PeerJ Preprints: Parasitologyhttps://peerj.com/preprints/index.atom?journal=peerj&subject=2300Parasitology articles published in PeerJ PreprintsDiscrete stochastic marine metapopulation disease modelhttps://peerj.com/preprints/264542019-11-282019-11-28Gorka BidegainTal Ben-Horin
Some marine microparasitic pathogens can survive several months in the water column to make contact with or to be absorbed or filtered by hosts. Once inside, pathogens invade the host if they find suitable conditions for reproduction. This transmission from the environment occurs via pathogens released from infected and dead infected animals. Some recent modeling studies concentrated on the disease dynamic imposed by this complex interaction between population and water column at the host-pathogen level in single populations. However, only when a marine disease can be understood at the metapopulation scale effective approaches to management will become routinely achievable. The discrete-time disease model in this paper investigates both spatial and temporal dynamics of hosts and waterborne pathogens in a metapopulation system of three patches. This system with a patch providing infective particles and susceptible and infected individuals by dispersal tries to imitate the effect of current forces in the ocean on the passive dispersal of organisms. The model detects behaviours that are not present in single population continuous-time and deterministic models.
Some marine microparasitic pathogens can survive several months in the water column to make contact with or to be absorbed or filtered by hosts. Once inside, pathogens invade the host if they find suitable conditions for reproduction. This transmission from the environment occurs via pathogens released from infected and dead infected animals. Some recent modeling studies concentrated on the disease dynamic imposed by this complex interaction between population and water column at the host-pathogen level in single populations. However, only when a marine disease can be understood at the metapopulation scale effective approaches to management will become routinely achievable. The discrete-time disease model in this paper investigates both spatial and temporal dynamics of hosts and waterborne pathogens in a metapopulation system of three patches. This system with a patch providing infective particles and susceptible and infected individuals by dispersal tries to imitate the effect of current forces in the ocean on the passive dispersal of organisms. The model detects behaviours that are not present in single population continuous-time and deterministic models.First confirmation of the shell-boring oyster parasite Polydora websteri (Polychaeta: Spionidae) in Washington State, USAhttps://peerj.com/preprints/276212019-11-212019-11-21Julieta MartinelliHeather LopesLorenz HauserIsadora Jimenez-HidalgoTeri L KingJacqueline Padilla-GaminoPaul RawsonLaura SpencerJason WilliamsChelsea Wood
Invasions by the spionid polychaete Polydora websteri have resulted in the collapse of oyster aquaculture industries in Australia, New Zealand, and Hawaii. These worms burrow into the shells of bivalves, creating unsightly mud blisters that are unappealing to consumers and, when nicked during shucking, release mud and detritus that can foul oyster meats. Recent sightings of mud blisters on the shells of Pacific oysters (Crassostrea gigas) in Puget Sound, Washington, suggest a new spionid polychaete invasion. To determine the identity of the polychaete causing these mud blisters, we obtained Pacific oysters from two locations in Puget Sound and examined them for blisters and burrows associated with spionid infection. We then extracted polychaetes and sequenced mitochondrial (cytochrome c oxidase I [COI]) and nuclear (18S rRNA) genes to obtain species-level identifications for a subset of these worms. Our data confirm that P. websteri is present in mud blisters of Puget Sound oysters, constituting the first confirmed record of this species in Washington State. The presence of non-native P. websteri could threaten the sustainability of oyster aquaculture in Washington, which currently produces more shellfish than any other US state.
