GIS/GPS to document increased access to community-based treatment for tuberculosis in Africa. Geographic information system/global positioning system

Protocol for geolocating rural villages of women in Liberia utilizing a maternity waiting home

OBJECTIVE

Geospatial data are used by health systems and researchers to understand disease burdens, trace outbreaks, and allocate resources, however, there are few well-documented protocols for collecting and analyzing geographic information systems data in rural areas of low- and middle-income countries. Even with the proliferation of spatial technologies such as Open Street Map and Google Maps, basic geographic data-such as village locations-are not widely available in many countries in sub-Saharan Africa. The purpose of this paper is to report a step-wise protocol, using geographic information system techniques and tools, developed to collect and analyze the type of spatial data necessary to calculate the distance between rural villages and maternity waiting homes located near rural primary healthcare facilities in Bong County, Liberia.

RESULTS

Using a step-wise approach incorporating local healthcare provider knowledge, intensive field work, and spatial technologies such as Open Street Map and Google Maps for village geospatial data collection and verification, we identified village locations of 93.7% of the women who accessed the five maternity waiting homes in our study from 2012 to 2016.

Accessibility to tuberculosis control services and tuberculosis programme performance in southern Ethiopia

BACKGROUND

Despite the expansion of health services and community-based interventions in Ethiopia, limited evidence exists about the distribution of and access to health facilities and their relationship with the performance of tuberculosis (TB) control programmes. We aim to assess the geographical distribution of and physical accessibility to TB control services and their relationship with TB case notification rates (CNRs) and treatment outcome in the Sidama Zone, southern Ethiopia.

DESIGN

We carried out an ecological study to assess physical accessibility to TB control facilities and the association of physical accessibility with TB CNRs and treatment outcome. We collected smear-positive pulmonary TB (PTB) cases treated during 2003-2012 from unit TB registers and TB service data such as availability of basic supplies for TB control and geographic locations of health services. We used ArcGIS 10.2 to measure the distance from each enumeration location to the nearest TB control facilities. A linear regression analysis was employed to assess factors associated with TB CNRs and treatment outcome.

RESULTS

Over a decade the health service coverage (the health facility-to-population ratio) increased by 36% and the accessibility to TB control facilities also improved. Thus, the mean distance from TB control services was 7.6 km in 2003 (ranging from 1.8 to 25.5 km) between kebeles (the smallest administrative units) and had decreased to 3.2 km in 2012 (ranging from 1.5 to 12.4 km). In multivariate linear regression, as distance from TB diagnostic facilities (b-estimate=-0.25, p<0.001) and altitude (b-estimate=-0.31, p<0.001) increased, the CNRs of TB decreased, whereas a higher population density was associated with increased TB CNRs. Similarly, distance to TB control facilities (b-estimate=-0.27, p<0.001) and altitude (b-estimate=-0.30, p<0.001) were inversely associated with treatment success (proportion of treatment completed or cured cases).

CONCLUSIONS

Accessibility to TB control services improved despite the geographic variations. TB CNRs were higher in areas where people had better access to diagnostic and treatment centres. Community-based interventions also played an important role for the increased CNRs in most areas.

Determinants and spatial patterns of adult overweight and hypertension in a high HIV prevalence rural South African population

We conducted a large population-based survey among adults measuring weight, height, and blood pressure nested within an HIV survey in rural KwaZulu-Natal, South Africa, to identify and characterize clusters of overweight and hypertension in a typical rural African population and to explore whether geographic clusters can be accounted for by established individual-level risk factors. 58.4% of the participants were overweight and 22.6% were hypertensive. One cluster of high prevalence of overweight (RR=1.50, p<0.001) was identified using Kulldorff spatial scan statistic as the most likely cluster, whereas a low-risk cluster was identified in the nearby high-density settlement area (RR=0.62, p<0.05). No geographic clusters of hypertension were identified. After controlling for age, sex, educational attainment, household wealth, marital status, place of residence, and HIV status, no spatial clustering of overweight remained. The results provided clear evidence for the localized clustering of overweight. Identification of clustering of chronic disease could provide additional insights into the prevention and control for the rural South African population.

Using a GIS to model interventions to strengthen the emergency referral system for maternal and newborn health in Ethiopia

OBJECTIVES

To show how GIS can be used by health planners to make informed decisions about interventions to increase access to emergency services.

