Diagnosis of human hydatid disease in surgically-confirmed cases by the use of the indirect haemagglutination test based on a thermo-stable lipoprotein and on unfractionated hydatid cyst fluid.

A total of 204 sera, taken from healthy individuals or from individuals with various parasitic and bacterial infections, were examined by the indirect haemagglutination test. The tests were carried out using either a thermo-stable lipoprotein or unfractionated hydatid cyst fluid, and a titre of 1:64 or above was considered positive. Sixty-two of 70 sera from individuals with surgically-confirmed hydatid disease showed positive reactions with the thermo-stable lipoprotein--a sensitivity of 88%. No false positive reactions were obtained with sera from healthy individuals or from individuals with parasitic or bacterial infections, and no cross-reactions were observed with sera from individuals with multiple myeloma. The lipoprotein antigen thus showed a specificity of 100%. A sensitivity of 88% was obtained with the indirect haemagglutination test using whole hydatid cyst fluid; but positive reactions were obtained from healthy individuals and from individuals with schistosomiasis, leishmaniasis, taeniasis and malaria. No cross-reactions were obtained with sera from patients with gonorrhoea, syphilis or multiple myeloma. Because of the high sensitivity and specificity shown by the thermo-stable lipoprotein ('Antigen 880'), it is considered that this antigen is more useful than unfractionated hydatid cyst fluid in the diagnosis of human hydatidosis in Kenya.