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Identification of novel control methods through better understanding of the biology and physiology of the sheep scab mite. - OD0552

Description
Sheep farming represents a significant proportion of the UK livestock industry, with the latest available statistics (2005) estimating the UK flock at 35 million animals. The sheep scab mite, Psoroptes ovis, is the UKs most important and highly contagious sheep ectoparasite, causing an intensely pruritic, exudative dermatitis that is extremely debilitating and can be fatal. A survey in 1995 suggested that 5% of the national flock could be infested with the sheep scab mite, and current feedback from the industry suggests that the incidence of sheep scab is increasing, with resistance to current pesticide treatments being a key issue. We therefore urgently need to identify safe and effective alternatives to these conventional treatments.

We propose to build on our significant advances made in this proposals' predecessors (Projects ODO539 and ODO546) and complete the assessment of key physiological systems that could identify new targets for controlling sheep scab disease. The factors necessary to achieve and optimise completion of the life cycle off-host will be investigated, with emphasis on larval moulting. Successful off-host rearing of scab mites would provide mites in good condition and in sufficient numbers, permitting rapid screening of large numbers of potential control agents. The knowledge gained from the studies of off-host rearing will be used to refine the bioassay for slow-acting treatments developed during project ODO546. This bioassay will then be used to assess the off-host performance of commercially available formulations of insect growth regulators (compounds that control the life cycle of insects). IGRs can inhibit the development of insects when applied as a control treatment, but typically have low mammalian toxicity and have minimal environmental impact. The physiological process of water regulation as a novel target for control will also be investigated, as will novel, benign and other materials as potential control methods for sheep scab. The identification of an agent that disrupts the physiology or development of the mites but does not harm the host animal or the environment will offer a safer alternative to the conventional toxic compounds currently used.

The proposed work addresses the need of Defra to protect the welfare of sheep and to reduce the risks to consumers and the environment from pharmaceutical products, antimicrobials and other chemicals. The results from this study will represent an essential and major step towards finding suitable and sustainable alternatives to conventional means of control of the sheep scab mite by the development of new control methods to which resistance is less likely.
Objective
01 Investigate factors necessary to achieve and optimise completion of the life cycle off-host, with emphasis on larval moulting
02 Assess the off- and on-host performance of commercially available formulations of insect growth regulators.
03 The physiological process of water regulation as a novel target for control
04 Novel, benign and other materials as potential control methods for sheep scab
Time-Scale and Cost
From: 2007

To: 2010

Cost: £351,133
Contractor / Funded Organisations
Central Science Laboratory
Keywords
Animal Diseases              
Animal Health              
Control              
Plants and Animals              
Sheep              
Sheep Scab              
Fields of Study
Animal Health