Pathogenic Potential of Two Sibling Species,Anisakis simplex(s.s.) andAnisakis pegreffii(Nematoda: Anisakidae):In VitroandIn VivoStudies

Abstract

The pathogenic potentials of two sibling nematodesAnisakis simplexsensu stricto (s.s.) andA. pegreffiiwere compared byin vitroandin vivostudies. Live third-stage larvae of each species were subjected to agar blocks made using PBS or RPMI-1640, overlaid with different supernatants (artificial gastric juice, PBS, and RPMI-1640), and their penetration ability was compared. Their tolerance of artificial gastric juice was also tested. Further, they were introduced into rats by gastric intubation, and thein vivolocations of them were investigated.A. pegreffiishowed higher penetration ability thanA. simplex(s.s.) in most of the experimental conditions, except for the RPMI-1640 agar block overlaid with artificial gastric juice. In an acid tolerance test, the mean survival times were 6.1 days forA. simplex(s.s.) and 4.2 days forA. pegreffii. In an animal experiment,A. simplex(s.s.) stayed for a shorter time in the stomachs of rats thanA. pegreffii. SomeA. pegreffiiandA. simplex(s.s.) were embedded in the gastric mucosa or freely existed in the abdominal cavity. All of these results suggest thatA. pegreffiihas the pathogenic potential to cause anisakidosis in humans when ingested, as doesA. simplex(s.s.).