Anisakis Larvae Research Articles

Investigation on the risk of of Anisakis infection among high - risk populations along the coastal areas of Jiangsu Province

To investigate the risk of Anisakis infections among high-risk populations along the coastal areas of Jiangsu Province, so as to develop the strategy for the prevention and control of anisakiasis in the province. Three counties along the coastal areas of Jiangsu Province were selected as the study sites in 2018, including Rudong County in Nantong City, Haizhou District in Lianyungang City and Dongtai City in Yancheng City. The knowledge, attitude and practice (KAP) of anisakiasis prevention and control, and the prevalence of serum specific IgG antibody against Anisakis were investigated among high-risk populations among these three study sites, including fishermen, fish seller and people who liked eating fresh and live marine fish. Factors affecting the prevalence of the specific IgG antibody against Anisakis were identified using a multiple logistic regression model. In addition, Anisakis larvae infections were detected in fresh and live marine fish samples collected from local markets, and the prevalence and intensity of Anisakis infections were estimated. A total of 625 high-risk populations were investigated, including 349 men (55.8%). Only 13.0% of the subjects heard about anisakiasis, and a low awareness rate of anisakiasis prevention and control knowledge was seen among these three types of high-risk populations. There were 21.6% of the subjects eating raw or half-cooked marine fish, 5.8% eating undercooked marine fish, 3.2% presenting vomiting, nausea and diarrhea after eating marine fish, 5.1% developing systemic allergic symptoms, and 65.6% using the same chopping board for raw and cooked food. The sero-prevalence of the anti-Anisakis IgG antibody was 7.0% among the study subjects. Multiple logistic regression analysis identified education level [OR = 0.687, 95% CI (0.478, 0.987)] and development of systemic allergic symptoms [OR = 4.641, 95% CI(1.411, 15.268)]as factors affecting the positive anti-Anisakis IgG antibody among the study subjects. Among 494 fresh and live marine fish detected, the prevalence and intensity of Anisakis larvae infection was 64.0% and 8.1 larvae per fish, with high prevalence seen in Trichiurus haumela and Pneumatophorus japonicas. The awareness of anisakiasis prevention and control knowledge is low among the high-risk populations living along the coastal areas of Jiangsu Province, and there are high-risk behaviors, such as eating raw or half-cooked food, using the same chopping board for raw and cooked food. In addition, the prevalence of Anisakis infections is high in the marine fish in these areas. Therefore, the health education and health promotion for anisakiasis prevention and control should be intensified.

Anisakis physeteris y Pseudoterranova decipiens en el pez Mugil Curema comercializado en Tumaco, Colombia

Objective: Identification nematodes Anisakidae family in Mugil curema fish. Materials and methods: For this study, 16 Lisa fish (Mugil curema) were obtained from the port of Tumaco, a city on the Colombian Pacific coast. Morphological identification of larvae was made by classical taxonomy and the percentage of larval infestation was calculated. For molecular identification, a multiplex PCR was carried out with primers for six species, Anisakis physeteris, Pseudoterranova decipiens, Anisakis simplex sensu stricto, Contracaecum osculatum, Hysterothylacium aduncum and Anisakis pegreffii. Results: The taxonomic revision enabled the identification of type II larvae of the genus Anisakis and larvae of the genus Pseudoterranova. The larvae were isolated mainly from the intestine, where it was found that 94% of the fish were parasitized by anisakid nematodes. The multiplex PCR enabled the identification of the species A. physeteris (Larva type II), and P. decipiens. Conclusions: This study in the first report of nematode Anisakidae on Tumaco, Colombia. These results provide a compelling justification for further study into the Anisakidae family in Colombia, as a public health problem

Anisakid nematodes prevalence in Chilean hake (Merluccius gayi gayi) commercialized in the city of Talca, Chile

The main objective of this work was to determine the presence of anisakid larvae in fresh Chilean hake Merluccius gayi gayi coming from the coastal area near the city of Talca, Chile, commonly commercialized by a regional fish supply center located in the same city. Flesh and viscera of 214 fish were analyzed via direct observation, and the prevalence of parasitism was calculated. The results showed a prevalence of 100% and 24.3% in viscera and flesh, respectively. Morphologic characterization of 138 randomly selected larvae was performed via diaphanization technique, observing 106 larvae of Anisakis spp., 13 larvae of Pseudoterranova spp. and 19 nematodes classified as “unidentified.” All larvae here analyzed were viable based on the spontaneous movement ability of parasites. Overall, the high prevalence of fish infected with Anisakidae larvae highlights the importance of taking early intervention actions in order to prevent the occurrence of anisakidosis in the human Chilean population; particularly critical given the current culinary preference for raw fish dishes such as ceviche and sushi, which poses a public health issue.

