Breeding quirks of head lice offer insight into effective treatments
New insights into the unusual way in which lice reproduce could be key to managing outbreaks of the common pest.
The findings could inform new ways to target lice, by exploiting how genes that help the insects resist treatment are transferred through generations.
When the insects mate, the males pass on only DNA from their mothers to their offspring, instead of a mixture of DNA from both parents as happens in most species, scientists were surprised to find.
The discovery could aid development of new remedies targeting reproduction in both types of lice that infect humans – head lice and body lice.
For example, chemicals that affect the fertility of male insects could limit the extent to which treatment-resistant genes are inherited.
Head lice, although relatively harmless, are widespread throughout societies around the world. Body lice, common in homeless or refugee populations, can spread severe diseases and present a serious risk to human health. Both types incur a heavy economic burden.
Many conventional chemical-based therapies that kill lice outright have become ineffective as lice have evolved to resist treatment.
Researchers at the University of Edinburgh studied breeding experiments to show how genes are passed from parents to their offspring in head and body lice, and found that males passed on only those genes that they had inherited from their mothers. Surprisingly, this had never been observed in head lice, despite decades of extensive research on this widespread pest.
The study, published in the Medical and Veterinary Entomology Journal, was carried out with the University of Massachusetts Amherst. It was funded by the National Evolutionary Synthesis Centre, National Environment Research Council and the Darwin Trust.
These findings potentially offer a new approach to managing lice, by exploiting the unusual genetics involved when offspring inherit traits from their parents.
The unusual reproductive system of head and body lice (Pediculus humanus), Medical and Veterinary Entomology