Philometroides giginosantoroi n. sp. (Nematoda: Philometridae), a new muscle-infecting species in the Mediterranean moray (Muraena helena) revealed using integrative taxonomy.

Philometroides Yamaguti, 1935 is a genus of dracunculoid nematodes of the family Philometridae Baylis & Daubney, 1926 comprising tissue-infecting species worldwide. In the present study, a new species of Philometroides is described from the Tyrrhenian Sea (central-western Mediterranean Sea) using integrative approaches such as light and scanning microscopy, histopathology and 18S rRNA sequencing. Philometroides giginosantoroi n. sp. found in the skeletal muscles of the Mediterranean moray Muraena helena can be distinguished from its congeners by a combination of morphological traits and in particular by having the oral aperture with 3 large sclerotized triangular oesophageal teeth. The molecular analyses and phylogenetic reconstructions support its status as a new taxon and placed it within a clade of tissue-infecting species, although also confirmed mismatches in the generic assignment of several species. Philometroides giginosantoroi n. sp. is the second species of the genus found in the Mediterranean Sea and in general in the European marine waters and the third species of the family known to infect the family Muraenidae.

Two new Neotetraonchus species (Dactylogyridea, Dactylogyridae) parasitising the Peruvian sea catfish Galeichthys peruvianus (Siluriformes, Ariidae), including molecular data.

As part of a parasitological survey, several specimens of two new monopisthocotylean species, Neotetraonchus celsomanueli sp. nov. and N.peruvianus sp. nov. (Dactylogyridea, Dactylogyridae), were collected from the gill filaments of the Peruvian sea catfish Galeichthys peruvianus (Siluriformes, Ariidae) off Puerto Pizarro, Tumbes region, Peru. Neotetraonchus celsomanueli sp. nov. is characterised by an MCO with a T-shaped distal end and an accessory piece that is ribbed and expanded proximally with a worm-shaped termination. Neotetraonchus peruvianus sp. nov. is typified by its MCO, which has a sledgehammer-shaped distal end and an accessory piece with a claw-shaped distal end. Additionally, N.peruvianus sp. nov. is characterised by its jellyfish-shaped onchium. A partial 28S rDNA sequence was obtained from N.celsomanueli sp. nov., and a phylogenetic analysis was conducted. This analysis revealed the phylogenetic position of Neotetraonchus celsomanueli sp. nov. within a clade comprising monopisthocotylean parasites of diadromous and marine ariid catfishes, including Hamatopeduncularia spp., Chauhanellus spp., Thysanotohaptor Kritsky, Shameem, Kumari & Krishnaveni, , and Neocalceostomoides spinivaginalis Lim, 1995. This finding brings the number of known Neotetraonchus species to seven and represents the first described Neotetraonchus species infecting marine catfishes from Peru.

Myxobolus nekrasovae n. sp. (Cnidaria, Myxozoa) is a new species parasitizing the gills of the gibel carp, Carassius auratus gibelio.

A new Myxobolus species, Myxobolus nekrasovi n. sp., was found in the gill arch of the gibel carp Carassius auratus gibelio during investigation of fish myxosporean fauna of ponds of Lake Baikal basin. The parasites were studied on the basis of spore morphology, as well as with histological and molecular methods. Mature spores of M. nekrasovi n. sp. are ellipsoidal in frontal view and lemon-shaped in lateral view, measuring 13.84 ± 0.4 (12.2-15) µm in length, 9.73 ± 0.2 (8.5-10.7) µm in width, 6,75 ± 0.1 (6.0-7.6) µm in thickness. Polar capsules are unequal and pyriform, measuring: length 6.31 ± 0.1 (5.4-7.4), width 3.49 ± 0.04 (3.12-4) µm and length 2.88 ± 0.1 (2.1-3.5), width 1.4 ± 0.03 (1-1.6) µm. Phylogenetic analysis with the SSU rDNA gene shows Myxobolus nekrasovae n. sp. as a sister species of the subclade formed by Thellohanellus sinensis, Myxobolus acutus, M. zhaltsanovae that infect gibel carp Carassius auratus gibelio.

Synopsis of myxosporean species (Cnidaria: Myxozoa) parasitizing fishes from Vietnam.

