Dactylogyrus Extensus Research Articles

Antimicrobial and anthelmintic effects of copper nanoparticles against Koi carp parasites and their toxicity.

This study investigated the invitro antimicrobial and anthelmintic effect of copper nanoparticles (CuNPs) against the bacterium Aeromonas hydrophila, the monogeneans Dactylogyrus minutus, Dactylogyrus extensus, Gyrodactylus cyprini, and the cestode Schyzocotyle acheilognathi, as well as their toxicity to Cyprinus carpio Koi. In the antimicrobial invitro test, the inhibition zone method and minimum inhibitory concentration (MIC) were performed. In order to determine the time and efficacy of monogenean parasite mortality, the parasites were exposed to CuNP concentrations of 20, 50, 100, 150, 200, and 300 mg L-1, and a control group with tank water and one with copper sulphate pentahydrate (CuSO4.5H2O) at a concentration of 0.3 mg L-1, performed in triplicate. The parasites were observed every 10 min for 300 min, and mortality was recorded. For the cestodes, parasites were immersed in CuNP concentrations of 50, 100, 150, and 300 mg L-1. At the end of the invitro tests, the anthelmintic efficacy of each treatment was calculated. To assess the tolerance and toxicity in fish, they were exposed to CuNP concentrations of 0.6, 1.25, 2.5, 5, 10, 20, and 50 mg L-1 for 12 h. The MIC demonstrated that CuNPs effectively inhibited the growth of A. hydrophila up to a dilution of 12,500 mg L-1 and showed an inhibition zone of 14.0 ± 1.6 mm for CuNPs. The results of anthelmintic activity showed a dose-dependent effect of concentration for both groups of parasites, with the most effective concentration being 300 mg L-1 in 120 min. In the toxicity test, the carps showed tolerance to lower concentrations. The study indicated that CuNPs were effective against the studied pathogens. However, it proved to be toxic to fish at high concentrations. The use of low concentrations is recommended still requires further investigation.

The efficacy of salt treatment for Dactylogyrus extensus (Monogenea) infection in Carp (Cyprinus carpio)

Salt is widely recommended as a cost-effective and readily available compound against freshwater fish parasites in aquaculture; however, a limited number of studies provide scientific evidence regarding the efficacy of salt use despite its frequent use as an anti-parasitic in fish culture. Dactylogyrus is a severe gill parasite, causing considerable losses in freshwater aquaculture. The current study aimed to evaluate the anti-parasitic efficacy of salt against Dactylogyrus extensus in Cyprinus carpio. In vitro, mortality of D. extensus showed time- and concentration-dependent patterns. In vivo, the anti-parasitic effectiveness of salt to D. extensus was assessed at 23.56% after exposure to salt at a concentration of 1.25 g/L for 10 min. Anti-parasitic efficacy of salt in short-term application in carp can be categorised between slight and mild against monogenean, D. extensus.

Review of fish endoparasites in Tigris River, Iraq

Fish, like other living organisms, are susceptible to infection with a variety of parasites. Fish is almost not free of parasites, as internal and external parasites. Parasites are organisms of great importance because of their different types and multiple life cycles, they are used as evidence of environmental pollution, and the life of the host . This study dealt with the database of studies of fish parasites in Iraq. Which includes the following classes of parasites: Nematodes as Rhabdochona sp., Anisakis sp., Monogenic as Cichlidogyrus sclerosus , Dactylogyrus anchorayus, Discocotyle sagittata, Dactylogyrus arcuatus, Dactylogyrus extensus, Dactylogyrus simplex, Dactylogyrus Gussevi , Dactylogyrus inexpectatus. Ciliates as Trichodina cottidarum. Digenea as Allocreadium markewitschi, Centrocestus formosanus, Asymphylotrema macracetabulum, Asymphylodora markewitschi.

