Anisakidae infection in fish of the Aegean Sea

Nematode worms of the family Anisakidae are the causative agents of infections in humans when fish is consumed raw and of serious allergies up to the death, when fish is consumed raw or cooked by previously sensitized people. From April until November 2009, 462 fish belonging to 26 species, fished in three areas of the Aegean Sea were tested for Anisakidae larvae. Anisakidae larvae were detected in 87 (18.83%) fish of 13 species. These larvae were identified by morphology as the third-stage larvae of the genera Hysterothylacium sp. or Anisakis. Larvae of the genus Anisakis were identified by PCR-RFLP as belonging to A. simplex s.str., A. pegreffii, or as hybrids between A. simplex s.str and A. pegreffii.     

Molecular identification of Anisakis spp. from fishes collected in the Tyrrhenian Sea (NW Mediterranean)

The accurate identification of anisakid nematodes at any life cycle stage is important both to deepen the knowledge on their taxonomy, ecology, epidemiology and for diagnosis and control, as larval stages cause a clinical disease in humans known as anisakidosis. With the aim to investigate the presence of anisakid larvae, specimens of horse mackerel, Trachurus trachurus (Linnaeus, 1758), silver scabbardfish, Lepidopus caudatus (Euphrasen, 1788), European anchovy, Engraulis encrasicolus (Linnaeus, 1758) and opah fish, Lampris guttatus (Brunnich, 1788), were collected by trawling at depths ranging from 50 to 400 m. A molecular approach based on restriction profiles obtained after digestion of the nuclear ribosomal ITS region was used to identify Anisakis spp. larvae recovered in fish samples. Restriction profiles showed three banding patterns, corresponding to Anisakis pegreffii, Anisakis physeteris and to heterozygote pattern between A. pegreffii and Anisakis simplex s.s. Specimens showing the heterozygote restriction pattern were also analyzed by sequencing of the entire ITS region, to confirm the heterozygote status.     

用POR和POR-RFLP方法检测和鉴定进口海鱼中的异尖线虫幼虫

应用PeR和PCR—RFLP方法对厦门口岸进口的各种海鱼中的异尖线虫幼虫进行检测鉴定。结果在带鱼、竹荚鱼、金线鱼、大眼鲷和白姑鱼等海鱼中发现了简单异尖线虫、典型异尖线虫、对盲囊线虫和针回线虫等4种异尖线虫。带鱼和竹荚鱼的异尖线虫感染率达100％,竹荚鱼异尖线虫感染强度最高,白姑鱼感染率和感染强度相对较低。少数海鱼同时感染2种以上异尖线虫,从带鱼中同时检出简单异尖线虫和针蛔线虫,从竹荚鱼中检出简单异尖线虫、对盲囊线虫和典型异尖线虫。内切酶实验结果表明,应用限制性内切酶UinfI有效鉴别上述4种异尖线虫。     

用PCR和PCR-RFLP方法检测和鉴定进口海鱼中的异尖线虫幼虫

应用PCR和PCR-RFLP方法对厦门口岸进口的各种海鱼中的异尖线虫幼虫进行检测鉴定。结果在带鱼、竹荚鱼、金线鱼、大眼鲷和白姑鱼等海鱼中发现了简单异尖线虫、典型异尖线虫、对盲囊线虫和针回线虫等4种异尖线虫。带鱼和竹荚鱼的异尖线虫感染率达100%,竹荚鱼异尖线虫感染强度最高,白姑鱼感染率和感染强度相对较低。少数海鱼同时感染2种以上异尖线虫,从带鱼中同时检出简单异尖线虫和针蛔线虫,从竹荚鱼中检出简单异尖线虫、对盲囊线虫和典型异尖线虫。内切酶实验结果表明,应用限制性内切酶HinfI有效鉴别上述4种异尖线虫。     

Anisakidae larval infection in fish fillets sold in Belgium.

