The Pathogenesis of Trichostrongyloid Parasites. III. Some Physiological Observations in Lambs Suffering from Acute Parasitic Gastroenteritis

Abstract

Peripheral blood patterns, plasma iron components, plasma copper, and iron and copper stores of the liver were studied in 11 lambs suffering from mixed gastrointestinal parasitism as the result of infection by species of the family Trichostrongylidae. Where the pathogenic effects of Haemonchus contortus predominated, a severe anemia complicated by iron deficiency was noted. In all cases the liver iron stores were reduced, but only in lambs with iron stores of from 0.7 to 2.5 mg/100 g of fresh liver accompanied by marked anemia were plasma iron levels reduced. Dietary supplementation of FeSO4 did not significantly increase the liver iron stores even though all of the Haemonchus contortus parasites had been removed. It is concluded that this phenomenon was due either to interference with intestinal absorption or to the blood-sucking propensity of species of the genera Ostertagia and Trichostrongylus. It was estimated that Haemonchus contortus, and possibly other genera, removed 140 ml, or 12 to 14%, of the blood of one particular lamb each day. No changes in plasma or liver copper levels attributable to the nematodes were detected. The peripheral blood patterns of markedly anemic animals were commensurate with that of hemorrhagic anemia with superimposed iron deficiency.