Molecular Tools for Helminth Control and Elimination: Time to Get them Out of the Laboratory and itno Programmes and Policies?

By Corrado Minetti

On my way back from Ghana, where we have been testing the molecular protocols for the detection of filarial parasites in mosquitoes, in the laboratory of Mike Osei-Atweneboana at the Council for Scientific and Industrial Research (CSIR) in Accra; I had some thoughts about how far molecular diagnostics has come but also questioned how can we make it a sustainable reality to assist effectively in disease control and elimination.

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DNA extraction from pooled mosquitoes for the detection of filarial worms (on the left) and an example of amplification of parasite DNA (+) with the LAMP method (on the right) (Photo: Corrado Minetti)

In order to achieve the goals of the London Declaration on Neglected Tropical Diseases for the effective and sustainable control and long term elimination of Lymphatic Filariasis, onchocerciasis, soil-transmitted helminthiasis and schistosomiasis; the deployment of appropriate diagnostic tools is crucial at every stage of these disease control and elimination programmes from initial mapping to post-elimination surveillance. With the rapidly changing epidemiological scenario of these diseases due to the scaling up of mass drug administration, and the push towards more sustainable and cost-effective multi-disease interventions, the implementation of more sensitive and cost-effective diagnostic tools is a priority well recognized and advocated by the World Health organization.

Molecular diagnostics tools, including (multiplex) real-time polymerase chain reaction and more recent isothermal amplification assays such as loop-mediated isothermal amplification and recombinase polymerase amplification do offer increased sensitivity compared to traditional approaches but they are yet to be used in control and elimination programmes due to their cost and technical requirements. There are various gaps that need to be highlighted and solved in order to allow these approaches to become potentially embedded into disease control programmes & policies, and to inform decision-making.

In order to identify these much-needed gaps, we have recently published a review paper where we compared the features of published real-time PCR and isothermal amplification assays for the detection of Lymphatic Filariasis, onchocerciasis, soil-transmitted helminthiasis and schistosomiasis in clinical and vector/intermediate host samples. Despite the availability of a wide range of assays for both patient diagnosis and xenomonitoring (parasite detection in insect vectors or snails), little or no research has been devoted to estimate the real costs and logistics of implementing these approaches on a wider scale for control and elimination. We highlight the need for a major focus on the implementation aspects of these tools in developing countries, and how barriers for their full adoption in resource-poor settings could be overcome. Key issues are the technical requirements and the related need for capacity building, the abatement of costs and the economic sustainability of molecular screening over time. For example, diagnosing multiple parasites from the same clinical sample can heavily reduce the number of samples that a community may need to provide, resulting in a far less invasive procedure for the communities, as well as reducing significantly the cost of processing. A multi-disease approach to diagnostics will certainly benefit the health system as well, both logistically and economically.

Writing this review paper has been extremely valuable to get a clearer picture of the progress in the field so far and to identify the best and most cost-effective diagnostic approaches for our project. In a broader sense and within the COUNTDOWN research consortium, we hope this review could serve as a starting point of discussion in the NTDs control and elimination community, leading to a more comprehensive analysis of what molecular diagnostics can offer and how we can make sure these tools can finally get out from the laboratory becoming embedded into policy, to strengthen disease control and elimination programmes and the health system itself.

Find more information on COUNTDOWN’s activities visit us here.

Old dog, New Tricks? Assessing the Potential of Integrating Focal Vector Suppression with Drug Cure to Control and Eliminate River Blindness

By Louise Hamill

Onchocerciasis, also known as river blindness, is one of the vector-borne neglected tropical diseases (NTDs); in this case, transmitted by many different species of black fly. The majority of infections (99%) occur in sub-Saharan Africa. The disease was previously also found in South America but is now thankfully close to total elimination; with only a few isolated, extremely remote areas still to be verified disease-free. The aim for Africa is to achieve continent-wide interruption of transmission by 2025.  Current control of river blindness in Africa, which, as well as blindness, leads to debilitating, disfiguring skin pathology, is based upon the mass delivery of ivermectin to entire populations in endemic areas. Ivermectin kills microfilariae in the skin, but has no significant effects on adult worms. This necessitates repeated rounds of ivermectin mass delivery for a period of 12 – 15 years, with sustained high coverage of the at-risk population essential for successful disease control and eventual elimination.

