Volume 57, Issue 3

Echinoparyphium species are common, widely distributed intestinal parasites causing disease in animals worldwide. Intermediate hosts include snails, bivalves, and fish, whereas the definitive hosts are mainly birds and mammals. This review examines the significant literature on Echinoparyphium. Descriptive studies, life cycle, experimental and manipulative studies, and biochemical and molecular studies are presented. The influence of environmental factors, and toxic pollutants, are reviewed as well as studies on the pathology of Echinoparyphium.

Mammalian serum is essential for the growth of Giardia duodenalis cultivated under axenic conditions. Unfortunately, some factors present in bovine serum used as supplement in the culture medium may inhibit protozoal growth and activity. TYI-33-PACSR is a TYI medium supplemented with a serum replacement (PACSR) made up of Earle’s amino acid solution, Diamond’s vitamin-tween 80 mixtures and LCR (a lipid-cholesterol — rich mixture). PACSR was previously used in the culture media for axenic cultivation of Entamoeba histolytica and Trichomonas vaginalis. The main objective of this work was to demonstrate that TYI-33-PACSR is useful for axenic cultivation of G. duodenalis. Additionally, the activity of phospholipase A2 (PLA A2) in the sub-cellular vesicular fraction (P30) of G. duodenalis grown in TYI-S-33 and TYI-33-PACSR was compared. All strains of Giardia grown in TYI-33-PACSR reached relative cellular densities of 91 to 95% compared to controls growing in serum-supplemented TYI-S-33 medium. Additionally, PLA A2 activity was similar in the P30 sub-cellular fraction obtained from trophozoites growing in TYI-S-33 and TYI-33-PACSR. Thus, TYI-33-PACSR could be useful in analyzing the biological properties of G. duodenalis in the absence of serum.

This study concerns a new neogregarine parasitic in the great spruce bark beetle Dendroctonus micans (Kugelann) (Curculionidae, Scolytinae). The rate of infection was high, reaching 27.3%. There was no difference in the rate of infection of male and female beetles. The life-cycle stages of the pathogen were described by light and electron microscopy. Each gametocyst of the neogregarine included 8–16 actinocephalid oocysts measuring 11.19 ± 0.42 × 4.99 ± 0.25 μm. The described pathogen has the typical characteristics of members of the genus Menzbieria within the order Neogregarinida and it was identified as Menzbieria chalcographi. This is the first record of an infection of D. micans by M. chalcographi. Possibly, this pathogen could be useful for the biological control of this destructive bark beetle.

The objective of this study was to obtain primary information on the occurrence of blood parasites and intensity of infection in the Dunnock Prunella modularis in the montane region of Slovakia. Altogether 109 birds were examined during the years 2006–2010. The occurrence of Haemoproteus sp., Leucocytozoon fringillinarum and Trypanosoma sp. was documented. Blood parasite prevalences of 45% by microscopic examination and 55% by PCR diagnostics were found. The prevalence of Leucocytozoon sp. was found to be dependent on host sex with males showing a significantly higher intensity of infection with Leucocytozoon. Adult birds showed significantly higher infection prevalence than subadults. The prevalences of both Leucocytozoon sp. and Haemoproteus sp. were significantly dependent on bird age. The intensity of infection with Haemoproteus and Leucocytozoon was positively correlated and higher intensity of infection was confirmed in adult birds then in subadults birds. The prevalence of blood parasites in our samples was significantly higher in comparison to most other studies from different countries of Europe conducted at lower altitudes, indicating that the montane zone is especially favourable for the transmission of Leucocytozoon and Haemoproteus species.