Dactylogyrus extensus and Pseudomonas fluorescens dual infection in farmed common carp (Cyprinuscarpio)

Dactylogyrus extensus and Pseudomonas fluorescens are serious pathogens in Cyprinus carpio aquaculture causing severe impacts and substantial economic losses. During the early spring of 2021, abnormal mortalities were reported among farmed C. carpio. Moribund fish showed anorexia, respiratory distress, dermal ulcers, and septicemia. The water analysis revealed low dissolved oxygen (3.4 mg/L), and high un-ionized ammonia levels (0.65 mg/L). Seventy moribund C. carpio specimens were collected and subjected to parasitological and bacteriological examinations. The monogenetic trematode D. extensus was discovered in wet mounts from the gills of all the examined fish samples (100%). The identity of recovered parasites was confirmed by sequencing and alignment of the 28S rDNA gene. P. fluorescens was concurrently identified in the infested fish samples (58.5%) based on phenotypic characteristics using the API20 E. The identity of bacterial isolates was confirmed further by sequencing and alignment of 16S rRNA gene. The IL-1β and MHCII were upregulated in infested fish in tandem with the severity of infections. P. fluorescens isolates displayed high resistance to most of the tested antibiotics. The study is one of the earlier reports on D. extensus and P. fluorescens co-infections in farmed C. carpio and highlights the need of effective control programs to protect fish health and minimize losses.

In Vitro and in Vivo Studies of the Antiparasitic Effect of Aspirin Against Dactylogyrus Extensus (Monogenea) Invasion in Carp (Cyprinus carpio)

Abstract Aspirin is one of the most widely used medications globally as an analgesic and antipyretic drug. Aspirin use as an antiparasitic against fish parasites has never been tested. The parasite Dactylogyrus is considered a serious threat to freshwater aquaculture in relation to considerable losses. The present study is aimed to evaluate the antiparasitic effect of aspirin against Dactylogyrus extensus on Cyprinus carpio and alteration in gill histopathology. In vitro, aspirin exhibited antiparasitic activity with median effective concentration (EC50) values at one and six minutes of 8.137 g/L−1 and 1.629 g/L−1, were assessed for the first time. In vivo antiparasitic efficacy of aspirin to D. extensus was found to be 46.49%. Severe lesion profile was observed in histopathological evaluations of the gills.

Фауна моногенетических сосальщиков рода Dactylogyrus молоди карпа в прудах Оренбургской области

Monogenetic flukes, as a kind of the parasites with a direct development cycle, pose a particular danger to the fish farms. They adapt easier to new conditions due to the absence of intermediate hosts in their life cycle. Among the representatives of the class Monogenea flukes Dactylogyrus parasitize on carp’s gills. Dactylogyrosis are conditionally pathogenic ectoparasites that are dangerous for the young fish. The work presents the results of the parasitological studies of gill arches of carp juveniles grown in ponds of the Orenburg region. There are four species of dactylogyride found: Dactylogyrus vastator, Dactylogyrus extensus, Dactylogyrus achmerowi, Dactylogyrus anchoratus. Only two species of monogenetic flukes were found in fish most often at the early age: Dactylogyrus vastator and Dactylogyrus extensus. The comparison of the infestation of individual gill arches of carp juveniles with dactylogyrids showed that the helminths distribution is not the same in different areas of the gill apparatus. The dactylogyrids proportion on the gill petals of the second gill arc is greater than on the first and third arcs. The helminths proportion found on the petals of the first gill arc does not differ from the worm proportion on the third gill arc. When analyzing the distribution of dactylogyrids by gill sectors, it was found that from 58.9 to 66.0% of monogenetic flukes localize in the middle sector of the gill apparatus of fish, the most strongly washed area of gills. The worm proportions in the abdominal and dorsal sectors differ slightly, except for Dactylogyrus achmerowi, where the helminths proportion in the abdominal section of the gills is almost half less than in the dorsal sector, 14.0 and 27.0%, respectively.

Dactylogyrus extensus infection

This datasheet on Dactylogyrus extensus infection covers Identity, Associated Diseases, Pests or Pathogens, Distribution, Hosts/Species Affected, Pathology, Prevention/Control, Further Information.

Dactylogyrus Infestation in Farmed Common Carp Cyprinus carpio from Aquaculture Facilities in Macedonia

Abstract A total of 958 specimens of farmed common carp Cyprinus carpio from eight of the most significant and largest cyprinid aquaculture facilities in Macedonia (pond and cage culture systems) were examined for parasitological investigation for three years. The following parasite species of the genus Dactylogyrus were identified: Dactylogyrus extensus, Dactylogyrus minutus and Dactylogyrus anchoratus. The highest prevalence was determined for D. extensus (38.8%), followed by D. minutus (7.9%) and D. anchoratus (2.8%). The highest mean intensity was determined for D. extensus (6.2), followed by D. minutus (4.7) and D. anchoratus (3.8). By seasons, the highest prevalence (16.5%) was recorded for D. extensus in winter, while the lowest (0.6%) for D. minutus in autumn. The highest mean intensity (8.0) was also determined for D. extensus in winter, and the lowest (1.9) for D. minutus in spring.

