This review describes the current situation on highly pathogenic avian influenza virus in 2019 and predicts the possible further spread of avian influenza in Russia. In 2019 outbreaks were reported among wild birds and poultry, as well as human infections with influenza viruses of the subtypes H5Nx, H7N9 and H9N2 in several countries. In 2019, only two outbreaks of highly pathogenic avian influenza H5N8 in Russia occurred. Both outbreaks were recorded in January at poultry farm in the Rostov Region. In addition, in May 2019 avian influenza virus of H14N7 subtype was isolated from a wild bird during the avian influenza virus surveillance in Tomsk Region. In June 2019, a strain of H13N2 subtype was isolated in the territory of Kamchatka Region, then, in August 2019, an influenza virus of H13N6 subtype was isolated in the Saratov Region. It was revealed that some strains of avian influenza virus isolated in Russia have a high degree of identity with strains circulating in South-East Asia. This was shown by the phylogenetic analysis of A/ H5Nx influenza viruses previously isolated in the Saratov Region and the Socialist Republic of Vietnam during the avian influenza virus surveillance. Thus, it was demonstrated again that the territory of Russia plays a key geographical role in the global spread of avian influenza virus.

Проблемы особо опасных инфекций. 2019; 1 ОБЗОРЫ 42 вирусы гриппа относятся к семейству Orthomyxoviridae, которое включает четыре вида вирусов гриппа -A, B, C и D [1]. при этом, только вирусы гриппа а способны инфицировать широкий круг восприимчивых хозяев и представляют серьезную угрозу сельскому хозяйству и общественному здравоохранению. вирусы гриппа а подразделяются на субтипы на основании антигенных различий в поверхностных гликопротеинах. на сегодняшний день известно 18 субтипов гемагглютинина и 11 субтипов нейраминидазы. большинство известных комбинаций сохраняется в популяциях диких птиц, которые, как известно, считаются основным природным резервуаром вируса гриппа а [2, 3]. основную роль в

The ambient air monitoring of PCDDs/PCDFs and dl-PCBs using passive air samplers in a residential urban area in Hanoi between 2012-2020 was deteminated. The seasonal variations of PCDD/PCDF and dl-PCB levels in ambient air in three periods: between Spring 2012 and Autumn 2015, from Winter 2015 to Autumn 2018, and between Winter 2018 and Autumn 2020 are similar to a V-shape with the highest peak in winter, then decreasing gradually in spring, bottoming in summer and rising again in autumn. The upward temporal trends of PCDD/PCDF and dl-PCB pollution, and total TEQD/F&DL, total TEQD/F and total TEQDL has been confirmed over time. The concentrations of total PCDFs were dominant and were approximately 1.0 to 9.3 times higher and 2.4 times higher on average than total PCDDs. Total dl-PCBs were 5.8 to 38 times higher and 17 times on average higher than the total toxic PCDDs/PCDFs. The PCDD/PCDF congeners contributed 83% to 95% of the total TEQ value. The phenomenon of temperature inversion not only causes seasonal air pollution but also increases the concentration of PCDDs/PCDFs and dl-PCBs with a narrower range but at a higher average levels.

Passive air sampling (PAS) method has been successfully developed using isotope standards 13C-labeled PCDDs/PCDFs as surrogates on the PUF disks from the beginning of sampling to monitor PCDDs/PCDFs from different sources of pollution, with very different levels of PCDDs/PCDFs in ambient air in the actual conditions of monsoon tropical climates with hot, wet weather and high temperatures in Vietnam. The 13C-labeled PCDD/PCDF surrogates acted as quantitative standards in the seasonal PAS process (spring, summer, autumn, winter) in the North and/or every 3 months in the dry and rainy seasons in the Central. At least 96.9% of all surrogates had the retention efficiencies of 17% to 185% on PUF disks, which were equivalent to that required by US EPA 1613B method for the recovery efficiencies only at sample preparation. This development method was shown to be reliable with 91.6% of the total PCDD/PCDF congeners which their relative percent differences (RPDs) between PCDD/PCDF concentrations on the PUF disks of field duplicates were not exceed 40% and an average RPD of only 7.4% to 30.5% for both PAS process and laboratory analysis.

In the article the application of passive air sampler with PUF filter for seasonal monitoring PCDDs/PCDFs in Hanoi is studied. The efficiency of native PCDDs/PCDFs retention on PUF filters in summer, autumn, winter and spring is very high ranging from 87.2% to 89.6%. The 13C-labeled PCDDs/PCDFs standards added to the PUF filters from the beginning of the sampling are stable. Their recovery is found from 56,5% to 146,3%, which satisfies the requirements of sampling and analytical methods. The seasonal properties and pollution level of PCDDs/PCDFs congeners in the air at the study spot are quite similar. It is shown that the passive air sampler with PUF filter is feasible and suitable for seasonal monitoring PCDDs/PCDFs in air in tropical climate.