Parasites in fishery products - Laboratorial and educational strategies to control

The presence of parasites, including Anisakis spp. larvae in fishery products jeopardizes their safety and quality, which is a matter of concern and a challenge for official authorities, as well as for food businesses operators, and a potential health risk to consumers. In the last ten years, a total of 2367 samples from different seafood products, whole fish (n = 1022), fish steaks (n = 417), fish fillets (n = 46), roes (n = 11), canned fish fillets (n = 35), fish fingers (n = 705), and ready-made Japanese dishes (n = 131) were analysed at the Laboratory of Pathology of Aquatic Animals of IPMA. From the fishery products analysed, a total of 4643 visible Anisakis larvae were collected from eighteen different species of whole fish and there were two cases with numerous larvae, although live larvae were only found in fresh fish. Anisakis larvae (n = 523) were collected from fish steaks, (n = 20) from frozen fish fillets, (n = 7) from five different brands of fish fingers, (n = 2) from two cans of cod fillets and numerous viable larvae were collected from the serosae of European hake fresh roes. The great majority of the larvae were identified as L3 Anisakis larvae. Plerocercoids of Gymnorhynchus gigas and Hepatoxylon trichiuri and the myxosporean, Kudoa spp. were also observed and led to the withdrawal of the fish from the supply chain. No Anisakis larvae were collected from the farmed fish as well as from the ready-made Japanese dishes. However, Kudoa hexapunctata spores were observed in the tuna muscle from one sashimi meal. The data shows that fresh fish with live Anisakis larvae have been marketed. Educational strategies concerning parasites were implemented with workshops, “Parasites in Fishery Products” to train and instruct professionals within the fish supply chain and training activities for target groups, including children, were promoted, to raise awareness of this issue. One of the most relevant outcomes obtained was the improvement of implementation of parasite identification techniques in the industry, including private labs, and consequently: (1) decrease in the parasitological analysis number of common parasites and (2) reduction in the analysis of anatomical structures confused with parasites requested to IPMA's Laboratory of Pathology. In addition, the practice of freezing trash fish used to feed farmed fish, and the placement of nets at the water entry points of the earth ponds, in order to avoid wild fish introduction, were simple and important measures that were implemented to prevent Anisakis and other parasites entering fish farms. The two complementary parts of this work, laboratorial activities used to support the fish supply chain, and the educational strategies concerning parasites, have made an essential contribution towards the availability of data for assessing and minimizing the level of risk associated with fish consumption, and have particularly increased and improved awareness, regarding foodborne parasites.

Risk-based scoring and genetic identification for anisakids in frozen fish products from Atlantic FAO areas

BackgroundThe presence of Anisakis larvae in fish represents a major public health concern. Effective risk management procedures should be applied to prevent heavily infected products from reaching the market. The aim of the study is to provide preliminary data on parasite exposure and risk classification in frozen fish products by applying a risk categorization scheme (site, abundance, density and epidemiology – SADE) and Fish Parasite Rating (FPR) method. Fish and cephalopods samples (N = 771) from 5 different FAO Atlantic areas were examined and categorized after an accurate visual inspection and a chloro-peptic digestion.ResultsIn 25 out of 33 fish species parasite larvae were found. 10897 anisakids larvae were collected and identified to genus level. Molva dypterygia, Conger conger, Zeus faber and Aphanopus carbo were shown to be the most highly infected species. SADE and FPR scores were 1 and poor, respectively, for the referred species, because of the disseminated Anisakis infection and commercial rejection.ConclusionSADE/FPR method showed high specificity and accuracy. The information provided in this work could be used in early warning systems for the detection of parasites in fishery products and might help fishing industries in establishing management strategies for infected stocks in terms of cost saving decisions.