Epizootic aspects of young carp contamination with Dactylogyrosis in the ponds of the Orenburg region

Modern fish farming having intensive forms of farming provides for feeding fish with artificial feed, fertilizing ponds and compacting fish planting in nursery, finishing and wintering ponds. This leads to close contact of cultivated fish and, in this regard, favorable conditions for the pathogens accumulation in ponds, the distribution of infectious and invasive diseases. Invasive diseases are a significant danger among diseases including pond fish dactylogyrosis. Dactylogyrosis are monogenetic suckers, parasites with a direct development cycle, live on the fish gill filaments, belong to conditionally pathogenic parasites and pose a serious danger to young fish. Despite a fairly complete study of the biology of carp dactylogyrid, a number of questions regarding the formation of the parasitofauna of these young fish in the early stages of development - the most vulnerable period of their lives - remain little covered in the literature. The work presents data on the Dactylogyrus types found in young carp in the nursery ponds of the Orenburg region, the invasion extensiveness and intensity. 4 species of monogenetic suckers have been found: Dactylogyrus vastator, Dactylogyrus extensus, Dactylogyrus achmerowi, Dactylogyrus anchoratus. Among the four species of Dactylogyrosis, only two species, Dactylogyrus vastator and Dactylogyrus extensus, were found most often and from an early age, two other species were found in older fish, 20 and 25 days of age with little invasion extensiveness and intensity.

Helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State, Nigeria

The study examined helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of C.gariepinus and T. zillii) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus), Cestodes (Polyonchobothrium torulosus and P. clariae) and Trematodes (Dactylogyrus extensus and Glossiduim pedatum) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from C. gariepinus out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from T. zilli, of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P<0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, C. gariepinus had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in T. zillii.
 Key words: fish parasites, aquaculture, prevalence, C. gariepinus, T. zillii

Features of the parasitic system formation in common carp in the aquaculture of the north-eastern and eastern regions of Ukraine

The research aimed to determine the peculiarities of the formation of the parasitic system in common carp in the aquaculture of the North-Eastern and Eastern regions of Ukraine. According to the results of the research, 27 species of parasites were found in common carp (12 — protozoa, 6 — monogeneans, 3 — trematodes, 2 — cestodes, 4 — parasitic crustaceans). Three species (11.1%) of registered parasites were invasive. 22 species (81.5%) of detected common carp’s parasites develop directly and 5 (18.5%) — with the participation of definitive and intermediate hosts. 26 species (96.3%) of common carp’s parasitic fauna were found in crucian carp and 21 species (77.8%) in other coarse fish species (roach, rudd, bleak, perch). It has been established that among the protozoa, pathogens from the genera Trichodina, Chilodonella, and Ichthyophthirius were of epizootic importance for young common carp; Eimeria carpelli, Ichthyobodo necator, Myxobolus ellipsoides, and Myxobolus dogieli had relevance. The level of prevalence in common carp fingerlings during outbreaks of chylodonelosis was 72%, two-year-olds — 65%, three-year-olds — 27%, during outbreaks of ichthyoftiriosis — 45%, 56%, and 24%, respectively. Prevalence of Trichodina acuta and Trichodina nigra in common carp fingerlings was, respectively, 52% and 38%, Ichthyobodo necator — 16%, Eimeria carpelli — 22%, Myxobolus ellipsoides, and Myxobolus dogieli — 17–18%. Among the pathogens of helminthic diseases in the aquaculture, monogenetic suckers (Dactylogyrus anchoratus, Dactylogyrus extensus, Dactylogyrus vastator, Gyrodactylus cyprini, and Gyrodactylus katharineri), as well as cestodes (Bothriocephalus acheilognathi and Khawia sinensis) were the most epizootic significance for common carp. Prevalence of parasites from the genus Dactylogyrus reached 68–87% in fingerlings, from the genus Gyrodactylus — 21–36%. The highest level of Bothriocephalus acheilognathi infection (82%) was registered in fingerlings. The maximum prevalence of Khawia sinensis (62%) was observed in two-year-olds. Outbreaks of diseases caused by crustaceans Lernaea cyprinacea and Argulus foliaceus with a high level of prevalence have been reported in fish from fingerlings to three-year-olds. The level of prevalence of Lernaea cyprinacea was 69%, Argulus foliaceus — 22%

