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A Focus on Schistosomiasis and Soil-Transmitted Helminthiasis in Crater Lakes in Cameroon

By Deborah Sankey, Tim Day and Faye O’Hallaron

This blog describes some of the highlights and challenges of our work with Louis-Albert Tchuem-Tchuenté in Cameroon. We were privileged to learn a great deal about the day-to-day realities and practicalities of interventions against Neglected Tropical Diseases (NTD). Our experiences generated more stories than we have time to tell, but here is a brief overview about lakes Barombi Mbo and Kotto. We hope you enjoy reading this as much as we enjoyed our work with the team there.

Having attended several planning meetings and gaining local permissions in Kumba; our first day in the field involved getting ourselves and all our equipment to our first field site – the crater lake of Barombi Mbo. Getting there was challenging and our journey involved a one -hour commute each way in local hand-paddled canoes but was set within breath-taking scenery. We arrived on the other side of the lake and walked through the surrounding cocoa farms- the most valuable commodity of the region – to the village itself. After greeting several village elders, we were taken directly to the chief’s house to discuss our work. We requested their permissions and support to help us conduct our surveys and interviews.

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At this point the team split, half going back to the lake in search of aquatic snails and the remainder based inside the village church hall to begin collection of samples and conduct interviews by questionnaire. As the community rushed to be involved, our workload on the first day was greater than expected. We faced challenges in French-speaking situations.  Meanwhile on the lake the malacological team were working under the full might of the African sun. Wearing their armour of waders and sporting only a simple kitchen sieve (Sainsbury’s RRP £4.99) and a pair of tweezers, the intrepid team delved into the shallows in search of the miniscule molluscs.

After both teams had completed their quota of samples for the day (the importance of applied statistics for you!), we regrouped and made our way back to Kumba setting to work analysing all our samples.

Several further days were spent in Barombi Mbo following a similar pattern of work, before moving on to our second study site Barombi Kotto. At Kotto, due to its rural location, we stayed in the vicinity of the second lake for the duration of the survey. This involved a three-hour journey along mud tracks, which was tricky even when dry and almost impassable on our return visit where two vehicles had succumbed to the mud.

We set up the lab in the local health centre, and were pleased to see a modern looking lab with clean white tiles and all the mod cons, minus however running water and electricity! Each day we collected water from the local stream and we had the foresight to bring a portable generator. Using this within the health centre meant entertainment was on hand for while we worked. The surrounding children could watch DVD films in the evening and adults charge phones in the health centre while we beavered away in the laboratory until the late hours of the evening. Deborah and Faye, being women, were lucky enough to enjoy the hospitality of a local family living within their vicinity. Tim and the male staff took up residence in the abandoned maternity ward. The family welcomed us with great kindness, cooking for us excellent meals every day, and ensuring we had everything we needed, we even joined the family for morning prayers.

The days followed a similar pattern of questionnaires, sample collection, and then analysis. The main difference was that the majority of the population lived in an isolated community on an island in the middle of the Lake Kotto. Unlike the clear waters of Mbo, the lake was smaller and much less enticing. The canoes were very rickety, made of half a hollowed-out tree patched-up with cement, making for interesting journeys across the lake. This community were less accustomed to foreign visitors and our supervisor was invited to spend a night on the island. We were lucky enough to be told stories by the community elders about the village’s history. It gave us a greater insight into the local culture and traditions and just how important the water of the lake was to their community identity and beliefs.

We faced many challenges throughout our trip and were pushed to our limit physically, mentally and digestively. With team work and perseverance we achieved our goals. We learned more than we can convey.

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Anyone’s Disease: Ending Lymphatic Filariasis in Ghana

A Bed Net to Rule them all: Accelerating Lymphatic Filariasis Elimination through Malaria Control Programmes

 

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ONCHOCERCIASIS IN THREE DECADES PART II: Building the Next Generation of Parasitologists

By Pamela Bongkiyung

This post continues the discussion with Prof. Wanji on the strides undertaken towards the control of Onchocerciasis.

In this segment, he discusses his hopes for a drug that could not only work against Onchocerciasis but also Loa Loa without causing harm to the human host. He highlights the foundation he has laid down to help the next generation of parasitologists, empowering them to seek solutions to problems endemic to their respective environments.

Pamela: Understanding that we have just the one tool, does it complicate matters or make it worse that there is Loa Loa in all of this to deal with?

