Nematode Specimens Research Articles

Natterer in Neotropical Nematoda: Species Described by Rudolphi, Diesing, and Molin

Between 1817 and 1835 Johann Natterer collected 1,729 samples of endoparasitic helminths in Brazil and southern Venezuela. Of the 323 names that were assigned to the collected nematode specimens, 163 are still valid and accepted species, 84 are still doubtful, and 76 must be rejected. In this work, each name is analyzed and correlated to the literature to clarify its taxonomic status. The purpose of this review of the material collected by Natterer is to establish a complete list of all described species; their current status; and whether they are valid species, synonyms, or nomen nudum as well as to update the hosts and the original dates and localities where they were collected.

Pathohistological changes in the intestine, lungs and liver of sheep with spontaneous strongyloidiasis

Sheep diseases of invasive and non-invasive etiology are among the restrictive factors for Ukrainian sheep-breeding. The helminthiases are among the most widespread parasitical diseases, and particularly strongyloidiasis causes significant losses for sheep farms in cases of severe course. Young sheep are the most susceptible, showing growth and developmental lag, and death occurs in cases of high invasiveness due to severe pathologies induced by the parasites. Thus the aim of the present work was to study the morphological and histological changes in the intestine, lungs and liver of sheep with strongyloidiasis. Results of pathoanatomy showed that under spontaneous sheep strongyloidiasis with the intensity of the invasion from 50 to 136 specimens of nematodes, the main pathological changes occur at Strongyloides localization sites: intestine and parenchymatous organs (lungs and liver). Particularly, the small intestine showed catarrhal desquamative enteritis. Morphological changes of its mucosa demonstrated necrosis of the apical part of the villi, desquamation of epithelium, constriction and decrease of intestinal crypts. At the same time, massive diffusive cell infiltrates were detected in the intestinal mucosa lamina propria with the prevalence of eosinophilic leukocytes, inflammatory thickening of villi cylindrical epithelium and its mucous metamorphosis, pyknosis and lysis of enterocyte nuclei. In the large intestine, necrosis of the mucosa was detected, with edema, effusion of serum-cell exudate in its canal, diffusive infiltration of lymphocytes, eosinophils and plasma cells in the intestinal mucosa lamina propria. Lung tissue demonstrated parasite larvae localized in canals of the bronchi and in alveoli. These sites had diffusive hemorrhages in lung parenchyma, signs of inflammation and thickening of interstitial tissue caused by damage to vessel walls due to migration of parasite larvae. Histological changes in the liver of sheep with strongyloidiasis showed the development of granular dystrophy and necrotic changes in hepatocytes.

Comparative evaluation of different molecular methods for DNA extraction from individual Teladorsagia circumcincta nematodes

BackgroundThe purpose of this study was to develop a reliable DNA extraction protocol to use on individual Teladorsagia circumcincta nematode specimens to produce high quality DNA for genome sequencing and phylogenetic analysis. Pooled samples have been critical in providing the groundwork for T. circumcincta genome construction, but there is currently no standard method for extracting high-quality DNA from individual nematodes. 11 extraction kits were compared based on DNA quality, yield, and processing time.Results11 extraction protocols were compared, and the concentration and purity of the extracted DNA was quantified. Median DNA concentration among all methods measured on NanoDrop 2000™ ranged between 0.45–11.5 ng/μL, and on Qubit™ ranged between undetectable – 0.962 ng/μL. Median A260/280 ranged between 0.505–3.925, and median A260/230 ranged − 0.005 – 1.545. Larval exsheathment to remove the nematode cuticle negatively impacted DNA concentration and purity.ConclusionsA Schistosoma sp. DNA extraction method was determined as most suitable for individual T. circumcincta nematode specimens due to its resulting DNA concentration, purity, and relatively fast processing time.