Increasing intensities of Anisakis simplex third-stage larvae (L3) in Atlantic salmon of coastal waters of Scotland

BackgroundRed Vent Syndrome (RVS), a haemorrhagic inflammation of the vent region in Atlantic salmon, is associated with high abundance of Anisakis simplex (s.s.) third-stage larvae (L3) in the vent region. Despite evidence suggesting that increasing A. simplex (s.s.) intensity is a causative factor in RVS aetiology, the definitive cause remains unclear.MethodsA total of 117 Atlantic salmon were sampled from commercial fisheries on the East, West, and North coasts of Scotland and examined for ascaridoid parasites. Genetic identification of a subsample of Anisakis larvae was performed using the internal transcribed spacer (ITS) region of ribosomal DNA. To assess the extent of differentiation of feeding grounds and dietary composition, stable isotope analysis of carbon and nitrogen was carried out on Atlantic salmon muscle tissue.ResultsIn the present study, the obtained ITS rDNA sequences matched A. simplex (s.s.) sequences deposited in GenBank at 99–100%. Not all isolated larvae (n = 30,406) were genetically identified. Therefore, the morphotype found in this study is referred to as A. simplex (sensu lato). Anisakis simplex (s.l.) was the most prevalent (100%) nematode with the highest mean intensity (259.9 ± 197.3), in comparison to Hysterothylacium aduncum (66.7%, 6.4 ± 10.2) and Pseudoterranova decipiens (s.l.) (14.5%, 1.4 ± 0.6). The mean intensity of A. simplex (s.l.) represents a four-fold increase compared to published data (63.6 ± 31.9) from salmon captured in Scotland in 2009. Significant positive correlations between A. simplex (s.l.) larvae intensities from the body and the vent suggest that they play a role in the emergence of RVS. The lack of a significant variation in stable isotope ratios of Atlantic salmon indicates that diet or feeding ground are not driving regional differences in A. simplex (s.l.) intensities.ConclusionsThis paper presents the most recent survey for ascaridoid parasites of wild Atlantic salmon from three coastal regions in Scotland. A significant rise in A. simplex (s.l.) intensity could potentially increase both natural mortality rates of Atlantic salmon and possible risks for salmon consumers due to the known zoonotic role of A. simplex (s.s.) and A. pegreffii within the A. simplex (s.l.) species complex.

Asymptomatic Anisakiasis of the Colon Diagnosed and Treated by Colonoscopy

Anisakiasis can involve any part of the digestive tract, but most cases reported have involved the stomach; few reports have described colonic anisakiasis. Furthermore, asymptomatic colonic anisakiasis has been reported to be very rare. A 58-year-old Japanese male asymptomatically received colonoscopy due to a fecal occult blood testing positive, and an Anisakis larva was removed in the ascending colon. After colonoscopy, an detailed questionings concerning eating raw fish revealed that the patient ate the liver of raw filefish 21 days before the colonoscopy. Thus, questionings concerning eating the raw fish were very important and helpful for correct diagnosis. This case report demonstrated that colonic anisakiasis can be diagnosed by colonoscopy before severe complications (intestinal obstruction, perforation, and cancer development) occur. Also, biopsy forceps could be used to remove the Anisakis worms, demonstrating that diagnosis and treatment can be simultaneously performed.

Investigation of the Genus Anisakis Among Atlantic Chub Mackerels (Scomber colias Gmelin, 1789) in Tripoli's Main Fish Markets, Libya

Parasitism is a common incident in the marine environment and all species of fish are susceptible to being infested by various parasites. Thousands of parasitic species of fish are described in adult or larval form, which mainly belong to the groups of protozoa, arthropods, plathihelminths (trematodes and cestodes) and nematohelminths (nematodes). Anisakidosis is a zoonosis caused by the intake of the nematode of the genus Anisakis in its third larval stage (L3). Atlantic chub mackerel (Scomber colias Gmelin, 1789), has great importance, both ecologically and economically in the Libya. From the economic point of view, it is possible to mean that Atlantic chub mackerel is the one of most abundant and frequent medium-sized pelagic species of fishing in the Libyan coastline. Atlantic chub mackerel is one of the most commercial significant species for the Libyan fishery. Consequently, in the period between 1st March to 28th April 2018, a total of 83 Atlantic chub mackerels were collected from two main fish markets in Tripoli, Libya to evaluate the parasitosis by infective larvae of the genus Anisakis spp. by the dissection method. Among the all examined fish, 15 (18.07%) were infested in the abdominal cavity with nematodes parasites, and identified as a third stage larvae, belonging to the Anisakis simples. Statistical analysis revealed there is no correlation between abundance of the infection by A. simplex with the host length. Furthermore, values of the infection intensity were significantly higher in the female of S. colias. However, this study indicates the need to continue efforts for in-depth investigate this metazoan parasite in different fish and cephalopod species in the coast of Tripoli, to represent the adequate risk of anisakidosis, and to alert the possible chance of the initial man case of anisakidosis in Libya, particularly among people who are more occupationally susceptible; like the fishmongers, fish processors, as well as to some residents population who prefer consume the raw or lightly cooked fish.