Prof. Wanji: Of course because that tool presents a problem with Loa Loa. Just because it is one tool remains a problem but the fact that in some areas you cannot use it, makes it more difficult. It presents a double problem and sometimes people often talk of double penalty with regards to Loa Loa. That is something which was discovered recently that the area where Loa Loa exists, the tool which was being used to map Lymphatic Filariasis can have false positivity. It can be positive not because of Lymphatic Filariasis but because of Loa Loa. Loa Loa has been inflicting a double penalty for the control of lymphatic filariasis and onchocerciasis in the central African region.

Pamela: Is there a drug to mitigate Loa Loa as well as Onchocerciasis without causing any adverse reactions.  It appears there isn’t the one stone that can kill two birds but is there one that can kill each bird at a time?

Prof. Wanji: Unfortunately we do not have a drug that can kill Loa Loa safely for now. That is a major problem. In our laboratory, we are trying to develop experimental models but at the in vitro and invivo that can help screening and developing drugs for Loa loa. If we can have drugs that can kill Loa Loa alone, that already will be a great achievement. If we could have a good drug that could kill Loa Loa in a safe manner for the host (the human) and also kill onchocerciasis, that will be a tremendous achievement. Actually, we were handicapped, we don’t have a solution for Loa Loa as we stand today.

Pamela: This problem is very endemic in the Central Africa region. At the level of education especially within the universities, are there any incentives to get students more interested in research work for diseases that affect their environment? And is there available training to enable them conduct research that could possibly bring a much needed solution in the future?

Prof. Wanji: I think the teaching of parasitology (because all of this belongs to microbiology and parasitology), is difficult because most of our African students are likely to learn computer science, business administration and Economics.

We, at the University of Buea for the past five years in the Department of Microbiology and Parasitology have created postgraduate programmes that are specifically oriented to Neglected Tropical Diseases (NTDs). We have an MSc in Molecular Parasitology and Vector Biology, MSc in Microbiology, MSc in Epidemiology and Control of Infectious Diseases, a PhD in Cellular and Molecular Parasitology and a PhD in Microbiology. And if you look at our PhD and Master degree programmes, we have two arms: we have the arm of research and development which includes the MSc in Molecular Parasitology and vector biology, PhD in Cellular and Molecular Parasitology.

They give the basis for students to be involved in developing new tools for diagnosis of parasites, new tools for understanding the immune responses and developing vaccines, new tools for developing new drugs. The thing is that our students have to understand and be part of the momentum. But we also work with epidemiology and control orientation in the programme. We want them to be ready to uptake the product of the research to the end users because the epidemiology conceives control programmes, monitors and evaluates them. We want them to be able to say, this is what we have achieved, this is where we are having difficulties or encountering bottlenecks and we can do this to change.

We have conceived a programme to address the problem of NTDs and infectious diseases at large maintaining a parasitology focus.

Pamela: What legacy would you want to leave behind?

Prof. Wanji: Difficult question. Legacy is difficult because it is not easy to praise yourself. I would like to be known as somebody who conscious of the dimension and width of NTDs devoted part of his life to contribute, to understand and fight those tropical diseases; by teaching students about NTDs, creating and developing research capacity that has contributed to the training of those students; by participating in research work that has contributed to change people’s lives, contributing to fight in the field of those diseases and by anticipating what the future will be in my discipline; re-orienting the teaching programme at the university to get African students to be more proactive in the solution to those problems created by  NTDs.

Thank you for those last words Prof. Wanji.

 

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Onchocerciasis in Three Decades: Through the Lens of Prof. Samuel Wanji

By Pamela Bongkiyung

Prof. Samuel Wanji is Head of Department for Microbiology and Parasitology at the University of Buea, Cameroon. He is also Executive Director of the Research Foundation in Tropical Diseases and Environment, Buea. He heads the COUNTDOWN programme’s partnership with the University of Buea. He has worked extensively on Onchocerciasis control and been instrumental in its control. We caught up with him while he was on a visit to the Liverpool School of Tropical Medicine.

Pamela: Hello Prof. Wanji. Thank you for taking the time to talk to us. How long have you worked on Onchocerciasis?

Prof. Wanji:  My journey with onchocerciasis started as far back as 1988. We could be talking of almost 30 years of research in onchocerciasis. Everything started with an experimental model when I was doing my postgraduate studies in Paris, France. And later on, I remained within Filariasis/Onchocerciasis for my research and university career. So actually, it has been a very faithful relationship with research and onchocerciasis throughout my life as a student and a worker both for teaching and research.