Autochthonous, zoonotic Onchocerca lupi in a South Texas dog, United States

BackgroundOnchocerca lupi is an emerging, zoonotic filarioid nematode associated with ocular disease in companion animals in North America and the Old World. The areas where this parasite is assumed to be endemic in the USA comprise southwestern states. Thus far, all cases reported outside of the southwest are associated with travel or animal movement.MethodsAn 11-year-old, castrated male Pitbull dog from McAllen, Hidalgo County, southern Texas, with no travel history, was diagnosed with a perforating corneal ulceration of the right eye. Enucleation was performed and tissues submitted for histopathology.ResultsHistologically, sections of two filarioid nematodes were observed. DNA was extracted from formalin-fixed paraffin-embedded tissue using a commercial kit. We performed PCR targeting the cox1 gene of the mitochondrial DNA, followed by sequencing and phylogenetic analysis. Altogether, these results confirmed the identification of the nematode specimens as O. lupi, phylogenetically belonging to haplotype 1.ConclusionWe report the first autochthonous case of O. lupi in a dog from Hidalgo County, southern Texas, USA. Our finding suggests Texas as an additional state where this zoonotic nematode is endemic. Further investigations are required to understand the epidemiology of this parasite along the USA/Mexico border.Graphical

Description of a new species of Aplectana (Nematoda: Ascaridomorpha: Cosmocercidae) using an integrative approach and preliminary phylogenetic study of Cosmocercidae and related taxa

BackgroundNematodes of the family Cosmocercidae (Ascaridomorpha: Cosmocercoidea) are mainly parasitic in the digestive tract of various amphibians and reptiles worldwide. However, our knowledge of the molecular phylogeny of the Cosmocercidae is still far from comprehensive. The phylogenetic relationships between Cosmocercidae and the other two families, Atractidae and Kathlaniidae, in the superfamily Cosmocercoidea are still under debate. Moreover, the systematic position of some genera within Cosmocercidae remains unclear.MethodsNematodes collected from Polypedates megacephalus (Hallowell) (Anura: Rhacophoridae) were identified using morphological (light and scanning electron microscopy) and molecular methods [sequencing the small ribosomal DNA (18S), internal transcribed spacer 1 (ITS-1), large ribosomal DNA (28S) and mitochondrial cytochrome c oxidase subunit 1 (cox1) target regions]. Phylogenetic analyses of cosmocercoid nematodes using 18S + 28S sequence data were performed to clarify the phylogenetic relationships of the Cosmocercidae, Atractidae and Kathlaniidae in the Cosmocercoidea and the systematic position of the genus Aplectana in Cosmocercidae.ResultsMorphological and genetic evidence supported the hypothesis that the nematode specimens collected from P. megacephalus represent a new species of Aplectana (Cosmocercoidea: Cosmocercidae). Our phylogenetic results revealed that the Cosmocercidae is a monophyletic group, but not the basal group in Cosmocercoidea as in the traditional classification. The Kathlaniidae is a paraphyletic group because the subfamily Cruziinae within Kathlaniidae (including only the genus Cruzia) formed a seperate lineage. Phylogenetic analyses also showed that the genus Aplectana has a closer relationship to the genus Cosmocerca in Cosmocercidae.ConclusionsOur phylogenetic results suggested that the subfamily Cruziinae should be moved from the hitherto-defined family Kathlaniidae and elevated as a separate family, and the genus Cosmocerca is closely related to the genus Aplectana in the family Cosmocercidae. The present study provided a basic molecular phylogenetic framework for the superfamily Cosmocercoidea based on 18S + 28S sequence data for the first time to our knowledge. Moreover, a new species, A. xishuangbannaensis n. sp., was described using integrative approach.Graphical abstract

Zoonotic Thelazia californiensis in dogs from New Mexico, USA, and a review of North American cases in animals and humans.

