Rats and mice are arguably one of the most neglected pest problems the world over. Rodents attack and damage crops grown in the field, as well as damaging stored crops in homes, warehouses and factories. Hence, their damage and contamination of food is problematic across the value chain. We can add to this the problems rodents cause in our cities, where rodents feeding on our refuse go on to damage sewage and drainage systems, undermine foundations, damage electrical wires and gas supplies and generally terrorise the citizens. The economic and social costs of such damage occasionally make the news when hospital equipment fails or buildings burn down due to damaged wires, but such damage is rarely systematically quantified. Zoonotic diseases such as Lassa fever and bubonic plague are endemic problems in rural Africa, which sometimes lead to human-to-human disease outbreaks. More often than not, rodent-borne diseases are not recognised or diagnosed and poorly treated[1], with many thousands of poor rural people dying from rodent-borne diseases across Africa each year.[2] With rodents transmitting more than 60 diseases to people and domestic animals, damaging food production systems, and exacerbating sanitation problems, few would argue society’s rat problems have been solved. Despite this, research on rodent pest management is entirely absent in many African countries.[3]
Research on rodent pests is typically carried out by isolated researchers, and few institutions have sustainable teams of experts working on rodents. This low capacity for innovation has led to a situation whereby low investment in rodent research results in limited awareness and documentation of the scale of rodent pest problems, making the matter easy to ignore. Recent research funded by the European Development Fund[4] suggests this situation can be changed in Africa. Rodent pests are currently unsustainably and indiscriminately controlled using highly toxic poisons, but where there is great potential to develop agro-ecologically sustainable solutions that could lead to real positive changes in human well-being through enhanced food, nutrition and financial security, reduced environmental contamination and increased sustainable agricultural practices. In particular, indiscriminate large scale use of rat poisons is known to drive biodiversity loss which can down regulate ecosystem functions like predation (e.g. avian, mammalian and reptilian predators) and ecosystem resilience (e.g. increased invasion potential due to reduced biodiversity). Such changes in ecosystem function and diversity can trigger ecosystem cascading effects that could in extreme cases lead to outbreaks of zoonotic diseases.[5] Furthermore, the EcoRodMan project will strongly enhance inter-regional scientific research collaboration and cooperation by bringing together rodent researchers from across the continent. EcoRodMan combines the strengths of institutions across six countries from the South, Central and East of Africa to help build sustainable teams of rodent experts. This inter-regional research network will increase the quality of science produced through cross-training and the sharing of best practices that address the multiplicity of problems caused by rodents for African families. Because of the multiple impacts of rodents across agriculture and health, building Africa’s research capacities to tackle rodent pest problems by developing innovative and sustainable solutions could be one of the most important interventions of the 21st century across the continent to reduce poverty and improve people’s livelihoods.
Reducing rodent pest numbers can have a much larger impact on reducing poverty than any other single pest problem. In agriculture, rodents are both a pre-harvest and post-harvest pest problem, causing major impacts on food security, nutrition, food safety and human health. In the post-harvest sector, small holder farmer grain stores are subject to high levels of urine and faecal contamination that can lead to many bacterial, viral and parasitic diseases transmitted to people. Rodents also selectively eat the germ of stored grain, which reduces its nutritive content. On top of contamination and nutritional damage, post-harvest loss due to rodents for many African farmers is typically 5-20%, whilst crop losses in the field are documented to be much higher (20-40% and frequently >50%).[6] Despite being a well-recognised problem throughout the world, there has been relatively little research on rodent pest management since the advent of anticoagulant rodenticides in the 1950’s. The poor application and adaptation of rodent control measures to particular situations often results in treatment failures, leading to apathy and widespread acceptance of rodent pests in the environment. Many rural farmers suffer from low awareness, ingrained defeatism when trying to control rodents and acquiesce to rodent damage. In a global context, rodent pests are a clear poverty indicator; those households most exposed and proximal to rodents are usually the poorest of the poor who lack rodent management tools and knowledge.[7] Expected results of the EcoRodMan project are to deliver sustainable agricultural practices and new technology and understanding that can limit the multiple impacts of rodent pests on people’s lives. Both high-tech research solutions and the optimisation of indigenous practices can help deliver more ecologically sound rodent management that enhances food and nutrition security whilst protecting the environment and increasing agricultural intensification. EcoRodMan's results will help reduce the use of poisons that are dangerous to humans, other animals and the environment as well as develop new technology that will be more cost-beneficial, promoting One Health[8] principles.