Fish fillets (n = 1760) sold on the Belgium market were examined for Anisakidae larval infection. Seven sea fish species were examined by means of the candling technique over a period of 4 months, from November 1996 to February 1997. Third-stage larvae of Anisakis simplex and Pseudoterranova decipiens were identified. A. simplex was the most abundant species with a prevalence of 84.5%, and was found in 192 of the examined fillets (10.9%). Pollock (Pollachius pollachius) was the most heavily infected fish species (82.9%). The prevalence in cod (Gadus morhua), saithe (Pollachius virens), and whiting (Merlangius merlangus) was 34.7%, 26.7%, and 15.4% respectively. The prevalence in the three other fish species examined was low, namely 8.9%, 6.6%, and 3.8% for ling (Molva molva), catfish (Anarchias lupus), and Northeast red fish (Sebastes marinus), respectively. Pollock was the fish species with the largest number of Anisakis larvae (7.8 larvae/kg fish fillet).     

Anisakidae nematodes and Trypanorhyncha cestodes of hygienic importance infecting the king mackerel Scomberomorus cavalla (Osteichthyes: Scombridae) in Brazil

From February to October 2007, thirty specimens of the king mackerel, Scomberomorus cavalla (Cuvier, 1829) were purchased from markets in the municipalities of Niterói and Rio de Janeiro. The fishes were measured, filleted and further had their organs investigated for helminths. Ten out of the thirty fish specimens were parasitized with anisakid nematodes represented by Anisakis sp. and Contracaecum sp. with prevalence of 1% and 16%, mean intensity of 2 and 3.31 and mean abundance of 0.02 and 0.53, respectively. The infection range with Contracaecum sp. was 1-9. The sites of infection were the stomach serosa and mesentery. Seventeen fish specimens (53%) out of the 30 investigated were parasitized with Trypanorhyncha metacestodes, identified as Callitetrarhynchus gracilis, Pterobothrium crassicole, Callitetrarhynchus speciosus and Tentacularia coryphaenae in the mesentery, with prevalence of 26, 20, 6, 3%, intensity and mean intensity of 3.25, 3.5, 1, 2 and mean abundance of 0.86, 0.7, 0.06 and 0.06, respectively. The infection range due to C. gracilis and P. crassicole were of 1-5 and 1-20, respectively. Anisakis sp., C. speciosus and P. crassicole are reported in S. cavalla for the first time. Considerations on the zoonotic potential of the parasites and their rules in sanitary inspection are presented.     

简单异尖线虫过敏症研究进展

简单异尖线虫广泛存在于海洋动物并呈全球性分布,人因食用含有该线虫幼虫的生鱼或未煮熟的鱼产品而发生感染,其所引起的临床症状与虫体在消化道所处位置相关,主要引起肠黏膜水肿等过敏性症状。文章综述了该症流行病学、病理变化、症状、诊断、抗原、过敏原和预防措施等方面内容。     

Nematode infection in fish from Cartagena Bay, North of Colombia

Parasitic nematode infection indices were recorded in different fish species collected at Cartagena Bay, North of Colombia. Among 19 studied species, the Mugil genus presented the highest prevalence (83.9-100%), although Sciades herzbergii, Caranx hippos and Centropomus undecimalis were also found infected with nematodes. Parasites were found in the liver, intestinal mesenteries and encysted near the intervertebral joints, with an average parasite abundance of 4.0 ± 0.3 nematodes per fish. Morphological analysis allowed the identification of these nematodes as Contracaecum sp. A small, but positive correlation was found between parasite abundance and length (R=0.294, P<0.001) and weight (R=0.244, P<0.001). In contrast, the correlation between parasite abundance and condition factor was negative (R=-0.191, P<0.001). These results are the first describing the presence of nematodes in several fish species of this ecosystem, and it highlights the need for monitoring parasitism in Mugil species in order to avoid parasite ingestion during fish consumption.     

PCR-RFLP技术鉴别简单异尖线虫姊妹种的研究

为建立简单异尖线虫姊妹种分子生物学检测体系,以实现对其快速准确的鉴定,本实验对简单异尖线虫单条线虫总DNA进行PCR扩增,获得其rDNA-ITS序列,测序后与基因库中DNA序列比较,并根据rDNA-ITS序列比较结果鉴定线虫的种类,最后通过酶切技术获得线虫的PCR-RFLP图谱并以此作为线虫鉴定的分子标签。     