P: In the almost three decades that you have worked on various projects in relation to onchocerciasis, what changes have you observed?

PW: Yes, there have been changes. I started almost when Ivermectin was introduced as a new tool for the control of Onchocerciasis. And we witnessed the huge impact Ivermectin has made in the control of Onchocerciasis through the African Programme for Onchocerciasis Control – APOC. We were among the researchers involved in mapping the disease across Africa for the implementation of the control. We also witnessed the decline of the disease in many of foci where the endemicity was really high.

But what has been my major contribution for the control of onchocerciasis came from another filarial parasite Loa Loa. Originally, nobody knew that Loa Loa could cause a problem for the onchocerciasis control. So, when it was established that some people taking Ivermectin could develop severe adverse events and could even die, the link was established with Loa Loa and it became a priority to know those places where the endemicity of Loa Loa that is dangerous for the intake of Ivermectin was.

We participated in those early days around 2000 to develop the rapid assessment procedure for Loa Loa which was later on extended to 15 African countries, where we coordinated the mapping exercises in those countries, to generate the first map for Loa Loa in Africa. This map was operationally very useful in saying this place is very dangerous, this place is safe. And that is how we contributed heavily to the control of onchocerciasis in those areas where there was co-endemicity with Loa Loa.

Besides that, at the level of the laboratory we developed an experimental model in baboons to understand the mechanisms of encephalopathy due to Loa Loa with the treatment we have with Ivermectin. Today we know that the microfilaria are massively killed and they block the micro capillary of the brain and that is how people almost get killed. People become withdrawn and they go into coma because of such. We know that mechanism and we even have an idea of how such things could be prevented with ivermectin and aspirin. We have worked a lot through Loa Loa to see how the control of onchocerciasis could be safe in the forested areas of Africa.

P: What are the major impediments to controlling Onchocerciasis not just in Cameroon as you seem to have worked extensively across Africa, but also how does Loa Loa add to these impediments that you might have encountered in your work?

PW: As we know Onchocerciasis is a Neglected Tropical Disease. So just by that fact, it is already an impediment in controlling such disease. Less attention was paid to it. Fortunately for the past ten years there has been a lot of momentum around Neglected Tropical Diseases and Onchocerciasis has also benefitted from that.

As you can imagine that for almost 30years, the only drug that has been used for the control of Onchocerciasis has been Ivermectin. Ivermectin does not kill adult Onchocerciasis besides of the fact that it creates problems with Loa Loa in areas where the two diseases co-exist, Ivermectin kills only Microfilaria, the children of filarial of Onchocerca Volvulus (O. Volvulus).

So you need to take the drug for longer than 15years, to expect getting rid of the disease. And that is a very long time because people can easily go into fatigue. If the resources are not properly mobilised people may not have resources to sustain such long term control.

One probable consequence of such impediment has been the suspicion (and I will call it suspicion because there has been a lot of controversy around it) of sub-optimal response of the worms to Ivermectin. That means when you have a long term pressure of the same one medication on a parasite, the parasite may develop a strategy to not be sensitive to that drug anymore. And that has been a very shortcoming of onchocerciasis control to know that instead of having two or three drugs to play with, only one drug exists.

It is only of recent that there is a lot of work going on to develop microfilaria drug that will kill the adult worm. That is why in many areas we are really doubting how the elimination will be feasible. Those areas where the transmission was very high or is very high, we are almost sure that Ivermectin alone cannot do the job. We need alternative strategies. That is why you have been hearing about Doxycycline which was developed recently. Doxycycline can kill adult Onchocerca Volvulus but it needs at least 4weeks to do that job. The four weeks treatment is far better than 15years yearly treatments because with 15yrs yearly treatment you may have fatigue effect more than 4wks continuous treatment. At the level of the public health people think it is not suitable to have a regimen of 4wks, they insist on shorter regimens.

Here at the Liverpool School of Tropical Medicine, we have the AWOL consortium which is developing a shorter regimen of Anti-Wolbachia. Doxycycline is an anti-wolbachia. It is a drug that kills the bacteria that lives in a worm. Because that bacteria is starkly associated to the worm, they exchange some functions. So if you kill the bacteria, the worm also dies. It is an indirect effect. So the AWOL consortium is developing a shorter regimen of antibiotics that can do the same job like doxycycline. We hope that doxycycline will play its own role in the elimination of onchocerciasis or anti-wolbachia drugs globally. But we are expecting contributions from other drugs like Flubendazole which is in the pipeline.

