Spatiotemporal modeling of schistosomiasis in Ghana: linking remote sensing data to infectious disease

More than 90% of the worldwide schistosomiasis burden falls on sub-Saharan Africa. Control efforts are often based on infrequent, small-scale health surveys, which are expensive and logistically difficult to conduct. The use of satellite imagery to predictively model infectious disease transmission has great potential for public health applications. The transmission of schistosomiasis, a disease acquired from contact with contaminated surface water, requires specific environmental conditions to sustain freshwater snails. If a connection between schistosomiasis and remotely sensed environmental variables can be established, then cost effective and current disease risk predictions can be made available. Schistosomiasis transmission has unknown seasonality, and the disease is difficult to study due to a long lag between infection and clinical symptoms. To overcome these challenges, we employed a comprehensive 15-year time-series built from remote sensing feeds, which is the longest environmental dataset to be used in the application of remote sensing to schistosomiasis. The following environmental variables will be used in the model: accumulated precipitation, land surface temperature, vegetative growth indices, and climate zones created from a novel climate regionalization technique. This technique, improves upon the conventional Köppen-Geiger method, which has been the primary climate classification system in use the past 100 years. These predictor variables will be regressed against 8 years of national health data in Ghana, the largest health dataset of its kind to be used in this context, and acquired from freely available satellite imagery data. A benefit of remote sensing processing is that it only requires training and time in terms of resources. The results of a fixed effects model can be used to develop a decision support framework to design treatment schemes and direct scarce resources to areas with the highest risk of infection. This framework can be applied to diseases sensitive to climate or to locations where remote sensing would be better suited than health surveys.Published versio

Prevalence, circumstances and consequences of non-fatal road traffi c injuries and other bodily injuries among older people in China, Ghana, India, Mexico, Russia and South Africa

Unintentional injuries are one of the main contributors to mortality and disability in elderly populations in low- and middle-income countries. The aim of this study was to examine the annual road traffic and other bodily (not including falls) injury prevalence and associated risk factors among older adults across six lower and upper middle-income countries. A cross- sectional survey involving face-to-face household interviews were conducted in China (n=13,177), Ghana (n=4305), India (n=6560), Mexico (n=2318), the Russian Federation (n=3938) and South Africa (n=3840), resulting in population-based cohorts of persons aged 50+ years.  Measures included questions on injury, self-rated visual difficulties, alcohol use, depression treatment, sleeping problems, self-reported health status, and vision assessment using LogMAR (logarithm of Minimum Angle of Resolution) eye charts. It comprises rows of letters and is used to measure visual acuity. Results indicate that the overall annual non-fatal road traffic injury prevalence was 2.0% and for other bodily injury 2.1% (not including falls) across the six countries. The multivariate logistic regression analysis found that residing in a rural area, taking medications or other treatment for depression in the past 12 months and having a sleeping problem were associated with road traffic injury, while younger age, residing in a rural area, hazardous or harmful alcohol use and having a sleeping problem were associated with other bodily injury. Visual impairment was not associated with prevalence of road traffic injuries. This study provides the burden of non-fatal road traffic injury and other bodily injury and their associated risk factors across the six countries’ studies. The findings of this study improves the understanding of non-fatal road traffic injury and other bodily injury upon which policy makers, programme developers and researchers in public health can design strategic interventions to reduce these preventable injuries as well as improve safety associated with unintentional injuries.Keywords: injury, traffic, ageing, China, Ghana, India, Mexico, Russian Federation, South Africa

Small area variations and factors associated with blood pressure and body-mass index in adult women in Accra, Ghana: Bayesian spatial analysis of a representative population survey and census data

