance testing was undertaken.ResultsIn all, 34 participants started PR and 29 (85%) completed all data collection. The mean age of the 29 participants was 45 years, and 52% were female. The mean (95% confidence interval) CCQ score at baseline was 1.8 (1.5, 2.0), at the end of PR was 1.0 (0.8, 1.2), and at 6 weeks after the end of PR was 0.8 (0.7, 1.0). The Incremental Shuttle Walking Test (ISWT) was 299 m (268.5, 329.4) at baseline, 377 (339.6, 413.8) at the end of PR, and 374 (334.2, 413.5) at 6 weeks after the end of PR. Improvements were seen in measures of chest pain; 13/29 (45%) participants reported chest pain at baseline but only 7/29 (24%) at the end of PR, and in those with persistent pain, the mean pain scores decreased. Mild hemoptysis was reported in 4/29 (17%) participants at baseline and in 2/29 (7%) at the end of PR.ConclusionPR for people with p-TBLD in Uganda was feasible and associated with clinically important improvements in quality of life, exercise capacity, and respiratory outcomes. PR uses local resources, requires little investment, and offers a new, sustainable therapy for p-TBLD in resource-limited settings. With the rising global burden of CRD, further studies are needed to assess the value of PR in p-TBLD and other prevalent forms of CRD.

Subtotal Thyroidectomy with Local Cervical Block Anesthesia in Rural Uganda

Introduction: Thyroid disease remains endemic in many developing nations and is largely the consequence of iodine deficiency. Patients with large goiters may have associated compressive symptoms, hyperthyroidism, or report poor quality of life. Surgery is the principal treatment of large symptomatic goiters but remains particularly challenging in resource-limited settings. Constraints to the surgical management of thyroid disease in Uganda include more advanced disease because of delayed presentation, limited supplies and equipment, limited formal training in endocrine surgery, and limited access to anesthesia.1–4 With a population of >40 million people, Uganda has <100 qualified anesthesia providers, with only a minority of those being physicians.2,3 Owing to this shortage of anesthesia providers in Uganda, some surgeons opt to perform thyroidectomies under local anesthesia. This video demonstrates a subtotal thyroidectomy performed under local cervical block anesthesia for the treatment of a large symptomatic goiter. Materials and Methods: The aim of this video is to provide a demonstration of a subtotal thyroidectomy performed by using only local anesthesia. A 52-year-old female presented with a large symptomatic multinodular goiter. The operation was performed as part of a surgical outreach camp at Nebbi hospital in northwestern rural Uganda.5 Owing to inaccessibility of thyroid replacement hormone and low suspicion for malignant disease, a subtotal thyroidectomy was performed. The patient was alert and conscious throughout the procedure. A 0.25% lidocaine solution with diluted adrenaline was used as local anesthetic.6 The lateral aspect of the sternocleidomastoid muscle is injected bilaterally as it is the standard Kocher incision site. Owing to constraints of the operative facility, the procedure was performed without the use of electrocautery or suction irrigation. Hemostasis was achieved with hand-tied 3-0 or 2-0 silk sutures. The recurrent laryngeal nerve and parathyroid glands were identified intraoperatively. The patient's pain level and phonation can be tested throughout the procedure. The specimen was extracted en bloc and pathology analysis grossly demonstrated multinodular goiter. No drain was placed. Results: An effective subtotal thyroidectomy was performed without intraoperative complication. The patient tolerated the procedure well. The recurrent laryngeal nerve and parathyroid glands were preserved. The operative time was <2 hours and blood loss was minimal. There was no stridor, hoarseness, or symptoms of hypocalcemia identified postoperatively. Gross pathology analysis confirmed suspicion of multinodular goiter. Conclusion: Subtotal thyroidectomy for large symptomatic goiters may be performed safely in a resource-limited setting with the use of local anesthetic only. It is an excellent option for patients when access to anesthesia care is limited or unavailable. No competing financial interests exist. Runtime of video: 4 mins 38 secs

Enhanced passive screening and diagnosis for gambiense human African trypanosomiasis in north-western Uganda - Moving towards elimination.

