Studies towards infectious disease elimination on the Bijagos Archipelago of Guinea Bissau

Lead Research Organisation: London Sch of Hygiene and Trop Medicine
Department Name: Infectious and Tropical Diseases


So far, smallpox is the only infectious disease of humans that has been completely eradicated; but a number of so-called Neglected Tropical Diseases (NTDs), which cause a huge burden of disease among poor rural communities in low income countries, are targeted for global eradication, or at least for elimination from large parts of the world. Great progress has been made in reducing the number of cases of NTDs in some parts of the world but it has become clear that, for most of them, further research is needed to develop new tools and elimination strategies. Global eradication of malaria, which was attempted unsuccessfully in the 1960s, is back on the agenda, and malaria was eliminated from Sri Lanka in 2016, but it is clear that malaria will not be eliminated from Africa using the old methods.

We have been working on the elimination of blinding trachoma, one of the NTDs targeted for global elimination, in The Gambia since 1984, and showed that it could be cured with a single dose of the antibiotic azithromycin, given by mouth. 500 million doses of azithromycin have been donated to trachoma programmes by the manufacturer since then, and The Gambia has recently met the World Health Organization's elimination targets, but trachoma remains the leading infectious cause of blindness worldwide.

For the past 6 years we have been studying trachoma in the remote Bijagos Islands of Guinea Bissau where it remains an important cause of blindness, and have made considerable progress in understanding where it is being transmitted and how it might be controlled. Our aim in the next two years is to set up a trachoma elimination programme on the islands, using mass treatment with azithromycin and health education to reduce transmission, and a surveillance programme to make sure it is not re-introduced. We also plan to study the transmission of malaria on the islands, with a view to identifying the most promising strategies for malaria elimination in this setting, and to map the distribution of other NTDs. The programme will be led by Anna Last, a clinical lecturer in infectious diseases, who has recently completed a PhD on trachoma in the Bijagos Islands, and is fluent in the local language.

In two years time we will have established a laboratory and insectary on the islands, trained staff in how to do field surveys, how to diagnose malaria and NTDs and how to control mosquito populations, worked out where and how trachoma and malaria are being transmitted, and found out which other NTDs are present on the islands, we will be in a strong position to try out new interventions for eliminating these diseases. The islands are a particularly good place to evaluate the impact new tools and strategies for disease elimination, since they are relatively isolated, and can be randomly allocated to one strategy or another.

Technical Summary

We have been studying the epidemiology of trachoma, a neglected tropical disease (NTD) caused by Chlamydia trachomatis infection, which remains the leading infectious cause of blindness worldwide, in the Bijagos Islands of Guinea Bissau since 2010. We used whole genome sequencing and geospatial analysis to map the transmission of ocular C. trachomatis in these communities, and have shown that elimination of blinding trachoma should be possible through mass treatment with azithromycin, as recommended by WHO, although it is likely that behavioural interventions and improved sanitation will be needed to ensure that elimination is sustained. These remote islands are an ideal setting in which to evaluate new tools and strategies for the elimination of infectious diseases through cluster-randomised trials, since there is little migration between the 20 inhabited islands, and each can be treated as an independent cluster. Over the next two years we propose to use a multi-disciplinary approach to map the geographical distribution, routes of transmission and socio-behavioural determinants of malaria, trachoma and other NTDs including yaws, lymphatic filariasis, schistosomiasis, scabies and soil transmitted helminths on the islands, with the aim of developing new strategies for disease elimination that can be evaluated through cluster-randomised trials. We will establish a laboratory and insectary on the islands and train staff in diagnostic parasitology, mosquito collection and identification, and the collection of qualitative and quantitative data in the field. We will conduct population-based surveys to map the epidemiology of these diseases, using two-stage cluster sampling, and collect information on hygiene related behaviours, local beliefs concerning disease causation and attitudes towards potential interventions through direct observation, semi-structured interviews, focus group discussions and interviews with key informants.

