Assessment ofEpinephelus coioides(Hamilton, 1822) aquaculture systems in the Gulf of Tonkin, Vietnam, by using fish parasites (original) (raw)
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Parasite
With a long coastline stretching from tropical to subtropical climate zones, and an immense exclusive economic zone with over 4000 islands, the Vietnamese marine waters support a rich and biodiverse parasite fauna. Although the first parasitological record was in 1898, systematic studies of the parasite fauna have increased during the last 50 years. This comprehensive review covers the current state of knowledge of marine fish parasites in Vietnam and lists 498 species found in 225 fish species, and their geographical distribution. In addition, 251 marine parasite species have newly been added to the already known fauna of 247 species since 2006 (more than two-fold increase). The most speciose group was the Digenea, which accounted for 43% of the total parasite species biodiversity, followed by Monogenea (23.5%), Crustacea (11.6%), Nematoda, and Acanthocephala (8.0% each). The shallow and muddy Gulf of Tonkin showed a rich parasite fauna, accounting for 66.3% of the whole marine par...
The Korean Journal of Parasitology, 2008
Parasites are a ubiquitous phenomenon in the marine environment, and it is probable that all marine fish are infected with parasites [1]. Among these, fishborne zoonotic parasites, especially the trematodes (flukes) are a public health and food safety risk throughout the world [2]. While zoonotic parasites transmitted by freshwater fish are well-documented and have received considerable attention, especially the liver flukes, zoonotic intestinal flukes from marine and brackish water are far less characterized, although in many regions they are welldocumented as major public health problems [3]. The zoonotic flukes identified in countries, such as Korea, Japan, China, and Thailand, indicate that digeneans belonging to the Hete-rophyidae and Echinostomatidae are the most common intestinal flukes seen in humans [2]. A recent review demonstrates that the number of intestinal flukes transmitted to humans specifically from marine and brackish water fish is substantial [4]. Recently zoonotic species of fishborne intestinal flukes were reported for the first time in both humans and freshwater fish in Vietnam [5-9]. However, no reports on these parasites in marine or brackish water fish in Vietnam have appeared. Because of the growing economic importance of marine and brackish water aquaculture in Vietnam, it was of interest to investigate the trematode food safety risk associated with grouper (Epinephelus coioides and Epinephelus bleekeri), a very high value cultured fish. For comparison, wild-caught grouper seed which are captured for grow-out in culture, and wild-caught mullet were also investigated.
PLOS Neglected Tropical Diseases, 2010
Background: Northern Vietnam is an endemic region for fish-borne zoonotic trematodes (FZT), including liver and intestinal flukes. Humans acquire the FZT infection by eating raw or inadequately cooked fish. The production of FZT-free fish in aquaculture is a key component in establishing a sustainable program to prevent and control the FZT transmission to humans. Interventions in aquaculture should be based on knowledge of the main risk factors associated with FZT transmission. in Nam Dinh province, Red River Delta to investigate the development and risk factors of FZT infections in freshwater cultured fish. A total of 3820 fish were sampled six times at two-month intervals from 96 fish farms. Logistic analysis with repeated measurements was used to evaluate potential risk factors based on information collected through questionnaire interviews with 61 fish farm owners. The results showed that the FZT infections significantly increased from first sampling in June to July 2006 (65%) to sixth sampling in April to May, 2007 (76%). The liver fluke, Clonorchis sinensis and different zoonotic intestinal flukes including Haplochis pumilio, H. taichui, H. yokogawai, Centrocestus formosanus and Procerovum varium were found in sampled fish. Duration of fish cultured (sampling times), mebendazole drug self-medication of household members, presence of snails in the pond, and feeding fish with green vegetation collected outside fish farms all had a significant effect on the development of FZT prevalence in the fish.