This paper provides an updated checklist of species-level identified myxosporeans from marine and freshwater fishes in Vietnam. The list includes 51 nominal species (38 marine and 13 freshwater) belonging to 9 genera: Myxobolus Bütschli, 1882 (26 species); Kudoa Meglitsch, 1947 (6 species); Henneguya Thélohan, 1892 (6 species); Thelohanellus Kudo, 1933 (5 species); Unicapsula Davis, 1924 (2 species); Ceratomyxa Thélohan, 1892 (2 species), Zschokkella Auerbach, 1909 (2 species); Auerbachia Meglitsch, 1960 (1 species), and Meglitschia Kovaleva, 1988 (1 species). For each parasite species, information on myxospore morphology, line drawings, fish hosts, infection sites, and collection locality in Vietnam are reported. Where available, we also provide GenBank accession numbers for nucleotide sequence data. In addition, taxonomic status of several species was discussed and Myxobolus eszterbaueri nom. nov. is proposed as a junior homonym for Myxobolus hakyi Baska, Voronin, Eszterbauer, Müller, Marton & Molnár 2009, which is preoccupied.

A new species of Phoreiobothrium Linton, 1889 (Cestoda: Onchoproteocephalidea) from the spinner shark, Carcharhinus brevipinna (Valenciennes) off the coast of KwaZulu-Natal, South Africa.

The extreme sparsity of collection efforts in many parts of the word, including southern Africa, leaves a vast hidden diversity of marine cestode species, such as species of Phoreiobothrium. The examination of a common South African coastal-pelagic shark species, Carcharhinus brevipinna (Valenciennes), resulted in the discovery of a new species of Phoreiobothrium Linton, 1889. Phoreiobothrium martini sp. n. is undoubtedly different from all other congeners in several morphological characteristics, however, it is most easily distinguished from other species by its total length, the size of its hooks, and the number of post vaginal testes. The addition of P. martini sp. n. increases the total number of valid species of Phoreiobothrium to 20 worldwide. Furthermore, P. martini sp. n. marks the description of representatives of only the second onchoproteocephalidean genus from southern Africa, therefore expanding the generic biogeographical representation and introducing new host associations. Apart from the description of this new species of cestode, the discovery of additional species of Phoreiobothrium will be beneficial regarding future ecological investigations. With the high degree of host-specificity found amongst species of Phoreiobothrium, species such as P. martini sp. n. could be used as sentinel species for the accurate identification, separation and diagnosis of commonly misidentified shark species.

Biomonitoring of heavy metals using Contracaecum quadripapillatum (Nematoda) in comparison to its fish host, Lates niloticus, from the Nile River, Egypt.

Recently, fish parasites have been used as a biomonitoring tool to indicate the health status of ecosystems. Therefore, this research aimed to evaluate the potential capacity of Contracaecum quadripapillatum larvae as accumulation indicators for metal pollution and compare metal concentrations in host tissues of non-infected and infected fish: Lates niloticus from the Nile River. Accumulations of Cd, Cu, Fe, Mn, Ni, Pb, and Zn in larval nematodes and tissues of the liver, kidney, and muscles of both infected and non-infected fish were determined. All metal concentrations exhibit a significantly higher increase in larval nematodes than the muscles of infected fish and vice versa except Cd in the kidney. On the other hand, only Cd, Mn, Pb, and Zn concentrations were significantly higher in the parasite than in the host liver. Therefore, bioaccumulation factors were most obvious and effective in the muscles of infected fish than in the liver and kidney. Contracaecum larvae accumulate Cd and Pb more than other metals. The infrapopulation size of C. quadripapillatum correlated with metal concentrations in different host tissues, especially the kidney, while the correlations between metal levels in the tissues of both parasite and fish organs exhibit different patterns in each organ. The current work revealed that C. quadripapillatum larvae represent environmental monitors for metal pollution in the freshwater ecosystem.

First data on parasites of the invasive brown bullhead Ameiurus nebulosus (Siluriformes: Ictaluridae) in Ukraine.

