The association between SAα2,3Gal and avian influenza viral load in mallards (Anas Platyrhynchos) and blue-winged teals (Anas discors)

Background Individual heterogeneity in pathogen load can impact disease transmission dynamics; therefore, identifying intrinsic factors responsible for variation in pathogen load is necessary for determining which individuals are prone to be most infectious. Since low pathogenic avian influenza viruses (LPAIV) preferentially bind to alpha-2,3 sialic acid receptors (SAα2,3Gal) in the intestines and bursa of Fabricius in wild ducks ( Anas spp.), we investigated juvenile mallards ( Anas platyrhyncos ) and blue-winged teals ( Anas discors ) orally inoculated with A/northern pintail/California/44221-761/2006 (H5N9) and the virus titer relationship to percentage of SAα2,3Gal in the intestines and bursa. To evaluate the natural variation of free-ranging duck populations, birds were hatched and raised in captivity from eggs collected from nests of free-ranging birds in North Dakota, USA. Data generated from real time RT-PCR used to quantify virus titers in cloacal swabs, ileum tissue, and bursa of Fabricius tissue and lectin histochemistry used to quantify percentage of SAα2,3Gal was analyzed through a series of multiple linear regression and mixed models. Results In mallards, we found high individual variation in virus titers significantly related to high variation of SAα2,3Gal in the ileum, with sex being a significant factor. In contrast to mallards, individual variation in teals was minimal and significant relationships between virus titers and SAα2,3Gal were not determined. Collectively, teals had both higher virus titers and a higher percentage of SAα2,3Gal compared to mallards, which may indicate a positive association between viral load and SAα2,3Gal. Statistically significant differences were observed between infected and control birds indicating that LPAIV infection may influence the percentage of SAα2,3Gal, or vice versa, but only in specific tissues.Conclusions The results of this study provide quantitative evidence that SAα2,3Gal is related to LPAIV titers; thus, SAα2,3Gal should be considered a potential intrinsic factor of variation in LPAIV load.

Histopathology of lesions caused by Pseudocorynosoma constrictum (Acanthocephala: Polymorphidae) in the ileum of blue-winged teal

Pseudocorynosoma constrictum (Van Cleave, 1918) is a polymorphid acanthocephalan that attaches to the digestive tract of waterfowl to complete its life cycle, causing severe histological damage to its definitive avian hosts. In the present study, we present a histopathological analysis of the lesions that P. constrictum induced in the layers of the ileum of the blue-winged teal Anas discors. The results revealed that worms insert the attachment structures into the inner gut muscular layer, which causes substantial swelling, haemorrhaging and necrosis in the tissue near the parasite's proboscis. We also observed that the number of parasites attached to the tissue can obstruct the intestinal lumen; in the most serious case, we observed more than 30 parasites penetrating completely the walls of the bird intestine.

Resource partitioning among five species of waterfowl (Anasspp.) at an autumn migratory stopover: combining stable isotope and mercury biomarkers

The Saskatchewan River Delta (SRD) is North America’s largest inland delta and an important stopover site for waterfowl in the Central Flyway. However, little is known about their basic feeding ecology at this site and how species segregate or overlap in resource use. We used stable carbon (δ13C) and nitrogen (δ15N) isotopes and mercury concentrations ([Hg]) in liver tissue to trace use of local nutrient sources by five waterfowl species and tested for differences in diets among species, sexes, and age groups. Macrophytes were the dominant food source for Northern Pintail (Anas acuta L., 1758) and American Wigeon (Anas americana Gmelin, 1789) with median proportions of 0.86 and 0.98, respectively. There was also evidence of partitioning of resources, as Blue-winged Teal (Anas discors L., 1766) and Green-winged Teal (Anas carolinensis Gmelin, 1789) consumed invertebrates, as did a subset of Mallards (Anas platyrhynchos L., 1758), suggesting that these birds might minimize competition for resources during the short staging period in the SRD when waterfowl densities are high. Other isotopes or tracers, such as [Hg] that varied among sources (0.03–0.20 μg·g–1dry mass) and waterfowl species (0.22–3.19 μg·g–1dry mass), can be used for further refining dietary estimates.

Morfopatología Proventricular en Patos Silvestres (Anas discors) Infestados con Tetrameres americana

El estudio tuvo como objetivo describir los cambios morfopatológicos en proventrículo de patos silvestres (Anas discors) infestados con Tetrameres americana. Se realizó la necropsia a 89 cadáveres de patos adultos procedentes de Pinar del Río, Cuba, y se tomó un fragmento de 1 cm2 de 22 proventrículos con diagnóstico clínico de proventriculitis parasitaria para el estudio histopatológico. Los órganos se colectaron para su análisis parasitológico, clasificando las proventriculitis en leve y severa, según la cantidad de glándulas comprometidas con el nematodo y la magnitud del exudado catarral. El 25% (22/89) de las aves presentó proventriculitis catarral con presencia de T. americana, donde el 73% de los casos fue considerado como leve. Se observó erosión de la mucosa, degeneración con necrosis y formación de nódulos de 1 cm de diámetro en la yema glandular. Se concluye que la infestación con T. americana causa daños morfopatológicos en el proventrículo de A. discors.

Genome Sequence of a Novel H14N7 Subtype Influenza A Virus Isolated from a Blue-Winged Teal ( Anas discors ) Harvested in Texas, USA

We report here the complete genome sequence of a novel H14N7 subtype influenza A virus (IAV) isolated from a blue-winged teal ( Anas discors ) harvested in Texas, USA. The genomic characteristics of this IAV strain with a previously undetected subtype combination suggest recent viral evolution within the New World wild-bird IAV reservoir.

AVES MIGRATORIAS NEOTROPICALES RECAPTURADAS EN ALGUNAS LOCALIDADES DE LOS DEPARTAMENTOS DE ATLÁNTICO Y MAGDALENA, CARIBE COLOMBIANO

Information obtained from the recoveries of banded birds has historically been used to deduce their migratory routes and other key aspects of their life histories. This paper analyses information on Neotropical migratory species recaptured in the Colombian provinces of Atlántico and Magdalena between 1923 and 2011, using data obtained from the U. S. Bird Banding Laboratory. In this area 707 individuals of 14 species of waterbirds were encountered, among which were blue-winged teal (Anas discors) and royal tern (Thalasseus maximus) with the largest number of encountered individuals, as well as species with few records in Colombia: American wigeon (Anas americana), Northern pintail (Anas acuta), and roseate tern (Sterna dougalli). This analysis contributes to knowledge about the distribution of several species occurring in the country and assesses their migratory status; for instance, we determined that Eudocimus albus has both migratory and resident populations in Colombia. This paper attempts to promote the use of existing data on recaptured birds, and to bring attention to the fact that people who inhabit the study area are unaware of the bird banding goals, which has resulted in hunting of banded birds, illegal pet trade, and removal of the bands from birds.