Ultrastructural studies of larval and juvenile Austramphilina elongata (Platyhelminthes, Amphilinidea); penetration into, and early development in the intermediate host, Cherax destructor

• Published in: International journal for parasitology Vol. 19; no. 5; pp. 529 - 538
• Main Authors: Rohde, K., Watson, N.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.1989; Elsevier Science
• Subjects: Amphilinidea; Austramphilina elongata; Biological and medical sciences; Cestodaria; development; Fundamental and applied biological sciences. Psychology; Invertebrates; Life cycle. Embryology. Development; Nemathelminthia. Plathelmintha; penetration; Physiology. Development; Platyhelminthes; sense receptors; ultrastructure; Amphilinidea; development; sense receptors; Platyhelminthes; Austramphilina elongata; penetration; Cestodaria; ultrastructure; Scanning electron microscopy; Host parasite relation; Plathelmintha; Parasite; Macrura; Cherax destructor; Crustacea; Transmission electron microscopy; Penetration; Larva; Ultrastructure; Arthropoda; Morphology; Helmintha; Development; Intermediate host; Decapoda; Invertebrata
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/0020-7519(89)90083-0

Scanning and transmission electron microscopy were used to study penetration of larval Austramphilina elongata into and development in the intermediate host, freshwater crayfish. Larvae attach their anterior and posterior ends to the cuticle of crayfish. During penetration, the blades of the two serrate hooks on each side of the body are close to each other, between those of the two halberd-shaped hooks of the same side of the body. The blades of the median hooks are close to the midline, ventral to one pair of halberd-shaped hooks. The larva penetrates through the ruptured cuticle, leaving the epidermis behind. All or most sense receptors except the subtegumental ones are probably lost. Type I secretion was found in the host around the larvae, high levels of type I, II and III secretion were still present in the glands of the juvenile even 8 days after penetration. Some juveniles are already encapsulated by host tissue 24 h after penetration, such juveniles have a much thinner tegument than younger, not encapsulated juveniles. The tegument rapidly grows in thickness and develops numerous surface folds. Parts of juveniles of various ages may be without surface tegument, lined by the basal lamina, possibly indicating reversible or irreversible damage by the host. In juveniles 8 weeks after infection, clusters of a type of receptor not present in infective larvae were found: non-ciliate, with an electron-dense collar and numerous microtubules.