This approach has had notable successes in several areas, led by the efforts of the African Programme for Onchocerciasis Control (APOC). However in other areas, the impact of sustained delivery of ivermectin for fifteen years, and in some areas more than two decades, has yet to result in the predicted interruption of transmission. Furthermore, where the eye worm Loa loa and onchocerciasis occur together, mass delivery of ivermectin cannot be easily rolled out. Ivermectin causes unwanted side effects, and in rare cases death, in individuals infected with L. loa as the drug rapidly kills this parasite. L. loa is common in large swathes of West and Central Africa, allowing onchocerciasis to endure in these areas, where many people are still infected and transmission of both pathogens is actively taking place, despite ongoing control efforts. Clearly there is no one-size-fits-all approach to curtail river blindness, and there is a need to seek alternative strategies to ivermectin-based control in areas where river blindness and L. loa overlap.

In the nineteen seventies and eighties the WHO onchocerciasis control programme, OCP, ran an extremely successful vector control strategy against onchocerciasis in savannah areas of West Africa. This programme relied exclusively on aerial application of larvicide to kill black fly larval as they resided in rivers and streams. It is estimated this past use of vector control prevented 600,000 cases of blindness and prevented 40 million people being infected. The scale of this undertaking, including the huge financial cost and human resource needed, means that the use of mass vector elimination as a tool for onchocerciasis control is very much consigned to the history books. Before turning the page completely on this chapter of onchocerciasis control, are there any lessons to be learnt from this “old dog”?

The COUNTDOWN meeting on Focal black fly Control in Cameroon

This is exactly the question we set out to debate when COUNTDOWN convened a technical advisory panel at the Liverpool School of Tropical Medicine on 22nd of July 2016. Although mass vector control is out of the question, is there any way in which short-term, localised approaches can be used to augment and complement existing strategies?

Vector Meeting

Attendees at the COUNTDOWN meeting on Focal Black fly Control, from Left to Right: Professor Graham Matthews, Professor Rory Post, Dr Frank Walsh, Didier Bakajika, Dr John B. Davies, Dr Louise Hamill, Dr Hans Dobson, Dr Joseph Turner, Professor María-Gloria Basáñez, Professor Mark Taylor, Isobel Routledge, Professor Russell Stothard, Professor Robert Cheke. Not pictured; Professor Janet Hemingway, Dr Lisa Reimer.

Previous work in South West Cameroon by members of the COUNTDOWN consortium indicates that ten years of ivermectin delivery in our study area has not had the expected impact on disease prevalence. The average community-level of skin microfilaria prevalence stands at 52.7 percent, with the infection intense even in children under ten years of age. Additional work in South West Cameroon found current adherence to ivermectin mass delivery by local residents is not adequate to achieve onchocerciasis control. This is an area where alternative and complementary strategies are urgently needed.

The COUNTDOWN consortium has proposed that larvicidal treatment of vector breeding sites at the same time as testing and treating the human population with doxycycline could offer a complementary onchocerciasis control strategy. This two-pronged approach, it is hoped, will have a greater impact on disease transmission than using either technique in isolation. Doxycycline targets “friendly” bacteria living within the adult onchocerciasis worms, resulting in a significant shortening of their lifespans and giving doxycycline a very different mode of action to ivermectin. Since L. loa does not harbour the same bacteria, individuals co-infected with L. loa who take doxycycline will not suffer the same side effects as can happen with ivermectin. From the evidence above, it is clear to see ivermectin mass delivery has not had the desired impact on disease prevalence over the past ten years in this area of South West Cameroon; could targeted vector suppression jump start the path to onchocerciasis control?

At the meeting, debate revolved around the factors influencing choice of larvicide; when, how often & for how long the larvicide should be applied; the most suitable sampling methods to monitor impact of the larviciding on adult and larval black fly; and how best to undertake monitoring of the impact of insecticide application on non-target organisms. The optimal timing of any vector suppression to best amplify the impact of the community test-and-treat strategy is crucial. The way ahead is far from straight forward, highlighting the importance of rigorously assessing the evidence and our proposed strategy in this way. Although the use of localised vector control against black flies is not a new proposal, there is little information on how this could be implemented against free-living black fly larvae.

