[Persistency of serum antibodies against Entamoeba histolytica]

With the purpose to determine the duration of serum antibodies against E. histolytica by means of the contraimmunoelectrophoresis technique, 31 patients with the diagnosis of intestinal or liver invasive amebiasis were included in this study. In 92.3% of the 13 patients subjected to transversal study, no specific antibodies were found from 10 to 24 months after the occurrence of amebic disease. In 64.7% of 17 children with liver amebiasis who were studied longitudinally, no serum antibodies were found between 4 to 10 months after the disease. The possible factors involved in the varaibility of the duration of serum antibodies against E. histolytica are discussed.