HAMSTERS COINFECTED WITH LEISHMANIA DONOVANI AND BRUGIA MALAYI: HOST RESPONSES

摘要

Coendemieity of more than one parasitic disease in tropical countries is posing a serious challenge in developing control and treatment strategies since one infection may not only alter the host's response to another infection but also to preventive/therapeutic agents. Experimental findings revealed that helminth infection could modify the outcome of protozoal infection (Schmidt and Esslinger, 1981, Yan et al. 1997, Nacher et al, 2002, Spiegel et al. 2003). However, there is no report of influence of human filarial infection on the visceral leishmaniasis -a fatal disease. The study was therefore, aimed at investigating whether Brugia malayi, a human lymphatic filarial infection could modulate course of Leishmania donovani infection in rodent host. Healthy male inbred hamsters were infected with filarial life stages (microfilariae, infective larvae and adult worms) before or after inoculation with amastigote intracardially. The leishmania parasite burdens were determined on days 17-19 post amastigotechallenge (p.a.c). For filarial parasite burden the animals were sacrificed on day 90-100-post larval inoculation. The inhibition of amastigote multiplication in animals receiving L_3 before or after leishmanial infection observed was more than 90% and 60%, respectively, as compared to animals receiving leishmanial infection only. Animals receiving mf or adult worms also affected the leishmanial growth. Further, some strong cross-reactive molecules were identified in both filarial and leishmanial parasites. Thus, the findings of the present study indicate that life stages of the filarial parasite are capable of inhibiting the development of leishmanial infection.