Freshwater Aquaculture Nurseries and Infection of Fish with Zoonotic Trematodes, Vietnam
Emerging Infectious Diseases, 2010
Vietnam have a long tradition of eating raw fi sh. Fish-borne zoonotic trematodes (FZTs) are estimated to infect ≈1 million persons in Vietnam. It remains uncertain at what stages in the aquaculture production cycle fi sh become infected with FZTs. Newly hatched fi sh (fry) from 8 hatcheries and juveniles from 27 nurseries were therefore examined for FZT infection. No FZTs were found in fry from hatcheries. In nurseries, FZT prevalence in juveniles was 14.1%, 48.6%, and 57.8% after 1 week, 4 weeks, and when overwintered in ponds, respectively. FZT prevalence was higher in grass carp (p<0.001) than in other carp species. Results show that nurseries are hot spots for FZT infections in fi sh. Thus, sustainable FZT prevention strategies must address aquaculture management practices, particularly in nurseries, to minimize the risk of distributing infected juveniles to growout ponds and, subsequently, to markets for human consumption.
Checklist of the parasites of fishes of Viet Nam
2006
Résumé/Abstract This publication is a checklist summarizing information on the parasites of Vietnamese fishes contained in world literature dating from the earliest known record (Billet 1898) to the end of 2003. Information is presented in the form of parasite-host and host-...
Vector-Borne and Zoonotic Diseases, 2010
Nam Dinh province in Red River Delta, Vietnam, is an endemic area for the human liver fluke Clonorchis sinensis, but little is known about its occurrence in the fish intermediate host in this region. A cross-sectional study was carried out to identify fish-borne zoonotic trematodes (FZT) species diversity and to estimate the prevalence and infection densities of FZT in three major types of fish: cultured species and self-recruiting species from family ponds and wild-caught species from irrigation canals in Nam Dinh province. A total of 714 wild-caught fish from canals and 829 fish from family ponds were examined for FZT infection. Only a single fish from a pond was infected with Cl. sinensis. The intestinal fluke Haplorchis pumilio was very common and found in more than 50% of fish irrespective of origin. Four other intestinal FZT species were found at low prevalence (<4.0%) except Procerovum varium, which was found in 14.4% of wild-caught fish. There was no significant difference (p > 0.05) in FZT prevalence in cultured fish (64.3%) compared with wild-caught fish (68.9%), nor between cultured fish species (65.1%) and self-recruiting species obtained from ponds (58.1%). The prevalence of FZT in silver carp (Hypophthalmichthys molitrix) (82.7%), grass carp (Ctenopharyngodon idellus) (76.9%), and mrigal (Cirrhinus mrigala) (63.8%) was significantly higher than that in rohu (Labeo rohita) (49.1%) (p < 0.001). The density of FZT metacercariae in fish from canals (0.56 metacercariae=g) was significantly higher (p < 0.001) than that in fish from ponds (0.03 metacercariae=g). The frequent occurrence of intestinal flukes in all fish types indicates that wild-caught and cultured fish are equally at risk of infection with FZT, particularly in species commonly used in Nam Dinh to prepare raw fish dishes. These results underscore the need for greater awareness of the risk from raw fish dishes among public health agencies and consumers.
