Identification investigation and implementation of plant-based parasite control strategies

Poor farmers in developing countries world-wide very often cannot afford chemical drugs to treat their animals against internal and external parasites. In Ethiopia, this is resulting in high mortality, reduced productivity and economic losses as high as 50% of the value of their sheep and goats. For many generations, small-holder farmers and pastoralists in Ethiopia have used medicinal plants to try to cure their animals. However, from the large economic losses it is clear that this is not very effective. Although many poor people use plants to try to cure their animals, we do not know if they work, how they work and if there are side effects that need to be considered. If we know more about these possible positive and negative effects, then we may be able to increase the effectiveness of using plants to control animal disease. This project brings together traditional healers and researchers to promote a better use of plants to cure animal disease through systematically obtaining scientific evidence on the effectiveness of Ethiopian plants. Because such information will also help farmers in developed countries such as the UK, we will also study the effectiveness of extracts from chicory, which is a medicinal plant that grows in the UK. We hope that by bringing together many researchers with different research skills, we will achieve best possible use of plants for parasite control. We will make sure the knowledge of traditional animal health care practitioners does not get lost, and if we find good results from Ethiopian plants that this benefits Ethiopian agriculture. The optimum outcome would be that countries like Ethiopia use their own natural resources to control animal parasites as much as possible. We will tackle this research in five related steps, each step will result in new information that the next step will use. We start with an inventory of plants that farmers use in Ethiopia to try to control parasites. This will be followed by making extracts from a selection of these plants, as well as from chicory, proven to reduce parasite problems in sheep. These extracts will be tested to see if they can kill parasites by mixing them with worm eggs, worm larvae and adult worms. We will also spray them lice, ticks and mites and observe effects on controlling these parasites. We expect that several of these extracts will show negative effects on these parasites. Ideally, we would like to test all these extracts directly in sheep on farms. However, that would be much work, be costly and take too long. Therefore we will first test some of the best potential extracts on mice, which we will deliberately infect with parasitic worms. In this way, we will use mice to screen out those extracts that work best when given in a real life situation. The best ones will be used in sheep. These sheep will be infected with either parasitic worms or with mites. We will also give the extracts to non-infected sheep to estimate if there are side effects we need to consider at the next stage when the extracts will be used on farms. The best extracts from the sheep experiments will be trialled on farms, in Ethiopia and the UK. Extracts tested on farm will be those that are most likely to be effective at helping cure the animals of parasites. We would like to think that our project can be of use to any country that has native plants that show promise for possible animal disease control. We will therefore inform as many people as possible how we approached our research, what we have found and how the results can be used to improve animal health.

Farmers and traditional healers have relied, for centuries, on phytomedicine to treat parasitism, but large economic losses incurred in developing countries like Ethiopia indicate that its effectiveness is limited. This project brings together traditional healers and research scientists to sustainably promote phytomedicine and increase its efficacy through systematically obtaining scientific evidence on anti-parasitic efficacy, side effects and mode of action of preparations from Ethiopian plants towards endo- and ectoparasites. The approaches used will also be applied to chicory, a UK grown bio-active plant with known anti-parasitic effects upon grazing. The proposed work will make use of an ethno-botanical survey, and an array of biochemical, nutritional and parasitological methodologies. The ethno-botanical survey aims to identify up to 30 plants used by small-holder farmers and traditional healers to combat endo- or ectoparasites. Up to five types of plant preparations will be prepared, including a preparation used in practice. The ~150 resulting preparations will be screened in vitro for their anti-parasitic properties against gastrointestinal nematodes, using egg hatching, larval motility and adult survival assays, and against ecto-parasites, using topical application on mites, lice and ticks. Up to 10 bioactive plant preparations identified will be used in Heligmosomoides bakeri infected mice to assess their in vivo anti-parasitic efficacy and side effects on host performance. This will be followed by in vivo testing of up to 3 of the most effective bio-active plant preparations using sheep, infected with Haemonchus contortus, Teladorsagia circumcincta, or Psoroptes ovis (scab mite). The most promising approaches will be demonstrated in naturally infected sheep in both Ethiopia and the UK through a monitor farm approach, which is a dissemination methodology where groups of farmers jointly manage a flock or farm and implement new technologies.

This project is expected to provide an increased understanding of veterinary phytomedicine for parasite control in small ruminants. Its initial direct beneficiaries are the small-holder farmers and pastoralists involved in the monitor farm dissemination programme of this project, as they will be able to exploit the project outcomes first hand. Improvement of animal productivity, animal health and better economic returns can be expected within a matter of months rather than years or decades, although it appreciated that it will take some time before such effects will have resulted in reduced losses and improved economic returns at national level. In addition, since being able to keep healthy animals is of paramount importance for the social status of small holder farmers, successful phytomedicine contributes to social stability. Publicising our new knowledge and approaches used through workshops, booklets and dissemination activities beyond the boundaries and lifetime of the project has the potential to empower any resource poor, male and female small-holder farmers to manage their animals' health cost-effectively, as affordability of pharmacotherapy will remain a major constraint to any developing country. Our proposed methodology and approaches will be disseminated to any organisation that wish to promote phytomedical parasite control strategies through increased use of plants native to them. Our literature review at the start of the project will identify these organisations, and they will be contacted accordingly. This has the potential to result in further collaborations outwith the current project. Promoting phytomedical parasite control strategies would also benefit developed countries, where anti-parasitic drug resistance is a constraint for sustainable parasite control. The project is expected to result in a large number of bio-active plant extracts, which will allow for the possible identification of the specific anti-parasitic compound. If so identified, the latter can form a basis to develop new drugs. The expectation would be that the latter will take place over a 5-10 year time period, and this should be achieved via classical drug development technologies rather than relying on plants to harvest active components. This is the case as it is recognised that care should be taken to prevent the situation that successful demonstration of phytomedical parasite control results in harmful overexploitation of local anti-parasitic plant species, especially when this is done for the benefit of developed countries mainly. The project also has impacts on future research opportunities and capabilities in Ethiopia at Hawassa University as well as in the UK. Ethiopian researchers will have access to and get trained in research methodologies in the UK which are not widely available to them. SAC will host an exchange programme to this effect, and will train Ethiopian researchers in research methodologies pivotal to the project, including the in vitro screening, in vivo efficacy testing in small ruminants and the monitor farm methodology. This will not only allow experimentation and dissemination both in Ethiopia and UK using common protocols, but will also facilitate rapid in vitro screening of a large number of plant preparations at the same time, whilst also testing efficacy of the same plant preparations under different small ruminant production systems. As a result, this project will establish a research capacity in Ethiopia that can continue to assess benefits and side effects of novel plants for parasite control beyond the lifetime of this project. Similarly, UK researchers will have access to Ethiopian plant preparations, which are otherwise not available to them. Identification of bioactive plant extract has the potential to be developed in new drug treatments, as described above.