Invasions by the spionid polychaete Polydora websteri have resulted in the collapse of oyster aquaculture industries in Australia, New Zealand, and Hawaii. These worms burrow into the shells of bivalves, creating unsightly mud blisters that are unappealing to consumers and, when nicked during shucking, release mud and detritus that can foul oyster meats. Recent sightings of mud blisters on the shells of Pacific oysters (Crassostrea gigas) in Puget Sound, Washington, suggest a new spionid polychaete invasion. To determine the identity of the polychaete causing these mud blisters, we obtained Pacific oysters from two locations in Puget Sound and examined them for blisters and burrows associated with spionid infection. We then extracted polychaetes and sequenced mitochondrial (cytochrome c oxidase I [COI]) and nuclear (18S rRNA) genes to obtain species-level identifications for a subset of these worms. Our data confirm that P. websteri is present in mud blisters of Puget Sound oysters, constituting the first confirmed record of this species in Washington State. The presence of non-native P. websteri could threaten the sustainability of oyster aquaculture in Washington, which currently produces more shellfish than any other US state.Deep transcriptomic analysis of Chromera velia under Mercury-stress conditionhttps://peerj.com/preprints/277502019-05-222019-05-22Abdoallah SharafRoberto De MicheleAyush SharmaMiroslav Oborník
The heavy metal pollution in ecosystems is of increasing global concern. The main sources of the metal toxicity are the industrial waste, mining and the use of pesticides containing heavy metals. Out of all heavy metals, mercury (Hg) is considered to be the one, easily accumulated in terrestrial plants as well as aquatic organism. Hg can induce more severe oxidative stress by triggering the production of reactive oxygen species (ROS) and damage macro-molecules. ROS serve not only as dangerous molecules that damage proteins, lipids and DNA but also as signalling molecules in the regulation of biological processes such as biotic and abiotic stress responses, growth and development. This study shows the change in the Chromera velia transcriptome due to Hg stress. C. velia is the recently discovered closest known relative of apicomplexans. Our study shows the first deep transcriptomic analysis of C. velia, specifically focusing on the expression level of the genes involved in detoxification defence systems under heavy metal stress. The results show that in total 1239 genes are differentially expressed. DEGs (Differentially expressed genes) showed overall up-regulation (1,070 genes) and only 169 up-regulated genes in cultures under Mercury stress (Cvel_mer) when compared to the control level (Cvel_cont). The qPCR expression analysis exhibited a positive correlation with the findings of RNA-seq data.
The heavy metal pollution in ecosystems is of increasing global concern. The main sources of the metal toxicity are the industrial waste, mining and the use of pesticides containing heavy metals. Out of all heavy metals, mercury (Hg) is considered to be the one, easily accumulated in terrestrial plants as well as aquatic organism. Hg can induce more severe oxidative stress by triggering the production of reactive oxygen species (ROS) and damage macro-molecules. ROS serve not only as dangerous molecules that damage proteins, lipids and DNA but also as signalling molecules in the regulation of biological processes such as biotic and abiotic stress responses, growth and development. This study shows the change in the Chromera velia transcriptome due to Hg stress. C. velia is the recently discovered closest known relative of apicomplexans. Our study shows the first deep transcriptomic analysis of C. velia, specifically focusing on the expression level of the genes involved in detoxification defence systems under heavy metal stress. The results show that in total 1239 genes are differentially expressed. DEGs (Differentially expressed genes) showed overall up-regulation (1,070 genes) and only 169 up-regulated genes in cultures under Mercury stress (Cvel_mer) when compared to the control level (Cvel_cont). The qPCR expression analysis exhibited a positive correlation with the findings of RNA-seq data.Sibling Bald Sea Urchin Disease affecting the edible Paracentrotus lividus (Echinodermata: Echinoidea) in Sardinia, Italyhttps://peerj.com/preprints/276442019-04-182019-04-18Daniele GrechIvan GualaSimone Farina
Different species of echinoids and bivalves are suffering infectious diseases as the effect of ocean warming. In Sardinia (Western Mediterranean Sea) the keystone sea urchin species Paracentrotus lividus (Lamarck 1816) is widely appreciated as edible resource. Recently, a number of individuals were found to be infected by a no specified bacterial morphologically matching to a “bald sea urchin disease” (Fig. 1). In February 2019, a sampling campaign took place in two locations in the West and East Coast, inside and in proximity of local Marine Protected Areas. Field samplings were approved by the Regione Autonoma Sardegna (Fishing License for scientific purposes n.310/AP SCIE/N.1 10/01/2019). Samplings were carried out at the end of February 2019, when water temperature was 13°C. For each sampled site we performed two replicates of fast 50 m belt transects to estimate the infection rate as the total individuals infected on the total counted. The estimated infection rate was around 5% in both of sampled locations. A higher level of preyed sea urchins was observed, compared to natural predatory level previously observed in all the surveyed sites. Moreover, an unusual amount of dead sea urchins has been observed stranded on the storm berm, neighbouring one of the sampled sites. Microbiological analysis puts in evidence bacterial infection as the potential causal agent that could be temperature-related. Previous mass mortalities of sea urchins due to this infection were reported in the northwestern Mediterranean Sea in the past, where populations of shallow waters sharply declined until 75% during the summer period. A number of papers argued global warming might be linked to the occurrence of catastrophic events in the Mediterranean Sea, which could alter the host/pathogen range and modify pathogen transmission rates. Thus, the spread of the infection could cause important consequences at genetic, population, community and ecosystem level. In the study area, it seems already evident how predatory pressure on populations sampled was increased probably due to the lowering of the natural defences of the sea urchin preys as consequence of the infection. Accordingly, the outbreak of this infection probably related with environmental changes could determine important effects on trophic interactions and generating unpredictable cascading effects. In this area, an increasing of the sea urchin disease and related mortality is expected in the next months with the temperature increasing. A long-term monitoring across the summer season will be crucial to understand the extent and magnitude of the phenomenon as its implications.
