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Abstract Background Monogenean parasites have never been formally reported on fishes from the Lufira River Basin. In this context, we decided to record the monogenean parasite fauna of three cichlid species found in the Upper Lufira River Basin for the first time by inventorizing their diversity (species composition) and analysing their infection parameters (prevalence, mean intensity and abundance). Methods The African cichlid fishes Oreochromis mweruensis, Coptodon rendalli and Serranochromis macrocephalus were selected for the study, given their economic value and their abundance in the Upper Lufira River Basin. Monogeneans were isolated from the gills and stomach, mounted on glass slides with either Hoyer’s medium or ammonium picrate-glycerin for identification under a stereomicroscope, based on morphological analysis of genital and haptoral hard parts. Indices of diversity and infections parameters were calculated. Results A total of 13 gill monogenean parasite species (Cichlidogyrus dossoui, C. halli, C. karibae, C. mbirizei, C. papernastrema, C. quaestio, C. sclerosus, C. tiberianus, C. tilapiae, C. zambezensis, Scutogyrus gravivaginus, S. cf. bailloni and Gyrodactylus nyanzae) and one stomach monogenean (Enterogyrus malmbergi) were identified. A species richness (S) of 10 for O. mweruensis, S = 6 for C. rendalli and S = 2 for S. macrocephalus was recorded. Five parasite species were reported to be common amongst O. mweruensis and C. rendalli. According to cichlid species, the most prevalent parasite species was C. halli (prevalence [P] = 80.9%) on O. mweruensis, C. dossoui (P = 92.9%) on C. rendalli and C. karibae and C. zambezensis (both P = 9.1%) on S. macrocephalus. The parasite species with the highest mean intensity (MI) were G. nyanzae (MI = 8.7) on O. mweruensis, C. papernastrema (MI = 17.1) on C. rendalli and C. karibae (MI = 15) on S. macrocephalus. The findings indicate new host ranges for five parasites species (C. quaestio, S. cf. bailloni, E. malmbergi on O. mweruensis, C. halli on C. rendalli and C. karibae on S. macrocephalus) as well as new geographical records for all of them as they are recorded for the first time in the Lufira River Basin. Conclusions This study highlighted the richness of monogenean communities in the Upper Lufira River Basin and is a starting point for future helminthological studies, such as on the use of fish parasites as indicators of anthropogenic impacts. Graphical Abstract

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.

Background: Monogenean parasites have never been formally reported on fishes from the Lufira River Basin. In this context, we decided to record the monogenean parasite fauna of three cichlid species found in the Upper Lufira River Basin for the first time by inventorizing their diversity (species composition) and analysing their infection parameters (prevalence, mean intensity and abundance). Methods: The African cichlid fishes Oreochromis mweruensis, Coptodon rendalli and Serranochromis macrocephalus were selected for the study, given their economic value and their abundance in the Upper Lufira River Basin. Monogeneans were isolated from the gills and stomach, mounted on glass slides with either Hoyer's medium or ammonium picrate-glycerin for identification under a stereomicroscope, based on morphological analysis of genital and haptoral hard parts. Indices of diversity and infections parameters were calculated. Results: A total of 13 gill monogenean parasite species (Cichlidogyrus dossoui, C. halli, C. karibae, C. mbirizei, C. papernastrema, C. quaestio, C. sclerosus, C. tiberianus, C. tilapiae, C. zambezensis, Scutogyrus gravivaginus, S. cf. bailloni and Gyrodactylus nyanzae) and one stomach monogenean (Enterogyrus malmbergi) were identified. A species richness (S) of 10 for O. mweruensis, S = 6 for C. rendalli and S = 2 for S. macrocephalus was recorded. Five parasite species were reported to be common amongst O. mweruensis and C. rendalli. According to cichlid species, the most prevalent parasite species was C. halli (prevalence [P] = 80.9%) on O. mweruensis, C. dossoui (P = 92.9%) on C. rendalli and C. karibae and C. zambezensis (both P = 9.1%) on S. macrocephalus. The parasite species with the highest mean intensity (MI) were G. nyanzae (MI = 8.7) on O. mweruensis, C. papernastrema (MI = 17.1) on C. rendalli and C. karibae (MI = 15) on S. macrocephalus. The findings indicate new host ranges for five parasites species (C. quaestio, S. cf. bailloni, E. malmbergi on O. mweruensis, C. halli on C. rendalli and C. karibae on S. macrocephalus) as well as new geographical records for all of them as they are recorded for the first time in the Lufira River Basin. Conclusions: This study highlighted the richness of monogenean communities in the Upper Lufira River Basin and is a starting point for future helminthological studies, such as on the use of fish parasites as indicators of anthropogenic impacts. [ABSTRACT FROM AUTHOR]

