Toxocara skin sensitivity tests and other observations in animals experimentally infected with Toxocara canis

Abstract

Ten white mice and 3 rhesus monkeys were used to demonstrate the specificity of Toxocara skin sensitivity tests in the presence of infection with Toxocara canis. Four of the mice used as controls, were either infected and tested with normal saline or uninfected and tested with antigen; 1 of the monkeys remained uninfected but was tested with antigen. Injection of saline was used as a control with the monkeys. Negative skin reactions were obtained in all animals before infection with eggs of T. canis, but positive reactions occurred after variable periods in the infected animals, but not in the controls. The time of conversion of the skin test did not appear to depend on dosage. The intradermal test with Toxocara antigen is probably specific for infection with T. canis is a valuable diagnostic test The total white cell counts and eosinophil levels were recorded at intervals in the monkeys. An increase in both was noted reaching a peak the 3rd post-infection wk and subsequently declining. No changes were observed in the total plasma proteins or in the albumin/globulin ratio. Inconclusive results were obtained with the filarial complement fixation test performed on the sera of the infected monkeys.