Where next?

The control and elimination of NTDs in Africa has repeatedly been in the post-millennium development goals policy spotlight, with (among others) the WHO roadmap to elimination, the London Declaration on NTDs and recently the launch of the Expanded Special Programme for Elimination of NTDS (ESPEN). Similar to the situation for lymphatic filariasis, scale-up of mass delivery of ivermectin will not be enough to achieve the London Declaration 2020 targets for onchocerciasis control and elimination. The use of both doxycycline and focal vector suppression are separately recommended by WHO and APOC as alternative onchocerciasis control strategies, to accelerate progress towards onchocerciasis control, however as relatively new control strategies evidence on their implementation is scarce and evidence on integrated, dual-strategy implementation is wholly absent. The specific contexts in which these tools could be successfully implemented together are unclear.  Going forward with our onchocerciasis work in Cameroon, COUNTDOWN’s focus is consolidation of the evidence gathered at the vector control meeting to assess the possibility of implementing localised vector suppression as an adjunct to existing and alternative control and elimination strategies. This will bridge vital evidence gaps and provide clarity on if and where these techniques can be used, and the optimal conditions in which to implement them.

 

 

 

A Bed Net to Rule Them All: Accelerating Lymphatic Filariasis Elimination Through Malaria Control Programmes

by Corrado Minetti

In rural areas of Africa, Lymphatic Filariasis (LF) is primarily transmitted by night-biting Anopheles mosquitoes, which also transmit malaria. Currently, the two major ways of controlling malaria vectors are the indoor residual spraying (IRS) of insecticides and the use of bed nets. It has been estimated that the combination of these two interventions, in the decade 2000-2010, has prevented  more than 200 million new cases and more than 1 million deaths due to malaria.

In areas where both LF and malaria occur and are transmitted by the same mosquitoes, should we then promote vector control alongside mass drug administration (MDA) to accelerate the elimination of LF through a better and more cost-effective integration of LF and malaria control programmes at the national level?

The answer is yes.

The importance of vector control for lymphatic filariasis elimination

Reducing mosquito numbers and preventing people being bitten has a significant impact in reducing the burden of LF and, ultimately, pushing towards its elimination. As it has been reported in various countries around the world the use of bed nets, IRS and/or reducing the mosquito breeding sites can all result in a significant reduction of LF transmission even in the absence of MDA. For example, in Papua New Guinea the deployment of insecticidal bed nets in communities where MDA was stopped 10 years before resulted in a reduction of the LF transmission potential down to zero within only 11 months following distribution.

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A long-lasting insecticidal net (LLIN) in Agyan (Ghana) (Photo: Corrado Minetti)

Mathematical models have clearly shown the strategic impact of implementing vector control alongside MDA for LF: reducing the human-mosquito exposure allows reaching the community and vector infection thresholds below which LF transmission will be interrupted faster and earlier compared with using MDA alone. As a result less rounds of MDA may be needed to reach elimination if vector control is in place, with important savings for the programme.  Furthermore, sustained vector control may avoid the resurgence of LF in treated communities in a post-elimination setting (after MDA has been stopped) due to the potential re-introduction of the disease through human movement.

The way forward: integration of lymphatic filariasis and malaria control programmes

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Mass distribution of ivermectin for LF elimination (on the left, source: www.mectizan.og) and bed nets for malaria control (on the right, source: www.usaid.org)

Given the importance of vector control for LF elimination; with LF and malaria being transmitted by the same mosquito vectors in West and rural Africa, integrated vector management (IVM) becomes crucial. There is a tremendous opportunity to effectively integrate the LF and the malaria control programmes, making both more efficient and cost-effective.

Establishing a synergy between MDA for LF and bed nets distribution/indoor insecticide spraying for malaria can have two major effects which will be extremely beneficial for the fight of both diseases. Firstly, a more efficient use of resources: the same community distributors delivering the drugs can distribute bed nets at the same time leading to important savings in terms of time and human resources. Secondly, a higher impact on the burden of both diseases: MDA campaigns can facilitate the distribution and penetration of bed nets in the community and vice-versa.