Thelazia californiensis is a spirurid nematode found in the conjunctival sac of domestic and wild animals, including humans, across the western United States of America. Herein, we report two cases of thelaziosis by T. californiensis in dogs from New Mexico, United States, based on integrated morphological and molecular approaches. Nematode specimens collected from the conjunctiva of both dogs were identified as T. californiensis based on morphology. Our study substantially expands the knowledge on morphometry of this nematode species. Therefore, these data will be useful for accurate diagnosis of thelaziosis in domestic animals, wildlife and humans in North America, using classical, microscopy-based methods. We characterized for the first time the mitochondrial cytochrome c-oxidase subunit 1 (COI) and 12S genes of T. californiensis. While these markers support the validity of T. californiensis, they were not very informative for elucidating the phylogenetic relationships among Thelazia species. Nevertheless, the characterization of these diagnostic markers for T. californiensis will be useful for studies on the epidemiology, molecular xenomonitoring of fanniid vectors, and population genetics of this multi-host, zoonotic parasite.

Redescription of Ascarophis distorta Fusco et Overstreet, 1978 (Nematoda, Cystidicolidae) from the stomach of some butterflyfishes off New Caledonia.

The nematode Ascarophis distorta Fusco et Overstreet, 1978 (Cystidicolidae), originally described from the butterflyfish Chaetodon paucifasciatus Ahl (Perciformes, Chaetodontidae) in the Red Sea, was established based solely on the light microscopical (LM) examination of specimens. However, the present taxonomy of cystidicolid nematodes is mostly based on details of the cephalic structures properly visible only with the use of scanning electron microscopy (SEM). Helminthological examinations of some marine fishes from coral reefs off New Caledonia, South Pacific, carried out in the years 2003-2007, revealed the presence of A. distorta in two Chaetodon spp. and thus enabled its redescription. The nematode specimens were studied with the use of both LM and SEM. The specimens of A. distorta were obtained from the stomach of the threadfin butterflyfish Chaetodon auriga Forsskål and the vagabond butterflyfish Chaetodon vagabundus Linnaeus. This is just the second record of this parasite since its description 43years ago. SEM, used in this species for the first time, revealed some taxonomically important, previously unreported or insufficiently described morphological features, such as details in the cephalic structure, the shape of deirids, structure of the distal tip of the left spicule, or the exact number and distribution of male caudal papillae. The finding of A. distorta in C. auriga and C. vagabundus off New Caledonia represents new host and geographical records. The examination of 39 specimens of butterflyfishes from off New Caledonia, belonging to 14 Chaetodon spp. and 3 Heniochus spp., revealed that the nematode was only present in the 2 fish species listed above. This parasite seems to be host-specific to only certain species of butterflyfishes (Chaetodon spp.), and is probably widespread in the Indo-Pacific region, as well as its hosts.

Integrative Taxonomy and Molecular Phylogeny of the Plant-Parasitic Nematode Genus Paratylenchus (Nematoda: Paratylenchinae): Linking Species with Molecular Barcodes.

Pin nematodes of the genus Paratylenchus are obligate ectoparasites of a wide variety of plants that are distributed worldwide. In this study, individual morphologically vouchered nematode specimens of fourteen Paratylenchus species, including P. aculentus, P. elachistus, P. goodeyi, P. holdemani, P. idalimus, P. microdorus, P. nanus, P. neoamblycephalus, P. straeleni and P. veruculatus, are unequivocally linked to the D2-D3 of 28S, ITS, 18S rRNA and COI gene sequences. Combined with scanning electron microscopy and a molecular analysis of an additional nine known and thirteen unknown species originating from diverse geographic regions, a total of 92 D2-D3 of 28S, 41 ITS, 57 18S rRNA and 111 COI new gene sequences are presented. Paratylenchus elachistus, P. holdemani and P. neoamblycephalus are recorded for the first time in Belgium and P. idalimus for the first time in Europe. Paratylenchus is an excellent example of an incredibly diverse yet morphologically minimalistic plant-parasitic genus, and this study provides an integrated analysis of all available data, including coalescence-based molecular species delimitation, resulting in an updated Paratylenchus phylogeny and the corrective reassignment of 18 D2-D3 of 28S, 3 ITS, 3 18S rRNA and 25 COI gene sequences that were previously unidentified or incorrectly classified.