Different species of echinoids and bivalves are suffering infectious diseases as the effect of ocean warming. In Sardinia (Western Mediterranean Sea) the keystone sea urchin species Paracentrotus lividus (Lamarck 1816) iswidely appreciated as edible resource. Recently, a number of individuals were found to be infected by a no specified bacterial morphologically matching to a “bald sea urchin disease” (Fig. 1). In February 2019, a sampling campaign took place in two locations in the West and East Coast, inside and in proximity of local Marine Protected Areas. Field samplings were approved by the Regione Autonoma Sardegna (Fishing License for scientific purposes n.310/AP SCIE/N.1 10/01/2019). Samplings were carried out at the end of February 2019, when water temperature was 13°C. For each sampled site we performed two replicates of fast 50 m belt transects to estimate the infection rate as the total individuals infected on the total counted. The estimated infection rate was around 5% in both of sampled locations. A higher level of preyed sea urchins was observed, compared to natural predatory level previously observed in all the surveyed sites. Moreover, an unusual amount of dead sea urchins has been observed stranded on the storm berm, neighbouring one of the sampled sites. Microbiological analysis puts in evidence bacterial infection as the potential causal agent that could be temperature-related. Previous mass mortalities of sea urchins due to this infection were reported in the northwestern Mediterranean Sea in the past, where populations of shallow waters sharply declined until 75% during the summer period. A number of papers argued global warming might be linked to the occurrence of catastrophic events in the Mediterranean Sea, which could alter the host/pathogen range and modify pathogen transmission rates. Thus, the spread of the infection could cause important consequences at genetic, population, community and ecosystem level. In the study area, it seems already evident how predatory pressure on populations sampled was increased probably due to the lowering of the natural defences of the sea urchin preys as consequence of the infection. Accordingly, the outbreak of this infection probably related with environmental changes could determine important effects on trophic interactions and generating unpredictable cascading effects. In this area, an increasing of the sea urchin disease and related mortality is expected in the next months with the temperature increasing. A long-term monitoring across the summer season will be crucial to understand the extent and magnitude of the phenomenon as its implications.First report of cestode infection in the crustacean Artemia persimilis from Southern Chilean Patagonia and its relation with the Neotropical aquatic birdshttps://peerj.com/preprints/276232019-04-012019-04-01Stella RedónGergana P VasilevaBoyko B GeorgievGonzalo Gajardo
The brine shrimp Artemia Leach (Crustacea, Branchiopoda), a keystone species in extremely saline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to elucidate “hidden fauna” (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50ºS-53ºS). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform birds). This is a new geographical record of C. podicipina and the undescribed species Fimbriarioides (?) sp. for the Neotropical Region, the latter being the most widely distributed species at both localities and seasons surveyed, and the only species recorded in autumn (April). Cestode community composition in the Los Cisnes population was characterised by dominance of Flamingolepis sp., representing more than 65% of the total cestode species recorded, whereas in the Amarga population the most abundant parasite (> 83%) was Fimbriarioides (?) sp. Significant seasonal variations were detected in Cisnes lagoon for Flamingolepis sp. and C. podicipina, with exclusive presence of them in spring (November). Besides providing novel information on cestodes infection in A. persimilis, this study provides new data on the life-cycle of cestodes of Neotropical aquatic birds such as South American flamingos and grebes. Our finding expands the knowledge on the biodiversity and population dynamics of extreme and unique environments from high latitudes (Patagonia), but makes evident the need of further taxonomical and ecological studies to better understanding the life cycle of avian helminth parasites in the Neotropics, and to elucidate the role of aquatic invertebrates in the parasite life cycle in hypersaline wetlands from the Americas.
