Experimental Anisakiasis: Cultivation and Temperature Tolerance Determinations1

Abstract

All stages of the anisakine life cycle—egg, larva, and adult—have been used to initiate cultures. Eggs develop to hatching larvae at different temperatures depending on the species or strain. Newly hatched larvae of Phocanema decipiens and Contracaecum osculatum grow to an average 31.1 mm in 52 weeks and 6.5 mm in 32 weeks, respectively. Larvae from fish or those previously cultivated will molt at 35 C in a complex culture medium. P. decipiens and Anisakis marina have produced eggs in vitro. A. marina eggs from cultured females produced viable larvae. Freshness of the larvae used to initiate cultures is considered a major factor in success. The histochemistry of the composition and structure of P. decipiens cuticle in larvae from fish and cultures has been defined; experiments have demonstrated that the processes of cuticular deposition and ecdysis are independent. It has been postulated and evidence provided that a neurosecretory mechanism controls ecdysis; it has also been shown that this system can be stimulated by an insect hormone and a synthetic analog. Larvae in vitro, in fish flesh, and in fried fish fingers, do not survive heating to 60 C for 1 min. The recommended time and temperature found in Japanese and European literature for freezing fish to kill anisakine larvae is −20 C for 24 h; however, some North American species survive after 52 h at this temperature.