The use of an intradermal test (Casoni) for the diagnosis of hydatid disease in livestock.

Abstract

A partially purified hydatid cyst antigen preparation was obtained by the precipitation of lipoproteins which were redissolved and then boiled at 100°C for 15 min to inactivate heat labile components. After the absorption of host components one thermostable protein remained which was shown to correspond to antigen B. Antigen B was used in an intradermal test for hydatid disease in cattle and goats. An attempt to determine the molecular weight was also made. When a 3 mm increase in skin thickness after 30 min was regarded as positive, intradermal tests in cattle gave a specificity of 97% and a sensitivity of 57%. In goats, however, there was a complete overlap in skin reactivity between animals with and those without hydatid disease.