Contracaecum Type Research Articles

Integrative species delimitation and community structure of nematodes in three species of Australian flathead fishes (Scorpaeniformes: Platycephalidae).

This study aimed to determine the integrative characterisation of nematodes from three species of edible flathead fishes (Scorpaeniformes: Platycephalidae) in New South Wales, Australia, and describe nematode communities within three species of flatheads. Tiger (Platycephalus richardsoni (Castelnau); n = 20) and sand flatheads (Platycephalus bassensis (Cuvier); n = 20), sourced from the Nelson Bay area, and dusky flathead (Platycephalus fuscus (Cuvier); n = 20) from the Manning River, Taree, were examined for the presence of nematodes. The nematodes were initially classified morphologically as 12 different morphotypes belonging to the families Anisakidae (Anisakis types I, II, and III, Contracaecum type II, Terranova types I and II), Raphidascarididae (Hysterothylacium types IV, VI, VIII, and H. zhoushanense larva), and Gnathostomatidae (Echinocephalus sp. larva), Capillariidae (Capillaria sp.), followed by genetic identification through sequencing of the internal transcribed spacer (ITS-1, 5.8S, ITS-2) regions. Phylogenetic analyses revealed the evolutionary relationship between the identified larval specimens in the present study with available GenBank larval and adult nematodes. Sand flathead was 90% infected with nematodes followed by tiger flathead at 85% and dusky flathead at 15%. Nematodes infecting estuarine dusky and oceanic sand and tiger flatheads contrasted markedly. The analysis of similarities (ANOSIM) showed significant differences (p < 0.001) in the composition of taxa within nematode communities between the three species of flatheads (global R = 0.208) with the highest difference being between sand and dusky flatheads (R = 0.308, p < 0.001). The findings of the present study provide a foundation for future investigations of the community composition, life cycles, and distribution of nematode populations in edible fish in Australia and explore and clarify their significance to public health.

Zoonotic nematode parasites infecting selected edible fish in New South Wales, Australia

Despite increases in the annual consumption of seafood in Australia, studies on the occurrence and prevalence of zoonotic parasites in fish and the risk they may pose to human health are limited. The present study was aimed at determining the occurrence of zoonotic nematodes in commonly consumed fish in New South Wales, Australia's most populous state. Three species of fish, including the Australian pilchard, Australian anchovy, and eastern school whiting, were purchased from a fish market and examined for the presence of nematode parasites. All Australian pilchards examined in this study were infected (100%; n = 19), followed by the eastern school whiting (70%; n = 20) and Australian anchovy (56%; n = 70). Nematodes were in the larval stage and, therefore, classified by morphotype, followed by specific identification through sequencing of their internal transcribed spacer (ITS) regions. Seven different larval types with zoonotic potential, belonging to the families Anisakidae (Contracaecum type II and Terranova type II) and Raphidascarididae (Hysterothylacium types IV [genotypes A and B], VIII, XIV and a novel Hysterothylacium larval type, herein assigned as type XVIII), were found. The new larval type was identified as Hysterothylacium thalassini, based on ITS sequence data. The presence of the infective stage of a range of zoonotic parasites in fish commonly consumed in New South Wales is important, particularly as, in some dishes, these fish are used whole, raw or undercooked. This study provides the basis for future research on other aspects of these parasites, in regards to public health.

New and known zoonotic nematode larvae within selected fish species from Queensland waters in Australia

Zoonotic fish-borne nematodes are a significant and growing global health concern. However, in Australia their occurrence and geographical distribution are not well known. Moreton Bay in Queensland, Australia, is a popular tourist destination for domestic and international visitors where seafood is a popular food item. The aim of this study was to determine the occurrence of zoonotic nematodes within four commercially significant teleost fish species from Moreton Bay; Surf Bream, Sea Mullet, Yellow-Fin Tripod fish and Gold-Lined Sea Bream. Overall, 34.03% of fish examined (n = 144) were found to be a host to at least one parasitic nematode. The seasonal dynamics and prevalence of nematode infection was tested by statistical means. Results indicated a significant difference in seasonal infection for Surf Bream (p < 0.005) only. Several potentially zoonotic larval morphotypes were found, including Contracaecum types I and II, and Terranova type II (Family Anisakidae), and Hysterothylacium types VI and XIV and a new Hysterothylacium larval type herein assigned as type XVII (Family Raphidascarididae). ITS sequence data showed that some Contracaecum type II and Hysterothylacium types VI found in the present study are genetically distinct from those previously reported. The new genotypes were assigned to Contracaecum type II Genotype B and Hysterothylacium type VI, Genotypes B and C. This study provides essential information for future research on specific identification and differentiation of infective stages of zoonotic nematoda in edible fish.