Morphometric and Molecular Analyses of Ostertagia leptospicularis Assadov, 1953 from Ruminants: Species Diversity or Host Influence?

Simple SummaryPathogenic nematode Ostertagia leptospicularis, as the sole member of the subfamily Ostertagiinae, occurs in both cervid and bovid host species. The broad host specificity of this parasite draws special attention and requires a more in-depth investigation. This study was carried out to find out whether the differences in the nematode morphology were only due to the host influence, or whether genetic differences should be taken into account. To resolve this issue, the classification of O. leptospicularis was raised and discussed based on its host specificity, as well as morphological and genetic characteristics. A combined morphological–molecular approach was used to compare specimens resembling O. leptospicularis collected from naturally infected hosts of various ruminant species (roe deer, red deer, fallow deer, and cattle). Both morphological and molecular analyses highlighted the distinctiveness of O. leptospicularis collected from cattle in Germany, and therefore should now be considered to be a different strain that those collected form cervids in central Europe.Ostertagia leptospicularis Assadov, 1953 was formally described in roe deer Capreolus capreolus and has been reported in a wide range of ruminants, including other Cervidae, as well as Bovidae. Nematode specimens derived from various host species exhibit morphological similarity; however, some differences can be observed. It is unclear if this is due to the differential reaction of one nematode species in different host species (i.e., host-induced changes) or because of distinct nematode species in these hosts (i.e., species complex). This paper focuses on specimens resembling O. leptospicularis f. leptospicularis and its closely related species (Ostertagia ostertagi f. ostertagi) collected from various hosts. Morphometric and molecular techniques were applied to assess host-induced changes in nematode morphology and to clarify its systematic classification. There was an overall effect of host species on measurements of nematodes resembling O. leptospicularis (both males and females), but the distinctiveness of the specimens from cattle Bos taurus were highlighted. The results obtained may suggest that the specimens of O. leptospicularis from cattle in Germany and cervids in central Europe belong to different strains. Furthermore, nematodes from the cervid strain appear to circulate within particular host species, which can be seen in the stated morphological variations.

Occurrence of Dirofilaria immitis (Nematoda, Onchocercidae) in Red Foxes (Vulpes vulpes) from the Suburbs of Kharkiv (Ukraine)

Dirofilariasis of animals and humans is a disease caused by nematodes of the genus Dirofilaria (Railliet et Henry, 1911). The role of wild predators, particularly the red fox (Vulpes vulpes) (Linnaeus, 1758) in the distribution of pathogen of the genus Dirofilaria in the world remains unclear. We studied the occurrence of Dirofilaria immitis (Leidy, 1856) in a population of the red fox. Twenty-seven foxes were examined during the winter hunting season of 2019–2020 in Dergachi district, Kharkiv region of Ukraine. All 27 examined foxes were older than 1.5–2 years old, 5 of them (18.5 %) were 4–5 years old. Dirofilaria immitis was found in 22.2 % of foxes. The intensity of infection ranged from 2 to 4 specimens of nematodes per host. In four foxes (66.7 % of infected hosts), the same number of male and female nematodes was detected, while two foxes (33.3 %) had each 1 male and 2 females of D. immitis. The length of D. immitis males (7 specimens) was 13.96 ± 0.29 cm and the length of females (9 specimens) was 19.58 ± 0.55 cm. Prevalence of infection of foxes with D. immitis presumably depends on their habitat and the presence of mosquitos (vectors of the nematode) in these areas.

Globocephalus urosubulatus (Alessandrini, 1909) (Nematoda: Ancylostomatidae) in Brazil: a morphological revisitation.

