To search for hyper-variable genetic markers that can distinguish regional populations of head lice, we screened the inter simple sequence repeats (ISSR) based on the genome database of body louse, which is closely related conspecific species. An ISSR mining software, SciRoKo 3.4, was employed to excavate ISSR markers from the genome database under the MISA mode (≥ 60 bp repeats). Entire body louse genome (ca.100 Mb) was loaded to SciRoKo for ISSRs mining. A total of 5,336 ISSRs were obtained, and primers specific to individual ISSRs were designed by the Primer 3 and DesignPrimer 1.0 softwares. In order to prove the compatibility of body louse ISSRs to head lice, 31 PCR primers were randomly chosen out of a total of 613 pairs, and their appropriateness was tested by comparing the amplified PCR band patterns between body and head lice. Eleven primer pairs that resulted in poor or little amplification were excluded, and 20 primer pairs were further tested for three head louse populations (California, Panama and Chung-ju, Korea). Finally, nine primer pairs ensuring robust amplification of highly variable band patterns were selected to use for population genetic study of head lice.

Body lice (Pediculus humanus humanus), obligatory human ectopasites, differ from conspecific head lice (Pediculus humanus capitas) in the choice of habitat and the capacity of disease transmission. Only body lice are known to naturally transmit a variety of human diseases, including epidemic typhus, trench fever and relapsing fever. Such differences in vectoral capacity are expected to be due to their differences in immune responses during pathogen invasion. Here, we annotated 94 immune related genes from the body louse genome and determined the differences in the transcription profiling of immune related genes between the head and body lice by qrt-PCR. In general, head louse females showed more sensitive immune responses than body louse females to Staphylococcu. aureus dermal challenge as judged by selective induction of defensin 2 in head lice. In contrast, when the 3rd nymphs were orally challenged, body lice exhibited more sensitive immune responses than head louse to Escherichia coli as judged by selective induction of defensin 1 and PGRP in body lice. These stage- and pathogen-specific differences in immune responses should provide basic insight on the vector competencies in the head and body lice.