Globally to answer your question, the impediment has come from the fact that we are dealing with only one tool, for the control of onchocerciasis.

To be continued…

Sabina facilitating the seasonal calendar

The Importance of Team Work and Shared Learning in Collaborative International Health Research

By Eleanor MacPherson

Leaving my two young children in the UK and travelling for work is always tough. But spending time in the company of the Dodowa Health Service research team made being away worthwhile. I, like many qualitative researchers, know that the skill of the person collecting the data is the most important factor to ensuring good quality data. Yet, anyone who has tried conducting a qualitative interview or focus group discussions knows how challenging it can be to do it skilfully. By spending ten days with the Dodowa Health Service research team, under Dr Margaret Gyapong’s excellent leadership, I learnt so much about how to provide rigorous inclusive training in collaborative research.

Here are my *Four Take Home Messages:

You have to understand the research topic before you can begin: Neglected tropical diseases are complicated! As a social scientist who has only recently begun working on these types of tropical diseases I know how challenging it can be to understand the complex way that a mosquito, black-fly or snail can ultimately contribute to the transmission of worms to people. Further, if someone is infected it may take a number of years for them to experience ill-health. The focus of this round of data collection is lymphatic filariasis and understanding why some districts in Ghana are still facing on-going transmission despite a number of rounds of preventative chemotherapy. The training began with an introduction as to what lymphatic filariasis is and how it is transmitted. Building on this information the team then discussed the purpose of the research and the groups who could best provide insights into these questions. During the training discussions in the group frequently returned to these areas. This allowed the team members, particularly those new to the topic, the opportunity to ask clarifying questions and gain further understanding.

Translating and refining the topic guide as a team can improve the tools: Conducting research on international health often requires the researchers to work across multiple languages. Yet, the way language is used is of the utmost importance to ensuring participants understand what is being asked of them. The Dodowa team took a two-step approach to translation. They went through the topic guides together in English first, discussing as a group whether they made sense; whether they had covered all the research objectives and whether the order of the topics worked. As the team went through they re-ordered some of the questions, removed questions that didn’t make sense and refined the language. The second stage was to translate the guides into Twi and Fante. At this point the whole team contributed to the translation taking turns to read the guide and holding spirited discussions about the correct meaning of the words.

Practice, practice, practice: The team used role-play as key part of the training. This gave every single member of the team an opportunity to practice conducting a qualitative interview and a focus group discussion multiple times. Sheila Addei or Mama She as the team like to call her oversaw the role play. She has more than a decade of experience conducting qualitative research studies and together with Dr Margaret who has more than twenty years’ experience provided fascinating insights into what has worked well and what hasn’t when conducting qualitative research! Mama Shelia told the team about how during one of her first interviews the participant told her off for failing to use the topic guide correctly. The team also took turns giving difficult responses to provide the researchers with an opportunity to practice managing these challenges before they went to the field. Every team members’ role was practiced including the note taker and the observer to ensure that the person undertaking this role fully understood their duties.

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From Left: Sheila Addei (Mama She), Dr Margaret Gyapong, Sabina Asiamah, Piloting the FGD & Seasonal calendar in the field, Dr Ellie MacPherson with team, Irene & Selase practising interview and Adriana Opong

Strong leadership combined with an empowered team is a powerful combination: One of my favourite parts of my time in Ghana was feeling part of such an empowered and well-led team. It was fantastic to witness even the most junior members of the team having their voices listened to, and thoughts respected. Creating space for reflection and shared-learning is such a core component of qualitative research but doing it well when working in a team can be challenging. Respect and inclusion are fundamental to qualitative research practice and by placing these at the centre of their work, the Dodowa team did a fantastic job. I am sure this practice will continue throughout the whole of the project.

I know I have returned to the UK a better researcher thanks to the team and very excited for the next stage of the collaborative research process.

Onchocerca infective larvae

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?

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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.

 

 

 

Anopheles gambiae, the major vector of lymphatic filariasis and malaria in rural Africa (source: www.scientistsagainstmalaria.net)

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.