The beneficial effects of an integration of MDA and bed nets distribution has been clearly shown in Nigeria, where the concomitant delivery of nets alongside MDA resulted in a significant improvement in insecticide-treated bed net ownership and use (up to 9-fold) and it did not negatively affect the MDA coverage.

Following the above evidence, in 2014 Nigeria has been the first country in Africa to launch a Nationwide Malaria and LF elimination Co-Implementation Plan alongside specific guidelines.

We now have the tremendous opportunity to promote a better cross-talk between the vector borne disease-specific communities, stakeholders and policy-makers in order to raise awareness on the importance of a sustained and better planned vector control leading to a more cost-effective and effective use of resources across disease control programmes.

Within the COUNTDOWN research consortium, we recognize that the scale-up of MDA won’t be enough to achieve the London Declaration 2020 targets for the elimination of lymphatic filariasis. In particular, following the example of Nigeria, we are seeking opportunities in Ghana for an integration of the national LF elimination and malaria control programmes to co-ordinate MDA distribution and delivery of vector control interventions and to evaluate the impact of such synergy on service delivery, community participation and cost-effectiveness.

Find more information on COUNTDOWN’s activities here.

Future directions in Neglected Tropical Diseases

By Eleanor MacPherson, Liverpool School of Tropical Medicine

On the 14th June I attended a meeting of the All-Party Parliamentary Group (APPG) on Malaria and Neglected Tropical Diseases (NTDs). It brought together a panel of four men to discuss Neglected Tropical Diseases and the Sustainable Development Goals. The panel included three members from the World Health Organisation: Dirk Engels (Director of NTDs), Christopher Fitzpatrick (Economist for NTDs), Bruce Gordon (NTD-WASH strategy) and Mr Andy Wright from GSK Uniting to Combat NTDs. The meeting was chaired by Jeremy Lefroy the MP for Stafford and coordinator for the APPG on Malaria and Neglected Tropical Diseases.

Here are five reflections on our discussions:

  1. Including women in community led mass drug administration can improve women’s standing within communities. Dirk Engles talked about the different ways that tackling NTDs could help meet the 17 Sustainable Development Goals but this one stood out. He described how including women as community drug distributors could be empowering for women because by taking a leadership role they were challenging gender norms. However, I would love to broaden this out to highlight the multiple ways gender shapes women and girls’ experiences of NTDs. These include the way social norms within communities often mean that women and girls are expected to interact with infected water sources on a near constant basis. Women can experience greater stigma from living with the clinical manifestations of NTDs. For instance, women living with swelling in their legs can lead to greater stigmatisation both within their families and in the communities more broadly. Expectations around who provides care in households can also mean that women and girls care for those living with the symptoms of NTDs. Making sure we highlight the diverse ways gender power relations shape vulnerability and experiences of living with the diseases is vital. One step to doing this would be the inclusion of women and girls voices in the design health and social programmes to ensure their needs are not overlooked.
  2. Despite free drugs being available not all countries request them: Understanding why countries do not request free drugs is important. Health systems in resource limited settings are often overburdened. Provision of free drugs is only part of a health programme. Many bottlenecks obviously exist that prevent countries from requesting and delivering these programmes. Taking a health systems approach that asks stakeholders what challenges governments face that stops them from requesting drugs could provide important insights.
  3. We need to look beyond just giving drugs: Where people live, whether they have access to safe water, whether they have access to health care, and what they do for a living can all affect their vulnerability to NTDs. Giving preventative chemotherapy has to be seen as a strategy that goes hand in hand with other interventions that aim to prevent people becoming infected in the first place. These include vector controls as well as Water, Sanitation and Hygiene (WASH).
  4. WASH is not always easy but it is necessary: WASH’s start-up and maintenance costs can be expensive but given the very real ways it can prevent illness and suffering investment should be made.
  5. Let’s not leave anyone behind: Millions of people, and their families, continue to be affected by NTDs. Making sure that these people’s health and social needs are considered and addressed within NTD programmes is of the upmost importance.

It was heartening to see the successes of NTD interventions such as the lymphatic filariasis programme from the last decade. However, it is clear that many challenges still remain if we are to live in a world free of NTDs.

