OBJECTIVEThe aim of this research was to investigate the third phase Anisakis simplex larvae (Anisakis L₃) infection in marine fish caught in Zhoushan Fishery and to find out its physicochemical and biological characteristics.

METHODSA total of 444 fish belonging to 29 species were dissected to isolate anisakis larvae which were then morphologically identified. The survival tolerance of Anisakis L₃ were observed in various conditions, such as in different temperature and medium.

RESULTSA total of 218 fish from 21 species were infected by Anisakis simplex larvae, yielding an overall infection rate of 49.10% (218/444). Trichiurus haumela, pneumatophorus japonicus, miichthys miiuy, argyrosomus argentatus and anguilliformes had high infection rate and had an average infection intensity of 15.28 per fish. 3332 Anisakis larvae were detected in 218 fish, among which Anisakis L₃ and Pseudoterranova larvae accounted for 99.46% (3314/3332) and 0.54% (18/3332) respectively. Anisakis L₃ was highly resistant to common condiment. We found the liquor with high concentration of alcohol showed better insecticidal effect than that with low concentration of alcohol (t = 4.105, P < 0.05) and low concentration mebendazole composite was not only more effective than high concentration mebendazole composite (F = 45.198, P < 0.01) but also more effective than other drugs, such as albendazole and mebendazole. Anisakis L₃ could live up to 9 h and 12 h at -20°C, -10°C respectively, however they were very sensitive to high temperature. It has been shown that they could only survive for less than 11 s and 1 s at 50°C and 60°C respectively.

CONCLUSIONThe observed Anisakis L₃ infection rate in the marine fish found in Zhoushan Fishery was very high. Anisakis L₃ showed high resistance to low temperature but not to high temperature.

Animals ; Anisakiasis ; parasitology ; veterinary ; Anisakis ; Fish Diseases ; parasitology ; physiopathology ; Fisheries ; Fishes ; parasitology ; Larva ; Temperature

The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae (AdL3) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb (0.093 x 0.221 mm in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL3 of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae.
Animal Structures/parasitology ; Animals ; Fish Diseases/*parasitology ; Gnathostoma/anatomy & histology/classification/*isolation & purification ; Gnathostomiasis/parasitology/*veterinary ; Microscopy ; Myanmar ; Smegmamorpha/*parasitology

A parasitological investigation on trematode metacercariae was made on 62 freshwater fishes of 13 species in northern Thailand; Cyclocheilichthys apogon, Puntioplites proctozysron, Labiobarbus siamensis, Barbodes gonionotus, Barbodes altus, Henicorhynchus siamensis, Osteochilus hasselti, Notopterus notopterus, Mystacoleucus marginatus, Anabas testudineus, Systomus orphoides, Morulius chrysophykadian, and Hampala macrolepidota. The fish were caught over the summer period (February-May 2007) from 2 Chiang Mai water reservoirs, i.e., the Mae Ngad (UTM 47Q E 503200, 47Q N 2119300) and the Mae Kuang Udomtara (UTM 47Q E 513000, 47Q N 2092600) Reservoirs in Chiang Mai province, Thailand. The prevalence of heterophyid (Haplorchis taichui and Haplorchoides sp.) metacercariae in these fish was 83.9% and 74.2% in the Mae Ngad and Mae Kuang Udomtara Reservoirs, respectively. The highest intensity of heterophyid metacercariae in H. siamensis in the Mae Ngad was 120.4 and that in P. proctozysron in the Mae Kuang Udomtara was 180.0. The fish, A. testudineus, C. apogon, and M. chrysophykadian, were not found to be infected with H. taichui metacercariae. The results show that the freshwater fish in Chiang Mai water reservoirs are heavily infected with H. taichui and Haplorchoides sp. metacercariae.
Animals ; Fish Diseases/*epidemiology/*parasitology ; Fishes/*parasitology ; Fresh Water/*parasitology ; Heterophyidae/*isolation & purification ; Thailand/epidemiology ; Trematode Infections/epidemiology/parasitology/*veterinary