Endoparasite fauna of Brycon amazonicus and B. melanopterus(Characidae, Bryconinae) from Negro and Solimões rivers, Amazon, Brazil

ABSTRACTCongeneric host species present similar biological and behavioral aspects, what may favor the presence of a similar parasite fauna. The aim of the present study was to compare the composition and structure of the parasite community from congeneric species, Brycon amazonicus and B. melanopterus, collected on the Negro and Solimões Rivers. The fish internal organs were longitudinally opened and analyzed under stereomicroscope. The examination revealed that B. amazonicuswas parasitized by Procamallanus(Spirocamallanus) inopinatus(26.7% and 35.5%), Contracaecum type 2 (10% and 16.13%) and Rhabdochona acuminata(0% and 3.23%), prevalence values for Negro and Solimões River, respectively. The analysis of B. melanopterus, a fish species found only in the Solimões River, revealed P.(S.) inopinatus(33.3%), Contracaecum type 1 (60%) and R. acuminata(3.34%). These results indicate that the taxonomic proximity of the hosts was a stronger influence on the parasite species than external host environment.

Occurrence and abundance of anisakid nematode larvae in five species of fish from southern Australian waters

The aim of the present study was to conduct, in southern Australian waters, a preliminary epidemiological survey of five commercially significant species of fish (yellow-eye mullet, tiger flathead, sand flathead, pilchard and king fish) for infections with anisakid nematodes larvae using a combined morphological-molecular approach. With the exception of king fish, which was farmed and fed commercial pellets, all other species were infected with at least one species of anisakid nematode, with each individual tiger flathead examined being infected. Five morphotypes, including Anisakis, Contracaecum type I and II and Hysterothylacium type IV and VIII, were defined genetically using mutation scanning and targeted sequencing of the second internal transcribed spacer of nuclear ribosomal DNA. The findings of the present study provide a basis for future investigations of the genetic composition of anisakid populations in a wide range of fish hosts in Australia and for assessing their public health significance.

Mutation scanning-coupled sequencing of nuclear ribosomal DNA spacers as a tool for the specific identification of different Contracaecum (Nematoda: Anisakidae) larval types

In the present study, various morphotypes of Contracaecum (Nematoda) larvae in different developmental stages were described and then genetically characterised using sequence data obtained from the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA (rDNA). The alignment of ITS-1 and ITS-2 sequence data for larvae investigated with those from well characterised adults in previous studies showed that fourth-stage Contracaecum larvae from the Australian pelican, Pelecanus conspicillatus, had the same sequence as Contracaecum microcephalum reported from the little pied cormorant, Phalacrocorax melanoleucos. In addition, four different morphotypes of third-stage larvae, including types I to IV, were found in various species of fish. Contracaecum type I larvae were composed of two distict genotypes; those collected from mullet, Mugil cephalus, had the same sequence as C. multipapillatum, and those from an unknown species of hardyhead (family Atherinidae) were C. pyripapillatum. Contracaecum type II larvae from mackerel, Scomber australasicus, had the same sequence as adult C. ogmorhini sensu stricto, found in the Australian and New Zealand fur seals ( Arctocephalus spp). Contracaecum type III larvae from flathead, Platycephalus laevigatus, had the same sequence as C. rudolphii D found in the black cormorant, Phalacrocorax carbo. The approach used herein was an effective means of matching incompletely identifiable larval nematodes with reference sequences and provides a basis for exploring the composition of populations of anisakid larvae in fish as well as their ecology, particularly their life cycles and transmission patterns.