The brine shrimp Artemia Leach (Crustacea, Branchiopoda), a keystone species in extremely saline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to elucidate “hidden fauna” (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50ºS-53ºS). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform birds). This is a new geographical record of C. podicipina and the undescribed species Fimbriarioides (?) sp. for the Neotropical Region, the latter being the most widely distributed species at both localities and seasons surveyed, and the only species recorded in autumn (April). Cestode community composition in the Los Cisnes population was characterised by dominance of Flamingolepis sp., representing more than 65% of the total cestode species recorded, whereas in the Amarga population the most abundant parasite (> 83%) was Fimbriarioides (?) sp. Significant seasonal variations were detected in Cisnes lagoon for Flamingolepis sp. and C. podicipina, with exclusive presence of them in spring (November). Besides providing novel information on cestodes infection in A. persimilis, this study provides new data on the life-cycle of cestodes of Neotropical aquatic birds such as South American flamingos and grebes. Our finding expands the knowledge on the biodiversity and population dynamics of extreme and unique environments from high latitudes (Patagonia), but makes evident the need of further taxonomical and ecological studies to better understanding the life cycle of avian helminth parasites in the Neotropics, and to elucidate the role of aquatic invertebrates in the parasite life cycle in hypersaline wetlands from the Americas.Molecular interplay between organisms by phylogenetic profilinghttps://peerj.com/preprints/273732018-11-212018-11-21Gabriella SferraMarta PonziElisabetta Pizzi
In recent years, several computational methods have been developed to predict protein-protein interactions (PPIs) at a genome-wide level. Between them phylogenetic profiling is routinely used to infer PPIs occurring within an organism. Recent improvements of the methods rely on the usage of large genomic datasets and on the distance correlation, a correlation-based measure, as novel measure of profile similarity. Here we adapted the robust improved phylogenetic profiling strategy to predict PPIs occurring between organisms. Specifically, we inferred PPIs occurring in the host-parasite system of Plasmodium falciparum, the deadliest human malaria parasite, and the human erythrocyte, in which the parasite performs an asexual reproduction and that is responsible of the greatest part of the parasitosis symptoms. By applying the method we could predict host-host, erythrocyte-erythrocyte and host-erythrocyte PPIs. As proof of principle, we demonstrated that the phylogenetic profiling can be extended to predict interactions that not necessarily are performed by proteins belonging to the same organism.
