Source ｜ Earth Knowledge Bureau (ID: diqiuzhishiju)
Author ｜ Nanisu, Editor ｜ Yakulta
Header image ｜ shutterstock / docter_k
The house leak happens to be overcast and rainy, and the ship is late to meet the lead. In 2020, the year of Gengzi Rat seems to have gone through the wrong way. Mountains of fire, locust plagues, plagues, floods, and other disasters have followed in various parts of the world.
Avian flu, a familiar and unfamiliar term, came quietly again at a time when the country’s new crown virus epidemic was grave.
Avian influenza virus under electron microscope, picture from wikipedia @ CDC / Dr. Erskine Palmer
On February 1, an outbreak of highly pathogenic avian influenza H5N1 subtype in poultry occurred in Shuangqing District, Shaoyang City, Hunan Province. There were 7,850 broiler chickens in stock, and 4,500 died. February 9, confirmed by the National Avian Influenza Reference Laboratory, a feed from a farm in Xichong County, Nanchong City, Sichuan ProvinceThe outbreak of H5N6 subtype highly pathogenic avian influenza in domestic poultry.
Why are these two different types of bird flu and what are the possible impacts?
Flu
Avian influenza belongs to influenza A virus, and is classified into three levels of high, medium and low (non-pathogenic) according to the pathogenicity of avian influenza virus. Due to the hemagglutinin structure of avian influenza virus and other characteristics, this virus generally only infected birds.
H5N6 virus and H5N1 virus are all avian influenza viruses. They sound like different numbers. In fact, behind these different numbers are variations in viral traits.
H1-H15, N1-N9 multiple combinations are mainly found in various birds, and in rare cases will be transmitted to humans, Picture from: wikipedia——Avian influenza
The outer membrane of influenza virus particles is covered by two different types of surface glycoproteins, namely H (hemagglutinin) and N (neuraminidase). H is divided into 15 subtypes and N is divided into 9 subtypes. Therefore, different subtypes of bird flu, that is, the arrangement and combination of these two surface glycoproteins are different.
InfluenzaThe structure of the poison, H (Hemagglutinin) and N (Neuraminidase) can be found on the surface, picture from California Department of Health Services
However, the virus has a simple structure with natural genetic instability, and gene reassortment is prone to occur during replication, resulting in structural changes. The subtypes can be said to be endless. Different combinations give different characteristics to avian influenza viruses, and even gain the ability to spread across species. Human infection with avian influenza is the reason for this.
Influx and replication of influenza virus, picture from Wikipedia / YK Times
H5N6 is a subtype of avian influenza virus. The source of the virus is poultry, which is highly pathogenic to poultry. However, few people have heard of this type of avian influenza. Because of this, when the new H5N6 virus was first discovered in Laos in 2013, it was not noticed.
It has always been a disease that only infected chickens and ducks. How could it be transmitted to people? Picture from: Vipavlenkoff / shutterstock.com
Until May 2014, a 49-year-old male patient who had been exposed to sick and dead poultry in Nanchong, Sichuan was infected with the H5N6 avian influenza virus, The clinical diagnosis was acute severe pneumonia, and the provincial and municipal joint expert groups spared no effort to rescue the invalid death. The deceased was the first case of human infection with the H5N6 subtype of avian influenza in the world, which means that this avian influenza virus can be infected by humans, and the current lethality rate is 100%. Since then the H5N6 subtype of avian influenza virus has been widely attention.
A large area of H5N6 bird flu occurred in the Philippines in 2017. Picture from: Wikipedia / Department of Agriculture (Philippines)
The H5N1 subtype avian influenza virus is even more notorious. The virus was first found in Hong Kong in 1997 to directly infect humans. As of March 2013, a total of 622 cases of human infection with highly pathogenic H5N1 avian influenza have been reported worldwide, including 371 deaths. There are 45 cases found in our country, 30 deaths, the mortality rate is extremely high, and most of them are young people and children, causing great social harm.
The reappearance of H5N1 subtype bird flu in Hunan today has not received much attention. This is entirely because the new crown virus has seized national attention. But given the deadly antecedent of the H5N1 avian influenza virus, this virus should also be given high attention.
In fact, it has been widely distributed in Asia, Africa and Europe. Picture reference: wikipedia-Influenzavirus A subtipo H5N1
Fortunately, there is no evidence of human-to-human transmission of the two avian influenza viruses that have appeared in China. It is not enough to just observe when it is necessary to take further measures to restrict human actions.
Avian influenza A H5N1 virus (gold), picture from Wikipedia / CDC
But the gospel of people is not good news for poultry. The chickens, ducks, geese and the farmers behind them have suffered heavy losses this time.
