Tissue migration capability of larval and adult Brugia pahangi

Infection with mosquito-born filarial nematodes occurs when hosts are bitten by a vector carrying the infective third stage larvae (L3) of the parasites. These larvae, deposited on the skin by the feeding mosquito, are presumed to enter the skin via the vector-induced puncture wound. Larvae of Brugia spp. must then migrate from the entry site, penetrate various skin layers, and locate a lymphatic vessel that leads to their lymphatic predilection site. We have recently established an intradermal (ID) infection model using B. pahangi and the Mongolian gerbil, allowing us to investigate the migratory capability ofB. pahangi. Larval and adult parasites recovered from the peritoneal cavities of gerbils were capable of establishing an infection following ID (larvae) or subcutaneous (adult) injection. Third and fourth stage larvae both migrated away from the injection site within hours, although data suggest they localize to different lymphatic tissues at 3 days postinfection (DPI). Immature adult (28 day) B. pahangi also migrated away from their SC inoculation site within 7 DPI. Mature (45 day) adult B. pahangi displayed little migration away from the SC infection site, suggesting tissue migration may be limited to developing stages of the parasite.