This study aimed to assess lipid peroxidation and antioxidant enzymes in goats naturally infected with Babesia ovis. Red blood cell count (RBC), hemoglobin (Hb) concentration, packed cell volume (PCV), malondialdehyde (MDA) concentration, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities and total antioxidant capacity (TAC) were determined in 15 goats naturally infected with B. ovis as well as same number of healthy goats. The parasitological diagnosis was confirmed using polymerase chain reaction (PCR) analysis by amplifying a partial 18S rRNA gene sequence of B. ovis. Percentage of parasitemia varied from 0.01 to 1%. The activities of erythrocyte GSH-Px, SOD, CAT and TAC were significantly lower (p<0.05) in the infected goats than in healthy ones. MDA concentration in erythrocytes of infected goats was significantly higher in infected goats than in healthy ones (pš0.05). Severity of parasitemia showed a positive correlation with the MDA and negative correlation with PCV, SOD, CAT, GSH-Px and TAC. Also, MDA was negatively correlated with PCV, SOD, CAT, GSH-Px and TAC. The results of this study suggested that oxidative damage to RBCs may contribute to the pathogenesis of anemia in caprine babesiosis.

Fine structural features of the vitellarium of two digeneans, Phyllodistomum angulatum and Azygia lucii, are documented and compared with those of other digenean species. The cytodifferentiation of immature vitelline cells (vitellocytes) assumes the production and subsequent accumulation in their cytoplasm of several inclusions. Mature vitelline cells of P. angulatum are characterized by the presence of vitelline clusters (∼2.7 μm in diameter, with ∼100 vitelline globules of ∼0.35 μm in diameter) and osmiophobic, saturated lipid droplets (∼2-3 μm in diameter), and in A. lucii vitelline clusters of the same diameter include much fewer vitelline globules (∼50 globules of ∼0.5 μm in diameter), osmiophilic lipid droplets and α-glycogen. In both P. angulatum and A. lucii, interstitial cells are also present within the vitellarium. Two types of contact sites (septate and tight junctions) between adjoining interstitial cells also occur in both digenean species. Judging from the present and previous ultrastructural studies, it is suggested that there are three potential discriminatory characters of the digenean vitellarium (the number of different types of cell components within the vitellarium, the presence and type of junctional complexes between these cells, and the isolation of the vitellarium from the surrounding tissue) which may prove useful for a better understanding of the biology and evolutionary history of the different digenean groups.

The lepocreadiid fauna of New Caledonia is reported and discussed and a new species and several new host and locality records presented. Hypoporus plataxi sp. nov. from Platax teira is described and distinguished from its only congener by its terminal genitalia, the structure of the anterior part of the alimentary system and other morphological features. New host and locality records and a description are given of Lepotrema cf. clavatum Ozaki, 1932 in Sufflamen fraenatum. New host and locality records are given of Lobatocreadium exiguum (Manter, 1963) in Pseudobalistes fuscus, which is also reported in the known hosts Abalistes filamentosus and Sufflamen fraenatum. New host and locality records are given of Opisthogonoporus amadai Yamaguti, 1937 in Branchiostegus wardi. A new host record is made for Holorchis plectorhynchi Durio et Manter, 1968 in Diagramma pictum. New records in New Caledonian waters are of Bulbocirrus aulostomiYamaguti, 1965 in Aulostomus chinensis, Echeneidocoelium indicum Simha et Pershad, 1964 in Echeneis naucrates, Lepidapedoides kalikali Yamaguti, 1970 in Pristipomoides auricilla, Neomultitestis aspidogastriformis Bray et Cribb, 2003 in Platax teira, Opechona bacillaris (Molin, 1859) in Rastrelliger kanagurta, Prodistomum keyam Bray et Cribb, 1996 in Monodactylus argenteus and Pseudopisthogonoporus vitellosus (Pritchard, 1963) in Naso brevirostris and N. annulatus. New metrical data are presented for Holorchis castex Bray et Justine, 2007 in Diagramma pictum, Hypocreadium patellareYamaguti, 1938 in Sufflamen fraenatum, Intusatrium robustum Durio et Manter, 1968 in Bodianus loxozonus and B. perditio and Lepidapedoides angustus Bray, Cribb et Barker, 1996 in Epinephelus chlorostigma, E. fasciatus, E. maculatus and E. retouti. Literature records are included and the fauna in general discussed.