This study describes the parasite community of non-native brown bullhead, Ameiurus nebulosus (Actinopterygii: Ictaluridae), collected at three sites in the river Vistula Basin (Lake Svitiaz, Lake Pisochne, and Lake on Plastova) and one site in the river Diester Basin (Lake Stryiska), in Ukraine. Our data represent the first comprehensive study of parasite community in this fish species in Europe. Sixteen parasite taxa were found, including species co-introduced from North America and species acquired in the European range. Maximum parasite richness (13 spp.) was recorded in Lake Svitiaz situated in a Natural Protected Area, while lowest species richness (3 spp.) was observed at Lake on Plastova, an artificial pond in the city of Lviv. Three co-introduced monogenean species, Gyrodactylus nebulosus, Ligictaluridus pricei and Ligictaluridus monticellii, are recorded in Ukraine for the first time, widening the knowledge of the European distribution of these North American parasites. Metric features for hard parts of invasive and native monogeneans showed overlap in ligictalurid parasites, but slightly smaller metrics in Ukrainian G. nebulosus, possibly reflecting water temperature during fish sampling. Though prevalence and abundance of acquired parasites was relatively low, infection parameters for metacercariae of Diplostomum spp. were relatively high at Lake Svitiaz and the natural Lake Stryiska in Lviv. In two lakes in the Vistula basin, we found high prevalence and abundance of Anguillicola crassus, an Asian nematode infecting eels, possibly supporting the invasional meltdown hypothesis. Our study confirms both further spread of non-native parasites in Europe and use of non-native fish as competent hosts for local native and introduced parasites.

Species complexes and life cycles of digenetic trematodes from the family Derogenidae.

The best way to study digenean diversity combines molecular genetic methods, life-cycle studies and elaborate morphological descriptions. This approach has been barely used for one of the most widespread digenean taxa parasitizing fish ­ the superfamily Hemiuroidea. Here, we applied the integrative approach to the hemiuroideans from the family Derogenidae parasitizing fish at the White and Barents Seas. Analysis of 28S, 18S, 5.8S rDNA, ITS2 and cox1 gene sequences from sexually adult worms (maritae) showed genetic heterogeneity for 2 derogenid species known from this area: Derogenes varicus and Progonus muelleri. Thus, 2 pairs of genetic lineages were found: DV1 and DV2, PM1 and PM2, respectively. Data from other regions indicate that 2 more lineages of D. varicus probably exist. Based on previous records from the White and Barents Seas, we hypothesized that the cercariae found in the moonsnails (family Naticidae) belong to the Derogenidae and may help to differentiate these lineages as species. According to our results, Cercaria appendiculata from Cryptonatica affinis matched DV1, similar nameless cercariae from Euspira pallida and Amauropsis islandica matched DV2, and Cercaria octocauda from C. affinis matched PM1. We provide new data on the structure of these cercariae and discuss the life-cycle pattern of the studied digeneans.

Fish parasites (special issue).

Fish (Elasmobranchia and Actinopterygii) inhabit the majority of aquatic habitats globally. They are crucial for human nutrition but they may be negatively affected by parasitic protists and metazoan parasites. Fish parasites are also an extraordinary group of animals because of their ecological and evolutionary importance and unique adaptations to parasitism. They also play a key role in ecosystem functioning. In the present special issue, 13 review and research articles on major groups of fish parasites are provided to document the current advancement in our understanding of different aspects of their biology, ecology and associations with their fish hosts. The existing gaps in our knowledge of these peculiar animals are mapped and future trends in their research outlined.

Phylogenetic relationships of philometrid nematodes (Philometridae Baylis & Daubney, 1926) inferred from 18S rRNA, with molecular characterisation of recently described species.

