Epidemiology of Trypanosoma brucei rhodesiense sleeping sickness in Eastern Uganda

Sleeping sickness is now recognized as one of the recent re-emerging but neglected diseases. In Uganda and the rest of sub-Saharan Africa, old foci of sleeping sickness persist despite donor-funded projects and there is evidence of expansion of these foci. The World Health Organization acknowledges a high level of undiagnosed sleeping sickness cases and has identified surveillance and treatment as the major control strategy for sleeping sickness. However, to date there have been no clear epidemiological surveillance markers applied for monitoring the burden of the disease at control implementation levels. There is therefore a need to obtain markers for surveillance and to apply these to monitor and improve this important strategy of sleeping sickness control, hence, the objective of this study.Data of sleeping sickness patients from 1987 to 2002 were collected from Tororo, Busia and Soroti districts. Using the ratio of early to late stage patients in an affected population, data from (Livestock Health Research Institute) LIRI hospital in Tororo district were applied to develop a model for estimation of sleeping sickness underdetection. The model was applied to data from a recent outbreak of sleeping sickness in Soroti district to determine the burden of the disease. Geographical information systems (GIS) were applied to quantify the effect of distance from the health units on early detection of sleeping sickness. A semi-structured questionnaire was administered to prospective sleeping sickness patients to determine their treatment seeking behavior. Spatial and temporal trends of sleeping sickness with and without control are described using the SatScan method for spatial temporal clustering. The potential role of remote sensing in surveillance of sleeping sickness was explored using a processed Landsat 7 series satellite image to determine association of land cover classes, vegetation indices, population density, distance to wetlands, distance to the sleeping sickness hospital to the outcome of village scale disease geographical distribution generated using GIS.In the Tororo and Busia area, for every 3 reported patients, 2 went undetected. The Disability Adjusted Life Years (DALYs) for sleeping sickness in the Soroti outbreak are greatly increased when under-detection is taken into account. There is a strong effect of distance to health unit on the surveillance of sleeping sickness. Children and xviii adolescents are less likely to be detected in early stage. During times of low incidence, the proportion of late stage detected patients increases. Most of the delay to diagnosis is attributable to service provider delay and most patients are referred to the sleeping sickness referral hospital by the community and not the health system. Proximity to wetlands and to the sleeping sickness hospital, low population density, vegetation wetness and smaller area of short grassland and larger area of cropland were significantly associated with the distribution of sleeping sickness affected villages in Tororo and Busia districts.Surveillance of sleeping sickness can be monitored by applying the early to late stage ratio of sleeping sickness as an epidemiological tool to determine the level of underdetection and subsequently the burden of disease. Optimal distribution of fixed post diagnostic units will greatly improve rhodesiense sleeping sickness surveillance. Surveillance programmes should regularly update health workers in the primary health care units in the vicinity of sleeping sickness affected populations. Similarly, the affected communities can be resourcefully used to refer sleeping sickness suspects to the appropriate health care facilities. Timely responsive disease surveillance and intervention can prevent spread of sleeping sickness. Remotely sensed maps can assist in accurately describing sleeping sickness foci and therefore, the area requiring application of control interventions

Common childhood kidney diseases in Uganda and their prevention

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Focus–specific clinical profiles in human African trypanosomiasis caused by <i>Trypanosoma brucei rhodesiense</i>

&lt;p&gt;&lt;b&gt;Background:&lt;/b&gt; Diverse clinical features have been reported in human African trypanosomiasis (HAT) foci caused by &lt;i&gt;Trypanosoma brucei rhodesiense&lt;/i&gt; (&lt;i&gt;T.b.rhodesiense&lt;/i&gt;) giving rise to the hypothesis that HAT manifests as a chronic disease in South-East African countries and increased in virulence towards the North. Such variation in disease severity suggests there are differences in host susceptibility to trypanosome infection and/or genetic variation in trypanosome virulence. Our molecular tools allow us to study the role of host and parasite genotypes, but obtaining matched extensive clinical data from a large cohort of HAT patients has previously proved problematic.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods/Principal Findings:&lt;/b&gt; We present a retrospective cohort study providing detailed clinical profiles of 275 HAT patients recruited in two northern foci (Uganda) and one southern focus (Malawi) in East Africa. Characteristic clinical signs and symptoms of &lt;i&gt;T.b.rhodesiense&lt;/i&gt; infection were recorded and the degree of neurological dysfunction determined on admission. Clinical observations were mapped by patient estimated post-infection time. We have identified common presenting symptoms in &lt;i&gt;T.b.rhodesiense&lt;/i&gt; infection; however, marked differences in disease progression and severity were identified between foci. HAT was characterised as a chronic haemo-lymphatic stage infection in Malawi, and as an acute disease with marked neurological impairment in Uganda. Within Uganda, a more rapid progression to meningo-encephaltic stage of infection was observed in one focus (Soroti) where HAT was characterised by early onset neurodysfunction; however, severe neuropathology was more frequently observed in patients in a second focus (Tororo).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions/Significance:&lt;/b&gt; We have established focus-specific HAT clinical phenotypes showing dramatic variations in disease severity and rate of stage progression both between northern and southern East African foci and between Ugandan foci. Understanding the contribution of host and parasite factors in causing such clinical diversity in &lt;i&gt;T.b.rhodesiense&lt;/i&gt; HAT has much relevance for both improvement of disease management and the identification of new drug therapy.&lt;/p&gt