Current rodent pest management practice largely depends on the use of rodenticide poisons. Although some of these poisons can work very well, their usage is increasingly challenged because of their damage to human health and the environment. The commercial private sector continues to advocate the use of poisons and is currently doing little to develop alternative rodent management technology. Safe and effective use requires extensive training, whilst many small holder farmers will also say rat poisons are ineffective, unaffordable or unavailable. Ultimately many African families resort to highly toxic and illegal substances for rat control. For example, the nematicide, Aldicarb (carbamoyloxime), is not licensed as a rodenticide but is illegally sold for killing rats, dogs and even people throughout Africa.[9] Many rat poisons are clearly linked to biodiversity loss, particularly endangered raptor species, small carnivores and insectivores. The proposed action will help reduce reliance on the use of rodenticides, by developing novel strategies within the technological paradigm of ecologically-based rodent management (EBRM). European funded initiatives in Africa (10th EDF contract FED2013-330223) have shown that key elements of EBRM can be cost-effective for rural farming communities, but that there is a great need to develop new technologies and management strategies by the public sector due to a lack of commercial investment on new technology. The EcoRodMan project aims to build on and synergise with this previous EC investment to develop ecologically-based rodent management strategies that are appropriate for Africa and for sustainable agricultural practice.
Many countries in Africa have severe problems with contagious rodent-borne diseases. More than 90% of all bubonic plague cases globally reported to the World Health Organisation now come from sub-Saharan Africa. Many of the 60+ diseases transmitted by rodents are directly linked to unsustainable agricultural practices and rural farming communities and highlight a lack of ecosystem resilience. The paradigm of One Health recognizes that the health of humans, animals and ecosystems are interconnected.[10] Although many questions remain about rodent-borne disease dynamics, it is clear that sustainable agricultural intensification is key to ensuring that agricultural practices do not exacerbate disease risks by undermining ecosystem services and resilience that lead to zoonoses affecting human and livestock health.[11] The need for better and more detailed research on ecologically-based rodent management is clearly an important priority for all African countries in terms of food production, nutrition and health. Most African countries will acknowledge rodents as a problem across the agriculture, environment and health sectors, but few have drafted strategies and action plans. Largely through European Commission-funded programmes, rodent research has been progressing through pan-African projects. The EcoRodMan project will synergise with and capitalise on these previous EC investments, and help build African capability to deliver relevant rodent research to help African families overcome their rodent pest problems.
[1] Crump JA, et al. 2013 Etiology of Severe Non-malaria Febrile Illness in Northern Tanzania: A Prospective Cohort Study. PLoS Negl Trop Dis 7(7): e2324; Peacock, S. J., and Newton, P. N. 2008 Public health impact of establishing the cause of bacterial infections in rural Asia. Trans of the R Soc of Trop Med and Hyg 102, 5–6.
[2] Meerburg BG, et al. 2009 Rodent-borne diseases and their risks for public health. Critical Reviews in Microbiology 35:221–270.
[3] Makundi, RH, Massawe, AW 2011 Ecologically-based rodent management in Africa: potential and challenges. Wildlife Research 38:588–595.
[5] Civitello, D. J., et al. 2015 Biodiversity inhibits parasites: Broad evidence for the dilution effect. Proceedings of the National Academy of Sciences 112(28): 8667-8671.
[6] Mwanjabe PS, et al. 2002 Crop losses due to outbreaks of Mastomys natalensis (Smith 1834) Muridae, Rodentia, in the Lindi Region of Tanzania. International Biodeterioration & Biodegradation 49:133–37.
[7] Oldewage-Theron, W. H., et al. (2006). Poverty, household food insecurity and nutrition: coping strategies in an informal settlement in the Vaal Triangle, South Africa. Public health 120, 795–804.
[8] Coker, R., et al. 2011 Towards a conceptual framework to support one-health research for policy on emerging zoonoses. The Lancet Infectious Diseases 11, 326–331.
[9] Rother, H.A. (2010). Poisonings in South Africa from super strength street pesticides. Pesticides News 90, 12–15; Rother, H.A. (2013). Falling Through the Regulatory Cracks: Street Selling of Pesticides and Poisoning among Urban Youth in South Africa. International Journal of Occupational and Environmental Health
[10] http://www.onehealthglobal.net/what-is-one-health
[11] Han, B. A., et al. (2015). Rodent reservoirs of future zoonotic diseases. Proceedings of the National Academy of Sciences 112, 201501598; Cascio, A., et al. (2011). The socio-ecology of zoonotic infections. Clinical microbiology and infection 17, 336–42.