Authors: Martha Powell, Future Science Group
At the end of September Infectious Diseases Hub attended the British Society for Parasitology Autumn Symposium, which focused on the multidisciplinarity of the field and the need for this broad approach in an ever changing world.
The first session focused specifically on the theme of on ‘an ever changing world’, beginning with a talk from Roy Anderson, Director for the London Centre for Neglected Tropical Disease Research and Professor of Infectious Disease Epidemiology at Imperial College London (UK). Anderson spoke on the positive outcomes mass-drug administration (MDA) has seen in controlling human helminth infections, citing that in 2015, 1.288 billion treatments were delivered to 998 million people.
However, the challenges ahead were also highlighted; for example, Anderson argued the need to broaden treatment from school-aged children to a community-based approach and also put forwards the need for individual-based longitudinal records on drug compliance. Finally, Anderson spoke on the promise of a vaccine against schistosomiasis, the positive results already observed and the potential issues this could face in terms of manufacture.
Hear more from Roy in our video interviews on the London Centre for Neglected Tropical Disease Research, his career and his current undertakings.
The opening talk was followed by the awarding of the International Federation for Tropical Medicine (IFTM) medal to David Rollinson (Natural History Museum (NHM), London, UK) by Santiago Mas-Coma, President of the IFTM including some personal anecdotes – featuring food poisoning and lightning storms – from Vaughan Southgate. Rollinson took the opportunity to say a few words, highlighting that although much has been achieved in tackling parasitic diseases over the past few years, there is still more to be done.
The theme of a changing world then continued, with a presentation from Santiago Mas-Coma on the spread of human fascioliasis and how this has been impacted by mankind’s history. Mas-Coma posed three primary points of interest: the huge diversity in fascioliasis’ geographic hotspots (including variations in climate, endemic situation and altitude); the unexpected conservation of DNA markers observed in nuclear and mitochondrial DNA; and the surprising heterogeneity seen at the genome level in these parasites. He then went on to describe the archeoparasitological and paleoparasitological approaches that have linked these surprising features to human influences and the influence of animal domestication.
Starting discussion around schistosomiasis, which would become a major theme of the symposium, Louis-Albert Tchuem Tchuenté (University of Yaoundé, Cameroon) gave an overview of schistosomiasis control activities in Cameroon. The significant impact of MDA in school-aged children was again highlighted, but Tchuem went on to focus on recent studies from March 2017 that have demonstrated a renewed increase in schistosomiasis prevalence – up to 45% in some schools – making reinfection a real threat. He summarized by speaking on some of the challenges faced in moving from control to elimination, and the need for intensified interventions.
The morning session concluded with an insight from David Molyneux (Liverpool School of Tropical Medicine (LSTM), UK) on moving towards the development agenda amidst change. Molyneux spoke about the new ‘bottom billion’, which is shifting from those living in failed and fragile states to the poorest individuals in middle-income countries. In addition, he highlighted the impact of mental health, which is predicted to be one of the biggest global health problems by 2030, on those suffering neglected tropical diseases (NTDs). Looking forwards, Molyneux highlighted that we should “expect the unexpected”, view NTDs through the lens of poverty and be mindful of emerging drug-resistance, climate change and other challenges that might impact the endgame for NTDs.
This session was followed by a quick question-and-answer discussion and speed poster presentations to stimulate discussion during the subsequent viewing. Following lunch, and the opportunity to view the posters in greater detail, the second session focusing on ‘the multidisciplnarity of parasitology’ began.
The first presentation was from Robin Gasser (University of Melbourne, Australia) who gave a personal perspective on the expanding world of parasite genomes, first highlighting the tools that made the genomic revolution possible. Gasser then focused on his own research using genomics to gain deeper insights into parasite biology and host–pathogen interactions with the focus of improved intervention methods. In addition, Gasser spoke on the exciting aspects of parasitic genomics, including orphan genes and the ability identify ‘essential’ genes as drug targets, concluding that the field has a need for capacity building and cross-disciplinary interactions to elucidate these genomes further.