IntroductionThe incidence of gambiense human African trypanosomiasis (gHAT) in Uganda has been declining, from 198 cases in 2008, to only 20 in 2012. Interruption of transmission of the disease by early diagnosis and treatment is core to the control and eventual elimination of gHAT. Until recently, the format of available screening tests had restricted screening and diagnosis to central health facilities (passive screening). We describe a novel strategy that is contributing to elimination of gHAT in Uganda through expansion of passive screening to the entire population at risk.Methodology / Principal findingsIn this strategy, patients who are clinically suspected of having gHAT at primary health facilities are screened using a rapid diagnostic test (RDT), followed by parasitological confirmation at strategically located microscopy centres. For patients who are positive with the RDT and negative by microscopy, blood samples undergo further testing using loop-mediated isothermal amplification (LAMP), a molecular test that detects parasite DNA. LAMP positive patients are considered strong suspects, and are re-evaluated by microscopy. Location and upgrading of facilities to perform microscopy and LAMP was informed by results of georeferencing and characterization of all public healthcare facilities in the 7 gHAT endemic districts in Uganda. Three facilities were upgraded to perform RDTs, microscopy and LAMP, 9 to perform RDTs and microscopy, and 200 to screen patients with RDTs. This reduced the distance that a sick person must travel to be screened for gHAT to a median distance of 2.5km compared to 23km previously. In this strategy, 9 gHAT cases were diagnosed in 2014, and 4 in 2015.ConclusionsThis enhanced passive screening strategy for gHAT has enabled full coverage of the population at risk, and is being replicated in other gHAT endemic countries. The improvement in case detection is making elimination of the disease in Uganda an imminent possibility.

The impact of a peer support group for children with rheumatic heart disease in Uganda

ObjectiveTo assess the impact of a peer-support group on knowledge, quality of life, and social support for children with rheumatic heart disease (RHD). MethodsChildren diagnosed with RHD and receiving 4-weekly injectable penicillin were invited to participate in a monthly support group for 6 months. Pre- and post-intervention assessments included a baseline RHD knowledge assessment, a measure of health related quality of life (HRQOL) (PedsQLTM4.0), and a measure of social support (Hawthorne Friendship Scale). Groups incorporated elements of cooperative play and team building, RHD education, and emotional support. Results42 participants attended ≥3 groups and were included in the analyses. Attending support groups resulted in increased total HRQOL scores (60.3v 70.2, p<0.001), as well as the following HRQOL sub-scores (physical functioning 55.3v 68.6 (p<0.001), social functioning 64.2v 75.8 (p<0.001) and school functioning 59.2v 69.1 (p=0.001)). Significant increases in Friendship Scale scores (15.4v 19.7, p<0.001) and RHD Knowledge scores were observed (3.6v 6.4, p<0.001). ConclusionsPeer-support groups may be effective at normalizing decreased HRQOL scores and increasing RHD disease knowledge and social support. Practical implicationsPeer-support groups implemented in conjunction with RHD screening can minimize the negative psychosocial effects associated with early RHD detection.

Kidney disease in Uganda: a community based study

BackgroundChronic kidney disease (CKD) is a major cause of morbidity and mortality in Sub-Saharan Africa (SSA). The majority of studies on CKD in SSA have been conducted among HIV-infected populations and mainly from large health facilities. We determined the prevalence of CKD and its predictors among populations in communities in central Uganda.MethodsA cross-sectional study was conducted in Wakiso district using multi-stage sampling. Data was collected on age, sex, socio-economic status, history of alcohol intake, diabetes mellitus, hypertension and smoking. Measurement of blood pressure, weight and height to determine body mass index (BMI) and investigations including HIV testing, fasting blood sugar, creatinine and urinalysis were conducted. Logistic regression was used to estimate the strength of the association between variables and the presence of CKD estimated using the Cockcroft Gault formula.ResultsA total of 955 participants aged 18–87 years were enrolled into the study. The median age was 31 years (Interquartile range 24–42) and majority (67%) were female. Up to 21.4% (204/955) had abnormal renal function with CKD stage 1 in 6.2% (59/955), stage 2 in 12.7% (121/955), stage 3 in 2.4% (23/955), CKD stage 4 in 0% and CKD stage 5 in 0.1% (1/995). Female gender OR 1.8 (95% Confidence Interval [CI] 1.2–2.8), age >30 years OR 2.2(95% CI 1.2–3.8) and high social economic status OR 2.1 (95% CI 1.3–3.6) were associated with increased risk of CKD while BMI > 25Kg/m2 was protective against CKD OR 0.1 (95% CI 0.04–0.2). Traditional risk factors such as HIV-infection, diabetes mellitus, smoking and alcohol intake were not found to be significantly associated with CKD.ConclusionWe found a high prevalence of kidney disease in central Uganda. Interestingly the traditional risk factors associated with CKD previously documented, were not associated with CKD.