Detecting Yersinia ruckeri on the death of carp (Cyprinus carpio) farmed in southern Russia

Yersinia ruckeri was first discharged from carp brood fishes (Cyprinus carpio) farmed in ponds in southern Russia. The death of fish was observed at a temperature of 15°C in March-April 2015. Ten fish with clinical signs of the disease were taken for research. Water samples were taken for hydrochemical analysis. The research results indicated a high level of permanganate index (2.4–2.8 MAC), nitrite nitrogen (1.5–2 MAC), nitrate nitrogen (1.4–1.5 MAC), and a low oxygen content in the bottom layers (2.0 mg/dm3). A parasitological study of fish revealed an invasion by monogenes (Dactylogyrus extensus) and mollusks (Unio pinctorum). As a result of bacteriological studies, 62 isolates were discharged, 30 from water and 32 from fish. The determination of bacteria was carried out according to morphological and enzymatic properties. The biochemical characteristics of the Yersinia ruckeri strains made it possible to classify them as serotype 1. All Yersinia ruckeri strains were sensitive to ciprofloxacin, tetracycline, chloramphenicol and resistant to furazolidone. MALDI TOF mass spectrometry and PCR were used for additional identification of bacteria. Serious pathological and histopathological changes in the fish tissues were not detected.

Occurrence of dactylogyrid and gyrodactylid Monogenea on common carp, Cyprinus carpio, in the Southern Caspian Sea Basin

In this study, we genetically characterised Monogenea found on common carp in Iran. In total, 5603 parasites were recovered from 112 fish. The parasites were first identified morphologically as Dactylogyrus extensus, D. anchoratus, D. vastator, D. minutus, D. achmerowi and Gyrodactylus sprostonae. Representative samples were then subjected to sequencing. This is one of the first studies which has provided both morphological and sequence data for Dactylogyrus spp. and G. sprostonae. Our findings provide a foundation for future research into the genetic make-up of these economically significant parasites and the establishment of effective strategies for their control and prevention in aquaculture systems.

CHECKLISTS OF PARASITES OF FISHES OF AL-DIWANIYAH PROVINCE, IRAQ

Literature reviews of reports concerning the parasitic fauna of fishes of Al-Diwaniyah province, Iraq till the end of December 2018 showed that a total of 43 parasite species are so far known from 13 valid fish species investigated for parasitic infections. The parasitic fauna included one euglenozoan, two myzozoans, six ciliophorans, three myxozoans, three trematodes, nine monogeneans, four cestodes, six nematodes, three acanthocephalans and six crustaceans. The infection with the trematodes, one monogenean, two cestodes and one nematode occurred with larval stages, while the remaining infections were either with trophozoites or adult parasites. Among the inspected fishes, Carasobarbus luteus was infected with the highest number of parasite species (20 parasite species), followed by Planiliza abu (17 species) and Cyprinus carpio (16 species) while two fish species (Ctenopharyngodon idella and Hypophthalmichthys molitrix) were infected with the minimum number of parasite species (three parasite species each). The ciliophoran Trichodina domerguei and the crustacean Lernaea cyprinacea were the commonest parasite species as they were reported from nine fish species each, followed by the monogenean Dactylogyrus extensus and the nematode Contracaecum sp. which were reported from eight and six host species, respectively, while the minimum number of one host species was reported for 22 parasite species.