The focus then shifted back to schistosomiasis, as Jürg Utzinger (Swiss Tropical and Public health Institute, Basel, Switzerland) discussed the interplay of parasitology and ecology with reference to shistosomes, snails and prawns. He discussed his research investigating the impact of prawns, which are predators for schistosomiasis-carrying snails, on the prevalence of these intermediate hosts and subsequent disease in humans – revealing no clear association had been found. Utzinger highlighted the plans for future experimental work aiming to unravel the complex host–prey relationship and assess impacts of prawns on schistosomiasis in different socio-ecological settings.
Bonnie Webster (NHM) followed, continuing the schistosomiasis focus and speaking on how molecular tools provide insights into schistosome diversity in Africa and beyond. Webster discussed the contrasting genetic diversity observed in S. heamatobium and S. masoni, asking whether this might impact their epidemiology and control. In addition she highlighted the identification of hybrids presenting mixed genetic profiles from interspecies breeding, again posing questions – do these hybrids have implications on pathogenicity? Might they affect response to treatment? Could they alter host range?
Tim Anderson (Texas Biomedical Research Institute, TX, USA) closed this series of presentations, introducing his work on the genetic basis of transmission-related traits in schistosomiasis. This included the identification of key genes that had been linked to traits such as schistosome chronobiology and the genetic basis of parasite–snail compatibility via linkage and genetic mapping. Anderson highlighted that population and functional genomics were yet to come.
The final session of the day was on ‘host–parasite evolution and control’, starting with a talk on a OneHealth approach to schistosomiasis by Joanne Webster (Royal Veterinary College, London, UK). Webster discussed the lessons we’ve learnt thus far from laboratory and field studies, including the potential for rapid parasite evolution and the challenges presented by the zoonotic nature of schistosomiasis. She went on to discuss possible praziquantel resistance, and how investigating this led her team to discover S. heamatobium – S. bovis hybrids infecting children. In fact a plethora of parasite combinations seen in children and adults in Niger, with offspring often viable and variations in hybrids seen between sites. As with Bonnie Webster, Joanne highlighted concerns around hybrids having different transmission potentials, drug efficacies or host ranges – already suggested by the presence of hybrids in humans. Webster concluded by emphasizing that animals must be included in control and elimination efforts arguing that ignoring these reservoirs make us unlikely to achieve elimination.
Find out more about Joanne’s research in our exclusive interview – Zoonotic parasites, an underappreciated area?
Next up was Lisa Reimer (LSTM), who spoke on her work in vector-borne disease surveillance – specifically the role of molecular xenomonitoring in the surveillance of lymphatic filariasis. Reimer outlined some of the issues currently facing this indirect method for assessing pathogen prevalence, including lack of time and expertise, the need for equipment and the absence of a gold standard for assessing results. She went on to discuss some new developments that may be starting to combat these challenges and the promise this surveillance approach might hold.
The focus then shifted to a veterinary stance, with Jozef Vercruysse (University of Ghent, Belgium) discussing the steps that will have to be taken to fully control helminth infection in ruminants by 2030. Vercruysse discussed vaccine approaches, and the possibility of exploiting genetic differences to select for resistant/resilient organisms, concluding that by 2030 more rational integrated control of infections will be required, and a shift in mind-set from mass treatment to an individual basis.
In the final presentation of this session Tim Littlewood (NHM) delved into palaeontology, summarizing what we currently know, and what can be learnt from fossil parasites to enhance our knowledge in the future. He highlighted that direct evidence of parasites in fossil records are rare, but there are increasingly more examples owing to new imaging techniques. Moreover, Littlewood called for increased awareness in both palaeontologists and parasitologists in order to make the most of the fossil records being uncovered.
The conference concluded with closing remarks form Mark Taylor, President of the British Society for Parasitology, who emphasized the need to embrace multidisciplinary approaches in parasitology – not only within teams but also across careers – to really advance the disciplines. This echoed the overarching theme of the day, which highlighted the need for collaboration and cooperation across fields, particularly with regards to NTDs, to monitor these diseases, correctly inform policy decisions and move towards elimination.