Photo credit: Lake Malawi by Eleanor MacPherson

The importance of good preparation in quality clinical diagnostics

It is said that prior planning prevents poor performance, so we were pleased to be joined in Liverpool by our colleague Jaco Verweij who is supporting the qPCR workshop which will take place in Ghana later in the month. As head of the clinical molecular diagnostics facility at Tilburg, Dr Verweij has developed an automated laboratory system that is capable of processing 100,000 samples a year with 45 multiplex DNA assays targeting a wide range of pathogens from multiple sample sources from blood to faecal.

As well as leading this state of the art molecular lab in the Netherlands he shares the same vision as COUNTDOWN, in terms of the need to scale up capacity in the Africa region.  During molecular workshops in Africa, he helped others to specialise in the use of Taqman® multiplex assays to identify some of the more damaging worm infections: from schistosomiasis to soil-transmitted helminthiasis.  With a higher diagnostic specificity and sensitivity than traditional parasitological methods these Taqman® assays use real-time polymerase chain reaction (qPCR) platforms. Adopting these methods allows for the development of a more detailed and accurate epidemiological picture several worm infections, strongyloidiasis in particular.

At the Ghana workshop a series of seminars and laboratory work will give the participants the skills and background knowledge to carry out faecal DNA extraction, qPCR, and the subsequent analysis of the results. The workshop will lay the ground work in skills development for the subsequent COUNTDOWN milestones for both the filariasis and helminth work as well as providing the skilled staff at the Global Polio Laboratory Network and the Council for Scientific and Industrial Research with the opportunity to increase their diagnostic horizons. We look forward to an exciting and productive trip that will sow the seeds for future work in the country.

COUNTDOWN on diagnostics for soil-transmitted helminthiasis and schistosomiasis in Ghana

By Russell Stothard

Shortly before Christmas, I had the pleasure of visiting Accra and Dodowa to discuss with the COUNTDOWN teams our research on DNA diagnostics. Previously, the surveillance of soil-transmitted helminthiasis (STH) and schistosomiasis has relied upon traditional parasitological methods. This involves rather old-fashioned techniques to visualise worm eggs in stool or urine samples by light microscopy. Although pragmatic in field-based surveys, these parasitological methods are insensitive and do not precisely capture the true levels of infections.

Improving diagnostics by introduction of modern molecular methods is important for two reasons. First and at a population level, infected cases are better detected leading to more accurate reporting and subsequently better allocation of treatment. Second and at an individual level, the more cryptic associations between infection and disease are unveiled. For example, for the latter in better describing the relationship between growth stunting and STH in children or the gynaecological impact of female genital schistosomiasis in adolescent girls.

A major research theme in COUNTDOWN is to develop and strengthen the molecular diagnostic capacity within the laboratory of Dr Mike Osei-Atweneboana. Mike will also explore future synergies with the Ghanaian polio programme based in the Ngouchi Institute, Accra which regularly collects thousands of stool samples from children. Regular access to these samples and heightened scrutiny with molecular diagnostics could provide a wider platform to assess STH throughout the country.

Last September, Dr Emily Adams visited Mike’s laboratory to make a preliminary situation assessment of his equipment needs. I was there in December to assist him with further planning for a forthcoming training workshop in DNA diagnostics. This is to be held the week of 14th March in Accra and in liaison with colleagues from the Ngouchi Institute. I visited a primary school in New Abarim where ongoing deworming had just taken place. We also made a spot-check visit on the local health centre in Adausena. It is clear that future application of DNA diagnostics in these settings will shed new light on the true burden of disease.

Ahead of the workshop in March, Emily and I will be taking steps with Lucas Cunningham to develop a training manual and also assemble the necessary DNA reagents for transfer to Ghana. To make a success of the training course, I am delighted to report that Dr Jaco Verweij, the world’s expert on DNA diagnostics, will be visiting the LSTM in February to provide use with best technical advice and later also join us in Ghana to develop best clinical international standards.

 

Come see COUNTDOWN at the Prince Mahidol Award Conference

We’re delighted to be attending this year’s Prince Mahidol Award Conference which is focussed on the theme of Universal Health Coverage. We’ll be represented by Kate Hawkins, Sally Theobald and Louis-Albert Tchuem Tchuenté.