Background Body-mass index (BMI) and blood pressure (BP) levels are rising in sub-Saharan African cities, particularly among women. However, there is very limited information on how much they vary within cities, which could inform targeted and equitable health policies. Our study aimed to analyse spatial variations in BMI and BP for adult women at the small area level in the city of Accra, Ghana. Methods and findings We combined a representative survey of adult women’s health in Accra, Ghana (2008 to 2009) with a 10% random sample of the national census (2010). We applied a hierarchical model with a spatial term to estimate the associations of BMI and systolic blood pressure (SBP) and diastolic blood pressure (DBP) with demographic, socioeconomic, behavioural, and environmental factors. We then used the model to estimate BMI and BP for all women in the census in Accra and calculated mean BMI, SBP, and DBP for each enumeration area (EA). BMI and/or BP were positively associated with age, ethnicity (Ga), being currently married, and religion (Muslim) as their 95% credible intervals (95% CrIs) did not include zero, while BP was also negatively associated with literacy and physical activity. BMI and BP had opposite associations with socioeconomic status (SES) and alcohol consumption. In 2010, 26% of women aged 18 and older had obesity (BMI ≥ 30 kg/m2), and 21% had uncontrolled hypertension (SBP ≥ 140 and/or DBP ≥ 90 mm Hg). The differences in mean BMI and BP between EAs at the 10th and 90th percentiles were 2.7 kg/m2 (BMI) and in BP 7.9 mm Hg (SBP) and 4.8 mm Hg (DBP). BMI was generally higher in the more affluent eastern parts of Accra, and BP was higher in the western part of the city. A limitation of our study was that the 2010 census dataset used for predicting small area variations is potentially outdated; the results should be updated when the next census data are available, to the contemporary population, and changes over time should be evaluated. Conclusions We observed that variation of BMI and BP across neighbourhoods within Accra was almost as large as variation across countries among women globally. Localised measures are needed to address this unequal public health challenge in Accra

A National Survey of Musculoskeletal Impairment in Rwanda: Prevalence, Causes and Service Implications

BACKGROUND: Accurate information on the prevalence and causes of musculoskeletal impairment (MSI) is lacking in low income countries. We present a new survey methodology that is based on sound epidemiological principles and is linked to the World Health Organisation's International Classification of Functioning. METHODS: Clusters were selected with probability proportionate to size. Households were selected within clusters through compact segment sampling. 105 clusters of 80 people (all ages) were included. All participants were screened for MSI by a physiotherapist and medical assistant. Possible cases plus a random sample of 10% of non-MSI cases were examined further to ascertain diagnosis, aetiology, quality of life, and treatment needs. FINDINGS: 6757 of 8368 enumerated individuals (80.8%) were screened. There were 352 cases, giving an overall prevalence for MSI of 5.2%. (95% CI 4.5-5.9) The prevalence of MSI increased with age and was similar in men and women. Extrapolating these estimates, there are approximately 488,000 MSI diagnoses in Rwanda. Only 8.2% of MSI cases were severe, while the majority were moderate (43.7%) or mild (46.3%). Diagnostic categories comprised 11.5% congenital, 31.3% trauma, 3.8% infection, 9.0% neurological, and 44.4% non-traumatic non infective acquired. The most common individual diagnoses were joint disease (13.3%), angular limb deformity (9.7%) and fracture mal- and non-union (7.2%). 96% of all cases required further treatment. INTERPRETATION: This survey demonstrates a large burden of MSI in Rwanda, which is mostly untreated. The survey methodology will be useful in other low income countries, to assist with planning services and monitoring trends

Musculoskeletal impairment survey in Rwanda: Design of survey tool, survey methodology, and results of the pilot study (a cross sectional survey)