The infection status of anisakid larvae was examined in 290 marine fish of 25 species and in 108 cephalopods of 3 species purchased in Bayuquan region, Yingko city nearby the coast of the Bohai Sea from may to August 1992. A total of 7,327 larvae were collected from 156 fish of 19 species and 8 squids of one species. The 3rd-stage larvae of Anisakis simplex were collected from 121 fish (63.4%) of 15 species (N = 191) and from 8 squids (14.8%) of one species (N = 54), and they were total, 5,992 (81.8%). Out of remaining 1,335 larvae, 154 (2.1%) were classified as Thynnascaris type B from 23 fish of 4 species, 1,013 (13.8%) as Thynnascaris type C from 79 fish of 13 species. 164 (2.2%) as Hysterothylacium China type V from 20 fish of 4 species, 3 (0.04%) as Raphidascaris from 3 fish of 2 species and one was Pseudoterranova decipiens larva.
Animal ; Anisakiasis/veterinary* ; Anisakiasis/parasitology ; Anisakiasis/epidemiology ; Anisakis/isolation & purification ; Anisakis/classification* ; China ; Fish Diseases/parasitology* ; Fish Diseases/epidemiology ; Fishes ; Larva ; Seawater ; Squid/parasitology*

In order to determine the current infection status of pond smelts, Hypomesus olidus, and other freshwater fishes with trematode metacercariae, a total of 4,861 pond smelts and 18 other freshwater fishes, collected from the Soyang and Uiam Lakes in Gangwon-do, the Unam Lake in Jeollabuk-do, the Jangseong Lake in Jeollanam-do, the Uirim-ji (lake) in Chungcheongbuk-do, and the Andong Lake in Gyeongsangbuk-do, were individually digested with 1% pepsin-HCl and examined under a dissecting microscope. In all pond smelts caught from the 6 lakes, we were unable to detect any known human infectious trematode metacercariae in Korea. However, in other freshwater fishes, such as, Squalidus japonicus coreanus (Unam Lake), and Zacco platypus (Jangseong Lake) and Opsariichthys uncirostris amurensis (Jangseong Lake), metacercariae of human-infecting trematodes, i.e., Clonorchis sinensis and Metagonimus sp. were detected, respectively.
Trematode Infections/*veterinary ; Osmeriformes/*parasitology ; Korea ; Humans ; Fresh Water ; Fish Diseases/*parasitology ; Animals

The metacercariae of Centrocestus formosanus, a minute intestinal trematode of mammals and birds, were detected in the freshwater fish, Puntius brevis, from Vientiane Municipality, Lao PDR. The metacercariae were experimentally fed to mice, and adult flukes were recovered in their small intestines 7 days later. The adult flukes were morphologically characterized by having 32 (rarely 34) circumoral spines arranged in 2 alternative rows, a large bipartite seminal vesicle, an oval-shaped ovary, and an X-shaped excretory bladder. Based on these characters, the adults were identified as Centrocestus formosanus (Nishigori, 1924). The taxonomic significance of C. formosanus, in relation to a closely related species, C. caninus (Leiper, 1913), is briefly discussed. It has been first verified by adult worm recovery that C. formosanus is prevalent in Vientiane areas of Lao PDR, taking the freshwater fish, P. brevis, as a second intermediate host.
Animals ; Fish Diseases/*parasitology ; Fishes ; Laos ; Trematoda/*classification/ultrastructure ; Trematode Infections/parasitology/*veterinary

The metacercariae of Centrocestus formosanus, a minute intestinal trematode of mammals and birds, were detected in the freshwater fish, Puntius brevis, from Vientiane Municipality, Lao PDR. The metacercariae were experimentally fed to mice, and adult flukes were recovered in their small intestines 7 days later. The adult flukes were morphologically characterized by having 32 (rarely 34) circumoral spines arranged in 2 alternative rows, a large bipartite seminal vesicle, an oval-shaped ovary, and an X-shaped excretory bladder. Based on these characters, the adults were identified as Centrocestus formosanus (Nishigori, 1924). The taxonomic significance of C. formosanus, in relation to a closely related species, C. caninus (Leiper, 1913), is briefly discussed. It has been first verified by adult worm recovery that C. formosanus is prevalent in Vientiane areas of Lao PDR, taking the freshwater fish, P. brevis, as a second intermediate host.
Animals ; Fish Diseases/*parasitology ; Fishes ; Laos ; Trematoda/*classification/ultrastructure ; Trematode Infections/parasitology/*veterinary

