International Congress on Phthiraptera (Lice) Australia, July 2002

The first International Congress was held 30 years ago, so ICP2, attended by delegates from some 20 countries, was a major event. Dr Stephen Barker, University of Queensland, was warmly congratulated for organising the Congress. In his opening remarks he commented on the change of emphasis that had occurred in the interim, moving from louse-borne diseases to solving the rising head louse problem. Delegates from countries as far apart as Israel, Argentina and Japan made presentations demonstrating the universal failure of the insecticides in current use. Dr Nigel Hill from the London School of Hygiene & Tropical Medicine showed that a number of factors determining the speed of resistance development can be controlled. He proposed that bodies such as the UK Medicines Control Agency should regulate, from their introduction, the supply and presentation of novel compounds, learning from past mistakes. To this end he argued for limiting all insecticide medication for head lice to prescription only (POM).

The Cochrane Review (2001) of interventions for treating head lice was severely criticised by the Belgian delegate, Dr Hilde Lapeere, who described it as biased. Ian Burgess (Cambridge, UK) responded on behalf of the author, Ciara Dodd, saying that she originally concluded that all available work on head louse treatment was sub-standard, but fulfilled the Cochrane assignment to produce a review inspite of her personal opinion.

Evidence was presented showing the value of the bug busting approach for detection and cure. This mechanical method, developed by the health charity, Community Hygiene Concern (CHC), has been imported from the UK to Belgium and Denmark. The need to apply the precise protocol of wet combing using the correct combs, provided in the Bug Buster Kit, was highlighted. Joanna Ibarra (CHC) presented findings that the tight tooth spacing of metal nit combs is a disadvantage for louse detection, as lice caught between the teeth remain unnoticed against the metal and are combed back into the hair at subsequent strokes.

Dr Caroline Priestley, from the School of Pharmacy, London, UK, has been testing botanical pesticides on rabbit-adapted body lice and spoke of their potential. This was received with great interest by pharmaceutical company respresentatives. However, several delegates made the point that ‘natural’ origin does not necessarily equal low human toxicity. In addition, it was pointed out that unless the botanical product was cultivated organically, test results could be affected by residues of pesticides used during horticulture. In the case of some botanical compounds already in widespread use, lice in the field could already be developing resistance to them. Experimental evidence of the pesticidal efficacy of botanical products against natural populations of head lice and their eggs was not presented to the Congress, but the repellent properties attributed to some was questioned.

Joanna Ibarra and Clarice Wickenden, Community Hygiene Concern delegates to ICP2