The role of improved housing in the African malaria recession

Lead Research Organisation: University of Oxford
Department Name: Zoology

Abstract

Malaria is a mosquito-borne disease, mainly confined to the tropics. Today, malaria control is at a pivotal juncture. The disease remains a major source of human illness and death, killing around 600,000 people annually. Yet the past fifteen years have seen great advances in controlling malaria, with a third reduction in the annual incidence of cases. These reductions have been mainly achieved by distributing chemically-treated bed nets for people to sleep beneath and by spraying houses with chemicals that kill mosquitoes. However, mosquitoes have become resistant to the chemicals used, meaning that additional tools are urgently needed to avoid losing the progress made.

Since malaria is a 'disease of poverty', strongly influenced by its environment, there is heightened interest in using broader, non-chemical approaches for its control, by working with sectors outside health such as agriculture, water and sanitation and urban planning. This is especially pertinent as we approach the launch of the Sustainable Development Goals for international development later in 2015. The research proposed here will specifically investigate how one such approach - improving housing - can help to reduce malaria in sub-Saharan Africa.

Good housing, traditionally a key pillar of public health, remains underexploited in malaria control. Yet most bites by malaria mosquitoes in sub-Saharan Africa are received indoors at night, so the home can be a risky place. Historically, improved living conditions and house screening contributed to malaria elimination in Europe and the USA. Today, studies have shown that well-built housing can help to protect against malaria in many African settings. However, house design has been largely neglected as a potential malaria control tool, due to reliance on other interventions.

Today, unprecedented population expansion and socioeconomic development in sub-Saharan Africa presents an unrivalled opportunity to build healthy homes. The continent's population is projected to double between 2010 and 2040 to nearly two billion and may surpass three billion by 2070, with 144 million new houses needed by 2030 in rural areas alone. Housing quality is also transforming across much of the continent, as incomes increase. This economic and cultural revolution represents an exceptional opportunity for malaria control.

The aim of this fellowship is to investigate the potential contribution of better housing to malaria control in Africa. This will be achieved by addressing three questions:
i) How is malaria associated with housing quality in different parts of sub-Saharan Africa?
ii) To what extent has housing improved in Africa, and how does this change relate to trends in malaria endemicity, 2000-2015?
iii) What is the potential impact of using better housing as an intervention against malaria?

To answer these questions, state-of-the-art modelling approaches will be used (1) to assess the association between house design and malaria in multiple African countries, (2) to quantify how housing improved in Africa between 2000 and 2015, (3) to understand how trends in malaria between 2000 and 2015 were related to changes in housing and (4) to estimate the total number of malaria cases in Africa that may be averted by ongoing housing improvements. This study will exploit the world's largest collection of malaria surveys, the Malaria Atlas Project, together with nearly 200 demographic and health surveys from over 40 countries in sub-Saharan Africa.

In summary, this study will evaluate the potential of building better homes to impact on malaria in Africa. The outcomes of this research will provide critical information to guide research and policy decisions relating to sustainable malaria control, at a pivotal time.

Technical Summary

BACKGROUND: Since most malaria transmission occurs indoors in sub-Saharan Africa (SSA), housing quality is an important determinant of malaria risk, through its effect on house entry by mosquitoes. Unprecedented population expansion and rapid socioeconomic development in SSA presents an unrivalled opportunity to advance malaria control and elimination by building healthy homes.

AIM: To investigate the role of improved housing in the African malaria recession.

METHODS: Two principal data sources will be used: (i) the Demographic and Health Survey (DHS), Malaria Indicator Survey (MIS) and Multiple Indicator Cluster Survey (MICS) programs and (ii) the Repository of Open Access Data of the Malaria Atlas Project (ROAD-MAP II). First, the association between house quality and prevalence of malaria in children will be examined (a) in Upper River Region, The Gambia, using a 2010 parasitological survey of c3800 children and remotely-sensed imagery to classify house type and (b) in 22 countries in SSA, by applying multilevel modelling to MIS and DHS surveys. Second, changes in housing quality at the district level across SSA, 2000-2015, will be estimated by fitting housing data from georeferenced DHS/MIS/MICS surveys within a multilevel model using a Bayesian framework. Third, the relationship between housing improvements and changes in malaria endemicity in SSA, 2000-2015, will be modelled at three spatial scales using data from Objective 2 and ROAD-MAP-II. Fourth, the total number of malaria cases averted in SSA in 2015 due to housing improvements during 2000-2015 will be estimated using a spatiotemporal model and counterfactual framework.

