EFFECT OF EMISSIONS FROM A MERCURY TREATING METALLURGICAL WORKS ON THE INTENSITY OF EXPERIMENTAL FASCIOLA-HEPATICA INFECTION IN SHEEP

A group of 14 improved Valashka lambs, aged 4 months, body weight 14-1 6 kg, were used in the experiment studying the effect of subchronic he avy metal intoxication on the course of experimental fasciolosis (Fasc iola hepatica). The animals were divided into two groups, each of 7 la mbs, 3 lambs - ewes and 4 lambs - rams. Each animal in group I was giv en orally for 27 days gelatinous capsules containing heavy metal emiss ions of the following composition: 4.5 mg Hg, 2.9 mg Pb, 147.8 mg Cu, 9.8 mg Zn, 0.9 mg Cr and 0.04 mg Cd per animal and day-Group II served as control. On bay 27, when the administration of heavy metals ceased , each animal in both groups received 250 F. hepatica metacercariae. T he animals were sacrificed on Day 110 post infection, their liver necr opsied and parenchymatous organs and muscles taken to examine the cont ent of heavy metals. The heavy metal concentrations are presented in T ab. I. In the emission-intoxicated group, the maximum permissible refe rence level of mercury in the kidneys, liver and muscles was exceeded on the average by 1.94, 0.87 and 0.020 mg Hg/kg, respectively. Cu exce eded the reference level only in the liver, with 261.3 mg Cu/kg. In th e kidneys and mucsles, Cu was below the reference levels. An analogous situation was with Zn, Cr and Cd. The F. hepatica infection mean inte nsity in this animal group was 38.3 +/- 3.01 specimens (min. 34 - max. 46 specimens). In control group, the heavy metal levels were several times lower than the reference values and the infection mean intensity was 27 +/- 5.4 (min. 19 - max. 35 specimens). In subchronically intox icated animals, the reference values for mercury were exceeded and so were partially those of copper in the parenchymatous organs and muscle s. The F. hepatica infection mean intensity also increased, compared w ith control. The results have proved the negative effect of the metal emissions on the animal immune system, which was manifested by the inc reased infection intensity.