Planned Impact

The results of these studies will inform the design of new strategies for the elimination of malaria and Neglected Tropical Diseases that can be evaluated in the Bijagos Islands, which could have a major impact on the burden of disease in West Africa and beyond. We will ensure that the results of these studies are made available to policy makers and control programme managers worldwide by publishing them in open access journals and presenting them at major international meetings, and through our close links with the World Health Organisation, the Bill and Melinda Gates Foundation, the International Trachoma Initiative and major NGOs such as SightSavers and the ChristophelBlinden Mission. The Guinea Bissau Ministry of Health (including the National Programme for Visual Health) and National Institute of Public Health will be able to use these data to define and plan health service provision and disease surveillance on the islands. All clinical, field and scientific staff involved in the studies will benefit from the research and clinical training. Foundation funding will be used to train clinical and field staff to conduct epidemiological and environmental surveys, train laboratory technicians (and provide a simple laboratory facility to perform basic diagnostics in a field setting), entomologists and social scientists, and to train an administrator/data manager to coordinate the studies. Through training and mentoring and support from research studies and collaborative partners, we aim to create a sustainable surveillance system on Bubaque, as we have shown to be possible with the development of a self-sufficient eye care unit in The Gambia as a result of our collaboration with Sightsavers and the Gambian National Eye Care Programme.


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Description We have identified the species of mosquito that transmit malaria on the islands. In the rainy season the main vector is Anopheles gambiae, whereas in the dry season it is Anopheles melas, which can breed in salty water. Between 30 and 40% of mosquitoes had reduced susceptibility to the insecticide used on bednets. We have found that skin infections are very common in children. In a survey of more than 1,000 children we found that 40% had at least one skin infection in the rainy season and 30% in the dry season. More than 20% of children had fungal skin infections and, in the rainy season, more than 10% had bacterial skin infections. Between 2 and 5% were suffering from scabies. We found that scabies was well known in the community, but that health care workers were not well informed about how to treat and control it. With a view to planning our new study, in which we are looking at the impact of mass drug treatment on malaria elimination on the islands, we studied population movement between the islands and its health implications. We found that both men and women moved frequently between islands for subsistence farming, family events and cultural festivities.
Exploitation Route We are using the results of these studies to inform our new study, which looks at the impact of mass treatment with the mosquitocidal drug ivermectin on malaria transmission and on the prevalence of neglected tropical diseases such as scabies..
Sectors Healthcare

Description The island communities, and the local health care workers are better informed about how to prevent malaria and neglected tropical diseases such as trachoma and scabies.
First Year Of Impact 2019
Sector Healthcare
Impact Types Cultural