SUMMARY: The application of geospatial modelling to large existing datasets will generate novel evidence on the relationship between housing and malaria and the impact of housing improvements on malaria endemicity, yielding critical and timely policy recommendations for sustainable malaria control.

Planned Impact

The proposed research will examine the potential for better housing to control malaria, helping to address the urgent need for vector control tools beyond long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). Immediate beneficiaries will be academics, policy-makers, malaria control programmes and non-governmental organisations. The ultimate beneficiaries will be the two billion people living at risk of malaria worldwide.

Academics within public health will benefit through the generation of new data on changes in housing quality in Africa, the assembly of new evidence on housing and malaria and the application of tailored statistical approaches to large survey datasets and Malaria Atlas Project data (see Academic Beneficiaries). The research will be of particular benefit to epidemiologists conducting field studies of housing as a malaria intervention, by generating macro-level data to (a) gauge the potential impact of housing in different settings and (b) guide the design of future field studies. Other beneficiaries will include public health entomologists seeking supplementary tools for malaria vector control; malaria elimination specialists seeking long-term, sustainable interventions; malariologists interested in understanding of the causes of the African malaria recession; and spatial epidemiologists and health geographers studying the effects of the environment on health. The use of large demographic and health survey datasets will benefit methodologists who work with similar data to study risk factors for health outcomes. Exploitation of the Malaria Atlas Project will make constructive use of this valuable resource. The research will exploit the UK Medical Research Council's strategic investments in health research in The Gambia (see letter). Academic beneficiaries outside the health sphere will include remote-sensing experts and urban geographers, who will benefit from the application of remotely-sensed data and the analysis of housing variables within large survey datasets; architects working on housing and health; and cross-disciplinary research teams from social science, public health and development economics, specialising the relationship between development and health.

Policy-makers and national malaria control programmes (NMCPs) will benefit in three ways. First, given that LLINs and IRS are increasingly threatened by insecticide resistance, there is an urgent need to evaluate supplementary methods of vector control, such as housing. Second, the proposed research will generate new evidence on multisectoral malaria control, with which to guide programme design and to support advocacy. Third, if housing shows potential as a sustainable intervention, the long-term costs of malaria control and elimination may be reduced. Tangible, short-term benefits for policy-makers and NMCPs will be: (a) estimations of the potential impact of housing improvements, (b) identification of the malaria transmission settings where housing is likely to be more and less effective and (c) generation of data and maps for advocating for multisectoral (housing-health) malaria control. In turn, the development and housing sectors will benefit from important new data documenting changes in housing quality at the district level in Africa since 2000 and from data to promote advocacy for better housing (the 2013 UNDP Multisectoral Action framework for Malaria states that 'encouraging better housing is a social objective, not simply a malaria control action'). Should housing improvements be more systematically implemented as part of the broader development and health agenda, the ultimate beneficiaries will be the populations of malaria-endemic countries, whose quality of life will improve through better health and access to decent housing.

Publications

10 25 50
 
Description Influencing policy guidelines (WHO Global Vector Control Reponse)
Geographic Reach Multiple continents/international 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
Impact The WHO Global Vector Control Response is the global plan for improving disease vector control 2017-2030. It will be presented to the World Health Assembly in May 2017 for approval. Within the GVCR, improving housing is strongly advocated as an inter-sectoral approach to VBD control. This is a landmark document since previously housing has not been considered important for malaria control policy.
URL http://www.who.int/malaria/global-vector-control-response/en/
 
Description Influencing policy guidelines (WHO guidance on housing and health)
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
 
Description Influencing policy guidelines (WHO guidance on malaria vector control)
Geographic Reach Multiple continents/international 
Policy Influence Type Participation in a advisory committee
 