BACKGROUND: Musculoskeletal impairment (MSI) is an important cause of morbidity and mortality worldwide, especially in developing countries. Prevalence studies for MSI in the developing world have used varying methodologies and are seldom directly comparable. This study aimed to develop a new tool to screen for and diagnose MSI and to pilot test the methodology for a national survey in Rwanda. METHODS: A 7 question screening tool to identify cases of MSI was developed through literature review and discussions with healthcare professionals. To validate the tool, trained rehabilitation technicians screened 93 previously identified gold standard 'cases' and 86 'non cases'. Sensitivity, specificity and positive predictive value were calculated. A standardised examination protocol was developed to determine the aetiology and diagnosis of MSI for those who fail the screening test. For the national survey in Rwanda, multistage cluster random sampling, with probability proportional to size procedures will be used for selection of a cross-sectional, nationally representative sample of the population. Households to be surveyed will be chosen through compact segment sampling and all individuals within chosen households will be screened. A pilot survey of 680 individuals was conducted using the protocol. RESULTS: The screening tool demonstrated 99% sensitivity and 97% specificity for MSI, and a positive predictive value of 98%. During the pilot study 468 out of 680 eligible subjects (69%) were screened. 45 diagnoses were identified in 38 persons who were cases of MSI. The subjects were grouped into categories based on diagnostic subgroups of congenital (1), traumatic (17), infective (2) neurological (6) and other acquired(19). They were also separated into mild (42.1%), moderate (42.1%) and severe (15.8%) cases, using an operational definition derived from the World Health Organisation's International Classification of Functioning, Disability and Health. CONCLUSION: The screening tool had good sensitivity and specificity and was appropriate for use in a national survey. The pilot study showed that the survey protocol was appropriate for measuring the prevalence of MSI in Rwanda. This survey is an important step to building a sound epidemiological understanding of MSI, to enable appropriate health service planning

Community-based Cluster Surveys on Treatment Preferences for Diarrhoea, Severe Diarrhoea, and Dysentery in Children Aged Less Than Five Years in Two Districts of Ghana

ABSTRACT Hospital-based surveillance for severe diarrhoea has been recommended to assess the burden of disease due to rotavirus. However, information on healthcare-seeking patterns of residents in the hospital catchment area is needed first to obtain the burden of disease in the community using the hospital data. A community-based cluster survey was conducted in two districts of Ghana, each served by a single district hospital, to determine the prevalence of severe diarrhoea among and treatment preferences for children aged less than five years. Caretakers of 619 children in Tema, an urban district, and caretakers of 611 children in Akwapim South, a rural district, were interviewed. During the month preceding the survey, the prevalence of severe diarrhoea in children aged less than five years was similar in the two districts (13.6% urban and 12.9% rural), as was the proportion of mothers who sought care outside the home (69.0% urban and 70.9% rural). 48.8% of urban mothers of children with severe diarrhoea visited public/private clinics, 9.5% pharmacies, and 3.6% the district hospital. Whereas, 22.8% of rural mothers visited public/private clinics, 19.0% pharmacies, and 13.9% the district hospital. Results of the study suggest that rotavirus surveillance should be guided by community studies on healthcare-use patterns. Where hospital use is low for severe diarrhoea, rotavirus surveillance should include other health facilities

Community-based Cluster Surveys on Treatment Preferences for Diarrhoea, Severe Diarrhoea, and Dysentery in Children Aged Less Than Five Years in Two Districts of Ghana

Hospital-based surveillance for severe diarrhoea has been recommended to assess the burden of disease due to rotavirus. However, information on healthcare-seeking patterns of residents in the hospital catchment area is needed first to obtain the burden of disease in the community using the hospital data. A community-based cluster survey was conducted in two districts of Ghana, each served by a single district hospital, to determine the prevalence of severe diarrhoea among and treatment preferences for children aged less than five years. Caretakers of 619 children in Tema, an urban district, and caretakers of 611 children in Akwapim South, a rural district, were interviewed. During the month preceding the survey, the prevalence of severe diarrhoea in children aged less than five years was similar in the two districts (13.6% urban and 12.9% rural), as was the proportion of mothers who sought care outside the home (69.0% urban and 70.9% rural). 48.8% of urban mothers of children with severe diarrhoea visited public/private clinics, 9.5% pharmacies, and 3.6% the district hospital. Whereas, 22.8% of rural mothers visited public/private clinics, 19.0% pharmacies, and 13.9% the district hospital. Results of the study suggest that rotavirus surveillance should be guided by community studies on healthcare-use patterns. Where hospital use is low for severe diarrhoea, rotavirus surveillance should include other health facilities

Overweight and obesity in urban Africa: A problem of the rich or the poor?