Description Improved diagnostic capacity at regional level
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Influenced training of practitioners or researchers
Impact The current research programme has the specific objective to build capacity and improve field diagnostic infrastructure. Our field lab technicians are jointly employed between our research project and the Ministry of Public Health (at regional level). Through refurbishing the laboratory (shared between clinical and research activities) (including provision and maintenance of microscopes, other equipment, reagents and consumables) and providing training and quality assurance to all our research lab activities, we have been able to improve clinical diagnostic capacity at the hospital's regional laboratory. This crucially means that patients using this service have better access to diagnostic tests and appropriate treatments. Most of our work in the laboratory has been focused on malaria, where diagnosis using laboratory (or field) tests is crucial in preventing morbidity and mortality. The training that we have provided is of clear educational benefit to our lab technicians, and results in a better quality clinical diagnostic service.
Description Review of national trachoma control programme
Geographic Reach Africa 
Policy Influence Type Gave evidence to a government review
Description Revision to planned NTD mass drug treatment in the region
Geographic Reach Local/Municipal/Regional 
Policy Influence Type Implementation circular/rapid advice/letter to e.g. Ministry of Health
Impact We were able to share our real-time detailed subdistrict-level NTD mapping data with colleagues in the National Program for Neglected Tropical Diseases and Sightsavers International (the programme implementing partners) to show that mass drug administration (MDA) with praziquantel for schistosomiasis was not required as it is not endemic in the Bijagos region. We were also able to refine the strategy for the MDA of soil-transmitted helminths (STH) by providing up to date, age-specific prevalence data to the programme director. This has obvious economic and clinical impacts and has increased the engagement between our research programme and the Ministry of Public Health in Guinea Bissau.
Title Development of remote mapping and GIS techniques applied to survey research 
Description This is a technological tool that we have worked on with our colleague at LSHTM (Chris Grundy, Associate Professor in GIS). It involves the use of offline, open-source mapping tools with random GPS coordinate generators to make random selections of units for inclusion in research surveys. We have validated this method in comparison to traditional epidemiological survey methods (population proportional to size and household head listing) and have found this to be superior, with the additional advantage of being able to undertake these selections remotely. MSc students who have participated in projects run during the course of this grant have contributed towards the validation of these data. We are proposing to use this method in all epidemiological surveys and clinical trials planned at this site. 
Type Of Material Technology assay or reagent 
Year Produced 2018 
Provided To Others? No  
Impact The publication relating to this tool is in preparation. We are using this method in our studies within this grant and also in other studies being undertaken by members of our research group. The ability to undertake remote mapping and centralise study unit selection has many advantages and saves much time in the field. 
Description Collaboration wih MRC Gambia for research and capacity building in diagnostic parasitology and entomology 
Organisation Medical Research Council (MRC)
Department MRC Unit, The Gambia
Country Gambia 
Sector Public 
PI Contribution We have recruited trainees in Guinea Bissau who have received training from our staff and from colleagues at MRC Gambia. Our staff will be processing clinical samples and mosquitoes collected in the ffield in Guinea Bissau at the MRC Gambia labs
Collaborator Contribution Provision of training, lab staff, entomologists and lab facilities
Impact Diagnostic parasitology and entomology. Staff have been trained and samples are being collected and processed
Start Year 2017
Description Collaboration with Imperial College London (Mathematical Modelling) 
Organisation Imperial College London
Department Department of Infectious Disease & Epidemiology
Country United Kingdom 
Sector Academic/University 
PI Contribution The malaria modelling group at Imperial College London have an interest in modelling the impact of interventions towards the interruption of transmission of malaria. We have worked with the group to provide baseline data to inform such models. We will be publishing these models collaboratively once the full data set has been analysed.
Collaborator Contribution Hannah Slater has provided the modelling expertise to run the simulations based on the data above.
Impact We have used the preliminary modelling data from the baseline malaria studies towards an application for follow-on funding for a clinical trial through the Joint Global Health Trial Scheme to reduce malaria transmission towards elimination.
Start Year 2018
Description Collaboration with Sightsavers International 
Organisation Sightsavers
Country Global 
Sector Charity/Non Profit 
PI Contribution We have worked closely with Sightsavers International as the implementing partners for the National Trachoma Control Program and the National Program for NTDs in Guinea Bissau. We have informed Sightsavers, with the national programmes, of our planned research activities to ensure alignment between research studies/surveys and treatment distributions/control activities. We have assisted with disease control activity implementation throughout these studies (including training, resource provision, early dissemination of results).
Collaborator Contribution Sightsavers are willing partners in the research we are undertaking. As outlined above, we have worked together to align implementation of control activities with the research programme.