Nematodes of the family Philometridae Baylis & Daubney, 1926 (Dracunculoidea Stiles, 1907) are generally poorly known, and there are many taxonomic issues within the family. Philometrids are parasites of fish and are found in various locations throughout the host, including within the subcutaneous tissues and musculature, the abdominal cavity and gonads; vast sexual dimorphism often means the males are not collected, leading to many species being described solely on female characteristics. Although there have been a number of studies utilising molecular data, the vast majority of species are yet to be sequenced. This study undertook genetic sequencing of 15 recently described species of philometrids across 4 genera, many of which were from specimens collected from waters off Australia. All of the sequences obtained were closely related with representatives of the family Philometridae. Species were found to be distributed in the phylogenetic trees within 4 clades based on a combination of site of infection within the host and host habitat. Family of host and geographical location was not as important for position within the trees. Clade A contained philometrids collected from the abdominal cavities and head tissues of South American freshwater fish. Clade B contained philometrids primarily from the abdominal cavities of freshwater European cyprinids. Clade C contained philometrids primarily from the ovaries of marine fish. Clade D contained philometrids from the body tissues of marine and freshwater fish. The potential co-evolutionary patterns between philometrids and their fish hosts are highlighted as an area of future research. This research also highlighted the importance of correct identification of any sequenced specimen.

Lecithaster (Lecithasteridae, Digenea) in the White Sea: an unnoticed guest from the Pacific?

Morphological discrimination of species is problematic in many digenean taxa. Parasites of marine fish from the genus Lecithaster Lühe, 1901 are a good example of this. Our goal was to understand which species of Lecithaster infect fish in the White Sea, and reveal their life cycles. We collected specimens of maritae from nine fish species, analysed their morphology and sequenced 28S ribosomal DNA and internal transcribed spacer 2 (ITS2). Contrary to previous accounts, all of them belong to a single species, Lecithaster salmonis Yamaguti, 1934, which was previously only recorded from the Pacific. Morphologically, our maritae specimens were highly variable, sharing characters of L. salmonis, Lecithaster confusus Odhner, 1905 and Lecithaster gibbosus (Rudolphi, 1802) Lühe, 1901. This variability did not correlate with the moderate differences in ITS2 among the specimens, and neither did the fish host species. Members of the subfamily Salmoninae appear to be the best suited definitive hosts, judging from the intensity rates. The intermediate hosts were also discovered: the first is Cryptonatica affinis (Gmelin, 1791) and the second are planktonic copepods. These lifecycle data from the White Sea are consistent with L. salmonis species identification and with the distribution of this species in the North Pacific. The geographical range of L. salmonis seems to be interrupted, and we discuss possible ways of L. salmonis expansion.

Functional Groups of Metazoan Parasites of the Dusky Flounder (Syacium papillosum) as Bioindicators of Environmental Health of the Yucatan Shelf.

We aimed to compare the percentage of explained variance given by the relationship of species and functional groups of metazoan parasites of the dusky flounder Syacium papillosum and environmental variables from water and sediments in the Yucatan shelf (YS). Parasite data were obtained from 127 S. papillosum specimens collected from 17 of 67 stations. At each station, 46 environmental variables were measured, including hydrocarbons, heavy metals, and physicochemical variables from water and sediments. Fifteen functional groups were defined based on biological characteristics of 48 parasite species. Our multivariate statistical analyses showed that species and functional groups produced similar explained variance values (47.3% and 50% respectively). However, using functional groups the time and financial resources were minimal compared with those used for morphological and molecular identification to produce the species composition matrix. Thus, functional groups are the best choice from the point of view of saving time and money.

Fins infestation induced by Myxobolus xiantaoensis in yellow catfish Tachysurus fulvidraco Richardson, 1846: Some pathophysiological and molecular insights.

The myxozoan parasite Myxobolus xiantaoensis is a fin pathogen of commercially important yellow catfish Tachysurus fulvidraco Richardson, 1846, in the freshwater ponds of China. In the present work, four geographical isolates of M. xiantaoensis were sampled from the fins of yellow catfish. It was found that the spores of four isolates exhibited few markable differences in morphometrics. The small subunit ribosomal DNA (SSU rDNA) sequences of four isolates were conspecific to the SSU rDNA sequence of M. xiantaoensis. No genetic level variation was observed, even in the characteristically more variable internal transcribed spacer (ITS) region. This absence of variability suggests high gene flow as a result of panmixia in the parasitic populations. ITS phylogeny placed four isolates of M. xiantaoensis in a clade together with myxozoans species infecting Siluriformes. The M. xiantaoensis infection inflicted severe hemorrhages on epidermis of ray-fins, which grew into inflammatory epithelial hyperplasia and lytic cartilage signs. The histochemical analysis of infected fins biopsies is characterized by damage of collagen components of cartilage, resulting in weakness, breaks, and missing fin rays. These tissue sections also had a remarkable inflammatory response around the fin cartilage, with the absence of mature spores and chondrocytes. These results indicate that the fin cartilage damage appeared before the development of tissue inflammation and the parasitic infestation of the fins. The present four geographical isolates of M. xiantaoensis were identified by a holistic approach of species characterization based on biological, morphological, and molecular evidence. These four isolates showed some morphological and genetic variations but within the intraspecific range.