Description New Urban Agenda
Geographic Reach Multiple continents/international 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
Impact Habitat III was a UN Conference on Housing and Sustainable Urban Development held in October 2016 in Quito, Ecuador. The meeting concluded with the adoption or the New Urban Agenda, which links with Sustainable Development Goal 11 to set global standards in sustainable urban development. Due to awareness and evidence generated through the work of myself and others on housing and malaria, vector-borne disease was included for the first time in the New Urban Agenda.
URL http://www.un.org/sustainabledevelopment/blog/2016/10/newurbanagenda/
 
Description Building out vector-borne disease in Africa 
Organisation Durham University
Department Department of Chemistry
Country United Kingdom 
Sector Academic/University 
PI Contribution This is a proposal submitted to the BBSRC-MRC to develop a network of specialists in housing and vector-borne diseases, as part of the Global Challanges Research Fund call. I conceived of and developed the Expression of Interest in its entirety. Due to a technicality over my eligibility to act as PI or CoI, I was unfortunately not able to submit the proposal and handed over to a colleague at Durham University. The EoI successfully reached round 2, and I have been included on the full proposal as a member of the Management Board.
Collaborator Contribution Leading the full proposal and bringing together collaborators.
Impact Full proposal to BBSRC-MRC to establish a network on housing and vector-borne diseases; decision expected March 2017.
Start Year 2016
 
Description Entomological Surveillance for Malaria Elimination 
Organisation University of California, San Francisco
Department Malaria Elimination Initiative
Country United States 
Sector Academic/University 
PI Contribution This project aims to improve entomological intelligence for evidence based vector control and malaria elimination by developing an entomological surveillance framework and priority indicators for low transmission countries. I am a member of the Working Group, providing technical advice and attending quarterly meetings in San Francisco.
Collaborator Contribution Leading and managing the project.
Impact Draft entomological surveillance framework.
Start Year 2016
 
Description Global Vector Hub 
Organisation London School of Hygiene and Tropical Medicine (LSHTM)
Country United Kingdom 
Sector Academic/University 
PI Contribution I am an external adviser to the Global Vector Hub, led by Arctec at the London School of Hygiene & Tropical Medicine as part of the European Commission-funded ZikaPLAN. I advise at monthly meetings giving scientific guidance and technical oversight.
Collaborator Contribution Creation of a Global Vector Hub website and associated resources.
Impact Outline website and plan for the Global Vector Hub.
Start Year 2016
 
Description Malaria Journal Thematic Series on Housing and Malaria 
Organisation London School of Hygiene and Tropical Medicine (LSHTM)
Department Arctec, Arthropod Control Product Test Centre
Country United Kingdom 
Sector Academic/University 
PI Contribution I am guest editor for a Malaria Journal thematic series on housing and malaria, with two co-editors at LSHTM. This series collates articles that contribute to the evidence base on approaches for improving housing to reduce domestic malaria transmission.
Collaborator Contribution Co-editing of the series.
Impact Peer-reviewed publications: Tusting LS, Willey B, Lines J (2016). Building malaria out: improving health in the home. Malaria J; 15: 320. Three papers edited and published within the series so far.
Start Year 2016
 
Description Program for Resistance, Immunology, Surveillance and Modelling of Malaria 
Organisation London School of Hygiene and Tropical Medicine (LSHTM)
Department Tropical Epidemiology Group
Country United Kingdom 
Sector Academic/University 
PI Contribution This collaboration continues my work with UCSF and LSHTM on the PRISM study (Program for Resistance, Immunology, Surveillance and Modelling of Malaria) in Uganda. Currently I am supervising a PRISM study clinician, Dr John Rek, as part of his LSHTM MSc. We are conducting a sub-study to investigate risk factors for sub-microscopic parasitaemia in Nagongera, Uganda. I am taking a lead role in data analysis and write-up and providing full support to the MSc candidate.
Collaborator Contribution My partners covered my travel costs to a meeting in Uganda in 2015, publication costs and additional data collection needed to support the analyses undertaken. Statistical support provided by LSHTM.
Impact Oral presentations at international conferences: American Society for Tropical Medicine & Hygiene, November 2014, New Orleans Peer-reviewed publications: 1. Tusting LS, Rek JC, Arinaitwe E, Staedke SG, Kamya M, Bottomley C, Cano J, Johnston D, Dorsey G, Lindsay SW, Lines J (2016). Why is malaria associated with poverty? Findings from a cohort study in rural Uganda. Infect Dis Poverty; 5: 78. 2. Tusting LS, Rek JC, Arinaitwe E, Staedke SG, Kamya K, Bottomley C, Lines J, Johnston D, Lindsay SW., Dorsey G. Measuring socioeconomic inequalities in relation to malaria risk: a comparison of metrics in rural Uganda. Am J Trop Med Hyg, 94: 650-8. 3. Wanzirah H, Tusting LS [equal contributor], Arinaitwe E, Katureebe A, Maxwell K, Rek J, Bottomley C, Staedke SG, Kamya M, Dorsey G, Lindsay SW, 2015. Mind the gap: house structure and the risk of malaria in Uganda. PLoS ONE, 10: e0117396.
Start Year 2016
 
