Forty-seven Newcastle disease virus (NDV) strains isolated from fecal samples of waterfowls in Alaska and Siberia from 1991 to 1996 were analyzed for their virulence. None of the viruses formed plaques on MDBK cells in the absence of trypsin. Of these, 29 strains showed virulent character by the mean death time with the minimum lethal dose in chicken embryos comparable to velogenic NDV strains. Of the 29 strains, 11 were sequenced for their fusion protein (F) gene. The results showed that 5 of them contained a pair of dibasic amino acids at the cleavage site of the F, which is of a virulent type. The present results suggest that potentially virulent strains of NDV are maintained in migratory waterfowl populations in nature, and that some of those may be transmitted to domestic poultry and acquire pathogenicity during passages in chicken population

Development of scientifically based activities for rehabilitation of waterfowl (ducks) against helminthoses on the territory of the Republic of Belarus was realized. In course of the study there were analyzed fauna of helminthes and revelation of the main ways of their circulation in environment conditions; expansion and species composition of mollusks of Belarusian Poozerye; determination of species composition of metacercaria revealed in mollusks. In course of determination of intermediate and additional hosts of helminth infestation of ducks it was noted that the main carriers of larval stages of helminthes in ducks were the following species of frash-water mollusks: Vivaparus contectus; Vivaparus vivaparus; Galba palustris; Radix ovata; Radix auricularia; Sphaerium subsolidum; Bithynia tentaculata; Planorbis carinatus; Planorbis planorbis; Coretus corneus. In the studied samples there were revealed metacercaria of Echinostoma revolutum; Hypoderaeum conoideum; Cataropis verrucosa; Echinostoma dietsi. Assumption that some representatives of molluscum (Viviparus contectus; Viviparus viviparus; Planorbis planorbis) were the transport hosts for echinostomiasis was not proved.

Research of a pancreas of geese in course of different age-specific periods was realized in the conditions of the Republic of Belarus. Ecological features of water fowl inhabitance, prevalence of phytogenous forages in a diet of led in first two life decades to rapid growth of body weight and pancreas which was capable to adapt an organism to new conditions of existence. The subsequent growth and differentiating processes in a pancreas of geese showed direct correlative dependence on the basic physiological states of their organism (plumage, a moult, puberty, egg production efficiency). By the beginning of egg production (6 months) the basic structural components of secretory parts of gland of geese reached a rather developed condition, but their full morphological and functional maturity occurred by 2-year-old age, possibly, because of a long reproductive period of life. | Проведено исследование поджелудочной железы у гусей в разные возрастные периоды. Экологические особенности среды обитания водоплавающих птиц, преобладание в рационе кормов растительного происхождения приводят в первые две декады жизни к бурному росту массы тела животных и поджелудочной железы, способной адаптировать организм к новым условиям существования. Последующие ростовые и дифференцировочные процессы в поджелудочной железе гусей проявляют прямую коррелятивную зависимость от основных физиологических состояний их организма (оперение, линька, половое созревание, яйценосная продуктивность). К началу яйценоскости (6 месяцев) основные структурные компоненты секреторных отделов железы гусей достигают достаточно развитого состояния, но их полная морфофункциональная зрелость наступает к 2-летнему возрасту животных, вероятно, из-за продолжительного репродуктивного периода жизни.