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Patience and prior knowledge: simple requirements for schistosomiasis control

By Suzy Campbell

Schistosomiasis is challenging and complex whichever way you look at it! From its six-syllable name, to its subtle but extensive disease burden, to its lifecycle in aquatic and mammalian hosts, to its control with preventive chemotherapy and – dare we hope – to its elimination by intersectoral action.

Take for example the schistosomiasis life cycle (see below). It’s so complicated that despite many attempts it was only unravelled 100 years ago, by a parasitological pioneer, Robert T. Leiper. Before this, it was not known that there was more than one type of schistosomiasis. Added to this the snail hosts’ roles were not clear and as a result little could be done to develop control strategies in any meaningful way. This meant that schistosomiasis struck fear in the hearts of many.

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There are so many interesting points to emerge from Leiper’s work. He first identified the separate African schistosome species; a contribution of tremendous value to parasitology because one (Schistosoma mansoni) is linked to intestinal schistosomiasis and the other (Schistosoma haematobium) to urogenital schistosomiasis.

Importantly, Leiper also identified and applied simple water safety measures as versatile ways to reduce schistosomiasis transmission. This included simple filtration, water boiling, use of disinfectants and resting water for 24 hours before use. In addition, his clarification of the snail intermediate hosts paved the way for attempts to remove or destroy the snails. These were all practical control strategies which were useful in schistosomiasis control, well in advance of deworming tablets being developed. All that was needed was a little patience and adequate temporary water storage.

Roll forward 100 years. Some things have changed. We are very fortunate in that we have very effective deworming tablets, although they only reach a small portion of the people who need them, and possibly not at the right frequencies to sufficiently control disease.

However, some things have not changed. The subtle morbidity of schistosomiasis is still under-recognised: for example the clinical significance of schistosomiasis in very young children and the importance of female and male genital schistosomiasis. Environmental strategies, such as water safety measures, seem to have largely been forgotten. In particular, our behaviour and perceptions of how water is used should be questioned. Water is not always safe (see below). Until we recall the prior knowledge imparted by the likes of Leiper, schistosomiasis should still strike fear in our hearts. It will not go away.

 

 

This is a village in Cameroon, showing a public tapstand as an improved water supply. But ‘run off’ water flows as an open stream, continuing through the centre of the village. Had a snail intermediate host been residing in this stream, schistosomiasis could have been prevalent despite the improved water source. (Photos: R. Stothard, S. Campbell)

A newly-released Special Issue Review in Parasitology gives an entertaining and thorough biography of Leiper’s contributions to parasitology and the developing field of ‘medical malacology’. This review covers 100 years of the history – and at times controversy – since Leiper’s elucidation of the Schistosoma life cycle and development of practical control strategies. The review goes on to illustrate how Leiper’s contributions still have relevance today, indicating a need for integrated control mechanisms, and introducing the COUNTDOWN research consortium which focuses on implementation research to provide tangible health improvements.

Globally, there is a paradigm shift for schistosomiasis, from morbidity control to transmission control, and eventual elimination as a public health problem. More than ever we are going to need to be guided by integrated and broad-based control strategies. This has been well-recognised by the World Health Organization (WHO), with their recent release of the Water, Sanitation and Hygiene (WASH) for Neglected Tropical Diseases (NTDs) Global Strategy 2015-2020. This calls for intersectoral collaboration to address NTDs by augmenting current control programmes with additional WASH activities.

Progression of a global NTD integration agenda is being increasingly recognised by NTD practitioners, researchers, and other policy makers. International consortia, such as the Schistosomiasis Control Initiative, and now COUNTDOWN, will play a part in driving this agenda. Some of the integration and WASH concepts will be elaborated upon at the annual COR-NTD meeting in November 2016. Work is also progressing within COUNTDOWN on two manuscripts to address aspects of environmental frameworks for schistosomiasis transmission control. The imperative lies with all NTD partners to ensure that Leiper’s work will continue resonating true today.

Find more information on COUNTDOWN’s activities.

mosq net

Anyone’s disease: ending Lymphatic Filariasis in Ghana

By Adrianna Opong

I used to think Lymphatic Filariasis – also known as elephantiasis – was a curse from the gods and hereditary, until I started working in health research. One day in my new job, I had a chat with Mr Samuel Odoom, the senior technical officer for the Neglected tropical Diseases Programme in the Ghana health service. He explained this to me:

Lymphatic Filariasis (LF) or elephantiasis is caused by infection from the filarial worm (a thread-like worm), which is transmitted from human to human via the female mosquito. The mosquito feeds on the blood of an infected person and then when it later bites an uninfected person, the worms are able to infect a new person. The filarial worms are in their third stage of development when they penetrate the bite wound of the uninfected person. They later become adults that live in the human’s lymphatic systems. This is a problem because the lymphatic system maintains the body’s fluid balance and also fights infections.