Rheumatic heart disease in Uganda: predictors of morbidity and mortality one year after presentation

BackgroundRheumatic heart disease (RHD), the long-term consequence of rheumatic fever, accounts for most cardiovascular morbidity and mortality among young adults in developing countries. However, data on contemporary outcomes from resource constrained areas are limited.MethodsA prospective cohort study of participants aged 5–60 years with established RHD was conducted in Kampala, Uganda, in which clinical exam, echocardiography, electrocardiography (ECG), and laboratory evaluation were done every 3 months and every 4-week benzathine penicillin prophylaxis was prescribed. Participants were followed up for 12 months and outcomes and predictors of morbidity and mortality were assessed using Kaplan Meier curves and Cox proportional hazards models.ResultsOf 449 subjects, 66.8% (300/449) were females, median age was 30 (interquartile range 20). 73.7% (331/449) had atleast one follow up visit. Among these, 35% (116/331) developed decompensated heart failure and, 63.7% (211/331) developed atrial fibrillation. Heart failure was associated with poor penicillin adherence (OR = 3.3, CI 2–5.4, p = 0.001), and left ventricular end diastolic diameter greater than 55 mm (OR = 3.16, CI 1.73–5.76, p = 0.001). Atrial fibrillation was associated with left atrial diameter >40 mm (OR = 7.5, CI 2.4–9.8, p = 0.001).There were 59 deaths with a 1-year mortality rate of 17.8%. Most deaths occurred within the first three months of presentation. Subjects whose average adherence to benzathine penicillin was <80% had significantly greater mortality (31% vs. 9%, log rank p < 0.001). In multivariate analysis, the risk of death among those with poor penicillin adherence was 3.81 times higher than those with better adherence (HR = 3.81, CI 1.92–7.63, p = 0.001). Other predictors of 1 year mortality included heart failure (HR 8.36, CI 3.28–21.31, p = 0.001) and left ventricular end diastolic diameter greater than 55 mm (HR = 1.93, CI 1.07–3.49, p = 0.02).ConclusionIn this study of RHD in Uganda, morbidity and mortality within 1 year of presentation were higher than in recently published from other low and middle income countries. Suboptimal adherence to benzathine penicillin injections was associated with incident heart failure and mortality over 1 year. Future studies should test interventions to improve adherence among patients with advanced disease who are at the highest risk of mortality.

’Why didn’t you see it coming?’: Surveillance by and in the media—Journalistic research on outbreak detection taking the example of Ebola Virus Disease in Uganda and West Africa

Purpose: A package of papers, “Avis de décès 2013/2014”: This I found at the radio station in Guéckédou/Guinea, close to the village where the spill-over of the Ebola virus had occurred. When the outbreak was detected in 03/2014, scientists and journalists arrived to trace the transmission chain of the virus. However, I went there to reconstruct the transmission chain of information: who had known what when? I also went to Uganda to see how the country had set up a completely new surveillance system after its first, severest Ebola outbreak. For me as a science journalist focusing on NTD, Global Health, Health Systems in LMIC, the purpose of this project was double-pronged: To inform the public: Surveillance and IHR are technical terms, difficult to illustrate to lay persons. But it is important and possible to do so. To correct misperceptions: The WHO and others were blamed for taking action too late during the early stages of the outbreak. But to be able to respond to an outbreak, organizations have to know that a potential public health emergency is occurring somewhere. Methods & Materials: Scientific approach: fieldwork in Uganda, Guinea; methods from social sciences, epidemiology, e.g. interviews with key persons, observational studies; triangulating collected data. Journalistic materials: audio/video recordings, photography. Results: In retrospect, it became obvious that the EVD outbreak in Guinea could have been detected earlier—if the information chain hadn’t been interrupted. Radio documentary: 27 min, manuscript: http://bit.ly/1YnzADF, audio: bit.ly/1UQBgZ6; Online multimedia story: 30 min, manuscript: bit.ly/1RP0Cq0, pageflow: http://bit.ly/1lTDvMH; both published by the German public radio news channel Deutschlandfunk on the occasion of the second anniversary of the death of “Patient Zero”. Conclusion: Journalists are strategic interlocutors in outbreak detection initiatives and IHR. They can contribute to surveillance structures or adopt a kind of epidemiological role. And sometimes journalists can even help to improve surveillance systems: After my stories were broadcast, I received a call: “The CDC in Guinea had no idea what the CDC in Uganda had done for the surveillance system and how well outbreak detection now works there. The people in Conakry just heard of your work and now reconsider their plans.”

