Survey on the presence of Anisakis and Hysterothylacium larvae in fishes and squids caught in Ligurian Sea

This study aims to investigate the occurrence of Anisakidae larvae (genera Anisakis and Hysterothylacium) in fishes and squids used for human nutrition and increase the knowledge of the distribution of Anisakidae larvae in this area of Mediterranean Sea. Distribution and correct identification of Anisakidae larvae in fish species is important for the assessment of their relative epidemiological role; especially when the fishes are of high commercial value and largely used in human nutrition. The study investigated the occurrence of Anisakidae larvae (genera Anisakis and Hysterothylacium) in 195 fishes owing to 22 different species and 60 squids (Illex coindetii) sampled in northern Ligurian Sea. A combination of morphological and PCR-RFLP methods have been used. A total of 177 anisakid larvae were isolated in 42/195 (21.5%) fish of 11 species and only one larva in one squid. These larvae were identified morphologically as belonging to the genera Anisakis (36/177) or Hysterothylacium (142/177). All Anisakis larvae were isolated from Trachurus trachurus and were identified at species level by PCR-RFLP as belonging to Anisakis pegreffii. Hysterothylacium sp. in short, larvae presence occurred in most of examined fish species with a higher density in Mullus barbatus (mean intensity 5.6 larvae) and Serranus scriba (MI 5.3).