Research, Technology

Bird flu is spreading around the world. Why is that bad?

Viruses are all around us.They are part of wildlife, despite the fact that they cannot be called fully alive. Disputes in academic circles continue to this day, and they are based on one interesting fact - viruses cannot reproduce outside living cells. And they do not have all the signs of living beings, so they cannot be attributed to this category. But whatever their nature, viruses keep us in fear, and two years of the pandemic proved it. And while we are fighting the new coronavirus, nature is taking its toll. So, at the end of 2021, millions of chickens in several countries of the world fell victim to the H5N1 influenza virus. The disease is accompanied by damage to the respiratory and digestive organs, and mortality is about 56%. There are currently no confirmed cases of avian influenza in humans, but experts are very concerned. Why?

Avian influenza is an acute infectious, especially dangerous disease transmitted to humans from animals, the causative agent of which is a type A virus.

Bird flu

The so-called plague of birds (bird flu)has been mowing birds for a long time, but it was possible to isolate the virus only in 1878. Prior to that, it spread naturally in the wild, affecting not only wild birds, but also other animal species. But it's one thing to spread in nature and quite another - in poultry farms.

For a long time it was believed that bird flu could notgo to the person. But in 1997, the first cases of infection appeared in Hong Kong. Since then, a large number of outbreaks have been reported in different parts of the world. In fact, the spread of H5N1 avian influenza among various species, including humans, could lead to a pandemic.

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From the affected regions, the export of eggs and poultry is prohibited.

Infected birds shed the virus through their saliva,mucous membranes and faeces, and human infection can occur when the virus enters the eyes, nose or mouth through inhalation. Another way to transmit the infection is through contact with contaminated surfaces and eating the meat and eggs of sick birds.

There were also cases in which there was no direct contact between a person and a sick animal, which indicates the ability of the virus to overcome the species barrier.

Human illness with avian influenza varies in severity, from asymptomatic or mild illness to severe illness leading to death.

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Feathered carriers

So, among the many viruses circulating inthe planet, the most dangerous are zoonotic infections - that is, those that are transmitted from animals to humans. Moreover, zoonoses account for a large percentage of all identified infectious diseases on Earth. For example, the H5N1 influenza virus is raging on poultry farms, and millions of chickens have been killed to contain the infection.

H5N1 is a type of influenza virus that causeshighly infectious severe respiratory disease in birds. Human cases are sporadic, and human-to-human transmission is rare. But when infection does occur, the risk of death is 60%.

All types of birds are susceptible to the flu, including chickens, turkeys, ducks, pheasants, guinea fowls, quails, wood grouses, storks, gulls and almost all other types of birds

When infected with avian influenza, the incubationthe average period is 2-3 days. After their expiration, symptoms appear: fever, body pain, disruption of the gastrointestinal tract, respiratory organs, nervous system, kidneys and liver.

But the problem, alas, occurs not only on farms.- cases of infection of migratory birds are known - they actively carry the disease without showing visible signs. Thus, the United States Department of Agriculture (USDA) has already confirmed that 385 birds are carriers of a highly pathogenic virus (data are given as of March 17, 2022).

Free flying wild birds can carrymany strains of avian influenza viruses. According to experts, the carriers can be both wild birds and chickens, turkeys, pheasants, geese and ducks.

The causative agent is the influenza virus type A (H5N1, H5N2, etc.)

Animal influenza viruses, such as bird flu,are genetically similar to human influenza viruses. Because of their potential for genetic evolution and transmission to humans, avian influenza viruses are considered a major public health problem.

See also: Intermediate hosts of dangerous diseases - who are they?

Major outbreaks of avian influenza

2022 is definitely not going to be quiet.This applies both to the international situation and the COVID-19 pandemic, as well as to the spread of outbreaks of other infectious diseases in animals and humans. So, recently we talked about foot and mouth disease, the victims of which were cattle.

There have been major outbreaks of avian influenzaand earlier - so, in 2014-2015, about 50 million birds were destroyed. Today, outbreaks have been recorded in the USA, Canada, Mexico, Great Britain, China, Albania, Latvia and others. Since the beginning of February, about four million chickens and turkeys have been destroyed on farms in the United States. The economic consequences are also a serious problem.

According to experts, following the coronavirus, an epidemic of avian flu could begin in the world, which can kill a billion people.

The danger of the flu lies in the fact that it very quickly leads to a complication of the disease in the form of pneumonia.

In Russia, bird flu was detected in 2021 -68 outbreaks were reported, 14 of which occurred in wild fauna and 54 in poultry. Given the migration, the likelihood of the introduction of the virus into the regions of Russia (both highly pathogenic and low pathogenic) remains high.

The H5N1 strain currently circulating around the worldwhich can be transmitted to humans, although US officials have said the risk is low. Yet experts are increasingly talking about the threat of a new pandemic, such as the Nipah virus or monkeypox. Read more about why these infections fell under surveillance here, we recommend reading.