Helminthiasis occurs frequently in wild or domestic pigs in the most varied environments or production systems; however, the literature includes few taxonomic studies for the purpose of expanding this knowledge about the parasitic diversity in these animals. Thus, in order to expand this knowledge regarding parasitic diversity in these animals, the present study reports the occurrence and redescribes Globocephalus urosubulatus infecting domestic pigs in the state of Pará, Brazil, using microscopy. Four hundred and ten specimens of Sus scrofa intestinal nematodes were collected extensively in the municipality of Moju, northeastern mesoregion of Pará and observed under light and scanning electron microscopy. Based on morphological characteristics, the nematodes were identified as G. urosubulatus, and new morphological data were added by light microscopy and scanning electron microscopy for the diagnosis of this parasite.

Identificación de nematodos gastrointestinales en búfalos faenados en un frigorífico de Corrientes, Argentina

<p>El objetivo del trabajo fue identificar y cuantificar los ejemplares adultos de nematodos gastrointestinales en los búfalos faenados en el frigorífico de Virasoro (Corrientes) mediante la necropsia parasitaria del tubo digestivo y, por intermedio de estudios coprológicos, correlacionarlos con el recuento de huevos por gramo de materia fecal y la proporción de géneros parasitarios de larvas de tercer estadio de los coprocultivos. Se realizaron en total 4 necropsias parasitarias que correspondieron a búfalos machos jóvenes, de los cuales el 50% presentó ejemplares adultos de Trichostrongylus sp y Haemonchus sp ubicados solamente en el abomaso. En los estudios coprológicos, el 75% de las muestras presentaron recuentos de huevos por gramo de materia fecal, de los cuales únicamente en dos casos se pudieron identificar larvas de tercer estadio de Haemonchus sp en los coprocultivos.</p>

Morphology, genetic characterization and molecular phylogeny of pinworm Skrjabinema longicaudatum n. sp. (Oxyurida: Oxyuridae) from the endangered Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae)

BackgroundThe Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae) is an endangered species of mammal endemic to the Qinghai-Tibetan Plateau. Parasites and parasitic diseases are considered to be important threats in the conservation of the Tibetan antelope. However, our present knowledge of the composition of the parasites of the Tibetan antelope remains limited.MethodsLarge numbers of nematode parasites were collected from a dead Tibetan antelope. The morphology of these nematode specimens was observed using light and scanning electron microscopy. The nuclear and mitochondrial DNA sequences, i.e. small subunit ribosomal DNA (18S), large subunit ribosomal DNA (28S), internal transcribed spacer (ITS) and cytochrome c oxidase subunit 1 (cox1), were amplified and sequenced for molecular identification. Moreover, phylogenetic analyses were performed using maximum likelihood (ML) inference based on 28S and 18S + 28S + cox1 sequence data, respectively, in order to clarify the systematic status of these nematodes.ResultsIntegrated morphological and genetic evidence reveals these nematode specimens to be a new species of pinworm Skrjabinema longicaudatum (Oxyurida: Oxyuridae). There was no intraspecific nucleotide variation between different individuals of S. longicaudatum n. sp. in the partial 18S, 28S, ITS and cox1 sequences. However, a high level of nucleotide divergence was revealed between the new species and its congeners in 28S (8.36%) and ITS (20.3–23.7%) regions, respectively. Molecular phylogenetic results suggest that the genus Skrjabinema should belong to the subfamily Oxyurinae (Oxyuroidea: Oxyuridae), instead of the subfamily Syphaciidae or Skrjabinemiinae in the traditional classification, as it formed a sister relationship to the genus Oxyuris.ConclusionsA new species of pinworm Skrjabinema longicaudatum n. sp. (Oxyurida: Oxyuridae) is described. Skrjabinema longicaudatum n. sp. represents the first species of Oxyurida (pinworm) and the fourth nematode species reported from the Tibetan antelope. Our results contribute to the knowledge of the species diversity of parasites from the Tibetan antelope, and clarify the systematic position of the genus Skrjabinema.