The origins of a new Trypanosoma brucei rhodesiense sleeping sickness outbreak in eastern Uganda.

BACKGROUND: Sleeping sickness, caused by two trypanosome subspecies, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, is a parasitic disease transmitted by the tsetse fly in sub-Saharan Africa. We report on a recent outbreak of T b rhodesiense sleeping sickness outside the established south-east Ugandan focus, in Soroti District where the disease had previously been absent. Soroti District has been the subject of large-scale livestock restocking activities and, because domestic cattle are important reservoirs of T b rhodesiense, we investigated the role of cattle in the origins of the outbreak. METHODS: We identified the origins of cattle entering the outbreak area in the 4 years preceding the outbreak. A matched case-control study was conducted to assess whether the distance of villages from the main market involved with restocking was a risk factor for sleeping sickness. We investigated the spatial clustering of sleeping sickness cases at the start of the outbreak. FINDINGS: Over 50% (1510 of 2796) of cattle traded at the market were reported to have originated from endemic sleeping sickness areas. The case-control study revealed that distance to the cattle market was a highly significant risk factor for sleeping sickness (p<0.001) and that there was a significant clustering of cases (27 of 28) close to the market at the start of the outbreak (p<0.001). As the outbreak progressed, the average distance of cases moved away from the cattle market (0.014 km per day, 95% CI 0.008-0.020 km per day, p<0.001). INTERPRETATIONS: The results are consistent with the disease being introduced by cattle infected with T b rhodesiense imported to the market from the endemic sleeping sickness focus. The subsequent spread of the disease away from the market suggests that sleeping sickness is becoming established in this new focus. Public health measures directed at controlling the infection in the animal reservoir should be considered to prevent the spread of sleeping sickness

Spatial Analysis of Sleeping Sickness, Southeastern Uganda, 1970–2003

Disease will likely spread into central Uganda

Analysis of risk factors for T. brucei rhodesiense sleeping sickness within villages in south-east Uganda

<p>Abstract</p> <p>Background</p> <p>Sleeping sickness (HAT) caused by <it>T.b. rhodesiense </it>is a major veterinary and human public health problem in Uganda. Previous studies have investigated spatial risk factors for <it>T.b. rhodesiense </it>at large geographic scales, but none have properly investigated such risk factors at small scales, i.e. within affected villages. In the present work, we use a case-control methodology to analyse both behavioural and spatial risk factors for HAT in an endemic area.</p> <p>Methods</p> <p>The present study investigates behavioural and occupational risk factors for infection with HAT within villages using a questionnaire-based case-control study conducted in 17 villages endemic for HAT in SE Uganda, and spatial risk factors in 4 high risk villages. For the spatial analysis, the location of homesteads with one or more cases of HAT up to three years prior to the beginning of the study was compared to all non-case homesteads. Analysing spatial associations with respect to irregularly shaped geographical objects required the development of a new approach to geographical analysis in combination with a logistic regression model.</p> <p>Results</p> <p>The study was able to identify, among other behavioural risk factors, having a family member with a history of HAT (p = 0.001) as well as proximity of a homestead to a nearby wetland area (p < 0.001) as strong risk factors for infection. The novel method of analysing complex spatial interactions used in the study can be applied to a range of other diseases.</p> <p>Conclusion</p> <p>Spatial risk factors for HAT are maintained across geographical scales; this consistency is useful in the design of decision support tools for intervention and prevention of the disease. Familial aggregation of cases was confirmed for <it>T. b. rhodesiense </it>HAT in the study and probably results from shared behavioural and spatial risk factors amongmembers of a household.</p

Human African Trypanosomiasis in a Rural Community, Democratic Republic of Congo

Human African trypanosomiasis places a substantial economic hardship on affected households

Blood pressure in primary school children in Uganda: a cross-sectional survey.