Sea lice (Copepoda: Caligidae) from South Africa, with descriptions of two new species of Caligus.

Thirteen species of sea lice (family Caligidae) are reported from a range of elasmobranch and actinopterygian fishes caught off South Africa or obtained from public aquaria in South Africa. Two new species of Caligus Müller, 1785 are described: C. linearis n. sp. from Pomatomus saltatrix (Linnaeus) and C. tumulus n. sp. from Chrysoblephus cristiceps (Valenciennes). A supplementary description is provided for both sexes of Caligus tetrodontis Barnard, 1948 taken from Amblyrhynchotes honckenii (Bloch) and previous records of this parasite from South African fishes are critically reviewed. It is concluded that Caligus material from Arothron hispidus Linnaeus was previously misidentified as C. tetrodontis and is in urgent need of re-examination. Morphological and molecular observations on Caligus furcisetifer Redkar, Rangnekar & Murti, 1949 indicate that this copepod is phenotypically and genetically identical to Lepeophtheirus natalensis Kensley & Grindley, 1973, and the latter becomes a junior subjective synonym of C. furcisetifer. We include new geographical distribution records for Caligus longipedis Bassett-Smith, 1898, C. rufimaculatus Wilson, 1905 and Lepeophtheirus spinifer Kirtisinghe, 1937, extending into South African waters, as well as both new distribution and host records for Alebion gracilis Wilson, 1905, Caligus dakari van Beneden, 1892 and Lepeophtheirus acutus Heegaard, 1943. The molecular analysis confirmed the monophyly of the genus Caligus. The South African species of Caligus did not cluster together, but the two included South African species of Lepeophtheirus were recovered as sister taxa.

Genetic diversity of Loma acerinae (Microsporidia: Glugeida) from different fish hosts and localities - Short communication.

Loma acerinae is a xenoma-forming fish microsporidium described from common ruffe Gymnocephalus cernua (Perciformes: Percidae) and also found in Ponto-Caspian gobies (Gobiiformes: Gobiidae). This casts doubt on the strict host specificity of this parasite. The largest subunit RNA polymerase II (rpb1) was used as a genetic marker of the parasite isolated from six host species of Perciformes (G. cernua from the Baltic Sea), Atheriniformes (Atherina boyeri from the Azov Sea) and Gobiiformes (Neogobius spp. and Zosterisessor ophiocephalus from the Black Sea and Ponticola kessleri from the Caspian Sea basin). Two major rpb1 haplogroups were found with 98.5% identity between the groups. Notably, Haplogroup I was associated with Neogobius spp. samples (n = 6) only, whereas Haplogroup II included the samples from other host species (n = 7). These findings confirm the broad distribution and host range of L. acerinae, but also indicate that certain patterns of host-driven intraspecific polymorphism may exist. Furthermore, the study revealed low similarity between the ribosomal RNA gene sequences of L. acerinae and the type species, Loma morhua (as well as other species of the genus). This suggests loose genetic association within the genus, and may raise the need for the taxonomic revision of L. acerinae.

In vivo and in vitro assessment of host-parasite interaction between the parasitic copepod Brachiella thynni (Copepoda; Lernaeopodidae) and the farmed Atlantic bluefin tuna (Thunnus thynnus).

