Master of Science (MS)


Veterinary Medical Sciences - Pathobiological Sciences

Document Type



The host-parasite interaction during early filarial nematode migration is poorly understood. The objective of this study was to develop a model of early cutaneous filarid migration using Brugia pahangi in the jird (gerbil) host and measure the histologic and cytokine responses during this period. Male gerbils were intradermally inoculated in the left hindlimb with 100 B. pahangi L3 then necropsied at 3 hours, 24 hours, 3 days, 7 days, and 28 days post-infection. Larvae were recovered and tissues collected for histology and cytokine measurement. At 3 hours, most larvae (96.3%) were recovered from tissues associated with the infection site. Migration away from the infection site occurred within 24 hours. By 7 days, larvae were dispersed throughout the lymphatic system, including the spermatic cord lymphatics. Larvae were identified on histologic exam at all time points and were located in the dermis, muscle, lymphatic vessels, and lymph nodes. Predominantly neutrophilic inflammation was frequently present around larvae in the dermis and muscle at 3 and 24 hours. Levels of the cytokines IL-6, TNF, IFN-gamma, and IL-4 were measured in the spleen and popliteal and renal lymph nodes. IL-6 and TNF both showed a peak at 3 hours followed by consistent decline in all tissues. No clear increase in expression was appreciated for IFN-gamma. IL-4 remained low through 7 days and rose by 28 days in all tissues. These results indicate the ability of filarid L3 to rapidly migrate through host tissue and they support intradermal gerbil infection as a model for early filariasis. Cytokine analysis and histology indicated an acute host inflammatory response following initial infection, with Th2 polarization occurring later in the course of infection.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Thomas R. Klei