Monogeneans of fish of the Mingechevir Reservoir of the Kura River basin

In 2010–2013, a study on fish of the Mingechevir Reservoir of the Kura River basin, for infestation with parasites belonging to the Monogenea class was conducted. 297 specimens of fish were subjected to parasitological dissections. These fish belong to the following 23 species: roach – Rutilus rutilus caspius, Caucasian chub – Leuciscus cephalus orientalis, asp – Aspius aspius taeniatus, tench – Tinca tinca, Kura nase – Chondrostoma cyri, Kura khramulya – Capoeta capoeta, chanari-barbel – Luciobarbus capito, goldfish – Carassius auratus gibelio, carp – Cyprinus carpio, Kura beardie – Barbatula brandti, Transcaucasica spined loach – Cobitis taenia satunini, catfish – Silurus glanis, mosquito fish – Gambusia affinis, pike – Sander lucioperca, big headed goby – Neogobius kessleri gorlap, monkey goby – N. fluviatilis pallasi. As a result of the research, 34 species of monogeneans belonging to 3 orders of 4 families and 5 genera were identified. The overwhelming majority (32 species) of monogeneans found are parasitic on the gill petals of fish, from two to six species are also found on the surface of the body and fins, in the nasal cavity of fish. Of the found monogeneans, 24 species (70.6%) are specific for one species or one genus of fish. It has been established that monogeneans parasitizing on several hosts infect the main of them more than others fish, and the intensity of invasion of fish with large sizes was higher than that of relatively small fish. By their origin, 23 species or 67.7% of all species belong to the boreal lowland faunistic complex. According to the ecological groups of this complex, they are distributed as follows: in the Ponto-Caspian group – 17 species, in the Palaearctic and amphiboreal groups – 3 species each. The Middle East faunistic complex is represented by six, the Indian lowland complex is represented by three, and the Ponto-Caspian marine complex by two species. Among the monogeneans of fish of the Mingechevir Reservoir, two species, Dactylogyrus extensus and D. vastator destroy gill petals of their hosts and cause their diseases. They are the cause of the mass death of juvenile fish.

Monogenean parasites infect ornamental fish imported to Australia.

The ornamental fish trade provides a pathway for the global translocation of aquatic parasites. We examined a total of 1020 fish imported from Singapore, Malaysia, Thailand, or Sri Lanka to Australia (including freshwater and marine fish species) for monogenean ectoparasites. Fish were received following veterinary certification that they showed no clinical signs of pests and diseases from the exporting country and visual inspection at Australian border control. Australian import conditions require mandatory treatment for goldfish with parasiticides (e.g. trichlorfon, formaldehyde, sodium chloride) for the presence of gill flukes (Dactylogyrus vastator Nybelin, 1924 and Dactylogyrus extensus Mueller and Van Cleave, 1932) prior to export. Over 950 individual parasites were detected in five imported fish species, representing 14 monogenean species. Seven Dactylogyrus spp. including D. vastator and three Gyrodactylus spp. infected goldfish, Carassius auratus Linnaeus, 1758, from Malaysia, Singapore, and Thailand. Dactylogyrus ostraviensis Řehulka, 1988, infected rosy barb, Pethia conchonius Hamilton, 1822, from Singapore, Sri Lanka, and Thailand while two Trianchoratus spp. infected three spot gourami, Trichopodus trichopterus Pallas, 1970 and pearl gourami Trichopodus leerii Bleeker, 1852, from Sri Lanka. Urocleidoides reticulatus Mizelle & Price, 1964, infected guppy, Poecilia reticulata Peters, 1859, from Sri Lanka. The discovery of D. vastator in goldfish, as well as 13 other monogenean species, shows that pre-export health requirements, which include chemical treatment of goldfish, and inspection of all ornamental fish species did not prevent infection by monogeneans. Inspection prior to exportation and at border control must account for the highly cryptic nature of monogenean parasites and consider alternatives to current pre-export conditions and visual inspection at border control.

Parasitic fauna and histopathology of farmed freshwater ornamental fish in Brazil

Ornamental fish farming represents a consolidated market over the world. However, confinement is a factor that favors the occurrence of diseases. This study aimed to report the parasitic fauna of ornamental fish from three facilities, as well as to observe the histological pathogenesis caused by the parasites. Between May 2015 and February 2016, a total of 781 ornamental fishes were used for parasitological and histopathological analysis. Water quality was measured in fishponds from each facility. Ciliate protozoans Ichthyophthirius multifiliis; Trichodina sp.; the monogeneans Dactylogyrus extensus, D. minutus and Diaphorocleidus kabatai; metacercariae of the digeneans; the cestode Bothriocephalus acheilognathi; the nematode Rhabdochona sp.; and the branchiuran Argulus japonicus were found in the examined fish. The greatest prevalence and mean intensity was observed in the gills of Gymnocorymbus ternetzi parasitized by D. kabatai, followed by the protozoan parasite I. multifiliis on the body surface of Xiphophorus maculatus. Histopathological analysis showed epithelial interlamellar hyperplasia of the secondary lamellae, partial fusion of the secondary lamellae, telangiectasia, justalamellar edema and eosinophilic inflammatory infiltrate. The intestine of cestode parasitized fish showed necrosis in the submucosa, intestinal obstruction and lymphoeosinophilic inflammatory infiltrate. It is important to know the parasitic fauna of farmed fish and the pathogenesis caused by the parasites in order to ensure fish production and the health of the hosts. Statement of relevanceOrnamental fish production as a consolidate activity around the world faces problems of parasite infection leading to fish mortality and economic losses. To ensure farming production, it is important to monitor the status of fish health. Parasitic fauna and histopathological analysis are used as important tools for the diagnosis of tissue lesions.

