Summary
With the deregulation of sheep lice by state government agencies in recent years, a self-driven approach is one option being used by some farmer groups to achieve local lice eradication. Working with these groups can be both challenging and rewarding. The challenges include allowing the group to make its own decisions at its own pace. Working with self-motivated groups can lead to better use of technology but this may be a slow process involving unexpected activities required by the group to develop fully. This paper provides an overview of one group’s initial approach to form a local lice action group and discusses the potential for success.
 
 

Summary
Philosophical position:

The use of chemicals to treat sheep infested with lice is expensive, can be dangerous and if used incorrectly will soon jeopardise access to European markets and very likely the other wool processing countries soon after. To treat sheep that are not infested is all of the above but also a waste of money

Solution:  If there are no lice and lice can be kept out, there is no need for chemicals.
 
 

Summary
The primary means of monitoring for lice is by inspection of sheep, but there has been little consideration of ways to optimise the efficiency of detection by this method. Studies are described that confirm a strong association between pruritic behaviour, fleece derangement and the presence of lice, particularly early in the development of an infestation. These signs are a valuable aid to selecting sheep for closer inspection. The spatial distribution of lice on sheep is discussed and it is concluded that to maximise the probability of detecting lice, inspections should be concentrated on the sides of the sheep at most times of the year. However, if the sheep has been recently shorn attention should also be focussed on sites below the neck, on the lower flanks and upper legs, particularly in areas where longer wool has been left.

Probabilities of detecting lice on individual sheep and in mobs by inspection regimes varying in numbers of sheep and numbers of partings per sheep are estimated for different levels of infestation. These estimates may provide an aid in developing inspection regimes to suit varying management circumstances.
 
 

Summary
It is likely that about 25% of Australian sheep flocks are lousy and up to 80% flocks are chemically treated to ensure that they are protected from lice infestation. It takes several months before any sheep show clinical signs of the infestation and the diagnosis of sub-clinical lice infestation is vital to any lice eradication programs. CSIRO Animal Health (currently CSIRO Livestock Industries), NSW Agriculture and the Woolmark Company have been working since 1996 towards the development of a test to diagnose sub-clinical louse infestations at shearing. CSIRO produced a series of monoclonal antibodies (MAbs) raised against various preparations containing antigens. A laboratory test based on a capture ELISA assay was developed. It was extremely sensitive with negligible background 'noise’, was specific for sheep body lice; used a sample that was easily collected at shearing (which theoretically, was representative of the whole mob) and it could be completed in less than 24 hours. A commercial partner is currently working on the development of a prototype kit – Mark II, utilising new batches of purified antibodies produced by both in vivo and in vitro methods. Australian Wool Innovations Limited (AWIL) has invited the group to submit a second project application to progress the development of the test. The new project has a strong commercial focus.
 
 

Summary
A potential approach to minimise residues from mid-season treatments for lice is to treat only the infested sheep or to remove the lousy sheep from the mob to reduce the spread of lice to other animals. However, inspecting sheep to determine if they have lice is time consuming and generally not a practical option. This study examined the effectiveness of using fleece derangement as a basis for selecting infested sheep for treatment or culling.

Treating or culling sheep with rubbed fleece early in the development of the infestation, before rapid exponential increase in louse numbers, provided the greatest gains. Once the louse population had reached the rapid phase of build up, the delay in population increase from removal of sheep with deranged fleece was short and louse numbers quickly returned to their pre-culling levels. Time between culling or treatment and shearing was also important and the greatest gains were achieved when there was only a small proportion of infested sheep in the mob and a short period of time to shearing. The rate at which the infestation developed significantly influenced the value of the strategies examined and some factors that can affect the rate of spread are noted. Manipulating these factors to slow the rate of increase in louse numbers would improve the effect from partial flock treatments or removal of the infested sheep. This emphasises the importance of taking an integrated approach to louse control.
 
 

Summary
In 1995, Dr George Downing and Sam Walker created a decision support spreadsheet model to assist producers in determining the most cost effective management practice when faced with lice in sheep with greater than four months wool growth.

The program was never validated and in the intervening period a number of significant developments have occurred. New products, product withdrawals and the released for public comment in June of the draft NRA Review of Selected Sheep Ectoparaciticides will have ramifications particularly in the area of OH&S.

Dr Bruce Farquharson (1998) conducted a review of the program and concluded that it had potential but would need a considerable rewrite to be of practical value. He listed a number of desirable changes that are currently being costed with a view to progressing the program to a useable stage.

This paper consists of a precis of Dr Downing’s (1993) paper on "Liceman" and Dr Farquharson’s (1998) review.

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