Toxocara canis: determination of the origin of antigenic materials released from infective larvae.

Indirect fluorescent antibody test (IFAT) revealed antigenic focal areas in the brain tissues of mice infected by Toxocara canis as determined by the light, electron and fluorescent microscopic examination of the infective larvae. The oesophageal gland was well defined and its secretory activity was evident. The oral orifice and the lumen of oesophagus were strongly fluorescing by using anti ES serum. These indicate the antigenic property of oesophageal gland secretion. Intestine appeared to be non-functional. There was a well-developed "H" shaped excretory cell with two lateral excretory columns. The sharing of the excretory system in released antigenic materials was evident by the fluorescence of its pore onto the parasite surface. An electron dense coat that covered the surface of the larva may be formed by products released from the oesophageal gland and the excretory system. Shedding of the outer larval surface was detected by IFAT at 37 degrees C.