Epidemical study of third stage larvae of Anisakis spp. infection in marine fishes in China from 2016 to 2017

BackgroundAnisakis, a genus of parasitic nematodes, can infect fish and potentially cause diseases in human. Yet it has not drawn public attention in China. It is urgent to conduct the first epidemical study on third stage larvae of Anisakis spp. infection in marine fishes across most coastal regions of China from 2016 to 2017. MethodsIn this study, 2422 samples of marine fishes were collected from eight coastal regions in China from 2016 to 2017. The third-stage larvae of Anisakis spp. were examined under a light microscope. The chi-square test, the Fisher's exact test and the logistic regression were applied in this study. ResultsThe infection rate was 28.70% (695/2422). Compared with live fish, the infection rate of fresh fish was higher at 31.88% (577/1810). Statistical analyses showed that there existed a significant difference in infection rate of different sampling months, which could be explained by fishing ban. ConclusionsThe result showed that sampling region, fish status, fish species and sampling month were the main factors influencing infection rate. Regulations or guidelines are urgent in China for the control of Anisakis spp. infection in marine fish.

Efficacy of Origanum syriacum Essential Oil against the Mosquito Vector Culex quinquefasciatus and the Gastrointestinal Parasite Anisakis simplex, with Insights on Acetylcholinesterase Inhibition.

Developing effective and eco-friendly antiparasitic drugs and insecticides is an issue of high importance nowadays. In this study, we evaluated the anthelminthic and insecticidal potential of the leaf essential oil obtained from Origanum syriacum against the L3 larvae of the parasitic nematode Anisakis simplex and larvae and adults of the mosquito Culex quinquefasciatus. Tests on A. simplex were performed by standard larvicidal and penetration assays, while mosquito toxicity was assessed relying on larvicidal, tarsal contact, and fumigation tests. To shed light on the possible mode of action, we analyzed the oil impact as acetylcholinesterase (AChE) inhibitor. This oil was particularly active on L3 larvae of A. simplex, showing a LC50 of 0.087 and 0.067 mg mL−1 after 24 and 48 h treatment, respectively. O. syriacum essential oil was highly effective on both larvae and adults of C. quinquefasciatus, showing LC50 values of 32.4 mg L−1 and 28.1 µg cm−2, respectively. Its main constituent, carvacrol, achieved larvicidal LC50(90) of 29.5 and 39.2 mg L−1, while contact toxicity assays on adults had an LC50(90) of 25.5 and 35.8 µg cm−2, respectively. In fumigation assays, the LC50 was 12.1 µL L−1 after 1 h and decreased to 1.3 µL L−1 in 24 h of exposure. Similarly, the fumigation LC50 of carvacrol was 8.2 µL L−1 after 1 h of exposure, strongly decreasing to 0.8 µL L−1 after 24 h of exposure. These results support the folk usage of Lebanese oregano as an antiparasitic agent, providing new insights about its utilization for developing new effective and eco-friendly nematocidal and insecticidal products.

Occurrence and molecular characterization of zoonotic Anisakis simplex sensu stricto and Anisakis pegreffii larvae in retail‐marketed fish

AbstractThe study aimed at investigating the occurrence and molecular characterization of zoonotic Anisakis larvae in imported, retail‐marketed smoked herring (Clupea harengus) and frozen mackerel (Scomber scombrus) in Egypt. A total of 154 fishes (84 ready‐to‐eat smoked herring and 70 frozen mackerel) were collected. The prevalence of Anisakis larvae Type I in the whole specimen of smoked herring and frozen mackerel was 19.05 and 42.86% with mean intensities of 4.71 and 1.83. While the prevalence in muscles was 8.33 and 5.71% with mean intensities of 4.29 and 5, respectively. The sequencing of 11 larval PCR products from fish muscles revealed the presence of two zoonotic species; Anisakis simplex sensu stricto and Anisakis pegreffii. The recovered strains showed high identities to GenBank Anisakis isolates of fish from the North Sea, nearby waters and from China. More surveillance studies are recommended on those areas to ensure food safety and minimize public health risks.Practical ApplicationFrozen fish imports by Egypt have been growing significantly since 2009 to cover the progressive elevation in fish consumption there. Anisakis is one of the commonly reported zoonotic parasites infecting humans through fish consumption. This study provides important information on the prevalence and molecular characteristics of zoonotic Anisakis species in edible muscles of imported, retail‐marketed frozen mackerel and ready‐to‐eat herring fish in Egypt. The study outlined some recommendations to reduce the public health risks from that biological hazard.