Effects of sediment disturbance on deep-sea nematode communities: Results from an in-situ experiment at the arctic LTER observatory HAUSGARTEN

The present study examines the effects of experimentally generated disturbance on bathyal nematode communities at the LTER (Long-Term Ecological Research) observatory HAUSGARTEN, situated in the Fram Strait, between Greenland and Svalbard. In order to understand the complex interactions between the biota and environmental perturbations we deployed a free-falling device (bottom lander) equipped with three rotating fork-like disturber units, able to perturbate the upper sediment layers with different disturbance frequencies at chosen time intervals. During a one-year deployment at 2493 m water depth, disturber unit DI was programmed to rotate every 14 days, DII every 28 days, and DIII every 72 days, resulting in 28, 14, and 7 perturbations, respectively. Sediment sampling following this experimental period was conducted with push-coring devices deployed by the Remotely Operated Vehicle “QUEST 4000” (MARUM, Bremen). These sediment cores were sub-sampled to determine the effect of the sediment perturbations on various sediment parameters (i.e., grain size distribution, chloroplastic pigment concentrations) as well as on benthic nematode communities.A total of 4773 nematodes from 27 families and 81 genera were identified. Nematode densities in the disturbed areas ranged from 617 ind. / 10 cm2 to 1566 ind. / 10 cm2, with a mean density of 1193 ind. / 10 cm2 observed overall in the disturbed sediments. Control sediments contained on average 20% more nematode specimens than were found within the disturbed sediments, with an average density of 1477 ind. / 10 cm2 observed. Nematode evenness (J'), genera richness (EG(51)) and heterogeneity (H′) were not significantly different between the treatments and controls (undisturbed vs disturbance). We found a significant effect of the interaction of disturbance frequency and sediment depth (interaction term Fr x De) on heterogeneity and genera richness, while evenness significantly differed between different sediment depths (De) and within the disturbed sediments between different disturbance frequencies (Fr). Although surface sediments in the three disturbed areas were effectively perturbated, sediment depth still has the most pronounced influence on nematode community attributes, while the experimentally induced disturbance had only a limited impact on nematode diversity and community structure. Although we found the density of some nematode genera was negatively affected by the disturbances, the deep-sea nematode community at HAUSGARTEN was generally characterized by a relatively high diversity and seemed to be largely resilient to the experimental disturbances.

First record of Ektaphelenchoides pini associated with Ips sexdentatus on Pinus nigra laricio in Italy

AbstractIn February 2015, an unexpected windstorm downed five hectares of a European black pine Pinus nigra subsp. laricio forest formation located close to Vallombrosa, Florence (Central Italy). In the following spring, an extensive survey was conducted in the area. Felled trees, stumps and all the suitable plant material were screened for the presence of the pinewood nematode (PWN), Bursaphelenchus xylophilus, by sampling wood and bark. Bark beetles were then collected from the gallery systems on the inner side of bark samples and observed in the laboratory. The following bark beetles were morphologically identified: Ips sexdentatus, Orthotomicus erosus, O. laricis and Pityogenes bidentatusa. The dissection of Ips sexdentatus allowed the extraction of numerous nematodes that were morphologically and molecularly identified as Ektaphelenchoides pini. Conversely, only few nematode specimens were isolated from either pine bark or wood. These individuals could be only molecularly identified and belonged to an undescribed nematode taxon. Even though no PWN was recorded in the investigated sites, our survey allowed the detection of a new association between E. pini and I. sexdentatus on P. nigra.