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Tilapia is one of the commercially important fish in Malaysia as well as in other parts of the world. An understanding of monogenean infection dynamics in tilapia fish may assist us in searching for some intervention measures in reducing the loss of fish caused by parasitic diseases. The present study aimed (1) to compare infection level of monogeneans between the wild and cultured Oreochromis niloticus, and between the cultured O. niloticus and cultured red hybrid tilapia, and (2) to examine the spatial distribution of monogenean species over the gills of the different host species. From a total of 75 fish specimens, six species of monogeneans from two genera: Cichlidogyrus ( C. halli, C. mbirizei, C. sclerosus, C. thurstonae, C. tilapiae) and Scutogyrus ( S. longicornis) were identified. Data showed that the infection level of cultured O. niloticus was higher than that of the wild O. niloticus, however, the former was lower than that of the cultured red hybrid tilapia. Higher species richness of monogeneans was observed in the cultured red hybrid tilapia as compared to the others. Results for spatial distribution showed that the monogeneans have no preference on the left or right sides of the gills. However, C. halli, C. mbirizei, and C. tilapiae showed preferences on specific gill arches in the cultured O. niloticus and red hybrid tilapia. In general, the gill arch IV harboured the least number of monogeneans. The susceptibility of monogenean infection between the different types of tilapia is discussed. [ABSTRACT FROM AUTHOR]

Background: Lake Tana is the largest lake in Ethiopia and the source of the Blue Nile. The lake harbours unique endemic cyprinid fish species, as well as the commercially important endemic Nile tilapia subspecies Oreochromis niloticus tana and the North African catfish Clarias gariepinus. Its endemicity, especially within the Labeobarbus radiation, its conservation importance and its economic indispensability attract scientific interest to the lake's ichthyofauna. Fish parasites of Lake Tana, however, are hitherto poorly known, and no formal report exists on its monogenean flatworms. For sustainable aquaculture and fisheries development, it is essential to study monogenean fish parasites in these economically most important fish species. Moreover, it remains to be verified whether this unique ecosystem and its endemicity gave rise to a distinct parasite fauna as well. Results: Nile tilapia and North African catfish hosts were collected from Lake Tana in 2013. Nine species of monogenean parasites of two orders, Gyrodactylidea Bychowsky, 1937 and Dactylogyridea Bychowsky, 1937, were recovered. Gyrodactylus gelnari Přikrylová, Blažek & Vanhove, 2012, Macrogyrodactylus clarii Gussev, 1961, Quadriacanthus aegypticus El-Naggar & Serag, 1986 and two undescribed Quadriacanthus species were recovered from C. gariepinus. Oreochromis niloticus tana hosted Cichlidogyrus cirratus Paperna, 1964, C. halli (Price & Kirk, 1967), C. thurstonae Ergens, 1981 and Scutogyrus longicornis (Paperna & Thurston, 1969). Conclusions: Except for M. clarii, all species represent new records for Ethiopia. This first study on the monogenean fauna of Lake Tana revealed that the lake's North African catfish, as well as its endemic Nile tilapia subspecies, harbour parasites that are known from these host species elsewhere in Africa. [ABSTRACT FROM AUTHOR]

Monogeneans are pathogenic flatworms commonly found in many fish species. To avoid the risk of economic loss, parasitological investigation is necessary. A survey of gill monogeneans from 45 red hybrid tilapias (Oreochromis sp.) in Kanchanaburi province, Thailand, was conducted. Fish samples were infested with 6 gill monogenean species, viz., Cichlidogyrus sclerosus, C. thurstonae, C. halli, C. mbirizei, C. tilapiae, and Scutogyrus longicornis. Morphologically, unidentified Cichlidogyrus species from cultured red tilapia (Oreochromis niloticus × O. mossambicus) in Nakhon Si Thammarat province, southern Thailand, collected in 2012 and C. mbirizei, found in this study, were similar. This finding provides new host and locality records for C. mbirizei as a new pathogenic gill monogenean in Thailand. According to the original type host (Oreochromis tanganicae) and habitat of C. mbirizei, it was strongly suggested that C. mbirizei can be translocated with the host during fish trading. For practical identification, a key of gill monogeneans on tilapia in Thailand is also provided herein. [ABSTRACT FROM AUTHOR]

