Microplastic ingestion by common terns (Sterna hirundo) and their prey during the non-breeding season.

Current evidence demonstrates the presence and persistence of microplastics in the marine food web. Seabirds are predators in marine ecosystems and are highly exposed to marine plastic debris through the food. The aim of this work was to examine the presence of microplastics in a long-distance migratory seabird, the Common tern (Sterna hirundo) (n = 10), and in their prey (n = 53) during the non-breeding season. The study was conducted in Punta Rasa, Bahía Samborombón, province of Buenos Aires, which is an important resting and feeding location for migratory seabirds and shorebirds in South America. Microplastics were found in all the birds examined. The occurrence of microplastics in the gastrointestinal tract (GIT) of Common terns (n = 82) was higher than in regurgitated prey (RP) (n = 28), which is likely reflecting trophic transfer process. Almost all microplastics found were fibers and only 3 were fragments. Microplastics were sorted by color; transparent, black and blue-colored fibers were the most abundant plastic types. Characterization of the polymer type by Fourier Transform Infrared Spectrometry (FTIR) revealed that cellulose ester plastics, polyethylene terephtalate, polyacrylonitrile and polypropylene were the most abundant types found in both the gastrointestinal tract and prey. Our results highlight the high levels of ingested microplastics in Common terns and in their prey, and reflect a concern in this important location for migratory seabirds.

Variation in blood mercury concentrations in brown skuas (Stercorarius antarcticus) is related to trophic ecology but not breeding success or adult body condition.

Mercury is a pervasive environmental contaminant that can negatively impact seabirds. Here, we measure total mercury (THg) concentrations in red blood cells (RBCs) from breeding brown skuas (Stercorarius antarcticus) (n = 49) at Esperanza/Hope Bay, Antarctic Peninsula. The aims of this study were to: (i) analyse RBCs THg concentrations in relation to sex, year and stable isotope values of carbon (δ13C) and nitrogen (δ15N); and (ii) examine correlations between THg, body condition and breeding success. RBC THg concentrations were positively correlated with δ15N, which is a proxy of trophic position, and hence likely reflects the biomagnification process. Levels of Hg contamination differed between our study years, which is likely related to changes in diet and distribution. RBC THg concentrations were not related to body condition or breeding success, suggesting that Hg contamination is currently not a major conservation concern for this population.

Plastic ingestion risk is related to the anthropogenic activity and breeding stage in an Antarctic top predator seabird species.

During the last decades plastic pollution has become a common issue in marine environments. Studies on seabirds have focused on species that ingest plastics mistaken for prey or indirectly through their preferred prey or, on how foraging strategy influences this behaviour. We evaluated plastic ingestion in relation to the proximity of nests to areas with different anthropogenic pressure, breeding status and breeding stage. We analyzed regurgitated pellets (n = 1001) from a seabird, the Brown Skua (Stercorarius antarcticus lonnbergi) at Esperanza/Hope Bay, Antarctic Peninsula. Plastics were found in 9% of pellets, only in breeders from an area with high antropogenic activity. The prevalence of plastic increased during the brooding of chicks stage, when skuas expand their feeding niche. Our results support previous work which demonstrated that seabirds with wider feeding niche show higher loads of plastics. Altogether, this provides insights into the dynamics of plastic transfer within the environment.

[Features of Paget's disease of bone in a new high-prevalence focus]. / Características de la enfermedad de Paget del hueso en un nuevo foco de elevada prevalencia.

We report the features of a group of 41 patients with Paget's disease (PD) who were identified in a cross sectional study in the "Sierra de la Cabrera" (Madrid). As the screening test, we used serum alkaline phosphatase quantification, and the diagnosis was confirmed by radiological study. This biochemical parameter shows an excellent diagnostic performance, with a sensitivity of 98% and a specificity of 85%. The prevalence in the population over 40 years of age is 6.37% (95% CI 4.79-7.95) which, comparing it with that from other areas, suggests that this region is a "focus" of PD. 51% of cases had the characteristic symptoms of the disease, bone pain being the most common (44%). We compared the abnormalities in the patients with those of a control group with strictly comparable features, and we found that bone deformity (34%) and a localized increase in skin temperature (27%) were the most discriminative data, while cranial symptoms (26%) were nonspecific. Cataracts and actinic keratosis were associated with PD in the crude analysis (p less than or equal to 0.01). When age was controlled for, the statistical significance of cataracts disappeared, whereas that of actinic keratosis was maintained (odds ratio 4.08, p less than or equal to 0.01). A high family incidence was found, with 15 proven cases (36.5%) in 6 families. Apart from a marked increase in alkaline phosphatase (mean: 407 mU/ml), other abnormalities or biochemical differences with the control were not found. These results suggest an interaction of genetic and environmental factors, and is wholly consistent with the multifactorial etiological hypothesis of PD.

Risk factors for Paget's disease: a new hypothesis.

A cross-sectional study was carried out in order to investigate likely risk factors in Paget's disease of bone. Associations were analysed by multivariate logistic regression. The odds ratio calculated for the consumption of bovid meat without sanitary control is high (odds ratio 2.18 95% Cl 1.05-4.49) and was not affected by other variables in our study. This finding supports the hypothesis of an infective slow agent in the genesis of Paget's disease of bone.