Molecular characterization of two non-native species of Dactylogyrus (Monogenea: Dactylogyridae) recovered from introduced hosts in India

Freshwater fish from the Guwahati in River Brahmaputra, Assam, India were screened for infection with Monogenea. The recovered parasites were diagnosed by PCR and sequencing the 18S and 28S rDNA subunit regions. Comparison of the obtained nucleotide sequences with sequences in GenBank identified the specimens as Dactylogyrus extensus Mueller and Van Cleave, 1932 and D. lamellatus Achmerow, 1952, recovered from Cyprinus carpio and Ctenopharyngodon idella (Cypriniformes: Cyprinidae) respectively. The obtained sequences differed by only 2-3 nucleotides from the sequences deposited in GenBank. The presence of D. extensus and D. lamellatus in India can result from the introductions of their respective host carrying their parasites with them.

Macroparasites of the Invasive Fish,Cyprinus carpio, in Patagonia, Argentina

The common carp (Cyprinus carpio L.) is probably the most widely distributed freshwater fish species and is cultured on almost all continents. In South America, studies on the parasites from C. carpio are limited. The aim of the present study was to report on the macroparasites from wild C. carpio populations inhabiting the Neuquen River, which is at the southernmost distribution of C. carpio in Argentina. From spring 2011 to winter 2012, four seasonal samples of C. carpio were collected from the Neuquen River at the Ingeniero Ballester dam using gill nets. Fish were dissected and all organs were examined using microscopy. All macroparasites were determined and counted and their prevalences and mean intensities calculated. In total, 33 fish were examined and the following six parasites were recorded: the monogeneans Dactylogyrus extensus (gills) and Pseudacolpenteron sp. (in the canals of the scales along the lateral line system); the cestode Bothriocephalus sp. (intestine); the nematode Contracaecum sp. (liver and visceral fat); and the acanthocephalans Pomphorhynchus patagonicus (intestine and liver) and Polymorphus sp. (liver and wall of intestine). The monogenean D. extensus was the most commonly encountered species and had the highest prevalence and mean intensity of all parasites detected. This study reports 6 new records of parasite species in C. carpio from Argentina.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa II. New locality records.

Baseline information on parasitic infections, including monogenean infections on wild fishes, may aid in implementation of proactive measures as opposed to reactive research aimed at crisis control with reference to future aquaculture applications. The aim of this project was to examine the freshwater monogenean fauna of the Vaal Dam, Vaal River system, South Africa. This short communication reports on infection statistics for monogenean species, some representing new locality records. Parasites were collected from host species other than Labeo spp. from the Vaal Dam, during a summer (January 2010) survey. Fish collected using gill nets of varying mesh sizes were weighed and measured. Mucous smears were prepared from the skin and fins with the aid of microscope slides. Fish were killed humanely by severing the spinal cord behind the head. Gills were carefully removed and divided into areas which were separately scraped to investigate potential parasite site preference. The areas examined were dorsal, median and ventral positions on both the anterior and posterior hemibranch. Both mucous smears and gill scrapings were examined with the aid of a stereo microscope. More parasites were collected from the first or second gill arches, the medial position on the gill, and the anterior hemibranch. Preference for either left or right gill set was inconclusive. Spatial distribution of parasites is thought to result from water flow over the gills during respiration. This paper reports a new locality record for the following monogenean species: Quadriacanthus aegypticus, Dactylogyrus extensus, Dactylogyrus minitus, Gyrodactylus kherulensis and Dactylogyrus lamellatus.