Organic Strategies for Head Lice Control
Scientific Name: Pediculus humanus capi
Appearance
The six-legged, wingless adult head louse is 1.5 mm to 3 mm long and ranges from tan to greyish-white in colour. Each of its six legs ends in a claw, which it uses to grasp the hair shaft.
Life Cycle
The eggs, or nits, of the louse are laid on the hair close to the scalp, around the ears and on the nape of the neck. The egg is coated with a glue-like substance that cements it to the hair. Most eggs are laid at night. Each female louse lives about 10 days and lays 50 to 300 eggs. Left undisturbed the eggs hatch in 7 to 11 days, nymphal lice emerge from the eggs, feed on human blood, mature to adults within 9 days, mate and repeat the cycle. Adults live for 9 to 10 days, making an approximate lifespan of at least 24 days.
Spread
Head lice cannot jump or fly but can move fairly rapidly. Most head lice are transmitted when an infested person comes into direct contact with another. For example, when children sit or sleep together. They can also be transferred via infested brushes, combs, hats, coats, bedding, towels and furniture. In the right temperature conditions, adult lice and eggs can live for days away from a host.
Damage
The louse bite itself is painless, but the saliva usually causes an allergic reaction that produces itching.
Control Strategies
Education
Keep in mind that head lice are just an insect that will infect children regardless of the parent's lifestyle or standard of hygiene. The biggest problem for parents achieving control is constant re-infection. This is a community issue that could be dealt with by better education of parents and children in the same way as first aid programs.
Heat
Head lice are very sensitive to heat; hair dryers may be effective in reducing lice numbers. Use water as hot as is tolerable to wash hair, but remember that the scalps of young children are very sensitive. Place bedding or hats in a clothes dryer for 30 minutes at the highest setting to kill lice and eggs.
Combing
Eggs are difficult to remove, due to the strong glue. Vinegar is sometimes recommended but doesn't seem to work. Combing is important to remove eggs that may not all be killed by pyrethrin-based shampoos. Shampoo the hair, rinse with hot water, shampoo a second time. Wrap unrinsed hair in a towel for 15-20 minutes. Comb the hair with a large-toothed comb to remove tangles, then comb with a special nit comb. Check all members of the family if one is infected.
Washing
Wash all clothing or bedding which has been in contact with the child at the same time as the initial treatment. Immerse clothing and bedding in hot water 60°C for 10 minutes.
Soap Shampoo
There is strong evidence that certain fatty acids, found in coconut or olive oil, are effective insecticides. Use soaps made from these oils regularly as shampoos for young children (detergents do not contain fatty acids). The soap will kill all stages of lice except for the egg. Shampooing once a week for 4 weeks should kill any newly hatched young lice. Re-infestation though, can occur at any time; so regular combing is a good idea.
Head Lice Treatments
In the past highly toxic products such as lindane, an organochlorine, were used as lice treatments. Lindane is absorbed through the skin, affects kidney function and accumulates in fatty tissue. The pyrethrins and permethrin (a synthetic pyrethroid) are safer and more effective than lindane. Commercial shampoos containing neem oil or tea-tree oil are available from some chemists. Do not use insecticides as a preventative. Repeated use of lice treatments will lead to resistance developing in the insect and the treatment becoming ineffective.
Study Reveals Pesticides Raise Child Risk of Leukaemia UK: January 17, 2006
London - Exposure to pesticides in the womb or as a child can double the risk of developing acute leukaemia, French scientists said on Tuesday. They discovered that children born to women who used insecticides in the home while pregnant and after the birth were nearly twice as likely as other youngsters to develop leukaemia. Even insecticidal shampoos to kill head lice raised the odds of the disease. "The results ... support the hypothesis that various types of insecticide exposure may be a risk factor for childhood acute leukaemia," said Dr Florence Menegaux, of the research institute INSERM Villejuif, France, in a report in the journal Occupational and Environmental Medicine. The researchers discovered the link after interviewing the mothers of 280 children who had been diagnosed with leukaemia and of 288 healthy children. They found that youngsters exposed to fungicides and garden insecticides had more than double the risk of the illness than other children.