The Body Louse, Pediculus humanus humanus (Phthiraptera: Pediculidae), Genome Project: Past, Present, and Opportunities for the Future

Abstract

The human body louse, Pediculus humanus humanus (L.) and the human head louse, P. humanus capitis, belong to the hemimetabolous order Phthiraptera. The body louse is the primary vector that transmits the bacterial agents of louse-borne relapsing fever, trench fever, and epidemic typhus. The genomes of the bacterial causative agents of several of these aforementioned diseases have been sequenced. Thus, determining the body louse genome will enhance studies of host-vector-pathogen interactions. Although not important as a major disease vector, head lice are of major social concern. Resistance has developed to traditional pesticides used to control head and body lice. It is imperative that new molecular targets be discovered for the development of novel compounds to control these insects. No complete genome sequence yet exists for a hemimetabolous insect species. In large part, this is because hemimetabolous insects often have large (2,000 MB) to very large (up to 16,300 MB) genomes. Fortuitously, we determined that the human body louse has one of the smallest genome sizes known in the insect world, making it a suitable choice as a minimal hemimetabolous genome in which many genes have been eliminated during its adaptation to human parasitism. Since many lice species infest birds and mammals, the body louse genome-sequencing project will facilitate studies of their comparative genomics. Recently, the body louse genome has been sequenced and the Body Louse Genome Consortium (BLGC) is currently annotating the genome. Questions that will be addressed by the BLGC are outlined in the following article. We also raise possible future directions for research on body lice.