Infection of Diplostomum spp. in invasive round gobies in the St Lawrence River, Canada.

The round goby (Neogobius melanostomus) is a successful invader of the Great Lakes-St Lawrence River basin that harbours a number of local parasites. The most common are metacercariae of the genus Diplostomum. Species of Diplostomum are morphologically difficult to distinguish but can be separated using molecular techniques. While a few species have been sequenced from invasive round gobies in this study system, their relative abundance has not been documented. The purpose of this study was to determine the species composition of Diplostomum spp. and their relative abundance in round gobies in the St Lawrence River by sequencing the barcode region of cytochrome c oxidase I. In 2007-2011, Diplostomum huronense (=Diplostomum sp. 1) was the most common, followed in order by Diplostomum indistinctum (=Diplostomum sp. 4) and Diplostomum indistinctum sensu Galazzo, Dayanandan, Marcogliese & McLaughlin (2002). In 2012, the most common species infecting the round goby in the St Lawrence River was D. huronense, followed by D. indistinctum and Diplostomum gavium (=Diplostomum sp. 3). The invasion of the round goby in the St Lawrence River was followed by a decline of Diplostomum spp. in native fishes to low levels, leading to the previously published hypothesis that the presence of the round goby has led to a dilution effect. Herein, it is suggested that despite the low infection levels in the round goby, infections still may lead to spillback, helping to maintain Diplostomum spp. in native fishes, albeit at low levels.

Prospective enzymes for omega-3 PUFA biosynthesis found in endoparasitic classes within the phylum Platyhelminthes.

The free-living infectious stages of macroparasites, specifically, the cercariae of trematodes (flatworms), are likely to be significant (albeit underappreciated) vectors of nutritionally important polyunsaturated fatty acids (PUFA) to consumers within aquatic food webs, and other macroparasites could serve similar roles. In the context of de novo omega-3 (n-3) PUFA biosynthesis, it was thought that most animals lack the fatty acid (FA) desaturase enzymes that convert stearic acid (18:0) into ɑ-linolenic acid (ALA; 18:3n-3), the main FA precursor for n-3 long-chain PUFA. Recently, novel sequences of these enzymes were recovered from 80 species from six invertebrate phyla, with experimental confirmation of gene function in five phyla. Given this wide distribution, and the unusual attributes of flatworm genomes, we conducted an additional search for genes for de novo n-3 PUFA in the phylum Platyhelminthes. Searches with experimentally confirmed sequences from Rotifera recovered nine relevant FA desaturase sequences from eight species in four genera in the two exclusively endoparasite classes (Trematoda and Cestoda). These results could indicate adaptations of these particular parasite species, or may reflect the uneven taxonomic coverage of sequence databases. Although additional genomic data and, particularly, experimental study of gene functionality are important future validation steps, our results indicate endoparasitic platyhelminths may have enzymes for de novo n-3 PUFA biosynthesis, thereby contributing to global PUFA production, but also representing a potential target for clinical antihelmintic applications.

Metacercariae of Heterodiplostomum lanceolatum (Trematoda: Proterodiplostomidae) found in Leptodactylus podicipinus (Anura: Leptodactylidae) from Brazil: a morphological, molecular and ecological study.

The trematodes from South American reptiles are poorly known, with only one life cycle completely characterized. We used molecular and morphological methods to characterize diplostomoid metacercariae found in 29 of 86 pointedbelly frogs, Leptodactylus podicipinus (Cope, 1862) collected in a marsh pond in Selvíria, in the central-west region of Brazil. The metacercariae were identified as Heterodiplostomum lanceolatum Dubois, 1936 (Proterodiplostomidae), a rarely reported species that matures in snakes. In phylogenetic analysis of partial sequences from 28S rDNA, H. lanceolatum fell within a polytomy with the proterodiplostomid Crocodilicola pseudostoma (molecular divergence of 4.1%) and other members of the superfamily Diplostomoidea. Our collections provide insights into the ecology of this parasite, in that infected frogs were smaller than uninfected frogs, and metacercariae were more numerous in the abdominal cavity and hindlimb muscles than in abdominal muscles, which suggests directions for future research on the transmission and pathology of this proterodiplostomid.

Completion of the life cycle of Tylodelphys mashonense (Sudarikov, 1971) (Digenea: Diplostomidae) with DNA barcodes and rDNA sequences.

The life cycle of Tylodelphys mashonense (Digenea: Diplostomidae), whose metacercariae occur in the cranial cavity of the widely cultivated catfish Clarias gariepinus, was resolved by the application of molecular markers. Both COI barcodes and ITS sequences obtained from diplostomid-like cercariae infecting Bulinus spp. from Mindu Dam, Morogoro, matched those acquired from metacercariae from the catfish C. gariepinus, and those from adult T. mashonense from the grey heron Ardea cinerea and the white egret Egretta alba. The success in linking the life cycle stages of T. mashonense using molecular tools highlights the usefulness of this approach in resolving the complex life cycles of digeneans in the absence of experimental establishment.

Morphometric and molecular analyses of Tylodelphys sp. metacercariae (Digenea: Diplostomidae) from the vitreous humour of four fish species from Lake Naivasha, Kenya.