BACKGROUND: Non-communicable diseases are an emerging concern in sub-Saharan Africa, and risks for these conditions are often based on exposures in early life, with premonitory signs developing during childhood. The prevalence of hypertension has been reported to be high in African adults, but little is known about blood pressure in African children. We studied prevalence and risk factors for high blood pressure (HBP) among school children in central Uganda. METHODS: Two urban and five rural schools were randomly selected from government schools in Wakiso district, Uganda. Questionnaires were administered and anthropometric measures taken. Blood pressure (BP) was measured three times in one sitting (on day 1) and the average compared to internationally-used normograms. Children with BP >95th percentile were re-tested at two additional sittings (day 2 and day 3) within one week, and at two further follow up visits over a period of six months. Those with sustained HBP were referred for further investigation. RESULTS: Of 552 students included, 539 completed the initial assessments (days 1-3) of whom 92 (17.1%) had HBP at the initial sitting. Age (adjusted odds ratio (aOR) 1.29 (95% confidence interval 1.14, 1.47), p< 0.001), body mass index (1.70 (1.25-2.31) p = 0.001) and soil-transmitted helminths (2.52 (1.04-6.11), 0.04) were associated with increased prevalence of HBP at the initial sitting. After further investigation, sustained HBP was seen in 14 children, yielding an estimated prevalence of 3.8% allowing for losses to follow up. Four children required treatment. CONCLUSION: It is feasible to measure blood pressure accurately in the school setting. A high HBP prevalence on initial readings gave cause for concern, but follow up suggested a true HBP prevalence commensurate with international normograms. Extended follow up is important for accurate assessment of blood pressure among African children

The diagnosis of trypanosome infections: applications of novel technology for reducing disease risk

Reliable DNA based methodologies to determine prevalence of trypanosome species in domestic livestock have been available for over 10 years. Despite this, they are rarely used to generate baseline data for control operations for these diseases in the field. Rather, such operations tend to rely on data which can be generated using low technology methods such as direct observation of parasites by light microscopy. Here we show the pitfalls of relying on such low tech methodology which, although simple in its application, can provide inaccurate and inadequate data on which to base control methodologies. Our analysis of 61 cattle selected for trypanosome carrier status by either microscopy, low PCV or poor condition score, showed that 90% were infected with trypanosomes while 84% of the total were infected with T. brucei. Diagnosis by PCR on buffy coat preparations on Whatman® FTA® matrices was the most sensitive methodology relative to the gold standard, whereas microscopy was the least sensitive. (African Journal of Biotechnology: 2002 1(2): 39-45

Incorporating scale dependence in disease burden estimates:the case of human African trypanosomiasis in Uganda

The WHO has established the disability-adjusted life year (DALY) as a metric for measuring the burden of human disease and injury globally. However, most DALY estimates have been calculated as national totals. We mapped spatial variation in the burden of human African trypanosomiasis (HAT) in Uganda for the years 2000-2009. This represents the first geographically delimited estimation of HAT disease burden at the sub-country scale.Disability-adjusted life-year (DALY) totals for HAT were estimated based on modelled age and mortality distributions, mapped using Geographic Information Systems (GIS) software, and summarised by parish and district. While the national total burden of HAT is low relative to other conditions, high-impact districts in Uganda had DALY rates comparable to the national burden rates for major infectious diseases. The calculated average national DALY rate for 2000-2009 was 486.3 DALYs/100 000 persons/year, whereas three districts afflicted by rhodesiense HAT in southeastern Uganda had burden rates above 5000 DALYs/100 000 persons/year, comparable to national GBD 2004 average burden rates for malaria and HIV/AIDS.These results provide updated and improved estimates of HAT burden across Uganda, taking into account sensitivity to under-reporting. Our results highlight the critical importance of spatial scale in disease burden analyses. National aggregations of disease burden have resulted in an implied bias against highly focal diseases for which geographically targeted interventions may be feasible and cost-effective. This has significant implications for the use of DALY estimates to prioritize disease interventions and inform cost-benefit analyses