Farmer awareness, coping mechanisms and economic implications of coffee leaf rust disease in Uganda

Coffee leaf rust (CLR) still remains a serious threat to the economics of coffee farming in Uganda. The disease is more severe on Arabica coffee (Coffea arabica) at mid and low altitude (1500 m and below) where crop losses is up to 50%. The objective of this study was to document farmers’ knowledge about the disease, economic implications and coping strategies across the Arabica growing zones in Uganda. A stratified random sampling procedure was adopted. The main data collection tool was a semi-structured questionnaire for face-to-face interview and checklist for focus group discussions (FGDs). SPSS for windows (Version 16) was used for statistical analysis. Overall, 83.8% had knowledge on the disease. The disease reportedly causes premature defoliation and loss of photosynthetic surfaces, leading to appearance of pale yellow spots on the lower surface of the leaves (72.3%) and expanding berries failing to fill up and young berries shedding off (11.5%). The most susceptible variety reported was SL14; while KP423 was reportedly tolerant. Results further revealed that rust incidence led to a significant (p ≤ 0.01) reduction in Arabica coffee productivity and income by 49.5%. As cope up strategies, farmers practiced timely weeding (81.5%), chemical spraying mainly using Bordeaux mixture (20.8%), phyto-sanitary methods (8.1%), concoctions (10.4%), fertiliser application (12.4%) and planting tolerant varieties (9.2%). The use of concoctions and phyto-sanitary methods significantly (P ≤ 0.01) reduced the impact of the disease on annual production per ha by 1139 and 1255 kg, respectively.Keywords: Coffee Leaf Rust, Indigenous knowledge, economic implication, Uganda

Genetic analysis of resistance to Alternaria leaf petiole and stem blight of sweetpotato in Uganda

Alternaria blight (Alternaria spp.) is an important sweetpotato disease in Uganda causing yield losses of over 50 % in susceptible genotypes. In Uganda, Alternaria bataticola and Alternaria alternata are the major species with A. bataticola the more aggressive of the two. The most effective control measure for this disease is the use of resistant genotypes. This study was conducted to determine the inheritance of resistance to Alternaria blight and the general and specific combining abilities of the available germplasm. Sixteen parental clones varying in reaction to Alternaria blight were crossed using the North Carolina II mating scheme. Due to incompatibility of some parents, two sets of compatible parents were formed. Differences among the families for Alternaria blight severity were significant while general combining ability (GCA) and specific combining ability (SCA) mean squares were highly significant (P < 0.001) for the disease with GCA sum of squares (SS) being more predominant at 67.4 % of the treatment SS for Set 1 and the SCA SS predominant at 54.0 % of the treatment SS for Set 2. This indicated that both additive and non-additive effects are important in controlling this trait. Some parents with high, negative GCA effects produced families with undesirable SCA effects and the reverse was also true. This implies that the best parents should not be chosen on GCA alone but also on SCA of their best crosses. The wide range in the area under disease progress curve for the families indicated that it was possible to select for highly resistant genotypes.

Child and teacher acceptability of school-based echocardiographic screening for rheumatic heart disease in Uganda.

A total of 255 students (mean 10.7 years; 48% male) and 35 teachers participated in our study. In total, 95% of the students and 100% of the teachers were happy to have participated in the screening; however, students reported feeling scared (35%) and nervous (48%) during the screening process. Programmatic strengths included the following: knowing one's health status, opportunity to receive treatment, and staff interactions. Although 43% of the patients did not suggest a change with open-ended questioning, concerns regarding privacy, fear of the screening process, and a desire to include others in the community were noted. Discussion School-based echocardiographic rheumatic heart disease screening was well received by students and teachers. Future programmes would likely benefit from improved pre-screening education regarding the screening process and diagnosis of rheumatic heart disease. Furthermore, education of teachers and students could improve screening perception and establish realistic expectations regarding the scope of screening.