고래회충유충증 감별 진단을 위한 18S ribosomal DNA (rDNA) PCR-RFLP 법 적용

고래회충유충증은 해산어류에 기생하는 고래회충과(family Anisakidae)에 속하는 선충류 유충에 의한 질병으로 유충의 직접적인 위장관내 침입으로 인한 병변과 더불어 유충의 분비 배설물에 의한 알레르기 질환도 유발될 수 있다. 고래회충유충증은 A. simplex를 비롯하여 Contracaecum, Pseudoterranova, Hysterothylacium 등의 유충에 의해 야기될 수 있으나 이들에 대한 형태학적 감별 진단은 유충의 형태적 유사성으로 인하여 매우 어려운 경우가 많다. 이러한 형태학적 진단의 어려움을 극복하고 분자생물학적 감별진단 방법을 확립하기 위하여 A. simplex, Contracaecum type A. type C' 및 Goezia 유충을 숭어, 도다리, 고등어, 아나고, 참돔 등 5종의 어류에서 분리하였다. 각각의 유충으로부터 분리한 18S rDNA를 PCR로 증폭한 후 Taq 1, Hinf I, Hha I, Alu 1, Dde I, Hae III, Sau 96I, Sau 3AI 등 8종의 제한효소를 사용하여 PCR-RFLP를 시행하였다. PCR product의 크기는 약 2.0 Kb였으며 Hinf l, Alu 1, Hha I, Dde 1 및 Hae III로 A. simplex와 Contracaecum type C'을 구분할 수 있었다. 그러나 Contracaecum type A의 경우에는 Taq I, Hinf I, Alu I 및 Dde I의 경우에는 2가지 패턴으로 나타났으며 이들 가운데 일부는 A. simplex, Contracaecum type C', 및 Goezia와 동일한 분석 패턴을 보이기도 하였다. Goezia는 사용한 8개의 제한 효소 모두에서 A. simplex 및 Contracaecum type A 및 type C'과 각기 다른 양상을 보였다. 이러한 결과로 18S rDNA PCR-RFLP 방법은 A. simplex와 Contracaecum type C'의 감별 진단에 유용한 것으로 밝혀졌으며, Contracaecum type A의 분류에는 제한적으로 사용되어야 함은 물론 형태학적 분류 기준에 대한 재검토가 뒤따라야 할 것으로 사료되었다. Anisakidosis is caused by anisakid nematodes (family Anisakidae) larvae which can cause not only direct tissue damage but also a severe allergic response related to excretory-secretion products. Lots of different species of anisakid larvae, including Anisakis simplex, Contracaecum, Goezia, Pseudoterranova, and Hysterothylacium, cause the anisakidosis. But it is difficult to diagnosis the species of larvae since the morphologies of larval anisakid nematodes are almost indistinguishable. In order to diagnosis the differential infections of larval anisakid nematodes, polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) of 18S rDNA - was conducted. Three major species of anisakid larvae including A. simplex, C.ontracaecum spp, and Goezia spp. were collected from mackerel (Scomber japonicus), mullet (Mugil cephalus), founder (Paralichthys olivaceus), eel (Astroconger myriaster) and red sea bream (Pagrus major). PCR amplified 18S rDNA from each species of anisakid larvae was digested with eight restriction enzymes including Taq I, Hinf I, Hha I, Alu I, Dde I, Hae III, Sau96 I, and Sau3A I. The original sizes of PCR amplified 18S rDNA were 2.0Kb in both anisakid larvaes and Goezia. Restrction enzymes including Hinf 1, Alu 1, Hha I, Dde 1 and Hae III cut differently and distinguished the A. simplex and Contracaecum type C'. However, Contracaecum type A showed two different restriction enzyme cutting patterns by Taq 1, Hinf I, Alu 1, and Dde 1. One of the patterns was the same as those of A. simplex, Contracaecum type C' and Goezia and the other was unique. These results suggest that PCR-RFLP pattern by Hinf 1, Alu 1, Hae I, Dde 1 and Hae III can be applied to differential diagnosis of human infection with A. simplex and Contracaecum type C'. Contracaecum type A needs further study of classification by morphological characteristics and genetic analysis.

Endoparasite infracommunities of Hemisorubim platyrhynchos (Valenciennes, 1840) (Pisces: Pimelodidae) of the Baía River, Upper Parana River floodplain, Brazil: specific composition and ecological aspects.