Description Program for Resistance, Immunology, Surveillance and Modelling of Malaria 
Organisation University of California, San Francisco
Department School of Medicine (UCSF)
Country United States 
Sector Academic/University 
PI Contribution This collaboration continues my work with UCSF and LSHTM on the PRISM study (Program for Resistance, Immunology, Surveillance and Modelling of Malaria) in Uganda. Currently I am supervising a PRISM study clinician, Dr John Rek, as part of his LSHTM MSc. We are conducting a sub-study to investigate risk factors for sub-microscopic parasitaemia in Nagongera, Uganda. I am taking a lead role in data analysis and write-up and providing full support to the MSc candidate.
Collaborator Contribution My partners covered my travel costs to a meeting in Uganda in 2015, publication costs and additional data collection needed to support the analyses undertaken. Statistical support provided by LSHTM.
Impact Oral presentations at international conferences: American Society for Tropical Medicine & Hygiene, November 2014, New Orleans Peer-reviewed publications: 1. Tusting LS, Rek JC, Arinaitwe E, Staedke SG, Kamya M, Bottomley C, Cano J, Johnston D, Dorsey G, Lindsay SW, Lines J (2016). Why is malaria associated with poverty? Findings from a cohort study in rural Uganda. Infect Dis Poverty; 5: 78. 2. Tusting LS, Rek JC, Arinaitwe E, Staedke SG, Kamya K, Bottomley C, Lines J, Johnston D, Lindsay SW., Dorsey G. Measuring socioeconomic inequalities in relation to malaria risk: a comparison of metrics in rural Uganda. Am J Trop Med Hyg, 94: 650-8. 3. Wanzirah H, Tusting LS [equal contributor], Arinaitwe E, Katureebe A, Maxwell K, Rek J, Bottomley C, Staedke SG, Kamya M, Dorsey G, Lindsay SW, 2015. Mind the gap: house structure and the risk of malaria in Uganda. PLoS ONE, 10: e0117396.
Start Year 2016
 
Description Roll Back Malaria Housing and Malaria Work Stream 
Organisation Roll Back Malaria
Country Switzerland 
Sector Charity/Non Profit 
PI Contribution The Housing and Malaria Work Stream of the Roll Back Malaria Partnership's Vector Control Working Group aims to bring together the housing and malaria communities and establish a network of interested parties from academia, national governments, WHO and other policy makers, to support basic and applied research and develop pathways to scale-up housing interventions against malaria and other vector-borne diseases through inter-sectoral collaboration. There are currently 75 members. I was a founding member of this Work Stream in 2014 and in November 2016 was made Co-Chair, providing leadership and convening the annual meeting in Geneva, the most recent of which was held in February 2017.
Collaborator Contribution Provide administrative and financial support for the hosting and maintenance of the Work Stream.
Impact Policy documents: Consensus Statement on Housing and Malaria, released by RBM, UNDP and UN-Habitat October 2015.http://www.rollbackmalaria.org/files/files/working-groups/VCWG/RBM%20VCWG%20Housing%20and%20Malaria%20Consensus%20Statement_final.pdf
Start Year 2016
 
