Comparison of anisakid infection levels between two species of Atlantic mackerel (<em>Scomber colias</em> and <em >S. scombrus</em>) off the Atlantic Portuguese coast

Abstract

Summary:Anisakiasis is a problematic zoonotic infection associated with the consumption of raw or undercooked fish. Atlantic mackerel (Scomber colias) is of high commercial interest in Portugal and has been reported as a common host of Anisakis spp. In this study, the occurrence of anisakids is evaluated in S. colias and also Scomber scombrus, and the potential zoonotic risk associated with consumption of these two fishes is evaluated according to the recorded infection levels. These were found to be high for both fish species: a mean intensity and prevalence of 21.7 worms/fish and 85% for S. colias, and 16.4 worms/fish and 83.3% for S. scombrus, respectively. No correlation was detected between anisakid intensity and host total length, total weight, condition factor, and hepatosomatic and gonadosomatic indices for both fish species, but significantly higher intensity values were detected for more mature S. scombrus, i.e. fish recording a higher gonadosomatic index. Molecular tools allowed the identification of two species of Anisakis, A. simplex (s.s.) and A. pegreffii. They differed in their occurrence: in S. colias the prevalence of A. simplex (s.s.) was 18% and that of A. pegreffii was 82%, whereas in S. scombrus the prevalence of A. simplex (s.s.) was 73% and that of A. pegreffii was 27%. Occasionally, worms of Hysterothylacium aduncum were identified for both fish. The different infection levels of the two Anisakis species in both hosts off the Portuguese coast raise the hypothesis of a different life cycle at the level of the invertebrate intermediate host. S. colias lives in deeper waters than S. scombrus, and the differences found in infection levels suggest that A. pegreffii main first intermediate host also live in deeper waters, compared with A. simplex (s.s.) main first intermediate host. The higher infection levels of A. simplex (s.s.) (most infectious to humans) in S. scombrus suggest that its consumption when slightly cooked, as in grilled fish (so popular in Portugal), could be more problematic for the development of anisakiasis in humans than the consumption of S. colias and thus be of potential public health concern.Keywords: anisakids; Anisakis pegreffii; Anisakis simplex (s.s.); Atlantic mackerels; Portuguese coast; molecular identification; food safety. Comparación de los niveles de infección de anisákidos entre dos especies de caballa del Atlántico (Scomber colias y S. scombrus), de la costa atlántica portuguesaResumen: La anisakiasis es una zoonosis problemática asociada con el consumo de pescado crudo o poco cocinado. La caballa del Atlántico (Scomber colias) es un pez de mayor interés comercial en Portugal y se ha informado que es un hospedador común de Anisakis spp. En este estudio, la incidencia de anisákidos se evalúa en S. colias y Scomber scombrus, y el potencial riesgo zoonótico asociado con el consumo de estos dos peces se evalúa de acuerdo a los niveles de infección registrados. Estos se encontraron altos para ambas especies de peces -intensidad media y la prevalencia de 21.7 gu...

Seasonality of salmonid parasites from flow‐through aquaculture in northern Germany: Emphasis on pathogenicity of Diplostomum spp. metacercaria

“…We did not find any zoonotic fish parasites that might get transferred to humans through the aquaculture fish. According to Santos et al (2017), several fish borne zoonotic parasites have been recorded…”

Fish Parasite Community of Three Lakes with Different Trophic Status in Mecklenburg-Western Pomerania, Germany

“…Nematoda/Anisakidae : The region of rDNA comprising the ITS-1, 5.8S, ITS-2 and flanking sequences (= ITS+) was amplified using the primers Forward TK1 (5′-GGC-AAA-AGT-CGT-AAC-AAG-GT-3′) and Reverse NC2 (5′-TTA-GTT-TCT-TTT-CCT-CCG-CT-3′). PCR cyclic started with an initial denaturation at 95 °C for 1 min, 40 cycles of 94 °C for 45 s (denaturation), 55 °C for 45 s (annealing), 72 °C for 45 s (extension) and a final extension at 72 °C for 10 min [ 25 ].…”

Potential hazards associated with the consumption of Scombridae fish: Infection and toxicity from raw material and processing

“…Fish dishes prepared from mackerel are among most popular food specialties in Mediterranean countries. For example, In Portugal grilled mackerel fish, especially Scomber colias and Scomber scombrus are among the most famous food specialties consumed by local and tourist people (Santos et al, 2017). In France, mackerel fish is traditionally consumed pickled with large amounts of salt.…”

“…Fish dish traditionally prepared in some Mediterranean countries with raw or undercooked mackerels present serious risk of Anisakis spp. Infection (Debenedetti et al, 2008; Mattiucci et al, 2008; Santos et al, 2017). Zoonotic infections caused by anisakiasis pose a potential risk and can cause a major public health concern in these countries.…”