Parasites & Vectors, 2015
Background: Fish-borne zoonotic trematodes (FZT), such as Clonorchis sinensis, Opistorchis viverini (Opisthorchiidae) and intestinal trematodes of the family Heterophyidae, constitute a public health hazard in Vietnam and infections with these trematodes has been linked to consumption of raw or undercooked fish from aquaculture. The FZT transmission pathways, however, are more complicated than just the presence of intermediate snail hosts in aquaculture ponds as ponds may exchange water with surrounding habitats such as rice fields and irrigation canals and thereby these surrounding habitats may be a source of snails and cercariae and contribute to FZT infection in cultured fish. Methods: This is a longitudinal descriptive study on selected farms (n = 30) in Nam Dinh Province which is endemic for FZT. At each farm, we sampled one pond, a small irrigation canal used to supply the pond with water, and a nearby rice field. At each of these three sites, we estimated the density of the FZT intermediate snail hosts and determined their trematode infection status. Comparative analysis was performed for the prevalence and density of FZT infections in fish and snails. Results: Species of the Thiaridae, and most notably Melanoides tuberculata, the most important host species for FZT belonging to the Heterophyidae, were particularly abundant in ponds and small canals, i.e. M. tuberculata was found in 27 ponds and 13 small canals. Bithynia fuchsiana, a potential host for both Heterophyidae and Opisthorchiidae, was rarely found in fish ponds but common in rice fields. A total of 12 types of cercariae were found in the snails and pleurolophocercous cercariae, primarily FZT, constituted about 40 % of all cercarial infections. The fish species cultured were mainly carp species and Haplorchis pumilio was the dominating trematode species infecting fish. Clonorchis spp. were not recorded in any of the ponds. FZT transmission to fish was intense during the summer period (May-June to November) but less intense during the winter months (December-January) partly because cercarial emergence ceases due to the low temperature. Conclusion: Our findings highlight the complexity of FZT transmission within aquaculture farm settings and suggest that efforts to control these infections must take a holistic approach using interventions against all stages of the transmission cycle.
Aquaculture, 2010
The occurrence of four species of potentially zoonotic trematode metacercariae in Sutchi catfish Pangasianodon hypophthalmus from four provinces in the Mekong Delta of the Southern Vietnam is reported. A total of 1127 fish were collected from pond cultures comprising farm house systems (FHS) (279) and from farm household systems (FHHS) (848) and examined by classical and molecular methods. The trematode metacercariae Haplorchis pumilio, H. taichui, Centrocestus formosanus and Procerovum sp. were detected and the infections were analysed in relation to season, farm management type, host size and infection site in the host tissue. Generally, prevalences in the fish were higher during the rainy season from April to October when compared to the dry season. The infection rates and densities were lower in fishes from FHHS than from FHS. Fish at an age of 61 to 90 days posthatch showed the highest parasite loads reflecting the presence of a continuous infection risk in the ponds following stocking. The parasites were found in the body musculature, head, fins and especially at the base of fins. The importance of Sutchi catfish farming is increasing both at the local and international markets and management practices in farms and industrial processing may reduce the infection levels and thereby improve the food hygienic standard of the products.
Fishborne zoonotic parasites and aquaculture: A review
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: http://www.elsevier.com/copyright A large number of parasites infect fish but only a few cause illnesses in humans. Due to their high incidence the following helminth families deserve particular attention: Opisthorchiidae and Heterophyidae (Class Trematodea, subclass Digenea), Anisakidae and Gnathostomidae (Phylum Nematoda), and Diphyllobothridae (Class Cestoda). Humans acquire these fishborne parasitic zoonoses through the consumption of infected raw, undercooked, or inadequately preserved fish. Though the transmission of these parasites through fish caught in the wild has been well documented, the association between cultured fish and human parasitic illness has for long been neglected and it is only recently, during the last 10–15 years, that this association has gained increased consideration. This review summarizes and considers this recent evidence linking fish farming to human pathogenic parasites, and discusses the need and opportunities for prevention and control of these zoonoses.
Impact and control of protozoan parasites in maricultured fishes
Parasitology, 2013
SUMMARYAquaculture, including both freshwater and marine production, has on a world scale exhibited one of the highest growth rates within animal protein production during recent decades and is expected to expand further at the same rate within the next 10 years. Control of diseases is one of the most prominent challenges if this production goal is to be reached. Apart from viral, bacterial, fungal and metazoan infections it has been documented that protozoan parasites affect health and welfare and thereby production of fish in marine aquaculture. Representatives within the main protozoan groups such as amoebae, dinoflagellates, kinetoplastid flagellates, diplomonadid flagellates, apicomplexans, microsporidians and ciliates have been shown to cause severe morbidity and mortality among farmed fish. Well studied examples are Neoparamoeba perurans, Amyloodinium ocellatum, Spironucleus salmonicida, Ichthyobodo necator, Cryptobia salmositica, Loma salmonae, Cryptocaryon irritans, Miamien...