Nematofauna of red piranha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) from Amazonia, Brazil.

Between March and October 2008, 355 specimens of Pygocentrus nattereri were collected from the lowland lakes of Central Amazonia, Brazil, to study their nematode fauna. A total of 1.116 specimens of Nematoda were collected, belonging to six species. Procamallanus (Spirocamallanus) inopinatus was the species with the highest parasite indices. Larvae of Anisakis sp. have zoonotic potential and were found parasitizing the intestine and liver of Pygocentrus nattereri. Some of these nematode species were new records for the host P. nattereri. The diversity of nematodes that use P. nattereri as a host indicates the important role of this fish species in the maintenance of these six nematode species in the lowland lakes of Central Amazonia.

Occurrence of Anisakis pegreffii (Nematoda: Anisakidae) Larvae in Imported John Dory (Zeus faber) from Senegalese Coast Sold in Turkish Supermarkets.

West African goatfish Pseudupeneus prayensis, bluespotted seabream Pagrus caeruleostictus and John Dory Zeus faber are commercially marketed as fresh and frequently imported from Senegalese coast (FAO area 34.3.12) in Turkish supermarkets. The aim of the current study was to collect data of occurrence and molecular identification of Anisakis species in imported P. prayensis, P. caeruleostictus and Z. faber caught in the Senegalese coast and to support epidemiological report for a risk evaluation of Anisakis species in Turkish supermarkets. Forty imported fish from each species at a total of 120 samples were investigated for the presence of Anisakis larvae. Based on ITS region of RFLP analysis Anisakis larvae were identified and randomly selected five larvae were also sequenced for further confirmation for cox2 gene. No Anisakis larvae were isolated from P. prayensis, P. caeruleostictus whereas Anisakis larvae were only found in Z. faber. A total of 156 Anisakis larvae were collected from Z. faber. All larvae were molecularly identified as Anisakis pegreffii. The prevalence (%), intensity and abundance of Anisakis infection in Z. faber were detected to be 82.5%, 8.3 and 6.8, respectively. This is the first assessment of the occurrence of A. pegreffii in imported Z. faber from the Senegalese coast in Turkish supermarkets. Moreover, consuming imported P. prayensis and P. caeruleostictus present low to non-existent risk for anisakiasis in Turkish consumers. Furthermore, the presence of A. pegreffii larvae in imported Z. faber from the Senegal waters could have public health implications in Turkish consumers.

Multidisciplinary approach in study of the zoonotic Anisakis larval infection in the blue mackerel (Scomber australasicus) and the largehead hairtail (Trichiurus lepturus) in Northern Taiwan.

Anisakid larvae are the food-borne pathogen highly prevalent among numerous marine fishes. Accidental consumption of infected raw or poorly cooked fish fillets may cause anisakiasis. This study used the multidisciplinary approach to investigate the occurrence of Anisakis nematodes in commonly consumed fish species, Scomber australasicus and Trichiurus lepturus purchased in Taipei Xinyi traditional fish market. All the Anisakis larvae collected herein were identified morphologically as Anisakis type I or Anisakis type II. The prevalence and the mean intensity of Anisakis larvae collected from S. australasicus was 80.77%, 26.8 (10-32) and 100%, 49.0 (27-70) for T. lepturus. Using molecular analysis, 83.33% (180/216) were identified as Anisakis pegreffii, 6.05% (13/216) as Ascaris typica, 1.85% (4/216) as Ascaris physeteris and 8.80% (19/216) as hybrid genotype (A. pegreffii+Anisakis simplex) in S. australasicus. In T. lepturus, 86.31% (290/336) were identified as A. pegreffii, 2.38% (8/336) as A. typica, and 11.31% (38/336) as hybrid genotype (A. pegreffii+A. simplex [s.s]). The molecular phylogenetic analysis shows two cluster clades, one group includes A. pegreffii complex and the other include Ascaris paggiae, Ascaris brevispiculata, and A. physeteris. Thus, A. pegreffii is the most abundant species and may be the potential causes of human infection.

