Third- or early fourth-stage larvae measure anywhere from 17 to 50 millimeters in length, 1 to 2 millimeters in diameter. Characteristic features include large anterior excretory gland cells, a ventriculus between the esophagus and the intestine, three lips, a small anterior boring tooth, prominent Y-shaped lateral chords, and a spinelike structure (a mucron) at the anterior end.

The larvae of Anisakis species tend to be pink and tightly coiled in the flesh of the fish; the larvae of Pseudoterranova tend to be yellow-brown to brown and are loosely coiled.

Larvae isolated from a patient in Spain.... Figure 1: Larvae is 25 mm long, 0.7 mm in diameter. This figure clearly shows the transverse cuticular striations on the lateral side of the larvae. Figure 2: The anterior part of the larvae presents prominent lips. Figure 3: Posterior view of the larvae.

 

 

Transverse section through the body of A. simplex shows a large, Y-shaped lateral chord (LC)

Link to Case Study #3