In recent years, several computational methods have been developed to predict protein-protein interactions (PPIs) at a genome-wide level. Between them phylogenetic profiling is routinely used to infer PPIs occurring within an organism. Recent improvements of the methods rely on the usage of large genomic datasets and on the distance correlation, a correlation-based measure, as novel measure of profile similarity. Here we adapted the robust improved phylogenetic profiling strategy to predict PPIs occurring between organisms. Specifically, we inferred PPIs occurring in the host-parasite system of Plasmodium falciparum, the deadliest human malaria parasite, and the human erythrocyte, in which the parasite performs an asexual reproduction and that is responsible of the greatest part of the parasitosis symptoms. By applying the method we could predict host-host, erythrocyte-erythrocyte and host-erythrocyte PPIs. As proof of principle, we demonstrated that the phylogenetic profiling can be extended to predict interactions that not necessarily are performed by proteins belonging to the same organism.Persistent phylogeographic structure of an emerging virus on a homogeneous landscapehttps://peerj.com/preprints/272602018-10-072018-10-07Trieste MusialScott Duke-SylvesterRolan DavisRoman BiekLeslie A. Real
Landscape composition and structure influence animal movement, which in turn can affect transmission of their diseases. Spatio-temporal variation in host diffusion, caused by landscape heterogeneity, is thus expected to generate corresponding phylogeographic patterns in the pathogen. However, establishing causative links between genetic structure in pathogen populations and environmental variation does require appropriate null models. Here, we present an empirical example of the emergence and multi-decade persistence of phylogeographic structure on a homogeneous landscape in a rapidly diversifying pathogen in the absence of any apparent landscape heterogeneity. By applying phylogeographic inference to 173 sequences of a raccoon-specific strain of rabies virus, we reconstruct patterns of the virus’ evolution and diffusion on the Florida peninsula, USA, from its first emergence in the 1940’s to the present. Consistent with a lack of significant landscape heterogeneity relevant to raccoon movement in Florida, we found that the speed of rabies virus diffusion was spatially homogeneous across the peninsula. In contrast, we document the emergence of strong phylogeographic structure in the virus, in the form of five monophyletic lineages that diverged during the early years of colonization and now each occupy a distinct sub-region of Florida. Based on samples taken over multiple decades, we show that the spatial distribution of these lineages has changed little over the past four decades. This phylogeographic stability allowed us to retrospectively identify a small set of counties within Florida as the likely source of the virus strain that seeded a much larger rabies outbreak in the northeastern USA in the 1970s. Our results provide a rare empirical demonstration that spatial genetic structure can arise and be maintained in the absence of landscape heterogeneity, which has wider implications for the interpretation of phylogeographic data and the reconstruction of historical colonization patterns from molecular data.
Landscape composition and structure influence animal movement, which in turn can affect transmission of their diseases. Spatio-temporal variation in host diffusion, caused by landscape heterogeneity, is thus expected to generate corresponding phylogeographic patterns in the pathogen. However, establishing causative links between genetic structure in pathogen populations and environmental variation does require appropriate null models. Here, we present an empirical example of the emergence and multi-decade persistence of phylogeographic structure on a homogeneous landscape in a rapidly diversifying pathogen in the absence of any apparent landscape heterogeneity. By applying phylogeographic inference to 173 sequences of a raccoon-specific strain of rabies virus, we reconstruct patterns of the virus’ evolution and diffusion on the Florida peninsula, USA, from its first emergence in the 1940’s to the present. Consistent with a lack of significant landscape heterogeneity relevant to raccoon movement in Florida, we found that the speed of rabies virus diffusion was spatially homogeneous across the peninsula. In contrast, we document the emergence of strong phylogeographic structure in the virus, in the form of five monophyletic lineages that diverged during the early years of colonization and now each occupy a distinct sub-region of Florida. Based on samples taken over multiple decades, we show that the spatial distribution of these lineages has changed little over the past four decades. This phylogeographic stability allowed us to retrospectively identify a small set of counties within Florida as the likely source of the virus strain that seeded a much larger rabies outbreak in the northeastern USA in the 1970s. Our results provide a rare empirical demonstration that spatial genetic structure can arise and be maintained in the absence of landscape heterogeneity, which has wider implications for the interpretation of phylogeographic data and the reconstruction of historical colonization patterns from molecular data.Xeno-miRNet: a comprehensive database and analytics platform to explore xeno-miRNAs and their potential targetshttps://peerj.com/preprints/268872018-04-252018-04-25Yannan FanMaria HabibJianguo Xia
Xeno-miRNAs are microRNAs originating from exogenous species detected in host biofluids. A growing number of studies have suggested that many of these xeno-miRNAs may be involved in cross-species interactions by targeting host mRNAs. To date, hundreds of xeno-miRNAs have been reported in different hosts at various abundance levels. Many more miRNAs could be potentially transferred to human circulation system based on computational predictions. There is a clear need for bioinformatics resources and tools dedicated to xeno-miRNA annotations and their potential functions. To address this need, we have systematically curated xeno-miRNAs from multiple sources, performed target predictions using well-established algorithms, and developed a user-friendly web-based tool - Xeno-miRNet to allow researchers to search and explore xeno-miRNAs and their potential targets within different host species. Xeno-miRNet currently contains 1,702 (including both detected and predicted) xeno-miRNAs from 54 species and 98,053 potential gene targets in six hosts. The web application is freely available at http://xeno.mirnet.ca .
