Effects of Psoroptes ovis (Acarina:Psoroptidae) on certain biochemical constituents of cattle serum.

Sera from Psoroptes ovis-infested calves were examined for 17 selected biochemical constituents to determine if P. ovis caused changes in any of these constituents. In order to recognize a scabies effect, there had to be a statistically significant (P less than or equal to 0.10) scabies exposure X time interaction and the changes in the biochemical constituents should have been correlated with the changes in the mite infestation. Five serum biochemical constituents fulfilled these criteria. Total protein, alpha-, beta-, and gamma-globulin were increased and total cholesterol was decreased at the peak of the scabies infestation. Precipitating antibodies to a P. ovis antigen were detected by immunodiffusion in some of the stored sera of the infested calves just after the peak of the infestation. Total protein, beta-, and gamma-globulin values were probably increased as a result of antibody production; alpha-globulin values were probably increased as a result of inflammation. As the scabies infestation declined, the mean values of all the above constituents from the infested calves, except cholesterol, began declining. Decreases in total cholesterol occurred, but they could not be entirely attributed to scabies. Examination of the serum biochemical constituents from a heavily infested calf that died during the test suggested that, in addition to antibody production and inflammation, kidney and liver damage may have occurred.