Remote Integrated Systems for Controlling Nematodes using Emerging Technology for Both Resource-Poor and Commercial Farmers (RISC-NET)

Lead Research Organisation: Moredun Research Institute
Department Name: Vaccines and Diagnostics


Gastrointestinal parasitism has been identified as the greatest animal health constraint to the poor in S.E. Asia and Africa South of the Sahara. Much of the small ruminant production in India and South Africa lies in the hands of resource poor small holder farmers (RPSF farmers) for whom blood feeding nematode parasites such as Haemonchus contortus in sheep and goats, Mecistocirrus digitatus in sheep and cattle are among the most important constraints on production. These parasites cause substantial blood loss in affected animals, impair production as defined by growth rate, meat quality and milk production and often cause death. Control is achieved by frequent dosing with anthelmintics, a strategy threatened by an increasing resistance to these drugs in the target nematodes. Solutions to be examined here are 1) to develop a more targeted drug treatment strategy where only animals suffering from worm challenge are treated in a flock/herd thus limiting exposure to the drug and reducing frequency of dosing and, hence, cost 2) to develop molecular tests which can be applied to monitor the drug resistant status of the parasites on a particular farm or regionally, information which can be used to predict the likely impact of novel control interventions such as 1) above and 3) the development of a vaccination strategy which relies on the fact that only very low (microgram) amounts of vaccine protein are required to induce protective immunity. The project builds on existing strong collaborations between the participants, provides researcher training and technology transfer and offers the prospect of enhancing the livelihood of RPSF.

Technical Summary

This project aims to enhance sustainable control against blood feeding nematodes in grazing livestock using a decision support system based on targeted selective treatment of individuals identified as requiring anthelmintic intervention. In addition, anthelmintic resistance status of parasites affecting livestock in Tamil Nadu, India will be assessed using standard laboratory tests and developing molecular tests. Finally, an element of the project focuses on vaccine development against these nematodes. The overall ambition is to develop and integrated control options applicable to the resource poor small holding farmer. The objectives will be addressed as follows: 1) To develop a computerised, automated decision support system to advise farmers on anthelmintic usage. This will build on existing FAMACHA datasets on parameters such as climate infection levels and anthelmintic use to improve an existing computer model and then to develop extension via mobile phone technology to resource poor small holder farmers. 2) To establish the levels of anthelmintic resistance.on geographically selected properties Tamil Nadu, India. This will be conducted on faecal samples with drug resistance being determined using the faecal egg count reduction test, egg hatch tests and mutation frequency. 3) To monitor the species prevalence and anthelmintic resistance status of the parasite population in Tamil Nadu plus the parasite response to control measures. We will employ a pyrosequencing assay to quantify benzimidazole resistance as well as microsatellite markers combined with phylogenetic analyses to study the population dynamics. 4) To develop cost effective vaccination, we will use native parasite proteins to protect against infection with Haemonchus contortus and Mecistocirrus digitatus, a control strategy which could be applied on a regional basis and greatly reduce selection for AR. This project also builds on established links and includes researcher training.

Planned Impact

Helminth infection is ubiquitous in cattle, sheep and goats world-wide and causes, amongst others, severely debilitating gastrointestinal disorders, Animals are exposed to infection by grazing on contaminated pastures. Although death can result from infection, production losses with no overt signs of disease arise and these losses have major implications, frequently threatening livelihood, for the resource poor small holder farmer (RPSF) Control costs are a major burden on the producer and are often beyond the means of the RPSF.The rapid development of anthelmintic resistance (AR) in the target parasites (particularly Haemonchus) to the major drug classes available has prompted the development of more targeted drug treatment strategies now commonly termed targeted selective treatment (TST). The practicality of such approaches is exemplified by the FAMACHA system to aid the control of haemonchosis in South Africa and progressively in the rest of Africa, the Americas, Asia and now even to a lesser extent in Europe. The impact and beneficiaries of this project can be summarised as follows: Provision of remote access to decision support for worm control which will greatly increase access to TST such as FAMACHA 1. Development of accessible decision support using mobile phone technology and routine updates based on submission of simple, on-farm generated data, with concominant computer modelling of key risk factors. 2. Defining the extent of anthelmintic resistance for the first time in Tamil Nadu, India which will allow the introduction informed decision support on strategic anthelmintic use - reducing and preventing unnecessary drug use. 3. Devising methods to reduce the spread of anthelmintic resistance using genetic markers. 4. Improved methods for the management of anthelmintic medication and resistance for the RSPF farmers. 5. Sustainable management of worms by farmers without frequent lab sampling 6. Towards the development of vaccines against blood feeding GI nematodes such as H. contortus and M.digitatus - expanding the control options available This has clear commercial implications in that the animal health sector is committed to the development of biologicals for worm control, both as an alternative to anthelmintics and also to provide a control option which could sustain their use by reducing dependency on them. 7. Technology transfer and training of researchers and end users. This project will promote methods to minimise anthelmintic use required to achieve control and, thus, through TST and alternatives such as vaccination to promote effective and sustainable use of anthelmintics. A central activity is to exploit epidemiological modelling capability to develop a remote decision support system which will be directly accessible to farmers using mobile phone technology. Thus, the project will promote sustainable worm control for R-P farmers. It will allow a growing number of both resource-poor and commercial farmers to manage worms economically and sustainably, without the need for frequent laboratory sampling and regular inputs by experts into day-to-day decisions on worm management. Technology transfer from South Africa to India will be a central theme allowing the FAMACHA TST control aproach to be applied in regions where blood feeding nematodes are endemic. This work will be underpinned by providing an improved assessment of the extent of the resistance problem in Tamil Nadu using the latest molecular tools. Knowledge of the extent to which resistance alleles arise independently on each farm versus arising rarely and being spread from farm to farm allow the appropriate control measures to be chosen eg, targeted selective treatments (TST), quarantine drenching and the control of animal movement. In addition, vaccination technology will be developed, the aim being to produce a bivalent prototype native protein vaccine for use in the control of Haemonchus and Mecistocirrus on a regional basis.