What we need to know about the 2020-2021 outbreak of Highly pathogenic avian influenza (Part 1)

Many researchers believe that the past is the headline of the future and in some cases, what happens in the future has somehow happened in the present or the past.

the recent outbreak of Avian Influenza, which has been occurring in parts since late 2020 that started in Russia and Eurasia and then spread to Europe, parts of Asia, and Africa, is a kind of resemblance to what happened between 2016 and 2017.

The author of this article does not intend to predict the events, but we believe that by reviewing what has happened in recent years, we can understand some of the events ahead.

According to initial assessments, experts believe that the viruses isolated from the recent outbreak of highly pathogenic avian influenza in European countries have a single genetic group in cloud, which is associated with the H5 viruses of the highly pathogenic avian influenza that Released since the beginning of July 2020 in Kazakhstan and the Russian Federation.

The H5N8 strain of the virus, which spread to Egypt in 2017 and then to Iraq in 2020, also bears many similarities to the recent virus. This may be why some researchers have identified the viruses, which have been circulating mostly in North Africa and Southwest Asia, as the cause of the recent virus.

The genomic characteristics of the recent virus in Europe have shown distinct gene forms, possibly due to several recurrence events with LPAI viruses in wild birds in parts of Eurasia and Africa. It should be noted that European experts have identified one subtype of the H5N8 virus, one subtype of the H5N1 virus, and three subtypes of H5N5.

In the 2016 epidemic, however, scientists found that the H5 subtype of the highly pathogenic avian influenza virus, which first spread to Eurasia and then Europe, was able to recur frequently classification by using the LPAI virus.

In a study, researchers were able to prove that the new genetic characteristics of the virus are more likely to come from wild birds (especially domestic ducks) and during their migration period, not only in China but throughout Europe.

This led researchers to gain a full understanding of how the virus adapts to wild birds and how it spreads in the population of these birds.

Currently, H5N8 viruses have been identified and sequenced in Belgium, Croatia, Denmark, the United Kingdom, Germany, Italy, the Netherlands, Poland, and Sweden. These viruses are very similar to the viruses that were previously identified in Iraq and Egypt.

Read more
Highly pathogenic avian influenza has spread from Asia to Europe

But viruses detected in the Netherlands and Italy (H5N1) may be linked to scans in places like Eurasia.

On the other hand, H5N5 viruses, which are prevalent in countries such as Germany and Belgium, are genetically very similar in their PB2, PB1, HA, NP, M, and NS genes to LPAI viruses isolated from wild birds in Russia.

To investigate the dynamics and invasion and spread of the virus causing the disease, European researchers have performed a kind of discrete phylogenetic analysis based on the genetic characteristics of H5Nx viruses. The results of this study confirmed that a new viral current entered Central Europe in the autumn from migratory birds.

The team identified scientists as the virus moving sharply across Nordic countries south of the continent, including the Netherlands, Germany, Belgium, and Denmark. Accurate phylogeographic reconstruction supports these findings and places more emphasis on the transmission of this wave of disease from northern to southern Europe.

to be continued…

By Dr.A.Gaeini

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