METHODS

A combination of data sources, including the 2008 national Ethiopian baseline assessment for emergency obstetric and newborn care that covered 797 geo-coded health facilities, LandScan population data, and road network data, were used to model referral networks and catchment areas across 2 regions of Ethiopia. STATA and ArcGIS software extensions were used to model different scenarios for strengthening the referral system, defined by the structural inputs of transportation and communication, and upgrading facilities, to compare the increase in access to referral facilities.

RESULTS

Approximately 70% of the population of Tigray and Amhara regions is served by facilities that are within a 2-hour transfer time to a hospital with obstetric surgery. By adding vehicles and communication capability, this percentage increased to 83%. In a second scenario, upgrading 7 strategically located facilities changed the configuration of the referral networks, and the percentage increased to 80%. By combining the 2 strategies, 90% of the population would be served by midlevel facilities within 2 hours of obstetric surgery. The mean travel time from midlevel facilities to surgical facilities would be reduced from 121 to 64 minutes in the scenario combining the 2 interventions.

CONCLUSIONS

GIS mapping and modeling enable spatial and temporal analyses critical to understanding the population's access to health services and the emergency referral system. The provision of vehicles and communication and the upgrading of health centers to first level referral hospitals are short- and medium-term strategies that can rapidly increase access to lifesaving services.

Spatial analysis of tuberculosis in an urban west African setting: is there evidence of clustering?

OBJECTIVES

To describe the pattern of tuberculosis (TB) occurrence in Greater Banjul, The Gambia with Geographical Information Systems (GIS) and Spatial Scan Statistics (SaTScan) and to determine whether there is significant TB case clustering.

METHODS

In Greater Banjul, where 80% of all Gambian TB cases arise, all patients with TB registered at chest clinics between March 2007 and February 2008 were asked to participate. Demographic, clinical characteristics and GPS co-ordinates for the residence of each consenting TB case were recorded. A spatial scan statistic was used to identify purely spatial and space-time clusters of tuberculosis among permanent residents.

RESULTS

Of 1145 recruited patients with TB, 84% were permanent residents with 88% living in 37 settlements that had complete maps available down to settlement level. Significant high- and low-rate spatial and space-time clusters were identified in two districts. The most likely cluster of high rate from both the purely spatial analysis and the retrospective space-time analysis were from the same geographical area. A significant secondary cluster was also identified in one of the densely populated areas of the study region.

CONCLUSIONS

There is evidence of significant clustering of TB cases in Greater Banjul, The Gambia. Systematic use of cluster detection techniques for regular TB surveillance in The Gambia may aid effective deployment of resources. However, passive case detection dictates that community-based active case detection and risk factor surveys would help confirm the presence of true clusters and their causes.

Development of a wearable global positioning system for place and health research

Background

An increasing number of studies suggest that characteristics of context, or the attributes of the places within which we live, work and socialize, are associated with variations in health-related behaviours and outcomes. The challenge for health research is to ensure that these places are accurately represented spatially, and to identify those aspects of context that are related to variations in health and amenable to modification. This study focuses on the design of a wearable global positioning system (GPS) data logger for the purpose of objectively measuring the temporal and spatial features of human activities. Person-specific GPS data provides a useful source of information to operationalize the concept of place.

Results

We designed and tested a lightweight, wearable GPS receiver, capable of logging location information for up to 70 hours continuously before recharging. The device is accurate to within 7 m in typical urban environments and performs well across a range of static and dynamic conditions.

Discussion

Rather than rely on static areal units as proxies for places, wearable GPS devices can be used to derive a more complete picture of the different places that influence an individual's wellbeing. The measures are objective and are less subject to biases associated with recall of location or misclassification of contextual attributes. This is important for two reasons. First, it brings a dynamic perspective to place and health research. The influence of place on health is dynamic in that certain places are more or less relevant to wellbeing as determined by the length of time in any location and by the frequency of activity in the location. Second, GPS data can be used to assess whether the characteristics of places at specific times are useful to explaining variations in health and wellbeing.

Methodology for optimising location of new primary health care facilities in rural communities: a case study in KwaZulu-Natal, South Africa

STUDY OBJECTIVE

To develop a quantitative methodology to optimally site new primary health care facilities so as to achieve the maximum population level increase in accessibility to care. The study aims to test the methodology in a rural community characterised by considerable heterogeneity in population distribution and health care access.