At the conference we’ll be presenting our poster on progress on control and elimination of Neglected Tropical Diseases (NTDs) as the ‘litmus test’ for Universal Health Coverage (UHC). Mass Drug Administration (MDA) has been successful in reaching high numbers of people affected by NTDs resulting in progress toward the control and elimination of NTDs in many contexts. However, numerous bottlenecks still remain for the scale-up of MDA if the WHO 2020 targets are to be met. If UHC is to be achieved these aspects need to be addressed and the health system strengthened. We outline the challenges that are being faced under the six health systems building blocks – financing, workforce, information and research, service delivery, leadership and governance, and medical products and technologies – and suggest some ways forward.

If you are attending the conference do come and find us. It would be good to connect.

We’re expanding our programme and partnerships in Nigeria!

This month COUNTDOWN has been awarded additional funding of £1M from the Research and Evidence Division within Department for International Development (DFID), UK. The expanded COUNTDOWN partnership allows implementation research to be undertaken within Nigeria, in Kaduna and Ogun States. By supporting and strengthening the activities of The Federal Ministry of Health and Sightsavers, COUNTDOWN will address several context-specific issues within neglected tropical disease (NTD) control. In so doing, this will foster the scale-up and sustainability of current and future interventions, encouraging a broader inter-sectoral dialogue within the health system.

Set up in December 2014 following an initial £7 million grant allocation from DFID, COUNTDOWN will trial and evaluate new approaches to drug distribution, which target those who are currently overlooked and excluded, examining how NTD programmes can be better integrated into broader health system responses. As a push towards universal access to health services, COUNTDOWN is working to support the achievement of the 2020 targets set out in the London Declaration on NTDs.

LSTM’s Professor Russell Stothard, COUNTDOWN Director, commented “Inclusion of Nigeria into the COUNTDOWN partnership is a key step within our research programme. We aim to ensure that our research leaves a lasting legacy in Nigeria, paving a way for increased domestic funding which ultimately increases the scale and scope of NTD control. Helping Nigeria reach the WHO 2020 targets is a major driving force in our work. I sincerely hope it will lead to a tangible benefit and improvement in the health of those populations in West and Central Africa vulnerable to NTDs”.

Photo courtesy of E Herrera

Social Science and Neglected Tropical Diseases in Cameroon – So what?

By Samantha Page, Laura Dean, Estelle Kouokam, Fabrice Datchoua, Hermine Jatsa Boukeng, Christian Duamor Tetteh, Mary-Sheena Maingeh, Manuela Ngo Bakale, and Theobald Nji

We recently completed the first social science meeting in Cameroon for COUNTDOWN where colleagues from The University of Buea, The University of Yaoundé and Liverpool School of Tropical Medicine came together to develop collaborative social science research protocols for COUNTDOWN. So what?

Using methods from social science generates important data that has the potential to reduce the prevalence of Neglected Tropical Diseases (NTDs) in Cameroon; data which cannot be captured from the biomedical sciences. However social science methods are often overlooked when addressing NTDs, or even sneered at.  Many ‘pure’ scientists cannot understand the value of conducting social science or what impact this academic discipline has in addressing these so called “diseases of poverty”.  So what?

So this is one of the challenges we face when working on a multidisciplinary programme that involves social science, parasitology, entomology, and vector biology. To combat this challenge we have come up with key research questions addressing each level of the health system in Cameroon, of which there are five: national, regional, district, health area and community.  These research questions can be grouped across five core areas which are critical to a holistic approach to NTDs. These are:

  1. Funding, governance and donor priorities;
  2. Health system integration and disease programme co-implementation;
  3. Partnerships and multi-sectoral working beyond the health sector;
  4. Community drug distributors; and
  5. Gender, disability, equity and NTDs.

So what does this mean in practice?

At the national level through key informant interviews and stakeholder workshops, linked to the research area of funding, governance and donor priorities, we will explore how donor priorities influence the way programmes are managed. In addition, we will assess how decisions made internationally support or challenge country priorities and processes for NTD control and elimination.

At the regional and district level through key informant interviews, stakeholder workshops, focus group discussions, direct observation and document review, linked to the research area of health systems integration and co-implementation, we will seek to understand how current platforms for NTD co-ordination are functioning and promoting co-implementation of disease programmes.

At the district level through key informant interviews, stakeholder workshops, focus group discussions, and direct observation, linked to the research area of partnerships and multi-sectoral working, we will identify what multi-sectoral partnerships are in place and what opportunities are missed.

