Dr Tony Downs, a Bristol-based dermatologist, has found schools where nearly half the children have lice. Parents are spending millions on lotions which often do not work. The Government has no clear strategy, and health authorities offer conflicting advice; for poorly funded and busy health professionals, lice, not being life-threatening, are a low priority. This is good news for the louse.
Head lice are mistakenly associated with poverty and dirt, so some people feel shamed by infestation. However, hair type or cleanliness do not seem to be factors; the louse is an equal-opportunity parasite and finds the blood of children from the wealthiest families as tasty as blood from those from the poorest.
In making my documentary on lice, I was surprised not only by how widespread lice were - hundreds of thousands of children must be affected - but also by how little information there is. Scientists are not even certain how they infect us.
The lack of research has created a vacuum which can be filled with all sorts of myths. Most parents believe children get head lice at school, though even this view is contested by at least one expert. As a young researcher, Dr John Maunder, a medical entomologist based in Cambridge, was told to work on lice as a punishment after upsetting a professor. But he found he like lice and has worked with them ever since. Dr Maunder believes they are not caught at school but come from "asymptomatic" adults. These are adults who are not even aware they have lice, yet will pass them to anyone who gets close enough.
One of the biggest worries about lice concerns chemicals in treatment lotions. Most experts believe these chemicals are safe so long as they are not used more than a few times a year; but doctors should be consulted before pregnant women and babies use them.
A major problem is that lice are becoming resistant to chemicals, leading to overuse of the treatments. When a lotion fails, one might, quite reasonably, try another product. However, many chemicals may have different names and make-up, but they are based on the same active ingredient. For example, Prioderm, Suleo M and Derbac M all contain the organo-phosphate malathion. If the louse is resistant to one, it is likely it will be resistant to the others.
Even if a lotion does kill adult lice, any eggs they have laid may live on to begin a new cycle. So one needs to do a second treatment about 10 days after the first to kill the lice that hatch before they too lay eggs.
One alternative to using chemicals is the wet-combing method, sometimes called "bug busting". It involves physically removing the lice from hair that has been soaked in conditioner. This scheme is based on understanding the life cycle of the head louse. If the first combing of the wet hair is done thoroughly, it will remove the adult lice but not the eggs, which are stuck fast to the hair. A strict regime of combing-out, every three or four days for two weeks, should remove the lice that hatch before they manage to reproduce.
There are also homoeopathic remedies, such as tea tree oil. In the US, olive oil is said to suffocate lice by blocking their breathing holes. Some people have found hair gel discourages the beasts, but there is really no quick fix. It seems that the best thing to do is to check a child's hair at least once a week by combing with the fine-tooth head-louse comb.
If you find lice, try a little detective work to find out where they came from - and be responsible: tell friends and relatives. If everyone did, it would help stop lice spreading.
`Facts of Lice', produced and directed by Maurice Melzak, is on Carlton tomorrow at 7.30pmReuse content