DESIGN

A geographical information system was used to estimate travel time to the nearest primary health care facility for each of the 26 000 homesteads in the subdistrict. The homestead's travel time estimate was then converted into an impedance to care estimate using distance decay (in clinic use) data obtained from the subdistrict. A map of total person impedance/km(2) was then produced using a 3 km standard Gaussian filter. The resulting map was used to site a test clinic in the largest contiguous area of high person impedance.

SETTING

Hlabisa health subdistrict, KwaZulu-Natal, South Africa.

MAIN RESULTS

The population level increase in accessibility that would be achieved by the construction of the test clinic would be 3.6 times the increase in accessibility achieved by the construction of the newest clinic in the subdistrict. The corresponding ratio for increasing clinic coverage (% of the population within 60 minutes of care) would be 4.7.

CONCLUSIONS

The methodology successfully identifies a locality for a new facility that would maximise the population level increase in accessibility to care. The same principles used in this research could also be applied in other settings. The methodology is of practical value in health research and practice and provides a framework for optimising location of new primary health care facilities.

Linking the global positioning system (GPS) to a personal digital assistant (PDA) to support tuberculosis control in South Africa: a pilot study

BACKGROUND

Tuberculosis (TB) is the leading clinical manifestation of HIV infection and caseloads continue to increase in high HIV prevalence settings. TB treatment is prolonged and treatment interruption has serious individual and public health consequences. We assessed the feasibility of using a handheld computing device programmed with customised software and linked to a GPS receiver, to assist TB control programmes to trace patients who interrupt treatment in areas without useful street maps. In this proof of concept study, we compared the time taken to re-find a home comparing given residential addresses with a customised personalised digital assistant linked to a global positioning system (PDA/GPS) device. Additionally, we assessed the feasibility of using aerial photographs to locate homes.

RESULTS

The study took place in two communities in Greater Johannesburg, South Africa: Wheillers Farm, a relatively sparsely populated informal settlement, and a portion of Alexandra, an urban township with densely populated informal settlements. Ten participants in each community were asked to locate their homes on aerial photographs. Nine from Wheillers Farm and six from Alexandra were able to identify their homes. The total time taken by a research assistant, unfamiliar with the area, to locate 10 homes in each community using the given addresses was compared with the total time taken by a community volunteer with half an hour of training to locate the same homes using the device. Time taken to locate the ten households was reduced by 20% and 50% in each community respectively using the PDA/GPS device.

CONCLUSION

In this pilot study we show that it is feasible to use a simple PDA/GPS device to locate the homes of patients. We found that in densely populated informal settlements, GPS technology is more accurate than aerial photos in identifying homes and more efficient than addresses provided by participants. Research assessing issues of, confidentiality and cost effectiveness would have to be undertaken before implementing PDA/GPS - based technology for this application. However, this PDA/GPS device could be used to reduce part of the burden on TB control programs.

Modelling and understanding primary health care accessibility and utilization in rural South Africa: an exploration using a geographical information system

Physical access to health care affects a large array of health outcomes, yet meaningfully estimating physical access remains elusive in many developing country contexts where conventional geographical techniques are often not appropriate. We interviewed (and geographically positioned) 23,000 homesteads regarding clinic usage in the Hlabisa health sub-district, KwaZulu-Natal, South Africa. We used a cost analysis within a geographical information system to estimate mean travel time (at any given location) to clinic and to derive the clinic catchments. The model takes into account the proportion of people likely to be using public transport (as a function of estimated walking time to clinic), the quality and distribution of the road network and natural barriers, and was calibrated using reported travel times. We used the model to investigate differences in rural, urban and peri-urban usage of clinics by homesteads in the study area and to quantify the effect of physical access to clinic on usage. We were able to predict the reported clinic used with an accuracy of 91%. The median travel time to nearest clinic is 81 min and 65% of homesteads travel 1h or more to attend the nearest clinic. There was a significant logistic decline in usage with increasing travel time (p < 0.0001). The adjusted odds of a homestead within 30 min of a clinic making use of the clinics were 10 times (adjusted OR = 10; 95 CI 6.9-14.4) those of a homestead in the 90-120 min zone. The adjusted odds of usage of the clinics by urban homesteads were approximately 20/30 times smaller than those of their rural/peri-urban counterparts, respectively, after controlling for systematic differences in travel time to clinic. The estimated median travel time to the district hospital is 170 min. The methodology constitutes a framework for modelling physical access to clinics in many developing country settings.

