Human body louse genome reveals details of vector-transmitted disease

The less than lovable human body louse got a boost this summer with the unveiling of its full genome. Pediculus humanus humanus, a human bacteria-transmitting body parasite is a close cousin to the human head louse, living north on our craniums, Pediculus humanus capitis. The body louse genome was published in late June in the Proceedings of the National Academy of Sciences (PNAS).

Also published in the paper is the genome of a bacterium inside the human body louse, Candidatus Riesia pediculicola. Though the louse receives its dietary essentials from human blood, it lacks an important gene for production of vitamin B5. This is where the Riesia bacterium plays a role by encoding the genes needed to make the vitamin.

This project was completed by an international collaboration involving more than 70 researchers.

The human body louse transmits disease pathogens after it infects the clothing of its victims and dines on their blood. Researchers in this analysis sought to understand the body louse genome more fully for purposes of learning more about parasite/host interactions, bacterial transmission, and evolutionary development of disease-causing parasites.

This type of research on microbes, parasites, and insect genomes plays a large role in the laboratories at the Broad Institute as well. Deciphering the genomes and biological mechanisms of these organisms lends vital information to disease regulation and prevention in humans. 

The Broad hosts (no pun intended) a specialized Microbial and Insect Vectors Genomes research group within the Genomes Biology Platform. Scientists in the Broad community are sequencing and analyzing the genomes of a wide range of insects and microorganisms to understand their genetic regulation, population variation, and specialized genomic mechanisms.

In particular, the Broad Institute Genomic Sequencing Center for Infectious Diseases (GSCID), was established by the National Institute of Allergy and Infectious Diseases (NIAID) to transform biodefense and infectious disease research by creating resources for DNA sequencing, genotyping and comparative genome analysis. The Broad GSCID offers high-throughput genomic technologies suitable for sequencing many hundreds of pathogens, including bacteria, viruses, and fungi, as well as parasites and insect vectors of disease. 

And the Broad’s Infectious Disease initiative currently works on malaria, another vector-borne disease transmitted by the bite of a mosquito infected with one of several Plasmodium parasites.  Here, malaria research employs comparative genome analysis, population genetics of pathogen populations and chemical screening to identify ways to block the malaria life cycle.