1Hanan Helmy, 2Mona Abdel Fatah, 2Magda Azab and 1Reda M. R. Ramzy
1Research & Training Center on Vectors of Diseases, Ain Shams University, 2Parasitology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
Clinical diagnosis of human cystic echinococcosis is currently achieved by imaging techniques supported by immunological assays. However, as yet, there is no widely accepted serological method of choice. The present study aimed to compare the useful utility of two antibody detection ELISA systems, the IgG1 and the NOVUM systems, for diagnosis of human hydatidosis. Sera collected from 35 surgically or clinically confirmed human cystic echinococcosis and from 30 healthy subjects, as negative controls, were tested by both ELISA methods. Of the 35 hydatidosis cases, 33 cases (94.3%) and 17 cases (48.6%) were ELISA positive by the IgG1 and the NOVUM systems, respectively. The difference between the sensitivity of the two systems in detecting the infection was significant (X2 = 14.16, p < 0.01). An arbitrary positive/negative cutoff value of 5 NOVUM units was calculated based on a panel of local negative controls. Such cutoff value increased the NOVUM sensitivity to 88.6%. All sera from the healthy subjects, known to be free from parasitic infections, were uniformly negative in both tests. We conclude that the IgG1 system is more sensitive and much cheaper than the commercial NOVUM system for primary serological diagnosis and for support of clinical diagnosis.