Parasites of 136 specimens of Hemisorubim platyrhynchos, popularly called jurupoca, were analyzed. Fourteen parasite species were recorded: four digeneans (Crocodilicola pseudostoma, one Gorgoderidae species, Sanguinicola platyrhynchi, and Sphincterodiplostomum sp.); three cestodes (Goezeella paranaensis, Spatulifer maringaensis, and Mariauxiella piscatorum); five nematodes (Contracaecum Type 1 larvae of Moravec, Kohn, & Fernandes, 1993; Contracaecum Type 2 larvae of Moravec, Kohn, & Fernandes, 1993; Cucullanus (Cucullanus) zungaro; Eustrongylides ignotus; and Goezia sp.); one acanthocephalan (Quadrigyrus machadoi), and one pentastomid (Sebekia sp.). Most of the helminth specimens were found in larval stages, confirming that H. platyrhynchos is a significant source of their transmission. No dominance was reported. With the exception of Contracaecum Type 2 (featuring random dispersion), the species had a clumped pattern of dispersion in the host sample. Evidence of competition among parasite species was not reported. Several species of parasites were correlated with host size and sex. This fact may be explained by increase in food content and possible behavioral modifications of male and female hosts. Infracommunity diversity was not related to host size or sex.

Aspectos ecológicos da fauna endoparasitária de Acestrorhynchus lacustris (Lütken, 1875) (Characiformes, Acestrorhynchidae) da planície de inundação do alto rio Paraná, Brasil

Fifty-one specimens of Acestrorhynchus lacustris (Lütken, 1875) collected on the Upper Paraná River floodplain were analyzed from February 2000 to November 2001. Of these, 35 (68.6%) were parasitized by at least one species of endohelminth. Eight species of endoparasites were found: five nematodes (Contracaecum Type 1 larvae of Moravec, Kohn and Fernades, 1993, Contracaecum Type 2 larvae of Moravec, Kohn and Fernades, 1993, Contracaecum sp., Eustrongylides sp. and Procamallanus sp.), two digeneans (Clinostomum sp. and Rhipidocotyle gibsoni Kohn and Fernandes, 1994) and one acanthocephalan (Quadrigyrus torquatus Van Cleave, 1920). Contracaecum sp. and Q. torquatus were positively associated and also had positively correlated abundances. There was significant difference in the prevalence and abudance of infection of Q. torquatus between hosts sexes. This parasite also presented negative correlation between its intensity and host standard length. There are significant positive correlation between the prevalence of Contracaecum Type 1 and host standard length

相模湾および駿河湾の魚介類におけるアニサキス幼虫感染

A total of 5, 555 fishes (17 marine fish and 1 squid species) from Sagami and Suruga Bays were examined for Anisakis larvae in 1995 to 1996. The larvae were detected from 6.1% of Japanese anchovies, 33.7% of chub macherels, 2.0% of white-tipped macherel scads and 23.1% of frigate macherels collected from Sagami Bay, as well as from 3.5% of Japanese anchovies, 0.5% of Japanese pilchards, 21.0% of chub macherels and 33.3% of dolphinfishes collected from Suruga Bay. The average numbers of larvae per fish were 1.5 (1 to 3) and 6.5 (1 to 31) in Japanese anchovies and chub mackerels, respectively. Most larvae parasitized in the visceral organs and abdominal cavity, while a few in the muscles. Most larvae obtained were of Anisakis Type I larvae, Anisakis simplex, and a small number of Anisakis Type II and IV, Contracaecum Type B and D and Spirurid larvae were detecfed.

Infection status of anisakid larvae in anchovies purchased from local fishery market near southern and eastern sea in Korea

A survey was carried out on the larval anisakis in anchovies (Engrauris japonica) which were caught from April to June in 1993 at the southern and eastern sea in Korea. Anisakids in anchovies were morphological classified into Anisakis type I and II and Contracaecum type B and C, after fixation in 70% alcohol and clearing in lactophenol. A total of 171 larval anisakids were collected from 150 anchovies (6.9%) out of 2,180 examined. The infection rates showed no relation with length of the anchovies. The numbers of anisakids by organs of anchovies were 96 (56.1%) from the muscle, 65 (38.0%) from the omentum, 7 (4.1%) from the intestine, 2 (1.7%) from the stomach and 1 (0.6%) from the testis. Infection rates of anchovies with anisakids by localities were 5.1% at Taebyon, 8.0% at Sokcho and 9.2% at Chungmu. The larval anisakids in anchovies may infect humans who often eat raw anchovies.