The Atlantic bluefin tuna (ABFT; Thunnus thynnus) today represents one of the economically most important species for Croatian fisheries industry. Although the most diverse and abundant parasitofauna is usually found in the largest specimens of wild ABFT, the opposite was observed in captivity where parasite populations significantly decline by the end of the farming cycle. Copepod Brachiella thynni, is a skin parasite frequently parasitizing tuna, whose population also decreases in number throughout the rearing process. In order to better understand the immunity mechanisms underlying ABFT reaction to B. thynni infection, we studied expression profiles of immunity related genes; interleukin 1ß (il1ß), tumour necrosis factors (tnfα1, tnfα2), complement component 4 (c4) and caspase 3 (casp3), in peripheral blood leukocytes (PBLs) during in vitro stimulation by B. thynni protein extracts (i.e. antigens) and in infected tissues at B. thynni parasitation site. Finally, a histopathological analysis of semi-thin and ultra-thin sections of tissues surrounding B. thynii attachment site was performed to evaluate the severity of parasite-induced lesions and identify involved cell lineages. In vitro stimulation of ABFT PBLs with B. thynii antigens caused a dose-depended upregulation of selected genes, among which tnfα1 showed the highest induction by both concentrations of B. thynni protein extract. However, targeted genes were not significantly upregulated in the infected tissue. Also, no significant alterations in ultrastructure of epithelial layers surrounding B. thynii attachment site were noticed, except local tissue erosion, necrosis of squamous epithelium and proliferation of rodlet and goblet cells. Our results suggest that B. thynii has evolved strategies to successfully bypass both innate immune response and the connective-tissue proliferation processes. Therefore, the observed disappearance of this copepod by the end of the rearing process is more likely related to its limited lifespan on the host and its inability to complete the life cycle in the rearing cages, rather than host's reaction.

Changes in local free-living parasite populations in response to cleaner manipulation over 12 years.

Predation on parasites is an important ecological process, but few experimental studies have examined the long-term impacts on the prey. Cleaner fish prey upon large numbers and selectively feed on the larger individuals of the ectoparasitic stage of gnathiid isopods. Removal of cleaner fish Labroides dimidiatus for 1.5-12.5 years negatively affects coral reef fishes, but the mechanism is unclear. A reduction in local parasite populations or the size of individual parasites would benefit all susceptible fishes. We tested whether cleaner presence reduces local gnathiid populations using 18 patch-reefs distributed between two sites (both at Lizard Island, Great Barrier Reef) which were maintained cleaner-free or undisturbed for 12 years. Using emergence traps (1 m2), free-living gnathiid stages were sampled before and after cleaner fish were removed during the day and night, up to 11 times over the course of the experiment. There were effects of the removal in the predicted direction, driven largely by the response at one site over the other involving 200% more gnathiids, but manifested only in the daytime sampling after 4 months. There was also a main effect (36%) for the shared sample dates at both sites after 12 years. Gnathiid size occasionally differed with cleaner presence, but in no consistent way over time. Contrary to our predictions, changes in free-living gnathiid population numbers and their size structure rarely reflected the changes in fish populations and individuals observed on cleaner-free reefs. Therefore, evidence that this predator alone regulates gnathiids remains limited, suggesting other contributing processes are involved.

Molecular and morphological characterization of the metacercariae of two species of diplostomid trematodes (Platyhelminthes, Digenea) in freshwater fishes of the Batalha River, Brazil.

The Diplostomidae include a large group of flatworms with complex life cycles and are frequently found parasitizing the eyes and central nervous system of freshwater fishes. The morphological identification of the metacercariae at species level is not always possible. Thus, molecular tools have become essential to assist in the parasite species determination. This study was aimed at describing two diplostomid metacercariae found in freshwater fish in São Paulo, Brazil, based on morphological characters and in the genetic characterization of COI sequences. Our results showed that the two recognized taxa (Tylodelphys sp. and Diplostomidae gen. sp.) appear to be different from the species already described in South America. Tylodelphys sp. differs morphologically from Tylodelphys xenopi, T. mashonense, T. jenynsiae, and T. scheuringi. The metacercariae of T. clavata and T. conifera are smaller than Tylodelphys sp., while T. podicipina is larger than the metacercariae described here. The phylogenetic analysis of COI sequences yielded Tylodelphys sp. as the sister species of Tylodelphys sp. 4, a species reported from the brain of the eleotrid Gobiomorus maculatus in Oaxaca, Mexico. The metacercariae identified as Diplostomidae gen. sp. are morphologically different from the known diplostomid metacercariae and did not match with other diplostomid sequences available. Diplostomidae gen. sp. is recovered as the sister species of Diplostomum ardeae. Although the morphological evidence and the COI sequences differentiate the metacercariae found, the absence of adult specimens of both species precludes the specific designation. This is one of the first papers that use an integrative taxonomy approach to describe the species diversity of diplostomid trematodes in Brazil.

