Anisakid and Raphidascaridid parasites in Trachurus trachurus: infection drivers and possible effects on the host’s condition

Abstract

This study investigated the distribution of nematode larvae of Anisakidae and Raphidascarididae (genera Anisakis and Hysterothylacium) in Trachurus trachurus (Linnaeus, 1758) in the Ligurian and central-northern Tyrrhenian Seas. The relationship between the number of parasites and the length and weight parameters of the fish was assessed, and the possible effect of the parasites on the condition factor was evaluated. A total of 190 T. trachurus specimens were collected in July 2019. Parasites were found in 70 individuals. A total of 161 visible larvae were collected in the viscera. Morphological analysis revealed the presence of Anisakis spp. in 55 fish and Hysterothylacium spp. in 15 fish, while 5 fish showed coinfection with both genera. The specimens subjected to PCR (n = 67) showed that 85% of the Anisakis larvae analyzed belonged to the species A. pegreffii, while the remaining 15% belonged to hybrids of A. pegreffii-A. simplex (s.s.). A total of 58% (n = 7) of the Hysterothylacium larvae analyzed belonged to the species H. fabri, while 42% belonged to the species H. aduncum. Our results support the hypothesis that infection with these parasites does not affect the condition of the fish host analyzed, and that body size and depth are major drivers in determining infection levels with Anisakid and Raphidascaridid nematodes.

Effect of Anisakis pegreffii (Nematoda: Anisakidae) on Biochemical and Haematological Characteristics of Chub Mackerel (Scomber japonicus Houttuyn, 1782) Caught in the Dardanelles at Çanakkale, Türkiye

“…The third-stage A. pegreffii larvae (L3) are infective to fish and cephalopods and are commonly found in the viscera and the musculature of these host species. Consuming infected animals raw or undercooked causes a disease called Anisakiasis in humans (Macchioni et al, 2021;Mattiucci et al, 2008;Mattiucci & D'Amelio, 2014;Mladineo & Poljak, 2014;Sakanari & McKerrow, 1989).…”

Review of the parasitic nematodes of marine fishes from off the American continent

“…Genetic markers used for raphidascaridids are the most diverse, followed by those used for cucullanids and anisakids (see Supplementary Material 2 for details). Raphidascaridid and anisakid larval forms are commonly found in marine fish and, in addition to their zoonotic potential (Mattiucci et al, 2014;Macchioni et al, 2021), specific diagnosis based upon larval morphology is almost impossible (Moravec, 1994(Moravec, , 1998, facts that can boost the genetic characterization of these parasites and, increasingly, the search for new markers. Cucullanids and philometrids currently are the most specious taxa of nematode parasites in marine fish from the Americas (see Fig.…”