Mr Odoom told me that although the parasites damage the lymphatic system, most LF cases do not show clinical symptoms. However, a small proportion of infected people develop complications in the acute stages. It leads to lymphedema which is fluid collection and swelling of some parts of the body such as legs, arms, breast, genitalia. Affected people also have more bacterial infections in the lymph and skin and experience hardening and thickening of the skin. Hydrocele or swelling of the scrotum is very common in men. The complications of LF such as swelling of the legs and arms can only be managed, not cured.

Lymphedema can be prevented from getting worse by:

  • Carefully wash the affected/swollen areas thoroughly with soap and clean water every day
  • Wash in-between folds/toes with a piece of cloth
  • Dry the affected/swollen area with a clean piece of cloth
  • Disinfect any wounds and sores, use antibiotic (antifungal or anti bacterial) ointment/cream if necessary
  • Elevate and exercise the affected/swollen areas to move the fluid and improve the lymph flow.

Hydrocele can only be corrected through surgery. In 2002 Samuel Odoom, together with NTDP, set up a lymphedema clinic to manage the burden of LF complications. Mr Odoom said, “ NTDP trained a consultant who goes around the regions in the country and some other African countries to train physicians on how to do hydrocele surgeries”. Now in Ghana, there are 12 health facilities that conduct hydrocele surgeries.

Prevention and control

 LF is endemic in nine out of the ten regions in Ghana, so it is a serious health issue. It can of course be prevented by avoiding mosquito bites. Mosquitoes that carry the filarial worms usually bite between 5pm to 5am. The advice for people in endemic communities is to sleep under a treated mosquito net, use mosquito repellent on exposed skin and wear clothes that cover all the body. Yet for people in communities, preventing mosquito bites is not always possible.

In endemic communities, LF can be controlled or even eliminated with Mass Drug Administration of a single drug (ivermectin) through the Preventive Chemotherapy programme. The NTDP introduced the Mass Drug Administration in the year 2000, but only in a few districts. Today the programme has been able to cover all endemic districts in Ghana. But there are still some communities with a high prevalence of LF and some populations are still hard to reach.

It is with this in mind, that the COUNTDOWN research consortium is putting effort into investigating cost-effective, scale-up and sustainable solutions. In Ghana, the research is exploring how different factors within the health system hinder the scale up of the MDA and aims to integrate additional strategies to complement the MDAs in the control and elimination of LF by 2020.

I have now spent a year working with COUNTDOWN, embedded with the NTDP. I have come to the realisation that LF can affect anybody living in an endemic community, who does not or cannot protect themselves from mosquito bites. It is also very clear that we need to put more resources and research into finding sustainable solutions so that all communities in Ghana will be free from LF now and in the future.

Lake Malawi

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

Collecting patient data.

Control of schistosomiasis in Cameroon: searching for evidence

By Russell Stothard and Louis-Albert Tchuem-Tchuenté

Schistosomiasis, also known as Bilharzia, is a disease that often doesn’t show any symptoms for several months or even years. Worms that cause schistosomiasis live in fresh water. Having been infected with these parasites that burrow through the skin, it is only after some time that people might get a high temperature, cough, diarrhoea and then progressive damage to the internal organs such as the bladder and bowel. Symptoms might disappear after a while too, but the parasite stays in the body causing serious long-term ill health, for example, infertility in women. The parasite also continues to be transmitted back into the environment, spreading further.

This neglected tropical disease needs more attention. De-worming tablets can make all the difference, and COUNTDOWN’s second integrated complementary strategy theme (ICST-2) is going to research the effectiveness and acceptability of expanded access to this deworming medication in Cameroon and Ghana.

For example, Cameroon only provides annual praziquantel (PZQ) treatment by mass drug administration to school-aged children. It’s possible to buy PZQ over the counter in local pharmacies, but the availability of this drug within the general health system is poor. Pre-school aged children and women of reproductive age are vulnerable here because without regular treatment they will continue to suffer. The parasites continue to be fed back into the environment, via stool or urine, first infecting snails then others in the community.

