Sustainable control of livestock schistosomiasis in Africa to improve human and animal health and productivity

The One Health approach recognises that the health of humans is connected to the health of animals and the environment, and aims to identify and implement holistic solutions that create co-benefits for all. A critical aspect of One Health is the co-production of knowledge and solutions and therefore encourages collaborative efforts of multiple agencies and population groups to achieve the best outcomes for each. Schistosomiasis is a neglected tropical disease of profound medical importance. Over 240 million people are infected, 90% of these amongst the poorest of sub-Saharan Africa. Although generally ignored, schistosomiasis is also a disease of substantial veterinary importance. Recent environmental and anthropogenic changes appear to exacerbating opportunities for the mixing and subsequent viable hybridization between human and animal schistosomes. We have demonstrated that novel zoonotic hybrid schistosomes within West Africa are having a substantial impact on the epidemiology, evolution and clinical outcomes of disease, with further challenges and constraints for effective control. It is thus apparent that schistosomiasis in many parts of sub-Saharan Africa cannot be eliminated if there are animal reservoirs of infection leading to continued transmission to both humans and animals. Furthermore, animals often suffer severe morbidity and mortality due to schistosomiasis, further impacting the livelihoods of their owners. Livestock are vital for and integral to the social construction of human life and productivity in these regions.
This new research will provide increased knowledge on human-livestock interactions, quantify the costs incurred to subsistence farmers with infected animals, elucidate the potential risks of drug resistance developing if both animal and humans are accessing drug treatments, help enable access to and appropriate use of suitable veterinary-approved drug formulations and ultimately, working within a One Health framework, aim to implement and improve sustainable disease control. Inherent within our design, this research aims to improve local capacity, influence national and international policy, and improve human and animal health, lifting rural human populations out of poverty in both the short and the sustained longer term.

Schistosomiasis is a NTD of profound medical and veterinary importance, inflicting suffering on poor rural communities in many parts of the developing world. This research has the potential to disentangle the metaphorical Gordian knots imperative if the WHO's recent ambitious goals towards 'elimination of schistosomiasis as a public health problem in Africa' are to be achieved.
Our directly-applied research will, through evaluating and designing a sustainable treatment plan for livestock, reduce the risk of animal Schistosoma species circulating in the environment for hybridized ongoing transmission to humans and at the same time reduce the morbidity and mortality inflicted upon infected animals.
Using a range of disciplines (from social surveys, economic and predictive mathematical models, empirical parasitological and molecular data), we will quantify cost-benefits, potential acceptance and impact of a targeted test-and-treat policy to maximise the impact on livestock health whilst at the same time minimizing the risk of evolving PZQ-resistance emergence.
We will enhance the capacity of the staff of our African partner institution in aspects of disease research, surveillance and control, as well as help accommodate local farmers and key stakeholders' perspectives to help co-construct new platforms. Contributing to the effectiveness of the project will enhance local veterinarians' and community members' ability to anticipate, recognize and respond to schistosomiasis infections in livestock and humans, better understand the importance of animal-human interactions for cross-infection, and underscore identification of 'at risk' practices that may be in play. Results will be fed into, from local community workshops and broader symposia, to national and international policy and control progamme implementation. The outcomes should lead to improved animal management practices with a concurrent increase in animal and human health.

With the vision of "a world free of schistosomiasis", the World Health Organization's (WHO) revised strategic plan, in conjunction with the London Declaration and NTD coalition, recently set the ambitious goals for the control, elimination as a public health problem (EPHP) and/or interruption of transmission of schistosomiasis within selected SSA countries by 2020 and 2025 respectively. Much of this success rests on the assumption that schistosomiasis in SSA, in contrast to the situation in Asia, is a human-only disease, and thus targeted Mass Drug Administration (MDA) aimed at school-aged children alone should achieve these targets. The potential role of animal schistosomiasis in SSA, either in terms of disease control, economic impact, or in terms of a potential zoonotic risk for maintaining transmission to humans, has been largely ignored for decades. This research has the potential to disentangle the metaphorical Gordian knots imperative if the WHO's ambitious goals towards are to be achieved.
Lessons learned should inform and guide future control activities and assist local livestock farmers. In terms of both international impact, as well as national impact on society, the new research proposed here should minimize both socioeconomic losses due to the direct effects of animal schistosomiasis-associated morbidity and mortality, and minimise the significant risk we have demonstrated in terms of ongoing schistosomiasis transmission through viable hybridization between human and livestock schistosomes. Together these should help achieve targets and improve the health and welfare of the poorest of the poor people and their animals.
The results of the research will be disseminated through publication in open access international scientific journals and by presentation at national and international conferences. In country co-applicants have direct connections with their Ministries within Government particularly the Ministries of Health and Education, as well as local and national veterinary services departments, and will use these links to directly communicate findings of interest and relevance to ongoing control programmes. Results will be discussed at WHO Expert Advisory Group meetings on evaluating drug efficacy and the new 'WHO Guideline Development Group (GDG) for the implementation of control and elimination of schistosomiasis'.
A further impact component will be the evaluation and optomization rapid, inexpensive, point-of-contact diagnostics assays. New molecular data relating to parasites will also be generated throughout the project, and new DNA sequences generated will be deposited in the NCBI GenBANK open access sequence repository for access by other workers. Schistosome collections will be archived at the SCAN facility. Prevalence and intensity data will be made available to interested parties (such as WHO, NGO's, national ministries of health and of environment etc) and shared with the Infectious Disease Data Observatory (iddo.org) schistosomiasis.
Detailed appreciation of interactions between schistosomes of humans and animals, coupled with enhanced understanding of how famers and communities approach schistosomiasis treatment, will provide decision-makers and national and community health services with improved tools to target interventions. Pressure can then be placed for the access and implementation of alternative PZQ treatment regimens for both people and animals living in zoonotic high transmission zones, applying a One Health framework for schistosomiasis control. Such helps ensure the sustained efficacy of the only available drug for human and animal schistosomes whilst improving the health and productivity of humans and their livestock now.
The high quality research produced from this research will help scientists and policy-makers alike realise that animal schistosomiasis, and their hybridization with human schistosome species, is an emerging public and veterinary health concern.