BACKGROUND: Obesity is a well recognized risk factor for various chronic diseases such as cardiovascular diseases, hypertension, and type 2 diabetes mellitus. The aim of this study was to shed light on the patterns of overweight and obesity in sub-Saharan Africa, with special interest in differences between the urban poor and the urban non-poor. The specific goals were to describe trends in overweight and obesity among urban women; and examine how these trends vary by education and household wealth. METHODS: The paper used Demographic and Health Surveys data from seven African countries where two surveys had been carried out with an interval of at least 10 years between them. Among the countries studied, the earliest survey took place in 1992 and the latest in 2005. The dependent variable was body mass index coded as: Not overweight/obese; Overweight; Obese. The key covariates were time lapse between the two surveys; woman's education; and household wealth. Control variables included working status, age, marital status, parity, and country. Multivariate ordered logistic regression in the context of the partial proportional odds model was used. RESULTS: Descriptive results showed that the prevalence of urban overweight/obesity increased by nearly 35% during the period covered. The increase was higher among the poorest (+50%) than among the richest (+7%). Importantly, there was an increase of 45-50% among the non-educated and primary-educated women, compared to a drop of 10% among women with secondary education or higher. In the multivariate analysis, the odds ratio of the variable time lapse was 1.05 (p < 0.01), indicating that the prevalence of overweight/obesity increased by about 5% per year on average in the countries in the study. While the rate of change in urban overweight/obesity did not significantly differ between the poor and the rich, it was substantially higher among the non-educated women than among their educated counterparts. CONCLUSION: Overweight and obesity are on the rise in Africa and might take epidemic proportions in the near future. Like several other public health challenges, overweight and obesity should be tackled and prevented early as envisioned in the WHO Global strategy on diet, physical activity and health

Spatial variation and socio-economic determinants of Plasmodium falciparum infection in northeastern Tanzania

<p>Abstract</p> <p>Background</p> <p>Malaria due to <it>Plasmodium falciparum </it>is the leading cause of morbidity and mortality in Tanzania. According to health statistics, malaria accounts for about 30% and 15% of hospital admissions and deaths, respectively. The risk of <it>P. falciparum </it>infection varies across the country. This study describes the spatial variation and socio-economic determinants of <it>P. falciparum </it>infection in northeastern Tanzania.</p> <p>Methods</p> <p>The study was conducted in 14 villages located in highland, lowland and urban areas of Korogwe district. Four cross-sectional malaria surveys involving individuals aged 0-19 years were conducted during short (Nov-Dec) and long (May-Jun) rainy seasons from November 2005 to June 2007. Household socio-economic status (SES) data were collected between Jan-April 2006 and household's geographical positions were collected using hand-held geographical positioning system (GPS) unit. The effects of risk factors were determined using generalized estimating equation and spatial risk of <it>P. falciparum </it>infection was modelled using a kernel (non-parametric) method.</p> <p>Results</p> <p>There was a significant spatial variation of <it>P. falciparum </it>infection, and urban areas were at lower risk. Adjusting for covariates, high risk of <it>P. falciparum </it>infection was identified in rural areas of lowland and highland. Bed net coverage levels were independently associated with reduced risk of <it>P. falciparum </it>by 19.1% (95%CI: 8.9-28.2, p < 0.001) and by 39.3% (95%CI: 28.9-48.2, p < 0.001) in households with low and high coverage, respectively, compared to those without bed nets. Households with moderate and lower SES had risk of infection higher than 60% compared to those with higher SES; while inhabitants of houses built of mud walls were at 15.5% (95%CI: 0.1 - 33.3, p < 0.048) higher risk compared to those living in houses built by bricks. Individuals in houses with thatched roof had an excess risk of 17.3% (95%CI: 4.1 - 32.2, p < 0.009) compared to those living in houses roofed with iron sheet.</p> <p>Conclusions</p> <p>There was high spatial variation of risk of <it>P. falciparum </it>infection and urban area was at the lowest risk. High bed net coverage, better SES and good housing were among the important risk factors associated with low risk of <it>P. falciparum </it>infection.</p