First Report of Root-lesion Nematode, Pratylenchus on New Host, Deverra tortuosa, in Mersa Matruh Coast, Egypt- A Pilot Study

Nematode survey was carried out in 2019 on wild plants viz., Aeluropus lagopoides (Molleih), Ammophila arenaria (Gazzoof), Cakile maritime (Figl el-gamal), Deverra tortuosa (guezah), Euphorbia paralias (Sakrran), Inula crithmeides (Golden samphire), Lotus polyphyllus (Qam el- gamal or Qrana), Ononis vaginalis (Hotaiba), Pancratium maritimum (Bosseil), Polygonum equisetiforme (Horsetail knotweed), Thymelaea hirsute (Mithnaan), and Zygophyllum album (Ratrayt), colonized the coastal sand dunes habitat of mersa matruh, Egypt. specimens of root-lesion nematodes (Pratylenchus spp.) were collected from rhizosphere soil of D. tortuosa Synonym: Pituranthos tortuosus (Desf.) Benth. & Hook f. Asch. & Schweinf herb (family: Apiaceae, old family: Umbelliferae). Root-lesion nematode was identified based on morphological characteristics of females. According to available literature, this is the first report of Pratylenchus on wild plant (D. tortuosa) growing in Egypt. More surveys are needed to identify other genera or species of phytonematodes that might occur in Egypt, including weeds, grasses and wild plants in desert areas, also the dissemination of lesion nematode must be explored as well as other plant-parasitic nematodes and it is advisable to investigate the nearby cultivated plants.

Anisakidae Skrjabin & Karokhin, 1945 and Raphidascarididae Hartwich, 1954 nematodes in lutjanidae (pisces: perciformes) from the Brazilian Northeast Coast.

The present study aimed at describing and evaluating the fauna of Anisakidae and Raphidacarididae nematodes of lutjanid fish (snappers) from the Brazilian northeastern coast unloaded at the city of Aracaju, capital of the State of Sergipe. A total of 186 lutjanids of 5 different species were analyzed including 69 Lutjanus analis, 51 L. vivanus , 29 Ocyurus chrysurus, 23 L. synagris, and 14 L. jocu. Nematode specimens found in the viscera of these fish were clarified with lactophenol. Illustrations of each of these specimens were prepared to help identify these samples and compose their taxonomic description and classification. At necropsy, 3,183 nematodes belonging to two families were collected from fish viscera which included the following: Anisakidae: Anisakis, Terranova , Contracaecum, and Goezia; Raphidascarididae: Raphidascaris (Ichthyascaris) and Hysterothylacium . A total of six genera of nematodes were found at postmortem examination of which adult worms of only three genera (Goezia, Raphidascaris and Hysterothylacium) were detected in the fish examined. Larvae of Terranova sp. were found only in the musculature of O. chrysurus . Most of the nematode larvae were present in the mesentery and organs of the fish necropsied. Therefore, the zoonotic potential of these nematodes cannot be ruled out. There was a significant negative correlation between the intensity of parasitism by anisakids and the total body length of O. chrysurus; the intensity of parasitism was greater in smaller and shortef fish. There was a significant positive correlation between the abundance of these parasites and the length of L. synagris; the presence of these parasites increased according to the fish's body length. To the authors' knowledge, these are the first records of Raphidascaris (Ichthyascaris ) sp. and Hysterothylacium sp. in L. vivanus , of Terranova sp. in O. chrysurus and L. jocu, and of Goezia sp. in L. analis. These novel findings add the Brazilian northeast coast and the State of Sergipe in the geographic distribution of these parasites in the country.

Gastro-intestinal helminths in the red-bellied squirrel introduced in Argentina: accidental acquisitions and lack of specific parasites