Detection and identification of etiological agents (Liberibacter spp.) associated with citrus greening disease in Uganda

Citrus Huanglongbing (HLB), commonly referred to as citrus greening, is one of the major disease challenges of citrus. In Uganda, there was limited information on Liberibacter spp., the causal organisms of HLB disease, and its psyllid vectors despite the presence of HLB symptoms on citrus. The objective of this study was to identify the Liberibacter spp. and psylla vector species responsible for HLB in Uganda. Other native plant species that could be hosts to pathogens and the psyllid vectors, but are not in the citrus genus, were also investigated. A survey was conducted in 15 citrus growing districts, and symptomatic citrus leaf samples collected, as well as citrus psyllid nymphs and adults for isothermal detection of pathogens in the laboratory. Two types of bacterial pathogens responsible for HLB were detected, namely Candidatus Liberibacter africanus (CLaf), known as the African type; and Candidatus Liberibacter asiaticus (CLas), known as the Asian type. CLaf was found in Mukono and Wakiso districts in Central Uganda and in Mbarara in Western Uganda; while CLas was found in Budaka and Tororo districts in Eastern Uganda. Citrus psyllids, which are the major known disease vectors were present in seven out of the fifteen districts. Psyllid vector identification by morphological means indicated Trioza erytreae, the African psyllid to be the insect vector. Psyllids were common on tangerines (66.7%), Sour Orange (13.3%) and Rough Lemon (13.3%); and least on Washington Navel (6.7%). Three non-citrus plants, Stephania abyssinica (Dill. &amp; A. Rich) walp var. tomentella (Oliv.) Deils (Menispermaceae), Diospyros mespiliformis (Ebenaceae) and Ficus spp (Moraceae) were found to be alternative host plants for the psyllid.Key words: Candidatus, Diospyros mespiliformis, Psyllids, Trioza erytreae

Family, Community, and Health System Considerations for Reducing the Burden of Pediatric Sickle Cell Disease in Uganda Through Newborn Screening.

Sickle cell disease (SCD) is associated with high mortality for children under 5 years of age in sub-Saharan Africa. Newborn sickle screening program and enhanced capacity for SCD treatment are under development to reduce disease burden in Uganda and elsewhere in the region. Based on an international stakeholder meeting and a family-directed conference on SCD in Kampala in 2015, and interviews with parents, multinational experts, and other key informants, we describe health care, community, and family perspectives in support of these initiatives. Key stakeholder meetings, discussions, and interviews were held to understand perspectives of public health and multinational leadership, patients and families, as well as national progress, resource needs, medical and social barriers to program success, and resources leveraged from HIV/AIDS. Partnering with program leadership, professionals, patients and families, multinational stakeholders, and leveraging resources from existing programs are needed for building successful programs in Uganda and elsewhere in sub-Saharan Africa.

A mathematical model for the dynamics and cost effectiveness of the current controls of cassava brown streak disease in Uganda

In this paper, Cassava brown streak disease (CBSD), transmitted from white fly vector to the host plant and vice versa, is a major threat to cassava production in Uganda and other cassava growing countries in Africa, e.g. Kenya, Tanzania, Malawi, Mozambique, e.t.c. The seriousness of the situation is that almost all varieties of cassava resistant to cassava mosaic disease (CMD) are susceptible to the new strain of CBSD. Numerous control measures are practiced by farmers, however, the cost effectiveness of these control measures have not been quantified. Therefore it is imperative that we formulate a mathematical model to investigate the transmission dynamics of CBSD and the cost-effectiveness of the control measures. In the analysis of the model we derived the basic reproduction number which helps us in establishing the stability of disease free and endemic equilibrium points. The model is then modified as an optimal control problem with an aim of minimizing the number of infected plants while keeping the cost low. Two time dependent controls are used in the model and an objective function which is a combination of the actual and relative costs associated with the controls is designed. Pontryagins Maximum Principle (PMP) is used to establish the necessary conditions for optimal control of the disease. The incremental cost-effectiveness ratio (ICER) is also computed and used to analyse the cost-effectiveness of the control strategies. Numerical results show that strategy B (uprooting and burning of infected plants) is cost effective, however if the government intervenes with massive spraying, strategy C (spraying with chemicals and uprooting and burning of infected plants) gives the farmer more yield.

Updated estimate of the duration of the meningo-encephalitic stage in gambiense human African trypanosomiasis.

