Contamination parasitaire des sédiments marins. Étude sur le site de Barcelone

Les apports contaminants d'origine continentale jouent un rôle fondamental dans le processus de contamination du milieu marin. Une étude a été réalisée sur le site de Barcelone, afin de réaliser un inventaire des sources de pollution et de déterminer l'influence de ces apports sur la contamination des sédiments marins; ce lieu d'expérimentation ayant été retenu du fait de la multiplicité des types de rejets effectués en mer : eaux usées, boues de station d'épuration... Les sédiments ont été prélevés à partir du navire océanographique au cours de 3 campagnes de novembre 1987 à juin 1988 à des distances de 50 mètres à 4 km de la côte et à des profondeurs de 10 à 52 métres. Globalement 88,8 % des échantillons analysés renfermaient des oeufs d'helminthes (Nématodes et/ou Cestodes) à des concentrations variant de 5 à 256 oeufs 100 g-1 de sédiments Si des oeufs de Nématodes (Ascaris, Toxocara, Trichuris, Capillaria) sont retrouvés dans tous les échantillons positifs, seulement 44,4% renferment des oeufs de Cestodes (Taenia, Hymenolepis). Chez les Nématodes, les oeufs de Toxocara ont été retrouvés avec une très grande fréquence (66,6 %) chez les Cestodes des oeufs de Tenia (38,8 %) prédominent Il faut donc noter la moindre résistance des oeufs de Cestodes dans le milieu marin. Quant à la viabilité réalisée sur les oeufs d'Ascaris, elle s'échelonne selon les prélèvements de 5 à 100 %. Des études ultérieures devraient être poursuivies pour vérifier si ces oeufs viables ont encore conservé leurs potentialités infectieuses.Microbiological pollution of the marine environment is often the result of man's presence in the coastal zone (offshore flow of sewage sludge or effluents from raw or treated wastewater).Although many studies have been carried out on the viral and bacteriological pollution of the marine environment, very little is known about parasitological contamination of this important resource. This investigation is aimed at the problem of parasitological contamination by examining its sources and their effect on the contamination of marine sediments of a specific coastal region.Barcelone was selected as the study site because of the many types of effluent flowing into the sea. These are due to : two highly polluted rivets (the Besos river and the Llobregat river), treated and raw wastewater. Sewage sludge is transported offshore front Barcelone through a deep conduit.Marine sediments were collected at distances between 50 m. to 4 km of the shores of urban Barcelone at depths varying from l0 to 52 m. Samples obtained by the oceanographic vessel « Garcia del Cid » required use of a Reineck device.Parasite density was too low for direct microscopic examination, thus all the samples underwent an enrichment procedure. A preliminary study had shown that, out of all the various concentration methods available, the one described by Janeckso-Urbanyl was the best adapted 10 the samples investigated here. This method uses a high density (d = 1.44) potassium lodomercurate solution with low viscosity so that the eggs rise rapidly to the surface. The slides were enlarged 100 times and numbered with a Mac Master slide. The determination of the viability of Ascaris eggs was studies after a n-butanol treatment. The results are expressed as number of eggs per 100 g-1 sample.Helminth eggs were found in 88,8 % of 36 samples analysed with levels ranging from 5 to 256 eggs per 100 g-1 of sediment. During the 3 campaigns, in November 1987 (first campaign) was obtained the smallest number of positive samples (9/12) and in March 1988 (second campaign) the highest number of positive samples seize all these samples contained helminth eggs. These eggs were of the Nematode and/or the Cestode class. All the positive samples (32/36) contained Nematode eggs whereas Cestode eggs are found only in 16 samples. The Nematode eggs were Ascaris, Toxacara and Trichuris, Capillaria; Cestode eggs Hymenolepis and Taenia. All the samples with Nematode eggs contained in decreasing amounts Toxocara (66,6 %), Ascaris (61 %) and Trichuris, Capliaria (22,2 %). Cestodes were predominantly Taenia (38,8 %), Hymenolepis (16,6%). The difference in behaviour between Nematode and Cestode eggs, the latter being much less frequent, was probably due to the greater fragility of Cestodes in a marine environment. The viability of the Ascaris eggs found on samples at the Besos area was 100 %. The samples from the effluent zone contained Ascaris eggs with viability ranging from 0 to 100 %. In the Barcelonetta area, 5 to 42 % of Ascaris eggs were viable.These results obtained front seawater emphasize the necessity of further investigation into the extent of parasitological pollution on the marine environment by offshore flowing of treatment plant sludge, paying particular attention to the viability and the infection potential of the helminth eggs