Introduced species may lose their natural parasites when invading a new habitat, may acquire new, local parasites or may introduce parasites from their native range. We studied the gastro-intestinal helminth fauna associated with the red-bellied squirrel Callosciurus erythraeus (Pallas, 1778) introduced in Argentina to evaluate its role as a host of either specific or acquired parasites in two invasion foci. We analyzed entire digestive tracts of 72 red-bellied squirrels captured in the main invasionfocus(Lujan, provinceofBuenosAires)betweenFebruaryandMay2011, andinasecondary focus (Canada de Gomez, province of Santa Fe) in December 2008. We only found two nematode specimens: an adult male belonging to the genus Pterygodermatites (Paucipectines) Quentin, 1969 and another adult male belonging to the genus Stilestrongylus (Freitas, Lent and Almeida, 1973). None of these genera were previously listed for the red-bellied squirrel in introduced areas, but a species of the genus Pterygodermatites was previously reported for this squirrel in its native habitat. These results indicate that, to date, the red-bellied squirrel in Argentina is accidentally parasitised by nematodes acquired in its new environment and has no specific gastro-intestinal helminths. This could be related with a “founder eect” and/or the lack of sciurid rodents that prevent the red-bellied squirrel to be colonized by pre-adapted helminth taxa. Other factors that may play a role are the small number of mammals with arboreal habits and some “encounter barriers” in the new environment that prevent the acquisition of helminths with a wide host spectrum.

The Description of Nematode in Barbonymus schwanenfeldii at Kenyir Lake, Terengganu

Cucullanus sp is a genus of nematode infecting Barbonymus schwanenfeldii. It is categorized under Family Cucullunidae. The genus Cucullanus sp consists of various species around the world, parasitizing freshwater, brackish-water or marine fishes. Cucullanus sp are mainly found in internal organs like stomach, intestine, kidney, and spleen. This parasitic organism can cause an economic impact, especially for animals with high market value, which are commercialized and used for human consumption. The objectives of this study are to study the morphological characteristics of Cucullanus sp and to identify genus of Cucullanus sp which are found on tinfoil barb, Barbonymus schwanenfeldii at Kenyir Lake, Terengganu. There is not enough data on Cucullanus sp on B. schwanenfeldii. Six samples of tinfoil barb were collected at Kenyir Lake from 25 to 27 October 2018. Each sample of fish was measured and recorded for length and weight using ruler and weighing balance respectively. The fish were examined at camping site at Lawit Resort, Kenyir Lake. The nematode species found were brought back to Health of Aquatic Organism laboratory. The abdominal and gastrointestinal tracts of the fishes were dissected and placed in petri dishes. The nematodes found were collected and observed under the dissecting microscope. The nematode specimen was placed on a glass slide with a drop of lactophenol and observed under the compound microscope fitted with dino-eye. The sample was later fixed with 70% alcohol. The morphological characteristic was drawn using camera lucida fitted to a compound microscope. (40X magnification). The picture of nematode was captured by using Advanced Research Microscope (Nikon Eclipse 80i) and measurements of the nematode was also made. Hence, the nematode found was identified as male Cucullanus sp.

DESCRIPTION OF NEW SPECIES OF METARHABDITIS LONGICAUDATUS (NEMATODA: RHABDITIDAE) WITH THREE NEW RECORDS FROM SINDH, PAKISTAN

Many rhabditid nematodes like Metarhabditis belonging to the bacteriophage group are considered to be necromenic associates of insects and used to be facultative entomopathogenic nematodes or as biocontrol agents. These nematodes can be safely used against insect pests of different crops and vegetables. In the present study, nematode specimens of new and known species were collected from different areas of Sindh and isolated from soil samples by baiting technique using last instar Galleria mellonella. One new nematode species Metarhabditis longicaudata n. sp. and three new records of M. adenobia, M. amasactae, and M. rainai (Nematoda: Rhabditidae) were found from Sindh. M. longicaudata n. sp. differed from the species of the genus Metarhabditis by having long un-covered tail spike. It was also characterized by a large sized male 1286 (1154-1325) µm; longer male tail 69.5 (62-76) µm; longer spicule 43 (40-46) µm; leptoderan bursa; longer gubernaculum 27 (20-34) µm. The female was also of large size of 1507 (1366-1684) µm with larger tail 102 (94-112) µm and longer pharynx 231 (206-265) µm. The genus Metarhabditis is reported for the first time from Sindh, Pakistan.