Objective: To investigate the infection status of Anisakis simplex larvae in marine fishes for sale in Shantou.
Methods: Marine fishes were randomly collected from markets in Shantou City from February to December 2013, and then classified. The viscera and muscle of each fish were carefully dissected and thoroughly examined for anisakids. The larvae were examined under a light microscope. The infection rate and intensity of Anisakis simplex larvae were calculated.
Results: A total of 382 fish specimens belonging to 52 species were examined. 42 out of 52 species (80.8%) were found infected by A. simplex larvae. The overall infection rate reached 47.4% (181/382), and average 5.5 larvae parasitized per infected fish (995/181). The survival rate of larvae was 100%. The highest infection rate observed was 100% in Scomber australasicus (4/4), Trachurus japonicus (9/9), Decapterus maruadsi (8/8), Lutjanus lutjanus (9/9), Argyrosomus argentatus (4/4), Nibea albiflora (4/4), Nemipterus bathybius (12/12), Trachinocephalus myops (7/7) and Mene maculata (9/9), followed by 16/18 in Pneumatophorus japonicus, 6/7 in Lutjanus ophuysenii and 5/6 in Lutjanus fulvus. A. simplex larvae were not detected in 10 fish species, namely, Megalaspis cordyla, Lutjanus argentimaculatus, Lutjanus fulviflamma, Acanthopagrus australis, Acanthopagrus latus, Plectorhinchus nigrus, Dentex tumifrons, Psenopsis anomala, Scatophagus argus, and Seriola lalandi. The infection intensity was the highest in Lutjanus fulvus (21.0 per fish), followed by Trachinocephalus myops (16.7 per fish), Saurida filamentosa (14.0 per fish) and Mene maculate (10.1 per fish). The lowest infection intensity was found in Rastrelliger kanagurta, Kaiwarinus equula, Atule mate, Lutjanus russellii, Plectorhinchus cinctus, Priacanthus tayenus, Branchiostegus argentatus, Branchiostegus albus, Sphyraena pinguis, Formio niger, Trachinotus blochii, Siganus fuscescens and Choerodon azurio (less than 2 per fish). The highest infection rate (34.3%, 131/382) was found in the mesentery. The infection intensity was highest in pyloric appendage (3.5 per fish). A. simplex larvae were not found in muscle. The highest infection rate (60.2%, 74/123) was found in fishes with body weight of 100-200 g. The infection intensity was highest in fish with body weight of 301-400 g (7.8 per fish).
Conclusion: The infection rate of A. simplex larvae is high in marine fishes from Shantou markets.