Over the coming years, COUNTDOWN will seek to foster the scale-up and wider access of PZQ treatment to people who are not currently targeted within national control programmes. We will also assess acceptability and find out it is both sustainable and cost-effective at the community level. In addition, expanded access to PZQ treatment could also accelerate progress towards the reduction of schistosomiasis transmission in the environment.

Water, sanitation and hygiene

The parasites that cause schistsomiasis – also known as schistosomes – live inside freshwater snails. Schistosomes are able to multiply themselves to enormous numbers each day and although the stages are short lived – they typically dying within 24 hours – a new wave of parasites are released the next day from infected snails.

While this is well known to many parasitologists, its importance and significance has been largely ignored within the water, sanitation and hygiene (WASH) community and agenda. Put simply, any aquatic habitat that people use and that contains infected freshwater snails is a high-risk location for schistosomiasis. Some very simple water hygiene measures – if used daily – can make the water safe, yet they remain out of reach for millions in rural Africa.

Furthermore, any efforts to make water safe needs to be tailored specifically to each demographic group in the population, as they each have different requirements and abilities to accept change. Mothers, for example, collect water for their domestic chores and typically bathe their children with it.

image002 (1)

A child washing at Barombi Kotto

Eliminating schistosomiasis

How can we eliminate schistosomiasis? It’s a big question. The influential and heavily cited paper by Rollinson et al. (in which we both played a part) first outlined the need to develop a guiding framework for the surveillance of schistosomiasis in the environment. This has become ever more pressing and an issue for even closer consideration within the European health sector, given the recent focus of urogenital transmission on Corsica. Developing a strategic framework is especially important in the context of the WHO 2020 Roadmap targets. Here, certification of elimination of transmission will be needed or any reasons for its failure will need to be explored.

It is obvious that PZQ treatment should be expanded to all groups at risk of infection, as highlighted by the World Health Organization. It is less popular, however, to justify its use in reducing schistosome transmission. This year, several mathematical modelling studies suggest we should no longer overlook the significant environmental transmission of schistosomiasis from groups outside school-aged children. Moreover, as we slowly gain control of the disease, the relative roles each group plays in sustaining local transmission will also be dynamic.

With this in mind, we are looking for examples in Cameroon where COUNTDOWN activities are able to develop new coordinated intersectoral actions. This will provide a more holistic vision of how to expand access to treatment for people who need it, alongside environmental studies that measure reductions in transmission.

Cameroon: searching for evidence

In Cameroon, the communities at Barombi are at greatest risk of urogenital schistosomiasis, largely because of the presence of a key species of Bulinus, the genus of freshwater snail that are permissive hosts for Schistosoma haematobium in Africa. It is the absence of other snail species at Barombi that allows us to focus on urogenital schistosomiasis alone.

image003 (1)

A snail distribution map of Barombi Kotto with species indicated in green and blue

Our recent field surveys undertaken in June 2016 in the crater lakes of Barombi Mbo and Barombi Kotto are starting to reveal the need to further develop a guiding strategic framework. It would measure schistosome infection alongside local environmental transmission. The sampling framework is appropriate and implementable with resources typically at hand in the sub-Saharan African region.

Since urogenital schistosomiasis also has links with female health, we can better research reasons why this parasite, which is transmitted in urine and not stool, remains a considerable health burden at Barombi Kotto and Barombi Mbo. Significant investment at Barombi Mbo has meant the building of safe water sources with piped water available to all households. However, we need to assess how current WASH interventions can be further refined to dampen local parasite transmission. For example, social science investigations could reveal why some people are unable to benefit from these interventions or continue to use unsafe water.

The two locations of Barombi are important areas for multidisciplinary studies. Here, our research will test the effectiveness and acceptability of expanded access of de-worming PZQ treatment and record any changes in environmental transmission. The research also examines biannual treatment schedules, as a way to promote equity of treatment, but also to accelerate reduction in transmission and elimination. Evidence is needed to support elimination, as there is currently no formalised WHO framework to do this. While guidelines for lymphatic filariasis with transmission assessment surveys (TAS) exist, there are none for schistosomiasis. Both national and international policies are lagging behind in this area. It is a great opportunity for our COUNTDOWN research to make an impact.

Our initial results will be presented on the 14th and 15th June at the meeting Global Schistosomiasis Alliance in China, so please watch this space!