Description Vector control for malaria elimination 
Organisation University of California, San Francisco
Department Malaria Elimination Initiative
Country United States 
Sector Academic/University 
PI Contribution The project, led by UCSF and funded by the Parker Foundation, had multiple components all with the broad aim of identifying new vector control interventions for malaria elimination. I led one component of the project, a systematic review of the evidence for all malaria vector control interventions. I remotely managed a UCSF-based analyst and guided the project from conception to execution and submission for publication. I had a consultancy contract and the work was 2 days per week.
Collaborator Contribution UCSF was responsible for the overall management of the project. I received payment as an external consultant.
Impact Oral presentations at international conferences: Pan African Mosquito Control Association, Dar es Salaam, October 2015 American Society of Tropical Medicine and Hygiene, Atlanta, November 2016 Poster presentations: Royal Society for Tropical Medicine and Hygiene, Cambridge, UK, September 2016 Peer-reviewed publications: 1. Williams Y, Tusting LS, Killeen G, Okumu F, Feachem R, Tatarsky A, Gosling R. Expanding the vector control toolbox for malaria elimination: a systematic review and meta-analysis (Under review at Lancet Infectious Diseases) 2. Killeen GF, Kiware SS, Okumu FO, Sinka ME, Moyes CL, Massey NC, Gething PW, Marshall JM, Chaccour CJ, Tusting LS. Going beyond personal protection against mosquito bites to eliminate malaria transmission: Population suppression of malaria vectors that exploit both human and animal blood. BMJ Global Health (In press). 3. Killeen GF, Tatarsky A, Diabate A, Chaccour CJ, Marshall JM, Okumu FO, Brunner S, Newby G, Williams Y, Malone D, Tusting LS, Gosling RD. Developing an expanded vector control toolbox for malaria elimination. BMJ Global Health (In press). 4. Measuring, manipulating and exploiting behaviours of adult mosquitoes to optimize malaria vector control impact. BMJ Global Health (In press).
Start Year 2015
 
Description Global health conference (ASTMH, Atlanta, USA, November 20016) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I presented the findings of the first objective of my fellowship, a multi-country analysis of housing and malaria risk in African children, as a poster.
Year(s) Of Engagement Activity 2016
URL https://www.astmh.org/ASTMH/media/Documents/ASTMH-2016-Annual-Meeting-Abstract-Book.pdf
 
Description Online/social media presence 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I have maintained a strong online presence through Google Scholar, Twitter and my institutional webpages, to raise awareness of the MRC funding for my research and to promote issues and outputs of broad public interest.
Year(s) Of Engagement Activity 2016,2017
URL https://twitter.com/lucytusting
 
Description Paper dissemination 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Social media and institutional coverage of a paper from my fellowship on housing and malaria.

http://www.ox.ac.uk/news/2017-02-22-modern-housing-may-cut-malaria-risk-sub-saharan-africa
http://researchnews.plos.org/2017/02/21/fly-on-the-wall-modern-housing-and-malaria/
https://www.lshtm.ac.uk/newsevents/news/2017/modern_housing_malaria_risk.html
http://www.map.ox.ac.uk/modernhousing/
Year(s) Of Engagement Activity 2017
URL http://www.ox.ac.uk/news/2017-02-22-modern-housing-may-cut-malaria-risk-sub-saharan-africa
 
Description Policy meeting (Roll Back Malaria, Geneva) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Presentation of research from fellowship on housing and malaria to an international audience of 250 people, which sparked numerous questions and interest in the potential of improved housing to reduce malaria within National Malaria Control Programmes. Attendance by members of national governments, UN-Habitat and WHO.
Year(s) Of Engagement Activity 2017
URL http://www.rollbackmalaria.org/architecture/working-groups/vcwg
 
Description Press release 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Press release for new publication on malaria and housing, released through the journal (PLOS Medicine) and University of Oxford.
Year(s) Of Engagement Activity 2017
URL http://researchnews.plos.org/2017/02/21/fly-on-the-wall-modern-housing-and-malaria/
 
Description Radio interview (Voice of America) 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact I gave a radio interview with Steve Baragona, Voice of America on 17th February 2017, regarding recently published research on malaria and housing (from my fellowship).

NB interview URL is not yet live.
Year(s) Of Engagement Activity 2017
 
Description University seminar (Durham) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact I gave a presentation on my research and my career to date to a group of 40 Biology undergraduate students at Durham University. There was a drinks reception afterwards during which I was asked many questions about doing a Masters and routes into academic research. The department reported increased interest in further study amongst these students.
Year(s) Of Engagement Activity 2017
URL http://community.dur.ac.uk/philip.stephens/SBBSSeminars.htm