Molecular Identification of Anisakis Larvae Extracted by Gastrointestinal Endoscopy from Health Check-up Patients in Korea.

Anisakiasis is a zoonotic disease induced by anisakid nematodes, and endoscopic inspection is used for a diagnosis or remedy for it. Anisakis simplex, Anisakis physeteris, and Pseudoterranova decipiens had been reported to be the major species causing human infections, particularly, in Japan. However, in Korea, recent studies strongly suggested that Anisakis pegreffii is the major species of human infections. To support this suggestion, we collected anisakid larvae (n=20) from 20 human patients who were undergone gastrointestinal endoscopy at a health check-up center in Korea, and molecular identification was performed on the larvae using PCR-RFLP analysis and gene sequencing of rDNA ITS regions and mtDNA cox2. In addition, anisakid larvae (n=53) collected from the sea eel (Astroconger myriaster) were also examined for comparison with those extracted from humans. The results showed that all human samples (100%) were identified as A. pegreffii, whereas 90.7% of the samples from the sea eel were A. pegreffii with the remaining 9.3% being Hysterothylacium aduncum. Our study confirmed that A. pegreffii is the predominant species causing human anisakiasis in Korea, and this seems to be due to the predominance of this larval type in the fish (sea eels) popularly consumed by the Korean people. The possibility of human infection with H. aduncum in Korea is also suggested.

Viability of Anisakis spp. Larvae After Direct Exposure to Different Processing Media and Non-Thermal Processing in Anchovy Fillets

Anisakiasis is fish-borne zoonoses caused by nematodes of the genus Anisakis, contracted by the ingestion of live L3 infective larvae through consumption of raw, undercooked or thermally unprocessed seafood products, such as carpaccio, and white marinated and dry-salted anchovies. In order to maintain the organoleptic properties of the product, the freezing of fish prior to processing is often ignored, especially in households, and traditional processing methods are not sufficient to kill Anisakis larvae. In this study, we investigated the survival and resistance of Anisakis spp. larvae in different processing solutions including varying salt and sugar content, lemon juice, acetic acid, alcohol, wine, and apple vinegar. We also performed a viability test of larvae during processing in anchovy fillets. When exposed directly to different NaCl concentrations, larvae were killed after approximately three days in the strongest (35%) and 10 days in the weakest solution (5%). In lemon juice and lemon juice with added acetic acid, the survival of larvae was around 5 days. In intact alcohol vinegar, larvae were killed under less than 48 h, while in the solution with water their resistance was prolonged to almost 40 days. In fillets, larvae showed increased resistance during carpaccio and white wine vinegar marinades and only dry salting was effective in destroying Anisakis spp. larvae.

Respiratory analysis as a tool to detect physiological changes in Anisakis larvae subjected to stress.

Human infection due to eating fish parasitized by live Anisakis larvae in the third stage is considered an important health problem, and the application of treatments to ensure their mortality in the fish products is crucial to prevent the risk of infection. Mobility is used to assess viability, but mobile larvae may not always be infective and immobile larvae may be erroneously considered as non-viable. The objective was to establish whether the analysis of respiratory activity by means of the oxygen consumption rate (OCR) of Anisakis could be used to identify subtle differences between larvae that were still considered viable in terms of their mobility but had been subjected to thermal and/or chemical stress. The metabolic modulators FCCP [carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone] and sodium azide were used and the basal, maximum, spare and residual respiration rates calculated. Results showed that maximum respiratory capacity of larvae subjected to freezing significantly decreased immediately after thawing, but after some acclimatization, they recovered their capacity fully. However, when these larvae were stored at 4.6°C, their mitochondria became dysfunctional faster than those of untreated larvae. OCR also showed that mitochondria of larvae were affected by incubation at 37°C in NaCl or gastric juice. To conclude, OCR of Anisakis in the presence of metabolic modulators can help to identify subtle changes that occur in the larva. These measurements could be used to characterize larvae subjected to various stresses so that a broader picture of Anisakis pathogenic potential can be gained.