A survey was performed to investigate the infection status of fishborne trematode (FBT) metacercariae in freshwater fish from Guangxi Zhuang Autonomous Region, China. A total of 307 freshwater fish of 31 species were collected from 5 administrative regions of Guangxi Zhuang Autonomous Region. They were examined by artificial digestion method from July 2003 to August 2004. No metacercariae were detected in fish from Fusui-xian. In fish from Mashan-xian and a market in Nanning, 3 species of metacercariae, Haplorchis taichui, Haplorchis pumilio, and Centrocestus formosanus, were mainly detected. Metacercariae (8 in number) of Clonorchis sinensis were found in 1 Chanodichthys dabryi purchased from a market in Nanning. In fish from Yangshuo, Metagonimus yokogawai metacercariae were detected from all 18 fish species examined. Total 13 C. sinensis metacercariae were found in 3 out of 10 Hemibarbus maculatus from Yangshuo. All 7 Zacco platypus from Yangshuo were infected with 8-112 Echinochasmus perfoliatus metacercariae. In fish from Binyang-xian, H. pumilo metacercariae were mainly detected in all 5 fish species examined, and only 1 metacercaria of C. sinensis was found in a Hemiculter leucisculus. From the above results, it was confirmed that some species of freshwater fish play a role of second intermediate hosts for FBT in Guangxi Zhuang Autonomous Region, China. In particular, 4 species of intestinal flukes, M. yokogawai, H. taichui, H. pumilio, and C. formosanus, were prevalent in fish hosts, whereas C. sinensis metacercariae were detected only in 3 fish species.
Animals ; China/epidemiology ; Fish Diseases/epidemiology/*parasitology ; Fresh Water/*parasitology ; Trematoda/cytology/*isolation & purification ; Trematode Infections/epidemiology/parasitology/*veterinary

To examine the infection status of freshwater fish with Gnathostoma spp. larvae in Myanmar, we purchased 15 snakeheads, Channa striatus, from a local market in a suburban area of Naypyidaw, the new capital city. Two larval gnathostomes were collected using an artificial digestion technique, and observed by a light microscope and a scanning electron microscope. The size of an intact larva was 2.65 mm long and 0.32 mm wide. The characteristic morphology of the larvae included the presence of a long esophagus (0.80 mm long), 2 pairs of cervical sacs (0.43 mm long), and a characteristic head bulb with 4 rows of hooklets. The number of hooklets in the 1st, 2nd, 3rd, and 4th row was 45, 48, 50, and 52, respectively. Based on these morphological characters, the larvae were identified as the advanced 3rd-stage larvae of Gnathostoma spinigerum. This is the first report of detection of G. spinigerum 3rd-stage larvae in the central part of Myanmar. Our study suggests that intake of raw meat of snakehead fish in Myanmar may result in human gnathostomiasis.
Animals ; Fish Diseases/parasitology ; Gnathostoma/*isolation & purification/ultrastructure ; Larva/ultrastructure ; Myanmar ; Perciformes/*parasitology ; Spirurida Infections/parasitology/*veterinary

To identify acanthocephala found in 'Changran-pickles' and 'Myungran-pickles' each organ was measured in permanent slides. In the present report, the results obtained were as follows: 1. Morphology of male worms: Worms possessed 18-19 longitudinal rows, with 4 hooks per row, which became smaller towards the base of proboscis. Each worm contained two testis and six cement glands arranged linearly. Body 22.0 by 0.8-0.6 mm and 15.0 by 0.6-0.4 mm, proboscis 284.8 by 227.6 microgram and 524.9 by 151.4 microgram, proboscis sheath 1570.7 by 72.7 microgram and 751.9 by 280.4 microgram, lemnisci length 2566.7 and 1085.6, testis 2202.9-1860.5 by 737.0-575.7 microgram and 1033.8-981.1 by 463.1-351.6 microgram, cement glands 940.2 by 441.2 microgram and 610.0 by 369.1 microgram. 2. Morphology of female worms: Worms possessed 14-18 longitudinal rows, with 6-10 hooks per row and become smaller toward the base of proboscis. Each worm contained an uterine bell and uterus in the posterior portion and the eggs filled the body cavity. Body 14.0~51.0 mm by 0.7-0.5~2.2-1.4 mm, proboscis 466.1-268.9 microgram by 259.9-252.0 microgram, proboscis sheath 1550.7-506.0 by 298.8-231.1 microgram, lemnisci length 1325.7-473.1 microgram, eggs 112.4 by 28.5 microgram~51.7 by 14.0 microgram. In this present study, the acanthocephala collected in 'Changran-pickles' and 'Myungran-pickles' were identified as Echinorhynchus gadi by morphological features.
Acanthocephala/anatomy & histology/classification/*isolation & purification ; Animals ; Female ; Fish Diseases/*parasitology ; Fishes ; Helminthiasis, Animal/*parasitology ; Korea ; Male ; Seafood/*parasitology