Immunodiagnostics of visceral toxocariasis

Twenty five suspected cases of visceral toxocariasis and 25 apparently healthy controls, were tested in four serological tests, namely precipitin absorption test (PAT), counter immunoelectrophoresis (CIEP), indirect fluorescent antibody test (IFAT), and enzyme linked immunosorbent assay (ELISA). Adult Toxocara worm antigen was used in PAT & CIEP as saline extract and as frozen sections (FS) in IFAT while the embryonated eggs (EE) were used as saline extract in ELISA and as a whole in IFAT. The percentages of positivity reported were 44% by PAT, 24% with CIEP, 52% with IFAT (EE), 48% with IFAT (FS), and 52% in the ELISA. In the apparently healthy control group, only one subject gave positive result with PAT, and ELISA at titres of 1/16 and 1/64 respectively. The EE antigen proved to be more sensitive than adult worm antigen, where it was used in IFAT & ELISA and gave the highest percentage of positivity and the highest titre (1/256 & 1/4096 respectively). It was noticed that the children below the age of 10 years, were statistically significant (P less than 0.05) by all tests except CIEP.