Food-borne parasitic infections — A review

A review of food-borne parasitic infections is presented. Parasitic infections in conventional slaughtered animals and seafood (fish and shellfish) constituting a public health hazard are discussed. To the former category belong cysticercosis, echinococcosis and trichinellosis, and to the latter category belong various trematole, cestode and nematode infections. Examples of trematode infections are heterophyidiasis, transmitted to man by marine fish and Paragonimus spp. parasites, transmitted by crustaceans. Cestode infections include diphyllobothriasis transmitted by freshwater fish and fish from brackish waters. Special attention is drawn to the condition known as sparganosis. Of the nematode infections the eosinophilic granulomatous enteritis is mentioned. It is due to infections with members of the genera Anisakis, Phocanema and Contracaecum and is transmitted to man by either marine fish of crustaceans. Two other nematode infections Angiostrongylus cantonensis and Capillaria philippinensis can also be transmitted to man by marine fish.Apart from a possible direct effect of these parasites, chemical alterations in seafood resulting from the presence of parasites may also be deleterious to the consumer.Special attention is drawn to a newly developed serological detection method, the enzyme-linked immunosorbent assay, enabling not only detection of infection at the slaughter-house, but also in large herds at the farm.Strategies to control parasitic infections both in conventional slaughtered animals and in seafood are discussed.     

Anisakiasis with proventricular perforation in a greater shearwater (Puffinus gravis) off the coast of Georgia, United States

A juvenile male greater shearwater (Puffinus gravis) found off the Georgia coast, United States, was lethargic, hypothermic, dehydrated, and emaciated. It was provided with supportive care but subsequently died. The coelomic cavity contained fibrinous fluid intermixed with hundreds of nematodes, some of which protruded through a perforation in the proventriculus. Nematodes were embedded in the wall of the proventriculus from the lamina propria to the serosal surface and were surrounded by granulocytes, epithelioid macrophages, multinucleate giant cells, lymphocytes, and fibroplasia. A full-thickness tear in the proventriculus was lined by heterophils and multinucleate giant cells. The nematode histomorphology was consistent with Anisakis spp. The definitive hosts of Anisakis spp. are marine mammals, which are infected through ingestion of parasitized fish and crustaceans. Marine birds are aberrant hosts of Anisakis spp., and young, inexperienced, immunocompromised birds might be more susceptible to severe infestations. Fatal anisakiasis is rarely reported in birds.     

Evidence of infectious diseases in harbour porpoises (Phocoena phocoena) hunted in the waters of Greenland and by-caught in the German North Sea and Baltic Sea.

The pathological, microbiological and serological findings in harbour porpoises hunted in Greenlandic waters were compared with the findings in animals accidentally caught in fishing gear in the German North Sea and Baltic Sea. The body condition of the Greenlandic animals was good, whereas nine of 23 German harbour porpoises were moderately to markedly emaciated. Both groups were infested with parasites. In the Greenlandic animals parasitism of the aural peribullar cavity with Stenurus minor, of the liver and pancreas with Orthosplanchnus mironovi, of the lungs with Halocercus species and of the subcutaneous and mammary tissue with Crassicauda species was generally associated with a mild inflammatory response. No diseases associated with bacteria were identified in any of the Greenlandic harbour porpoises. In the porpoises from the German North Sea and Baltic Sea, parasites were present in the aural peribullar cavity (S minor), liver (Campula oblonga), first and second gastric compartment (Anisakis simplex) and in the lungs (Pseudalius inflexus and Torynurus convolutus). Moderate to marked pulmonary parasitism and suppurative pneumonia, not observed in the Greenlandic porpoises, were present in 11 and 10, respectively, of the 23 German porpoises. The suppurative pneumonia was attributed to bacterial infection with beta-haemolytic streptococci and Escherichia coil var haemolytica. Four Greenlandic and 10 German porpoises had positive porpoise morbillivirus-specific antibody titres suggesting that the virus was circulating in both populations.     

Interactions between ecto- and endoparasites in trout Salmo trutta.

Trout fry were experimentally infected with endoparasites (Anisakis sp.) and/or ectoparasites (Gyrodactylus derjavini). During the following 3 weeks the infection level of G. derjavini was significantly lowered in fish infected with live anisakids compared to fish injected with physiological saline, a corresponding amount of Anisakis protein sonicate or to untreated fish. Subsequent scanning electron microscopy (SEM) of recovered nematodes from the trout showed an extensive colonization of the worms with host macrophages. It is indicated that the activation of the fish immune system by infection with live anisakids influences the skin response of the host with a subsequent negative effect on the ectoparasites G. derjavini.     