Infection status of the sea eel (Astroconger myriaster) purchased from the Noryangjin fish market with anisakid larvae

Although the sea eel (Astroconger myriaster) is suspected as one of the most important fish host for human anisakiasis in Korea, no report has been made on the infection status of the sea eel with anisakid larvae. In the present study, 26 sea eels (Astroconger myriaster) were purchased from the Noryangjin fish market in Seoul, and anisakid larvae were collected from their viscera, muscle, head and skin. The collected larvae were classified by their morphological types. A total of 1,351 anisakid larvae were collected from 15 of 26 fish examined. Among them, 1,269 were recovered from the viscera, 66 from the muscle, and 16 from the head and skin. Morphologically, most of the anisakids were classified into 6 known larval types, Anisakis type I (564 larvae) of Berland (1961), Contracaecum type A (409) and type D (5) of Koyama et al. (1969), Contracaecum type C' (83) and type D' (117) of Chai et al. (1986), and Contracaecum type V (1) of Yamaguti (1935). Remaining 172 specimens were new in the available literature, hence, designated as Contracaecum type A' (new type). The present results revealed that the sea eels caught in the Korean waters are heavily infected with anisakid larvae, not only in their viscera but also in the muscle, and Anisakis type I was the most common among the 7 larval types.

Surface ultrastructure of larval Anisakidae (Nematoda: Ascaridoidea) and its identification by mensuration.

The surface ultrastructure of larval Anisakis type I, Anisakis type II, Raphidascaris, Contracaecum type A, Thynnascaris type A and Thynnascaris type B was examined by scanning electron microscopy. These species were identified clearly by the presence of a boring tooth, a mucron, and other morphological features. The means of the distances between transverse striations (DBTS) of larval Anisakis type I (5.45 +/- 0.125 micron), larval Raphidascaris (2.92 +/- 0.051 micron), and larval Contracaecum type A (1.68 +/- 0.056 micron) are significantly different (p less than 0.05). There was a correlation between the diameter of worm trunk (DOWT) and DBTS among these three larval types. In most cases a larva could be identified from the mean value of DBTS and DOWT even if obtained as a fragment from a patient.

Larval anisakids collected from the yellow corvina in Korea.

Larval anisakids found in the yellow corvina (Pseudosciaena manchurica), a marine fish caught in the Yellow Sea, were classified by their morphological types. Total 1,068 anisakid larvae were collected from 30 fish examined, with the average number per fish of 35.6. They were classified into Anisakis type I larvae of Berland (859 in number, 80.4%), Contracaecum type A of Koyama et al. (13, 1.2%), Contracaecum type C'(new type) (55, 5.1%), Contracaecum type D of Koyama et al.(18, 1.7%), Contracaecum type D'(new type) (77, 7.2%), Contracaecum type V of Yamaguti(3, 0.28%), Raphidascaris sp. of Koyama et al. (1, 0.09%) and unidentified (42, 3.9%). Contracaecum type C' and D' were considered new in the literature.

アニキサス亜科幼線虫の食品衛生学的研究 Ｖ 香辛料精油および精油成分の殺滅効果

Larvae of Anisakis type I, Terranova type A and Contracaecum type A were gathered from liver, muscle and caecal pylorus of cod and Alaska pollack, respectively, and their mortalities were examined in a medium containing various spice essential oils and some food preservatives.The results were as follows;Pesticidal effects on Anisakis type I larvae were exhibited by the essential oils of nutmeg, cumin, clove, allspice, mace, coriander, and cinnamon. In addition, the essential oils of cumin, clove, allspice, coriander, cinnamon, thyme, dill and caraway showed a similar effect on Terranova type A larvae. Cumin aldehyde, cinnamic aldehyde, thymol, limonene, and eugenol, which are major components of some spices, exhibited strong pesticidal effects on all the three species of worms. The above results were regarded as significant by variance analysis.On the other hand, the pesticidal effects of the food preservatives on Anisakis type I larvae were observed only in the case of free acids such as sorbic acid, salicylic acid, benzoic acid and dehydroacetic acid.