Bridging the gap between fiction and nonfiction in the literature circle setting

Third grade students experienced literature circles as part of balance literacy program. First, students learned about literature circles and its importance. After several fiction literature circle cycles, the classroom teacher bridged the gap between fiction and nonfiction in a literature circle setting. This allowed students read nonfiction and learn about a topic connected to their previous fiction read. Students were excited to read nonfiction and began choosing this genre on their own. They realized the power of learning that was available to them in nonfiction text

Long‐term follow‐up of stereotactic radiosurgery for head and neck malignancies

BackgroundStereotactic radiosurgery is widely applied to deliver additional dose to head and neck tumors. However, its safety and efficacy remains equivocal.MethodsOne hundred eighty‐four patients with primary head and neck cancers treated between January 1990 and August 2012 with Gamma Knife stereotactic radiosurgery were retrospectively reviewed.ResultsTwo hundred fifteen sites were treated with Gamma Knife stereotactic radiosurgery among 184 patients. Fifty‐one percent of patients received concurrent external beam radiotherapy (EBRT), 72% had prior surgery, and 46% received chemotherapy. Most (44%) had squamous cell carcinoma and most patients (65%) were treated for recurrent disease. With a median follow‐up of 17.3 months, 12‐month local control was 82%. Late effects occurred in 59 patients with the most common being temporal lobe necrosis (15 patients).ConclusionRadiosurgery can provide tumor control for patients with head and neck cancers involving the skull base. Long‐term follow‐up is important in survivors to identify late effects. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1557–1562, 2015Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115998/1/hed23798.pd

Farmed salmonids drive the abundance, ecology and evolution of parasitic salmon lice in Norway

Sea cage fish farming is typically open to the environment, with disease transmission possible between farmed and wild hosts. In salmonid aquaculture, salmon louse Lepeophtheirus salmonis infestations cause production losses, reduce welfare for farmed fish and increase infestation rates for wild fish populations. The high density of hosts in farms likely also shifts the coevolutionary arms race between host and parasite, with ecological and evolutionary consequences for the salmon louse. Using farm-reported salmon and louse abundances and publicly reported estimates of wild salmonid host abundances and the salmon lice they carry, we estimated (1) the relative abundance of farmed and wild salmonid hosts and (2) the relative importance of each for the abundance of salmon lice for the coastal zone of Norway from 1998 to 2017. Farmed hosts increased in importance over time with the expansion of the industry. From 2013 to 2017, farmed salmonids outnumbered wild salmonids by 267-281:1. By 2017, farmed salmonids accounted for 99.6% of available hosts and produced 99.1% of adult female salmon lice and 97.6% of mated (ovigerous) adult female salmon lice in Norwegian coastal waters. The persistent dominance of farmed hosts has clear implications: (1) management decisions that aim to limit lice abundance can be guided by lice data from farms alone, as lice on wild salmonids make a trivial contribution to the national lice population; and (2) strategies to prevent or treat lice infestations are vulnerable to the evolution of resistance, as the pool of wild hosts is inconsequential and will not act as a refuge large enough to stem the evolution of resistance. As the Norwegian salmon industry expands and salmon lice infestations continue, farmed salmon will drive the ecology and evolution of salmon lice.publishedVersio

Determinants of heart rate in Svalbard reindeer reveal mechanisms of seasonal energy management

Funding. This study was supported by Norges Miljø- og Biovitenskape- lige Universitet (PhD Grant to L.M.T.) and Norges Forskningsråd (KLIMAFORSK project no. 267613). Acknowledgements. We thank two anonymous reviewers for constructive, detailed and insightful feedback that helped to strengthen our manuscript. We thank Mads Forchhammer and the logistics department at the University Centre in Svalbard for supporting the field campaigns. We also thank DVM Amanda Høyer Boesen for assistance with surgeries in 2018. Åshild Ø. Pedersen and Stein Tore Pedersen contributed to successful field campaigns. We are grateful for the technical support received from Ásgeir Bjarnason at StarOddi Ltd during logger programming and validations of recordings. Finally, we thank Lucy Hawkes, Andreas Fahlman and Katsufumi Sato for inviting us to contribute to the theme issue ‘Measuring physiology in free-living animals’.Peer reviewedPublisher PD