Nutritional value of fish meals in the diet for young pigs

A series of three experiments was conducted to evaluate the nutritional value of fish meals as protein sources in young pigs' diets. Four fish meals (menhaden; mackerel, dried at 85 degrees C and 70 degrees C; and herring, dried at 70 degrees C) were tested. For the first experiment, eight pigs (2 wk old) were surgically fitted with ileal cannulas and used to measure apparent digestibility of the fish meals over the age period of 3 to 7 wk. Compared with menhaden fish meal, mackerel and herring fish meals yielded higher (P < 0.05) ileal digestibility values for threonine, serine, alanine, valine, histidine, lysine, and arginine and also for the average of all amino acids. Ileal digestibility was increased (P < 0.05) as pigs grew. For the second experiment, four different diets each containing different fish meals were fed to 120 pigs to evaluate growth performance over the age period of 3 to 7 wk. Average daily gain was higher (P < 0.07) in pigs fed diets containing either mackerel or herring fish meal than in pigs fed menhaden fish meal during 3 to 5 wk of age and was highest (P < 0.07) in pigs fed a diet containing mackerel fish meal during 5 to 6 wk of age. Gain/feed was higher (P < 0.05) in pigs fed diets containing mackerel and herring fish meals than in pigs fed menhaden fish meal. Mackerel dried at 70 degrees C showed the highest value from the previous two experiments and was chosen to measure the relative bioavailability in comparison to spray-dried porcine plasma. A classical slope-ratio design was used to measure relative bioavailability of mackerel fish meal compared to porcine plasma protein. This study showed that mackerel dried at 70 degrees C can replace spray-dried porcine plasma with the same bioavailability during d 17 to 29 postpartum with additional crystalline lysine and amino acid supplementation to match amino acid profile of the spray-dried porcine plasma.     

Aspects of the ecology of the Asian tapeworm, Bothriocephalus acheilognathi Yamaguti, 1934 in yellowfish in the Vaal Dam, South Africa

Seasonal surveys were conducted at the Vaal Dam between April 2000 and January 2001. Twenty smallmouth yellowfish (Labeobarbus aeneus) and 20 largemouth yellowfish (Labeobarbus kimberleyensis) were collected with the aid of gill nets. Surface water quality variables were included. The cestodes were identified as either Bothriocephalus acheilognathi Yamaguti, 1934 or "other cestode spp.". The majority (99.8%) of the cestodes found in both yellowfish species were identified as B. acheilognathi (Asian tapeworm). The prevalence, mean intensity and abundance of B. acheilognathi in both yellowfish species were calculated. Ecological parameters including species specificity, seasonality, gender specificity and relationships between fish size and the Asian tapeworm prevalence were also included. In this study, B. acheilognathi preferred L. kimberleyensis over L. aeneus although a low intensity was observed in smallmouth yellowfish. Furthermore, the infection (in terms of prevalence, abundance and mean intensity) in largemouth yellowfish was markedly higher. Seasonal patterns observed in the Asian tapeworm's infection of smallmouth yellowfish are attributed to breeding and subsequent feeding patterns of this fish species with relatively high infections recorded in winter and spring. For L. kimberleyensis no explanation can be given regarding the seasonal patterns observed for the mean intensity and abundance of B. acheilognathi. The maximum and minimum mean intensity and abundance values in largemouth yellowfish were recorded in autumn and spring, respectively. In addition, the prevalence of B. acheilognathi was consistently high in all four seasons.     

