Effect of heavy metal emission on the immune response of sheep with experimental fasciolosis.

The effect of industrial heavy metal emission on immune reactions was studied in lambs subsequently infected with Fasciola hepatica. The heavy metal emission (Cu, Hg, Pb, Cd, Cr, Zn) was collected from grass at 5 km distance from a mercury plant. Administration of the emission for 28 days prior to infection of the animals reduced the percent circulating T- and B-cell populations when compared with untreated animals and animals infected with F. hepatica only. The administration of emission had no suppressive effects on the levels of circulating antibodies to F. hepatica following infection. The intensity of liver infection with mature F. hepatica in the emission-fed and infected lamb group increased by 21.5%. This difference in comparison with control infected animals was not significant.