Xeno-miRNAs are microRNAs originating from exogenous species detected in host biofluids. A growing number of studies have suggested that many of these xeno-miRNAs may be involved in cross-species interactions by targeting host mRNAs. To date, hundreds of xeno-miRNAs have been reported in different hosts at various abundance levels. Many more miRNAs could be potentially transferred to human circulation system based on computational predictions. There is a clear need for bioinformatics resources and tools dedicated to xeno-miRNA annotations and their potential functions. To address this need, we have systematically curated xeno-miRNAs from multiple sources, performed target predictions using well-established algorithms, and developed a user-friendly web-based tool - Xeno-miRNet to allow researchers to search and explore xeno-miRNAs and their potential targets within different host species. Xeno-miRNet currently contains 1,702 (including both detected and predicted) xeno-miRNAs from 54 species and 98,053 potential gene targets in six hosts. The web application is freely available at http://xeno.mirnet.ca .Rhabdias bufonis (Rhabdiasidae) from the lung of the African common toad, Amietophrynus regularis (Bufonidae) in Egypt. New data on the basis of light and scanning electron microscopic studyhttps://peerj.com/preprints/35232018-03-252018-03-25Kareem MorsySara AliFathy Abdel GhaffarHoda El FayoumiHeba Abdel Haleem
Background and Aims: Rhabdias bufonis (Rhabdiasidae) is a nematode parasite of family Rhabdiasidae infecting the lung of amphibians. The present study provides new morphological details for R. bufonis isolated from the lungs of the African common toad, Amietophrynus regularis based on observations of light and scanning electron microscopy. Methods: Forty specimens were collected during the period from March to August 2017 from its natural habitat; the damp, moist fields and gardens at Giza governorate, Egypt. Nematode worms were isolated from the lungs, fixed and then preserved. They were examined using light and scanning electron microscopy with further line drawings. Results: 14 specimens (35%) were found to harbor a large number of Rhabdias. Body of the gravid females were elongated, slender, measured 3.22–9.86 (5.64±0.03) long and 0.09–0.48 (0.23±0.02) mm wide at mid–length. Buccal capsule was with cylindrical lumen and sclerotised walls 13–31 (18 ± 2) long and 16–27 (24 ± 2) mm wide. Ovaries were almost straight. The uteri were located anterior and posterior to the vulva. Uterus filled with large number of eggs (17-42). Eggs were oval in shape, 0.120–0.132 (0.126±0.002) × 0.039–0.812 (0.517±0.02) mm and some of them were with fully developed larvae inside. The tail was comparatively short, gradually tapered, tail length 0.131–0.435 (0.320±0.02) mm long. SEM showed that worms possessed an oval anterior end with a simple, slit like oral opening. The lipless edges of mouth opening bordered with tiny cuticular elevations, radiated outwards. Two pairs of submedian cephalic papillae were observed around the oral opening as well as two amphids. Conclusion: The current study introduced new morphological details for R. bufonis isolated from the Egyptian frog, which was not reported in the previous studies, of them, the morphology of the slit–like mouth opening, the two pairs of cephalic papillae, two amphids and the three pairs of cuticular elevations supporting the area around mouth opening.