Use of satellite imagery in constructing a household GIS database for health studies in Karachi, Pakistan

Background

Household-level geographic information systems (GIS) database are usually constructed using the geographic positioning system (GPS). In some research settings, GPS receivers may fail to capture accurate readings due to structural barriers such as tall buildings. We faced this problem when constructing a household GIS database for research sites in Karachi, Pakistan because the sites are comprised of congested groups of multi-storied building and narrow lanes. In order to overcome this problem, we used high resolution satellite imagery (IKONOS) to extract relevant geographic information.

Results

The use of IKONOS satellite imagery allowed us to construct an accurate household GIS database, which included the size and orientation of the houses. The GIS database was then merged with health data, and spatial analysis of health was possible.

Conclusions

The methodological issues introduced in this paper provide solutions to the technical barriers in constructing household GIS database in a heavily populated urban setting.

A literature review of the problems of delayed presentation for treatment and non-completion of treatment for tuberculosis in less developed countries and ways of addressing these problems using particular implementations of the DOTS strategy

Tuberculosis is the cause of a large burden of disease in less developed countries. With the development of drug resistance and the co-epidemic of HIV, tuberculosis has already started to make a comeback in wealthier countries. The WHO's solution to this global tuberculosis epidemic is the DOTS strategy, the implementation of which presents many problems. The two issues most common to the majority of locations are delay in presentation for treatment and non-completion of treatment. This review looks at the reasons for these problems in the less developed world, and addresses some solutions. The main reasons for delayed presentation are: a lack of understanding about TB; the stigma associated with the disease; the inaccessibility of treatment; and a preference for private practitioners. The main reasons for non-completion of treatment are: the stigma of the disease; a lack of information; dissatisfaction with the treatment and its delivery; and inaccessibility of treatment. Successful implementations of the DOTS strategy need to address all these issues. There is little evidence that DOT enhances treatment completion unless combined with other strategies. Community-based, patient-orientated DOTS appears to be an appropriate way of addressing many of these issues. The involvement of volunteers in community-based strategies is common, but needs more research in order for this strategy to realise its full potential.

The application of geographical information systems to important public health problems in Africa

Africa is generally held to be in crisis, and the quality of life for the majority of the continent's inhabitants has been declining in both relative and absolute terms. In addition, the majority of the world's disease burden is realised in Africa. Geographical information systems (GIS) technology, therefore, is a tool of great inherent potential for health research and management in Africa. The spatial modelling capacity offered by GIS is directly applicable to understanding the spatial variation of disease, and its relationship to environmental factors and the health care system. Whilst there have been numerous critiques of the application of GIS technology to developed world health problems it has been less clear whether the technology is both applicable and sustainable in an African setting. If the potential for GIS to contribute to health research and planning in Africa is to be properly evaluated then the technology must be applicable to the most pressing health problems in the continent. We briefly outline the work undertaken in HIV, malaria and tuberculosis (diseases of significant public health impact and contrasting modes of transmission), outline GIS trends relevant to Africa and describe some of the obstacles to the sustainable implementation of GIS. We discuss types of viable GIS applications and conclude with a discussion of the types of African health problems of particular relevance to the application of GIS.

The application of GIS technology to equitably distribute fieldworker workload in a large, rural South African health survey

A method is presented that has numerous applications to health systems provision in developing countries where limited physical access to primary health care is a major factor contributing to the poor health of populations. An accessibility model within a geographical information system (GIS) is used to predict average inter-homestead walking times and subdivide the study area into units of equal completion time. The method could be used to ergonomically design home-based care and tuberculosis directly observed treatment programmes and inform the siting of health facilities. The paper highlights the use of GIS technology as a powerful tool in developing countries.

Emerging and reemerging infections in africa: the need for improved laboratory services and disease surveillance

Emerging and reemerging infections pose a serious public health threat to most countries of tropical Africa. In the past decade, epidemics of diseases including cholera, dysentery, meningitis, yellow fever and Ebola virus have resulted in significant morbidity and mortality. Improved laboratory services and disease surveillance systems are essential to monitor disease trends and to initiate public health action. The present situation of emerging and reemerging infections in Africa is described in this review, and strategies for improved disease surveillance and monitoring are discussed.