Contamination of soil with helminth parasite eggs in Nepal.

Contamination of soil with helminth eggs in Kathmandu Valley (n=122) and outside of Valley (n=34) in Nepal was investigated with the use of centrifugal floatation technique using sucrose solution (sp gr 1.200). The overall soil contamination rate was 36.5% (57/156). The prevalence was uniform in Kathmandu Valley (36.9%) and outside of the valley (35.3%). A mean of six helminth eggs per sample were detected out of which more than half were embryonated (potentially infective). In Kathmandu Valley, soil contamination rate was higher (48.3%) during wet season compared with that observed in dry season (33.3%) but without significant difference (p>0.05). Multiple species of helminth eggs were detected in 22.8% of total positive samples (n=57). Altogether five species of nematoda (Ascaris lumbricoides, Toxocarta sp, Trichuris trichiura, Capillaria sp and Trichostrongylus sp) and two species of cestoda (Hymenolepis nana and H. diminuta) were recovered. A. lumbricoides was predominant in Kathmandu Valley while Trichostrongylus was the commonest one in outside of valley.