Maximum Host Survival at Intermediate Parasite Infection Intensities

BACKGROUND: Although parasitism has been acknowledged as an important selective force in the evolution of host life histories, studies of fitness effects of parasites in wild populations have yielded mixed results. One reason for this may be that most studies only test for a linear relationship between infection intensity and host fitness. If resistance to parasites is costly, however, fitness may be reduced both for hosts with low infection intensities (cost of resistance) and high infection intensities (cost of parasitism), such that individuals with intermediate infection intensities have highest fitness. Under this scenario one would expect a non-linear relationship between infection intensity and fitness. METHODOLOGY/PRINCIPAL FINDINGS: Using data from blue tits (Cyanistes caeruleus) in southern Sweden, we investigated the relationship between the intensity of infection of its blood parasite (Haemoproteus majoris) and host survival to the following winter. Presence and intensity of parasite infections were determined by microscopy and confirmed using PCR of a 480 bp section of the cytochrome-b-gene. While a linear model suggested no relationship between parasite intensity and survival (F = 0.01, p = 0.94), a non-linear model showed a significant negative quadratic effect (quadratic parasite intensity: F = 4.65, p = 0.032; linear parasite intensity F = 4.47, p = 0.035). Visualization using the cubic spline technique showed maximum survival at intermediate parasite intensities. CONCLUSIONS/SIGNIFICANCE: Our results indicate that failing to recognize the potential for a non-linear relationship between parasite infection intensity and host fitness may lead to the potentially erroneous conclusion that the parasite is harmless to its host. Here we show that high parasite intensities indeed reduced survival, but this effect was masked by reduced survival for birds heavily suppressing their parasite intensities. Reduced survival among hosts with low parasite intensities suggests costs of controlling parasite infections; however, the nature of such costs remains to be elucidated

Predicting Bison Migration out of Yellowstone National Park Using Bayesian Models

Long distance migrations by ungulate species often surpass the boundaries of preservation areas where conflicts with various publics lead to management actions that can threaten populations. We chose the partially migratory bison (Bison bison) population in Yellowstone National Park as an example of integrating science into management policies to better conserve migratory ungulates. Approximately 60% of these bison have been exposed to bovine brucellosis and thousands of migrants exiting the park boundary have been culled during the past two decades to reduce the risk of disease transmission to cattle. Data were assimilated using models representing competing hypotheses of bison migration during 1990–2009 in a hierarchal Bayesian framework. Migration differed at the scale of herds, but a single unifying logistic model was useful for predicting migrations by both herds. Migration beyond the northern park boundary was affected by herd size, accumulated snow water equivalent, and aboveground dried biomass. Migration beyond the western park boundary was less influenced by these predictors and process model performance suggested an important control on recent migrations was excluded. Simulations of migrations over the next decade suggest that allowing increased numbers of bison beyond park boundaries during severe climate conditions may be the only means of avoiding episodic, large-scale reductions to the Yellowstone bison population in the foreseeable future. This research is an example of how long distance migration dynamics can be incorporated into improved management policies

Demographic and reproductive associations with nematode infection in a long-lived mammal

Infection by macroparasites, such as nematodes, varies within vertebrate host systems; elevated infection is commonly observed in juveniles and males, and, for females, with different reproductive states. However, while such patterns are widely recognized in short-lived model systems, how they apply to long-lived hosts is comparatively understudied. Here, we investigated how infection varies with host age, sex, and female reproduction in a semi-captive population of individually marked Asian elephants Elephas maximus. We carried out 1,977 faecal egg counts (FECs) across five years to estimate nematode loads for 324 hosts. Infection patterns followed an established age-infection curve, whereby calves (5 years) exhibited the highest FECs and adults (45 years) the lowest. However, males and females had similar FECs across their long lifespan, despite distinct differences in life-history strategy and clear sexual dimorphism. Additionally, although mothers invest two years in pregnancy and a further three to five years into lactation, nematode load did not vary with four different measures of female reproduction. Our results provide a much-needed insight into the host-parasite dynamics of a long-lived host; determining host-specific associations with infection in such systems is important for broadening our knowledge of parasite ecology and provides practical applications for wildlife medicine and management

Emergence of methicillin resistance predates the clinical use of antibiotics

The discovery of antibiotics more than 80 years ago has led to considerable improvements in human and animal health. Although antibiotic resistance in environmental bacteria is ancient, resistance in human pathogens is thought to be a modern phenomenon that is driven by the clinical use of antibiotics(1). Here we show that particular lineages of methicillin-resistant Staphylococcus aureus-a notorious human pathogen-appeared in European hedgehogs in the pre-antibiotic era. Subsequently, these lineages spread within the local hedgehog populations and between hedgehogs and secondary hosts, including livestock and humans. We also demonstrate that the hedgehog dermatophyte Trichophyton erinacei produces two beta-lactam antibiotics that provide a natural selective environment in which methicillin-resistant S. aureus isolates have an advantage over susceptible isolates. Together, these results suggest that methicillin resistance emerged in the pre-antibiotic era as a co-evolutionary adaptation of S. aureus to the colonization of dermatophyte-infected hedgehogs. The evolution of clinically relevant antibiotic-resistance genes in wild animals and the connectivity of natural, agricultural and human ecosystems demonstrate that the use of a One Health approach is critical for our understanding and management of antibiotic resistance, which is one of the biggest threats to global health, food security and development