Prevalence and Risk of Anisakid Larvae in Fresh Fish Frequently Consumed in Spain: An Overview

Anisakidosis is a fish-borne zoonosis caused by parasitic nematodes of the family Anisakidae, of which the species belonging to Anisakis simplex complex are the most representative. It is considered an emerging disease in Spain. The objective of this study is to analyse the presence of larvae in fish frequently consumed in Spanish supermarkets, inferring the risk of infection. In total 1,786 specimens of 9 different fish species, from two geographical origins (Atlantic and Mediterranean), acquired fresh and not eviscerated were examined for anisakid nematodes. Analysis showed that 33.7% of the samples were parasitized by Anisakis larvae. The horse mackerel (Trachurus trachurus) presented the highest total prevalence (66.0%), followed by the silver hake (Merluccius bilinearis) (59.5%), the mackerel (Scomber scombrus) (58.4%), the blue whiting (Micromesistius poutassou) (53.9%) and the European hake (Merlucius merlucius) (45.0%). In general, the prevalence was higher in Atlantic than in Mediterranean fish. In all the species analysed, a higher presence of the parasite was detected in the viscera than in the flesh, although in the most parasitized species a noteworthy prevalence and abundance was observed in the flesh. In conclusion, risk factors, like fish species and origin, should be considered by consumers, in addition of following the recommendations established by Commission Regulation (EU) No1276/2011 and the Spanish Royal Decree 1420/2006.

Presence of Anisakis nematode larvae in Indian mackerel (Rastrelliger spp.) along the Indian Ocean southern coast of East Java, Indonesia

Setyobudi E, Rohmah I, Syarifah RF, Ramatia L, Murwantoko, Sari DWK. 2019. Presence of Anisakis nematode larvae in Indian mackerel (Rastrelliger spp.) along the Indian Ocean southern coast of East Java, Indonesia. Biodiversitas 20: 313-319. In this study, we aimed to determine the prevalence (P), mean intensity (MI) and site of infection of anisakid larvae (Nematoda) in Indian mackerel (Rastrelliger spp.) at the Indian Ocean Southern Coast of East Java. A total of 341 fish were collected from Prigi and Muncar Fish Harbor, East Java during March-April 2018. Each fish specimen was measured in body length and weight, and then dissected for examination of Anisakis larvae in the body cavity, digestive tract, liver, gonad and muscle. The collected larvae were preserved in absolute ethanol for both morphological and molecular identification. The results of this research showed Indian mackerel was susceptible to Anisakis infection (P=17%, MI =6.8 larva/individual fish). Most of the larvae were found in the digestive tract and body cavity, 47.2% and 46.0% respectively. Only a few larvae were found in other internal organs and muscle. Based on morphological identification, these larvae corresponded to Anisakis Type I. Furthermore, in molecular identification using PCR-RFLP, the banding pattern clearly matched with Anisakis typica. The prevalence and mean intensity of Anisakis nematodes on Indian mackerel along the southern coast of East Java seem to be different in each locality and from other adjacent waters as has previously been reported, which may be due to differences in feeding habits and in the distribution of marine mammals as the final host. The results suggest that differences in prevalence and mean intensity of anisakis larvae infection could be developed as a biological indicator of fish stock discrimination. However, clear information regarding food habits of Indian mackerel and migration patterns of the paratenic hosts as well as of marine mammals as final host is needed.

Occurrence of Anisakis and Hysterothylacium larvae in commercial fish from Balearic Sea (Western Mediterranean Sea).

This study investigates the occurrence of anisakids and raphidascarids in commercial fish from Balearic Sea (Western Mediterranean). A total of 335 fish including 19 black anglerfish (Lophius budegassa), 33 white anglerfish (L. piscatorius), 129 European hake (Merluccius merluccius), 30 red mullet (Mullus barbatus), and 124 striped mullet (M. surmuletus) were examined using enzymatic digestion. A total of 948 nematode larvae were isolated (prevalence 52.53%) being the highest prevalence observed in striped mullet. Forty-six larvae were identified using molecular analyses which included PCR and sequencing of the 629-bp fragment of mitochondrial cox2 gene region. Anisakis pegreffii (80.43%), A. physeteris (8.69%), Hysterothylacium fabri (6.52%), and A. simplex (4.35%) were detected based on molecular analyses of larvae. Total nematode prevalence was positively correlated with weight, length, condition factor, and maturity stage of the host and also with fishing ground depth. Statistical differences between total nematode prevalence and geographical sector of capture were observed when fishing hauls were grouped according to the abundance of sperm whales or common bottlenose dolphins. The results also corroborate that fishing water depth may play an important role in anisakid and raphidascarid parasitization.