Levels of heavy metals in the straightfin barb Enteromius paludinosus (Peters 1852) from River Malewa, Naivasha, Kenya.

There have been several studies on heavy metals in Lake Naivasha. However, none of them has reported the levels of mercury (Hg), arsenic (As), and chromium (Cr). Moreover, there are no studies on the heavy metals' concentrations in the straightfin barb (Enteromius paludinosus, Peters 1852), a fish species that hosts a parasite (Ligula intestinalis), the latter having been reported to have a high ability to absorb heavy metals from its host. This paper therefore addresses the accumulation of heavy metals, namely arsenic (As), chromium (Cr), lead (Pb), and mercury (Hg) in the tissues of straightfin barb, Enteromius paludinosus (Peters 1852) from the mouth of River Malewa in Lake Naivasha, Kenya. A total of 1307 fish were collected during the month of November 2017. Water samples, sediment samples, 25 fish muscle tissues, and its endoparasite, the cestode Ligula intestinalis, were isolated, and heavy metal concentrations were determined using the thermal-electron atomic absorption spectrophotometer at the Lake Nakuru Water Quality Testing Laboratory. The concentrations of heavy metals in the sediment were below the lowest effect level in sediment, threshold effect concentration in sediment, severe effect concentration in sediment, and the shale values of sedimentary rocks thus showing no sign of pollution. In the muscle tissues of the fish, As, Cr, Pb, and Hg showed high levels with mean concentrations of 5.0696, 22.0854, 45.2108, and 1.5458 mg/kg ww, respectively. Bioconcentration factors further supported the observation that trace element accumulation was higher in fish compared with sediment and water. The target hazard quotients of As, Cr, Pb, and Hg obtained for both the female and male were > 1 indicating a possible health risk associated with the consumption of E. paludinosus. The bioaccumulation factors (BAFs) for L. intestinalis were 2.4093, 2.1873, 5.8601, and 5.1395 for As, Cr, Pb, and Hg, respectively, indicating the potential of the cestode in the accumulation of heavy metals from the host; hence, it can be used as an accumulation bioindicator.

Recombinant vs native Anisakis haemoglobin (Ani s 13): Its appraisal as a new gold standard for the diagnosis of allergy.

Recombinant allergens are currently the best option for serodiagnosis of human anisakiasis in terms of sensitivity and specificity. However, previous reports showed high rates of anisakiasis patients who were negative to Ani s 7 and especially to Ani s 1. Recently, Anisakis haemoglobin was described as a major allergen (Ani s 13). Although Ani s 13 belongs to a conserved protein family, it seems not to be a cross-reacting antigen because of the absence of IgE recognition against Ascaris haemoglobin in Anisakis patients. The aim of this study is to develop a more sensitive and specific diagnosis tool for Anisakis based on the recently discovered allergen Ani s 13. We obtained and purified recombinant Anisakis haemoglobin (rAni s 13) and the native form (nAni s 13). The recognition of both recombinant and native haemoglobins by anti-haemoglobin IgE from patients' sera was assessed by indirect ELISA and immunoblotting using 43 Anisakis sensitised patients and 44 non-Anisakis sensitised patients. Native Ani s 13 was also treated with periodate to study if oxidation of glycans destroys antibody binding. Furthermore, it was structurally characterised by negative staining electron microscopy and analytical ultracentrifugation. Recombinant Ani s 13 was only recognised by four patients with gastro-allergic anisakiasis (GAA) and immunoblotting analyses showed no bands. However, nAni s 13 was detected by 72.1% of Anisakis sensitised patients measured by indirect ELISA. Particularly, 18 (90%) out of 20 GAA patients were positive. Tetramers and octamers were the most abundant homomers of nAni s 13 but octamers had higher content of bound heme. None of the non-Anisakis sensitised patients were positive. Combined use of purified native form of Ani s 13 with current gold standards would improve the sensitivity and specificity for diagnosing anisakiasis.