Lymnaeid snails of the genus Radix serve as intermediate hosts of some schistosomes and fasciolids. In Europe, delineation of species within the genus Radix is unresolved and, therefore, spectrum of snail hosts susceptible to trematode infections is under discussion. We used and compared three criteria for species delineation using snails collected at 43 localities. (a) Sequence analysis of ITS-2 rDNA disclosed that the collected snails belong to four species — R. auricularia (Linnaeus, 1758), R. peregra (Müller, 1774), R. lagotis (Schrank, 1803) and R. labiata (Rossmaessler, 1835) (criteria and names are based on the work of Bargues et al. 2001). Occurrence of R. peregra in the Czech Republic was confirmed by molecular data for the first time. (b) Characterization of reproductive system disclosed differences in location, size and shape of bursa copulatrix and its ductus. Unfortunately, some R. labiata specimens shared morphological features of reproductive organs with R. lagotis. (c) Statistical analysis of shell morphology proved that significant differences exist among particular species. One prediction model showed that correct classification of species may be achieved in 82-84% of cases. However, identification of individual snails in the field (without knowledge of respective snail population and use of statistical tools) still remains a complicated issue due to overlaps of shell characteristics. Concerning the role in trematode transmission, R. lagotis, R. labiata and R. peregra are susceptible to Trichobilharzia regenti. Also, successful experimental infections of R. lagotis and R. labiata by Fascioloides magna were accomplished.

Neorickettsia is a genus of intracellular bacteria endosymbiotic in digeneans that may also invade cells of vertebrates and are known to cause diseases of wildlife and humans. Herein, we report results of screening for Neorickettsia of an extensive collection of DNA extracts from adult and larval digeneans obtained from various vertebrates and mollusks in the United States. Seven isolates of Neorickettsia were detected by PCR and sequenced targeting a 527 bp long region of 16S rRNA. Sequence comparison and phylogenetic analysis demonstrated that four isolates matched published sequences of Neorickettsia risticii. Three other isolates, provisionally named “catfish agents 1 and 2” (obtained from Megalogonia ictaluri and Phyllodistomum lacustri, both parasitic in catfishes) and Neorickettsia sp. (obtained from cercariae of Diplostomum sp.), differed from previously known genotypes of Neorickettsia and are likely candidates for new species. All 7 isolates of Neorickettsia were obtained from digenean species and genera that were not previously reported as hosts of these bacteria. Members of four digenean families (Dicrocoeliidae, Heronimidae, Macroderoididae and Gorgoderidae) are reported as hosts of Neorickettsia for the first time. Our study reveals several new pathways of Neorickettsia circulation in nature. We have found for the first time a Neorickettsia from a digenean (dicrocoeliid Conspicuum icteridorum) with an entirely terrestrial life cycle. We found N. risticii in digeneans (Alloglossidium corti and Heronimus mollis) with entirely aquatic life cycles. Previously, this Neorickettsia species was known only from digeneans with aquatic/terrestrial life cycles. Our results suggest that our current knowledge of the diversity, host associations and circulation of neorickettsiae is far from satisfactory.

Two tapeworm specimens collected in northeast China in 2009 and 2011 were identified as Diphyllobothrium latum based on morphological criteria. Molecular methods were used to confirm their identity and analyze genetic variations compared with published data for this species. Species identity was confirmed by molecular characterization of the 18S rDNA partial sequence, complete sequences of internal transcribed spacers (ITSs) and 5.8S rDNA, and partial sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) and mitochondrial NADH dehydrogenase subunit 5 (nad5). PCR amplification and sequence analysis of 18S rDNA (1472 bp), ITS regions (1218 bp), cox1 (885 bp), and nad5 (1028 bp) revealed that these four sequences showed more than 99% identity to reference sequences for D. latum, confirming that this species is D. latum. To date, a total of 12 diphyllobothriosis cases have been documented in China. This study represents the first molecular characterization of D. latum in China, providing molecular evidence of human diphyllobothriosis in China.

The scolex of the bothriocephalidean cestode Clestobothrium crassiceps was studied by means of scanning electron microscopy (SEM). The comparative results of various fixation procedures and techniques are presented. The scolex of C. crassiceps is oval to globular and exhibits two deep bothria which appear in the form of two lobes separated by a longitudinal groove. At the apex of the scolex, resembling a beret, an apical disc is present (oval, flattened and with a sinuous edge). Our results are compared with those previously reported in other species of Clestobothrium. This study represents the first report which highlights the presence of an apical disc in the scolex of C. crassiceps. It describes the effects of different procedures applied to our material during preparation and a comparative analysis results obtained using these various methods.