Even in the relatively well-characterized faunas of the developed world, it is difficult to discriminate species of metacercariae in the Diplostomidae using morphology, infection site or host use. The taxonomy, diversity and ecology of diplostomids infecting freshwater fishes in the African continent are particularly poorly known, but recent morphometric and genetic studies have revealed four species of diplostomids in the eyes and brains of siluriform fishes. In the present study, diplostomid metacercariae were collected from the eyes of 288 fish comprising two species within the Cyprinidae (Cyprinus carpio, n = 145, and Barbus paludinosus, n = 67), two Cichlidae (Oreochromis leucostictus, n = 56, and Tilapia zillii, n = 18) and one Centrarchidae (Micropterus salmoides, n = 2) caught in Lake Naivasha, Kenya. Morphometric (14 characters and 8 indices in 111 specimens) and molecular (sequences from the barcode region of the cytochrome c oxidase 1 gene in 11 specimens) data were used to discriminate species. All fish species except B. paludinosus were infected with Tylodelphys metacercariae that were initially separated into two types differing mainly in body length. However, this morphological distinction received only intermediate support in quantitative morphological analysis and molecular data indicated that both morphotypes were conspecific. All the specimens therefore are inferred to belong to a single unidentified species of Tylodelphys, which is not conspecific with any other diplostomid for which comparable molecular data are available, including four diplostomid species known from siluriform fish in Nigeria and Tanzania.

Estimating diet in individual pumpkinseed sunfish Lepomis gibbosus using stomach contents, stable isotopes and parasites.

The diets of 99 pumpkinseed sunfish Lepomis gibbosus from a pair of small, adjacent lakes in Ontario, Canada, were estimated from their stomach contents, trophically transmitted parasites and stable isotopes of carbon and nitrogen in fish tissue. The three methods provided virtually unrelated information. There was no significant correlation in the importance of any prey item across all three methods. Fish with similar diets according to one method of estimating diet showed no tendency to be similar according to other methods. Although there was limited variation in fish size and the spatial scale of the study was small, both fish size and spatial origin showed comparatively strong associations with diet data obtained with all three methods. These results suggest that a multidisciplinary approach that accounts for fish size and spatial origins is necessary to accurately characterize diets of individual fish.

Psychological predictors of injury among elite athletes.

OBJECTIVES: To establish injury rates among a population of elite athletes, to provide normative data for psychological variables hypothesised to be predictive of sport injuries, and to establish relations between measures of mood, perceived life stress, and injury characteristics as a precursor to introducing a psychological intervention to ameliorate the injury problem. METHODS: As part of annual screening procedures, athletes at the Queensland Academy of Sport report medical and psychological status. Data from 845 screenings (433 female and 412 male athletes) were reviewed. Population specific tables of normative data were established for the Brunel mood scale and the perceived stress scale. RESULTS: About 67% of athletes were injured each year, and about 18% were injured at the time of screening. Fifty percent of variance in stress scores could be predicted from mood scores, especially for vigour, depression, and tension. Mood and stress scores collectively had significant utility in predicting injury characteristics. Injury status (current, healed, no injury) was correctly classified with 39% accuracy, and back pain with 48% accuracy. Among a subset of 233 uninjured athletes (116 female and 117 male), five mood dimensions (anger, confusion, fatigue, tension, depression) were significantly related to orthopaedic incidents over the preceding 12 months, with each mood dimension explaining 6-7% of the variance. No sex differences in these relations were found. CONCLUSIONS: The findings support suggestions that psychological measures have utility in predicting athletic injury, although the relatively modest explained variance highlights the need to also include underlying physiological indicators of allostatic load, such as stress hormones, in predictive models.

Longitudinal evaluation of the Treatment Priority Index (TPI).

The Treatment Priority Index (TPI) is an epidemiologic tool used to rank malocclusions and assess the need for orthodontic treatment. The purpose of this study was to (1) evaluate the predictability of the TPI as an indicator of malocclusion severity, (2) evaluate the effect of orthodontic treatment on TPI values, and (3) compare the results with a national survey of American children aged 6 to 11 years and 12 to 17 years conducted by the United States Public Health Service. The TPI was recorded annually in a young student population of Juniata County, Pa., from 1975 to 1979, and later in 1985. The mean values of the TPI did not reflect the range of severity in the population. For this reason the Malocclusion Severity Scale (Burlington Growth Center) was used to identify four groups in 1985. Each group was tracked back to 1975. Further evaluation investigated the role of individual factors contributing to malocclusion over time (tooth displacement and occlusal factors). The conclusions are as follows: (1) the TPI is a valid epidemiologic indicator of malocclusion but does not predict the severity of individual malocclusions in the permanent dentition, (2) TPI values decrease with orthodontic treatment, and (3) the average TPI values for this population were higher than the national average between 6 and 11 years of age and slightly lower in late adolescence, but lie within a treatment-need range of slight to elective. A characterization of treatment need relative to malocclusion severity that is different from the available scale is suggested.

Medical preparation for travel in Africa.

Physicians are asked with increasing frequency to prepare individuals for travel in Africa. This paper presents an organized approach which includes medical screening, vaccination protocol, and malaria prophylaxis, as well as a discussion of personal hygiene for the tropics. African travel can be safe and enjoyable if the traveler is medically prepared and directs his or her concerns in an informed and intelligent way.

Effect of a mid-series anchor on absolute judgments of duration by schizophrenics, neurologically impaired, and normals.

36 normal, 36 schizophrenic, and 36 neurologically impaired Ss were compared for their ability to temporally discriminate brief auditory stimuli. The experimental task was the absolute judgment of 3, 5, or 9 stimuli ranging in duration from 0.10 to 1.90 sec. Half of the Ss in each group were "assisted" by the presentation of a repeated mid-series anchor. The interval between the presentation of the anchor and the variable stimuli was varied. With the addition of a mid-series anchor, normal Ss demonstrated an increase in information transmission and a decrease in response stereotypy; schizophrenics demonstrated a slight decrease in information transmission and a slight increase in response stereotypy; neurologically impaired Ss were essentially unaffected. Changes in interstimulus interval on the anchored judgment task did not influence information transmission.