Impact Reports and Updates of research activities. Real-time impact on programme activities based on research findings.
Start Year 2011
Title Enhanced chemoattractants (volatiles) for use in odour-baited traps 
Description This is an enhanced volatile that simulates human odour and attracts anthropophilic mosquitoes. The volatile is placed in a trap whereby the mosquitoes are captured. This set-up can be used in a research context for capturing and examining adult mosquitoes, but also has potential utility as a vector-control method through mass trapping of mosquitoes. There is already some evidence that this strategy may be successful (see URL above, Homan et al Lancet. 2016 Sep 17;388(10050):1193-201. doi: 10.1016/S0140-6736(16)30445-7. Epub 2016 Aug 9). The enhanced volatile compounds that we are proposing to do have been found to influence human biting behaviour (DeBoer JG et al Sci Rep. 2017 Aug 24;7(1):9283. doi: 10.1038/s41598-017-08978-9). 
Type Preventative Intervention - Physical/Biological risk modification
Current Stage Of Development Initial development
Year Development Stage Completed 2018
Development Status Under active development/distribution
Impact None yet, but this may be applicable as a vector control method. 
Description BBC News 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact BBC News report on the potential for groundbreaking research on the elimination of tropical diseases in the Bijagos Islands where our project is based
Year(s) Of Engagement Activity 2018
Description Community nobilisation workshops 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Community mobilisation events to inform the population about the proposed studies and encourage participation
Year(s) Of Engagement Activity 2017
Description Interview for LSHTM Feature 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact This was an interview with an independent journalist to publicise the current MRCGCRF studies. It has resulted in significant interest from post-graduate students from a variety of disciplines (Medical Entomology, Tropical Medicine and International Health, Control of Infectious Diseases and Medical Anthropology) who are currently undertaking field projects which will provide important pilot data towards the next steps in our research programme.
Year(s) Of Engagement Activity 2017
Description Podcast to publicise disease and vector mapping projects as part of MRCGCRF 
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 This was a podcast as part of a wider feature detailing the MRCGCRF funded research on the Bijagos Islands. As a podcast, it was able to reach further than the intended post-graduate audience through additional sites (Soundcloud). This podcast has encouraged interested students and volunteers to contact the research group to work with us. It has provided a forum for further discussion and questions.
Year(s) Of Engagement Activity 2017
Description Promotional piece for International Women's Day 2018 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact This was a news piece for International Women's Day 2018. The Bijagos Islands are traditionally a matriarchal society. Our research group (with female co-investigators) and our field research team (including field supervisor, nursing staff, field research assistants and laboratory technicians) in both the UK and Guinea Bissau are well-represented by women. This piece highlights the NTD work that we have done over the years and through the current grant to achieve significant results and build capacity.
Year(s) Of Engagement Activity 2018
Description Regular expanded training workshops on the Bijagos Islands 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Experts from our research group and additional invited colleagues from LSHTM have run regular workshops covering clinical, epidemiological, entomological and laboratory teaching. The audience has primarily been health care providers within our local field research team, but we have extended these to invite other local and regional health care workers to build capacity in the fields of clinical diagnosis, field diagnostics and appropriate treatment of identified conditions. For example we have run training workshops in trachoma grading, dermatological diagnosis, conjunctival photography, malaria and stool microscopy (at MRC The Gambia) and field entomology (including larval and adult mosquito collections, mosquito rearing and microscopic identification). We validate these skills and provide regular quality control through LSHTM and MRCG for use in our research studies.
Year(s) Of Engagement Activity 2017
Description Student blog relating to projects conducted during the current grant 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This was a public engagement activity as part of the Missing Maps ( project. Each year, disasters around the world kill nearly 100,000 and affect or displace 200 million people. Many of the places where these disasters occur are literally 'missing' from any map and first responders lack the information to make valuable decisions regarding relief efforts. Missing Maps is an open, collaborative project in which you can help to map areas where humanitarian organisations are trying to meet the needs of vulnerable people. Individuals and Institutions can host 'mapathons' where remote volunteers trace satellite imagery into OpenStreetMap (an open source world map ( Community volunteers (or in this case, our local research team) add local detail. The original aim of the project is that humanitarian organisations may use mapped data to reduce risk and plan disaster response activities that save lives. We have expanded the remit of this aim by using these tools to plan vector and disease mapping surveys using geographical information systems. The Bijagos Missing Maps event was hosted at LSHTM by Chris Grundy (Assistant Professor in GIS) and attended by MSc students at LSHTM. These data have already been well used by our research team and associated MSc students and these methods will continue to be used for these purposes.
Year(s) Of Engagement Activity 2017