A population of Hammerschmidtiella diesingi was detected in specimens of Periplaneta americana collected in Córdoba city (Argentina) was studied. Nematodes were characterized based on morphological, morphometric and genetic (D2–D3 expansion segment) analyses. New data are provided, especially on particular morphological characters that were a matter of controversy in previous studies. H. diesingi is reported in Argentina for the first time.

Aspiculuris tianjinensis sp. nov. recovered from the intestine of Clethrionomys rufocanus from Tianjin, China is described and illustrated using light microscopy and scanning electron microscopy. The new species differs from congeners in the shape of the cervical alae, and the number and arrangement of caudal papillae.

The little known ascaridoid nematode Raphidascaris (Ichthyascaris) lophii (Wu, 1949) is redescribed and illustrated based on newly collected specimens from the five different marine fishes: Lophius litulon (Jordan) (Lophiiformes: Lophiidae), Lophiomus setigerus (Vahl) (Lophiiformes: Lophiidae), Antennarius hispidus (Bloch et Schneider) (Lophiiformes: Antennaridae), Zeus faber Linnaeus (Zeiformes: Zeidae) and Ostichthys japonicus (Cuvier) (Beryciformes: Holocentridae) from the East and South China Sea. This species differs from all congeners in the subgenus Ichthyascaris by the length of the ventricular appendix (0.52–0.98 mm long), the number and arrangement of caudal papillae (26–32 pairs of precloacal, 3–4 pairs of paracloacal and 8–11 pairs of postcloacal) and the length of the spicules (0.49–0.88 mm long, representing 3.08–4.70% of body length). In addition, nematodes collected from these five different fishes have been characterized using molecular methods by sequencing and analysing the internal transcribed spacer (ITS) of ribosomal DNA. No variation in size and nucleotide polymorphisms is detected within the target sequence among all samples analysed. These data contribute to facilitate an accurate diagnosis of this poorly known nematode. An identification key to the species of the subgenus Ichthyascaris is also provided.

A new species of Colobomatus Hesse, 1873 is described from pores of the cephalic sensory system and nostrils of Argentine goatfish, Mullus argentinae Hubbs et Marini, 1933 (Perciformes: Mullidae), living along the southwestern Atlantic coast. The fish were collected at different latitudes, stretching from the State of Rio de Janeiro in the north, through Santa Catarina, Rio Grande do Sul (Brazil) to of Mar del Plata (Argentina) in the south. The prevalence of the infection ranged from 42% through 84%. The new species look alike to two other species, parasites of mullids (C. steenstrupi and C. mulli) particularly in the body shape and the number, shape, and ornamentation of cephalic, thoracic, and genital processes. The new species, however, can be readily distinguished by having the central cephalic process shorter than lateral ones, the later being bilobed at tip forked, and a relatively larger abdomen. Furthermore, C. steenstrupi possesses relatively wider trunk processes with rounded tips, a short abdominal dorsal process, and attains a larger size (up to 3.6 mm). C. mulli also differs by having all body processes with forked tips, and relatively shorter sixth thoracic somite and abdominal segments 1–3. This is the third record of a species of Colobomatus in South American Atlantic waters.

Ornithodoros quilinensis sp. nov. (Acari: Argasidae) is described from larvae collected on the small rodents Graomys centralis (Cricetidae: Sigmodontinae) in Argentina. The diagnostic characters for this new species are a combination of small size (520–540 μm), a dorsal plate oval in shape with a length of approximately 200 μm, 14 pairs of dorsal setae, hypostome short and narrower at the base (length from Ph1 to apex 133 μm (120–141)) with dental formula 2/2 and apex blunt, and the capsule of the Haller’s organ irregular in shape and without reticulations. The analysis of the 16S rDNA sequences available for the genus Ornithodoros indicate that, phylogenetically, O. quilinensis represents an independent lineage only related to a Bolivian tick species of the genus Ornithodoros yet not formally described.