Background and Aims: Rhabdias bufonis (Rhabdiasidae) is a nematode parasite of family Rhabdiasidae infecting the lung of amphibians. The present study provides new morphological details for R. bufonis isolated from the lungs of the African common toad, Amietophrynus regularis based on observations of light and scanning electron microscopy. Methods: Forty specimens were collected during the period from March to August 2017 from its natural habitat; the damp, moist fields and gardens at Giza governorate, Egypt. Nematode worms were isolated from the lungs, fixed and then preserved. They were examined using light and scanning electron microscopy with further line drawings. Results: 14 specimens (35%) were found to harbor a large number of Rhabdias. Body of the gravid females were elongated, slender, measured 3.22–9.86 (5.64±0.03) long and 0.09–0.48 (0.23±0.02) mm wide at mid–length. Buccal capsule was with cylindrical lumen and sclerotised walls 13–31 (18 ± 2) long and 16–27 (24 ± 2) mm wide. Ovaries were almost straight. The uteri were located anterior and posterior to the vulva. Uterus filled with large number of eggs (17-42). Eggs were oval in shape, 0.120–0.132 (0.126±0.002) × 0.039–0.812 (0.517±0.02) mm and some of them were with fully developed larvae inside. The tail was comparatively short, gradually tapered, tail length 0.131–0.435 (0.320±0.02) mm long. SEM showed that worms possessed an oval anterior end with a simple, slit like oral opening. The lipless edges of mouth opening bordered with tiny cuticular elevations, radiated outwards. Two pairs of submedian cephalic papillae were observed around the oral opening as well as two amphids. Conclusion: The current study introduced new morphological details for R. bufonis isolated from the Egyptian frog, which was not reported in the previous studies, of them, the morphology of the slit–like mouth opening, the two pairs of cephalic papillae, two amphids and the three pairs of cuticular elevations supporting the area around mouth opening.Helminth Parasites of Scorpaena brasiliensis and S. plumieri (Perciformes: Scorpaenidae) from reefs of Veracruz, Mexico, Southern Gulf of Mexicohttps://peerj.com/preprints/266942018-03-142018-03-14Jesus Montoya-MendozaSandra Edith Badillo-LópezIsabel Araceli Amaro-EspejoMaría del Refugio Castañeda-ChávezFabiola Lango-ReynosoIgnacio Herrera-Martínez
Both S. brasiliensis and S. plumieri are relevant species in reef systems, but little is known about their parasitic helminths and community structure. This work describes such community in terms of species richness and diversity. A helminthological study was conducted on 33 specimens of S. brasiliensis and 36 of S. plumieri, captured in the Pájaros and Cabezo Reefs, in the Veracruz Reef System National Park (VRSNP), Ver., Mexico. The helminth community structure was analyzed in both hosts. A total of 10 parasitic species was registered for S. brasiliensis (trematodes, 5; nematodes, 3; cestodes, 1; acanthocephals, 1). S. plumieri hosted 11 species (trematodes, 4; nematodes, 4; monogeneans, 1; cestodes, 1; acanthocephals, 1), with 8 common species. Overall, parasites had prevalences < 20%, as Pseudocapillaria (Icthyocapillaria) sp., with 18.2% and 19.4% in S. brasiliensis and S. plumieri, respectively. Community component richness for S. brasiliensis was S=10, with Shannon index diversity value of H’=2.08. For S. plumieri, such values were of S=11 and H’=1.91. The richness and diversity in the components community and infracommunity of parasitic helminths for both hosts are lower than in other parasite community of marine fish Southern Gulf of Mexico.
Both S. brasiliensis and S. plumieri are relevant species in reef systems, but little is known about their parasitic helminths and community structure. This work describes such community in terms of species richness and diversity. A helminthological study was conducted on 33 specimens of S. brasiliensis and 36 of S. plumieri, captured in the Pájaros and Cabezo Reefs, in the Veracruz Reef System National Park (VRSNP), Ver., Mexico. The helminth community structure was analyzed in both hosts. A total of 10 parasitic species was registered for S. brasiliensis (trematodes, 5; nematodes, 3; cestodes, 1; acanthocephals, 1). S. plumieri hosted 11 species (trematodes, 4; nematodes, 4; monogeneans, 1; cestodes, 1; acanthocephals, 1), with 8 common species. Overall, parasites had prevalences < 20%, as Pseudocapillaria (Icthyocapillaria) sp., with 18.2% and 19.4% in S. brasiliensis and S. plumieri, respectively. Community component richness for S. brasiliensis was S=10, with Shannon index diversity value of H’=2.08. For S. plumieri, such values were of S=11 and H’=1.91. The richness and diversity in the components community and infracommunity of parasitic helminths for both hosts are lower than in other parasite community of marine fish Southern Gulf of Mexico.