An investigation of gill monogeneans from the Nile tilapia Oreochromis niloticus and the blue spotted tilapia Oreochromis leucostictus (50 individuals per species) was done between the months of November 2014 to February 2015 in Lake Naivasha, Kenya. Standard parasitological procedures were used to examine fish gills for the presence of monogeneans. The observed monogeneans were collected, preliminarily identified using identification keys, quantified and fixed in 4 % formalin for morphological studies and absolute ethanol for molecular studies. Four parasite species comprising of three species of the genus Cichlidogyrus and one species of the genus Scutogyrus were recovered. Cichlidogyrus sclerosus and Cichlidogyrus tilapiae infested both fish species but the C. sclerosus was most prevalent in O. leucostictus (Prevalence ( P) = 100 %, Mean intensity (MI) = 3.4) and C. tilapiae in O. niloticus ( P = 8 %, MI = 4). Cichlidogyrus tilapiae had a P = 12 % and MI = 5.0 and a P = 6 % and MI = 3.0 in O. niloticus and O. leucostictus, respectively. Cichlidogyrus halli ( P = 4 %, MI = 15.5) and Scutogyrus gravivaginus ( P = 2 %, MI = 1.0) were only found in O. leucostictus. This is the first time that these monogeneans have been identified from Lake Naivasha, Kenya, presenting new geographical records. It was concluded that Ancyrocephalids ( Cichilidogyrus spp.) dominated the two cichlid fish species in Lake Naivasha, Kenya. [ABSTRACT FROM AUTHOR]

Four genetic groups of cultured tilapia ( Oreochromis spp.) were kept under aquacultural conditions (i.e., not controlled experimental conditions) and monitored for one year to investigate factors associated with variation in prevalence and mean abundance of the monogenean parasites Cichlidogyrus sclerosus , Cichlidogyrus dossoui and Scutogyrus sp. infecting the gills; overall, C. sclerosus presented the highest mean abundance. A significant, negative association was found between water temperature and parasite burdens. No significant correlations were recorded between parasite numbers and either host size or coefficient of body condition—no hematocrit values were recorded for these hosts. However, a group of juvenile fish from the same farm studied separately which harbored lower parasite burdens than those documented in this survey, showed a significant negative correlation between parasite abundance and hematocrit values, suggesting that infection may be detrimental to hosts. [ABSTRACT FROM AUTHOR]

Abstract: To overcome the limited regional and taxonomic coverage in previous studies of the Ancyrocephalinae (Monogenea, Dactylogyridae), we present further findings on the molecular systematics and phylogeny of a broader selection of specimens, aiming to build a molecular phylogeny of the Ancyrocephalinae, and to assess the monophyly of each available genus, using D1-D2 domain of LSU rDNA and the combined LSU and partial sequence of SSU rDNA data sets. Our studies showed that 18 Haliotrema species were highly dispersive to form several clades with species from ten closely related genera. The host range of Euryhaliotrematoides species was not only restricted in butterfly fishes (Chaetodontidae), but widen to include the Lutjanidae. Euryhaliotrema was phylogenetically more closely related to Aliatrema than to Euryhaliotrematoides. Given that the species Haliotrema kurodai, Haliotrema spirotubiforum and Haliotrema anguiformis had a funnel-shaped base of the coiled male copulatory organ (MCO) lacking an accessory piece, and our molecular evidence, we proposed to transfer the three species to the Aliatrema as new combinations. We proposed to combine Bravohollisia and Caballeria into one genus, mainly based on molecular evidence and their similar MCO characters. Using SSU+ITS1 data set, Scutogyrus was robustly resolved as a polyphyletic group and its status should be questioned. Based on the present molecular evidence and their similar MCO characters, we proposed to combine Cichlidogyrus and Scutogyrus into one genus, Cichlidogyrus, by treating Scutogyrus as the synonym of Cichlidogyrus. Generally, the present study indicated that the vagina can make little contribution for understanding the generic-level monophyly, due to its high variability even among phylogenetically very closely related species, but it was useful for species determination. Given that phylogenetically closely related species from the same or closely related host species may have similar MCO characters but distinct haptoral characters, we consider that it is dangerous to erect a genus mainly based on different haptoral characters, particularly those separated from existing genera. The resultant phylogenetic reconstructions indicated that the radiation of some Haliotrema species has correlated with their hosts, because species from closely related fishes have correspondingly shown close relationships. Though the present study can not provide the comparison of host–parasite associations, phylogenetically closely related Haliotrema species which have similar morphological characters (both MCOs and haptors) but distinct/distantly related host species may indicate a speciation model of host-switching. [Copyright &y& Elsevier]