Background The duration of the stages of HAT is an important factor in epidemiological studies and intervention planning. Previously, we published estimates of the duration of the haemo-lymphatic stage 1 and meningo-encephalitic stage 2 of the gambiense form of human African trypanosomiasis (HAT), in the absence of treatment. Here we revise the estimate of stage 2 duration, computed based on data from Uganda and South Sudan, by adjusting observed infection prevalence for incomplete case detection coverage and diagnostic inaccuracy.FindingsThe revised best estimate for the mean duration of stage 2 is 252 days (95% CI 171–399), about half of our initial best estimate, giving a total mean duration of untreated gambiense HAT infection of approximately 2 years and 2 months. ConclusionsOur new estimate provides improved information on the transmission dynamics of this neglected tropical disease in Uganda and South Sudan. We stress that there remains considerable variability around the estimated mean values, and that one must be cautious in applying these results to other foci.

English

Groundnut rosette virus disease is the most destructive disease of groundnut in Sub-Saharan Africa, Uganda inclusive. Over the past years, a wide range of management options for this disease have been developed and recommended for farmers in Uganda.&nbsp; Relevant efforts have also been made by researchers in disseminating improved technologies to farmers in several parts of the country. However, questions on the extent to which farmers are currently utilizing these technologies and their effectiveness in controlling the disease in their fields remain unanswered. This study aimed at assessing the effect of farmers&rsquo; practices on the severity patterns of groundnut rosette virus disease in Uganda. A survey was conducted within five agro-ecological zones in Uganda to obtain information on the various practices farmers employ in the management of the crop and disease in their fields using a structured questionnaire. Disease severity was scored in each farmer&rsquo;s field.&nbsp; Farmers were found to be employing a range of practices in groundnut production, including: early sowing, intercropping, use of improved groundnut genotypes, crop rotation; and uprooting and burning diseased plants among others. However, only two management practices: early sowing and use of improved varieties were found to significantly (P&lt;0.05) reduce rosette severity in groundnut fields. Special consideration should therefore be given to these two GRVD management strategies while developing and promoting management packages for this disease. &nbsp; Key words: Groundnut, rosette, incidence, severity, farmers, management.

Influence of Host Plant Resistance and Disease Pressure on Spread of Cassava Brown Streak Disease in Uganda

Cassava brown streak disease (CBSD) is a major constraint to cassava production in Uganda. The disease is caused by two ipomovirus species: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak vi rus (UCBSV), both transmitted by the whitefly vector ( Bemisia tabaci ). Since the outbreak of the CBSD epidemic in Uganda in 2004, knowledge of its spread in the field is still limited. In this study, five cassava genotypes with varying levels of resistance to CBSD: TME 204 (susceptible), I92/0067, MH 97/2961, MH 96/0686 (moderately tolerant) and NASE 3 (tolerant) were used to evaluate the effect of genotype and prevailing disease pressure on CBSD spread in Uganda. The experiment was established in a random ized Complete Block Design (RCBD) in three sites of varying CBSD disease pressure: high (Wakiso), moderate (Kamuli) and low (Lira) in

Cardiac surgery for patients with heart failure due to structural heart disease in Uganda: access to surgery and outcomes.

SummaryObjectiveFew data are available on heart failure (HF) in sub-Saharan Africa. We aimed to provide a current picture of HF aetiologies in urban Uganda, access to heart surgery, and outcomes.MethodsWe prospectively collected clinical and echocardiographic data from 272 consecutive patients referred for suspected heart disease to a tertiary hospital in Kampala during seven non-governmental organisation (NGO) missions from 2009 to 2013. We focused the analysis on 140 patients who fulfilled standardised criteria of HF by echocardiography.ResultsRheumatic heart disease (RHD) was the leading cause of HF in 44 (31%) patients. Among the 50 children included (age ≤ 16 years), congenital heart disease (CHD) was the first cause of HF (30 patients, 60%), followed by RHD (16 patients, 32%). RHD was the main cause of HF (30%) among the 90 adults. All 85 patients with RHD and CHD presented with an indication for heart surgery, of which 74 patients were deemed fit for intervention. Surgery was scheduled in 38 patients with RHD [86%, median age 19 years (IQR: 12–31)] and in 36 patients with CHD [88%, median age 4 years (IQR 1–5)]. Twenty-seven candidates (32%) were operated on after a median waiting time of 10 months (IQR 6–21). Sixteen (19%) had died after a median of 38 months (IQR 5–52); 19 (22%) were lost to follow up.ConclusionsRHD still represents the leading cause of HF in Uganda, in spite of cost-efficient prevention strategies. The majority of surgical candidates, albeit young, do not have access to treatment and present high mortality rates.