PATHOGENETIC FACTORS IN EXPERIMENTAL BOVINE OESOPHAGOSTOMOSIS .3. DEMONSTRATION OF PROTEIN-LOSING ENTEROPATHY WITH 51CR-ALBUMIN

Six calves infected with 10,000 larvae of Oesophagostomum radiatum and three worm-free calves were injected intravenously with 51Cr-albumin during the hypoproteinemic phase of the disease. In 5-7 days after injection the infected calves excreted in the feces a mean of 9.8% of the 51Cr administered, as compared with a mean excretion of 1.6% by the controls. The mean daily fecal loss of 51Cr by the infected animals was equivalent to 972 ml of plasma and that of the controls to 144 ml. The mean apparent half-life of the labeled albumin in the blood of the infected calves was 2.7 days, and 7.0 days in the wormfree animals. The abnormal losses of 51Cr commenced 20-21 days after exposure and continued for at least 5 weeks. Greatest losses of 51Cr occurred in the cecum and colon and were associated with the fifth stage of the parasite's life cycle. More than 60% of the 51Cr in solution in colon contents was protein-bound, and albumin was the predominant protein present, with a specific activity similar to that of circulating albumin. The results indicate that protein-losing enteropathy is a significant factor in the production of the hypoproteinemia of bovine oesophagostomosis. © 1969.