At the health area level through participatory methods such as ‘photo-voice’, linked to the research area of community drug distributors, we will identify how community drug distributors are currently supported and co-ordinated by and within the health system. We will explore how their role within communities can promote community ownership of the philosophy of eliminating NTDs.

At the community level using anthropological methods such as ethnographic journals, linked to the research area of gender, disability equity and NTDs, we will seek to understand how communities perceive and talk about NTDs and how we can be more responsive to their understandings, particularly in the way we generate health education messaging. We will consider the needs of individuals currently ‘invisible’ to existing NTD programmes, such as out of school children, people living with disability and pregnant women.  We will assess how stigma and disability present barriers in accessing treatment for NTDs.

The collaborative nature of social science within COUNTDOWN is not limited to work in Cameroon. Our work in Ghana takes a similar approach and the same is likely to be true in Liberia and Nigeria. So what?

Well, this allows for learning between these diverse African contexts who are in differing phases of disease control to address bottlenecks and implementation dilemmas to accelerate the elimination of NTDs. So what?

Social science may have a long way to go to prove its worth in the field of NTDs, but we believe that without it, elimination and eradication of diseases propagated by social processes is impossible. The medicines, the public health strategies are there. So what?

Control and elimination cannot succeed without the understanding and the explanation of the social process, social organisations, beliefs and perception of societies that are the principal actors and people affected by NTDs.

Defining Lymphatic Filariasis hotspots in Ghana

By Lisa Reimer, Liverpool School of Tropical Medicine

We must appreciate the heterogeneities of NTDs across communities and understand the factors that have resulted in persistent disease, only then can we apply a sustainable strategy for elimination.

Lymphatic Filariasis in Ghana

Lymphatic Filariasis (LF) is a mosquito-borne infection caused by filarial worms that can result in significant illness, disability and disfigurement. The LF Elimination Programme in Ghana has achieved great success with annual, community-wide distribution of microfilaricides. It is recommended that the drugs are distributed to the entire community for 5-7 years which is the estimated life span of adult worms. Mass drug administration (MDA) has been underway for over ten years, but there are still communities endemic for LF. So what is unique about these communities? Why has the recommended strategy failed to eliminate LF? Will scaling up MDA provide the final push towards elimination?

Hotspots and heterogeneities

These communities are often referred to as ‘hotspots’ and they are likely a product of the heterogeneous nature of vector-borne diseases. For example, there is great diversity among the vectors of LF ranging from those that are highly competent to incompetent, those that bite indoors and those that bite outdoors, those that preferentially feed on humans and those that are generalist feeders. There may be differences in village characteristics that can support a larger population of the most capable vectors. There may be greater risks to certain individuals of a community depending on their habits, house structure, house location and their occupation. There will be individuals in a community who decline treatment, are unavailable during distributions or prefer not to use a bed net. There may be other barriers to delivery of services and interventions. There may be differences in insecticide resistance or drug resistance influencing the efficacy of MDA and vector control.

It may not be enough to scale up access to MDA, we need to understand the dynamics that have contributed to persistent transmission in these communities in order to inform the most appropriate delivery of interventions.

Planning for change

I recently met with COUNTDOWN colleagues Dr. Benjamin Marfo, Dr. Nana Kwadwo-Britwum and Dr. Margaret Gyapong from Ghana Health Service and Dr. Mike Osei-Atweneboana from the Council for Scientific and Industrial Research, to lay the groundwork for our investigation of lymphatic filariasis hotspots in Ghana. We are planning an in-depth investigation into the social, entomological and epidemiological factors that are driving transmission. We will evaluate current epidemiology in the context of baseline prevalence. We will explore adherence to MDA, bed net usage, transmission, vector behaviours, vector competence, insecticide and drug resistance, community beliefs and practices, experiences of the health workers and drug distributors. This understanding will then inform a new approach to integrated delivery of vector control and MDA. Our study will evaluate the costs, experiences and the impacts of integrated complementary strategies for LF.

We are now making plans for our first visits to study communities in January 2016. I am particularly looking forward to joining postdoctoral researcher, Dr. Kingsley Badu for our mosquito surveys to evaluate vector behaviours and current transmission dynamics.