Pelagic eggs of marine fishes from Park Rynie,KwaZulu-Natal,South Africa: seasonal spawning patterns of the three most common species

For the period 1987 to 1998, pelagic eggs of marine fishes were collected from shelf waters at Park Rynie on the KwaZulu-Natal south coast. The three most numerous eggs collected were those of the mackerel Scomber japonicus,the sardine Sardinops sagax and the East coast roundherring Etrumeus teres. Together they comprised 67 % of all eggs collected. At times single-species egg densities were high, the highest accurately recorded was 850 eggs/cubic metre for S. sagax. All three species were predominantly winter to spring spawners. Theseasonal pattern of sardine eggs at Park Rynie suggests that after entering KwaZulu-Natal waters in June, sardines remain until November or December of each year before returning south to eastern Cape waters. Spawning in the East coast roundherring began in June, peaked in October to November, and tailed off in January. The mackerel showed a similar pattern of spawning, beginning in June and ending in December.     

Anisakid nematodes in beaked redfish (Sebastes mentella) from three fishing grounds in the North Atlantic,with special notes on distribution in the fish musculature

Parasitic anisakid nematodes commonly occur in the musculature and visceral organs of many fish species from the North Atlantic. In this respect, the presence of the third stage larvae of Anisakis spp. in the fish musculature may pose a potential consumer hazard due to the parasite's ability to cause anisakidosis. Thus, knowledge on the occurrence and distribution of these potentially zoonotic parasites in the commercially important North Atlantic fish species is crucial in order to evaluate and consequently prevent human infections.In the present study, 300 Sebastes mentella from three North Atlantic fishing grounds (Northern North Sea: Tampen; Barents Sea: off Bear Island; Irminger Sea: off SE Greenland) were examined for anisakid nematodes, with emphasis on occurrence and distribution in the musculature. Overall larval prevalence and mean intensity were significantly higher in redfish from Tampen (94%; 13.5 ± 20.0) and Bear Island (94%; 14.5 ± 19.4) than in fish from SE Greenland (75%; 6.0 ± 5.8; p < 0.01). The same trend was observed for larval infection in the musculature showing prevalence and mean intensities of 79%, 73%, and 55%, and 5.9 ± 6.6, 5.8 ± 6.5, and 3.2 ± 2.4, in the musculature of redfish from Tampen, Bear Island, and Greenland, respectively. Conventional microscopy and rDNA ITS-gene sequencing of various subsamples of muscle-dwelling nematode larvae of redfish from every catching locality revealed the presence of two anisakid species; Anisakis simplex sensu stricto and the non-zoonotic Hysterothylacium aduncum. Since the larvae of H. aduncum typically occur in or on the viscera of fish, our findings of two specimens in the belly flaps of redfish were unusual. Additionally, more than 92% of the muscle-dwelling larvae occurred in the belly flaps, i.e. the hypaxial part of the musculature surrounding the visceral organs on either fish side. Thus, trimming the fillets of beaked redfish by removal of most of the belly flaps would significantly reduce the probability of anisakid nematode larvae to be present in the final product.     

Pathological and immunohistochemical study of gastrointestinal lesions in dolphins stranded in the Canary Islands

This paper describes the gross, histopathological and immunohistochemical characteristics of gastrointestinal lesions and regional lymph nodes of six common dolphins (Delphinus delphis), 11 striped dolphins (Stenella coeruleoalba) and six Atlantic spotted dolphins (Stenella frontalis) found stranded along the coasts of the Canary Islands. The most common lesion was chronic granulomatous gastritis of the glandular stomach, associated with the parasite Pholeter gastrophilus, and characterised by the parasites, their eggs, or parasite debris in the mucosa, submucosa or tunica muscularis, surrounded by numerous lysozyme-positive macrophages and neutrophils, and more peripherally by abundant fibrous tissue containing variable numbers of immunoglobulin (Ig) G+ plasma cells, and small numbers of CD3+ T lymphocytes and IgM+ and IgA+ plasma cells. Anisakis simplex nematodes were found in two dolphins that were also parasitised by P gastrophilus and had parasitic granulomatous gastritis and multiple small chronic gastric ulcers. Lymphoplasmacytic enteritis was found in eight cases, three of them parasitised by Diphyllobothrium species; the lesion was characterised by moderate to severe infiltrations of CD3+ T lymphocytes and IgG+ plasma cells, with small numbers of IgM+ and IgA+ plasma cells in the lamina propria and submucosa, mainly of the small intestine. One dolphin had severe fibrinopurulent peritonitis, which may have been secondary to gastric perforation caused by the large mural granulomatous gastritis associated with P gastrophilus parasitism.