For example, in Xichong County, Sichuan, where avian influenza was exposed, the H5N6 subtype highly pathogenic avian influenza epidemic was found. According to the report of the China Animal Disease Control Center, there were 2,497 poultry in stock and 1,840 died. In order to avoid the spread of the virus and the entry of sick and dead poultry into the market, 2261 poultry were culled in accordance with the relevant plans and technical regulations for prevention and control. All the sick and culled poultry have been harmlessly treated.
Not only poultry, but wild birds are also infected with the avian flu virus. And because many wild birds have migratory characteristics, they may carry bird flu virus to spread to a larger space-time range.
Birds dying from bird flu are more uncontrollable than the centralized farms. Pictures from Wikipedia / Shpernik088
On January 21, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center and was confirmed by the National Avian Influenza Reference Laboratory. The H5N6 subtype highly pathogenic avian influenza epidemic occurred in wild swans in Daquangou Reservoir in Shihezi . There are more than 150 swans inhabiting the area, 19 are ill, and all died.
The waters of Daquangou belong to hot spring water. The warm winters have attracted many different species of waterbirds to come to winter. Wild birds such as Daquangou swans are one of the most unstable factors for bird flu transmission.
Broken Food
This outbreak of bird flu may seem accidental, but it has its inevitability. This has to mention the new crown virus epidemic we are experiencing.
In the winter and spring, there was a high incidence of various influenza. Human hospitals at this time mostly received influenza patients, and birds were no exception. Viruses that are highly sensitive to temperature and ultraviolet rays are the most active time in this season and are the basis for the emergence of bird flu.
In winter and spring, unexplained deaths of birds in the breeding plant are caused by farmers, and farmers must pay attention to them. Picture from shutterstock / kornnphoto
The logistics of the whole country has been affected by the new crown epidemic this year, and the poultry breeding industry has also been affected. There is no evidence that the new crown pneumonia epidemic is related to poultry, but live poultry trading markets have been closed in many places.
As the new crown pneumonia epidemic continues, many countries across the country have initiated the first-level response to major public health emergencies. In order to effectively prevent the spread of the pneumonia epidemic, including Henan, Hubei, Yunnan and other places issued documents calling for a complete ban on the sale of live poultry. In fact, before that, many places including Beijing, Shanghai, Zhejiang, etc. have required different levels of restrictions on live bird trading. This is currently the main method of trading poultry.
Live poultry is more popular than processed frozen meat in the township market. Picture from: Panjiang Stone / Picture Bug Ideas p>
A similar phenomenon has been staged in many places across the country. As a result, most of the broiler ducks that should have flowed into the market are accumulated in various farms. Farmers scattered all over the place are suffering but have no choice but to wait anxiously for the new crown pneumonia epidemic to improve.
Even if it ’s a chicken that can lay eggs, the life of the eggs is not good, and the price of the eggs is not satisfactory. The picture comes from the deposit / Tuworm Creative
During this process, the number of poultry and other poultry in the poultry farms gradually increased, and the pressure to clean, ventilate, and eliminate dead and dead poultry increased, and the manufacturers did not invest more power, which created the occurrence and spread of poultry diseases soil.
The average chicken area is getting smaller and smaller, and you ca n’t get enough to eat. The picture is from tpg / worm creative.
Furthermore, under the influence of the new coronavirus epidemic, not only birds cannot be transported out, but also feed cannot be transported in. Previously, the main feed sources of the Yangtze River Basin provinces were mostly corn and soybean meal transported by water from the Northeast and coastal areas.
Affected by road closures in various places, a large amount of feed cannot be transported into the farm, but is transported by small trucks. Due to the poor transportation of feed materials, local breeding companies have successively experienced different levels of grain outages, and once birds and other birds have insufficient feed intake, it is difficult to replenish their physical strength, and their immunity is further reduced, which will greatly increase the probability of bird flu.
嗷嗷 waiting to eat, picture from dreamstime / worm creative
Without food and high-load operation, the risk of avian influenza infection becomes inevitable by accident.
Dangerous live birds
Will bird flu become another health hazard after the new coronavirus? From the current information, it is not worth panic, but you have to guard against it.
Every year, different levels of bird flu outbreaks occur in China, and relevant health departments and large-scale farms already have plans. But this year’s situation is special, because the impact of the new crown virus, the corresponding response to the outbreak of bird flu has weakened accordingly.
Flu vaccines for birds are difficult to be 100% vaccinated. After all, they do not have an hukou and it is difficult to control the quantity. Picture from Shutterstock / docter_k
Avian flu is generally not transmitted to humans. However, with the changes in the global ecological environment, avian influenza, which was mainly prevalent in wild poultry, was frequently transmitted in poultry. The frequent contact between humans and poultry also makes it possible for the avian influenza virus to mutate in the human body. It constantly evolves and adapts in two directions, eventually causing disease to humans.
Research has also shown that direct contact with poultry or wild birds is an important route for transmission of the H5N6 subtype avian influenza virus. Therefore, people engaged in live poultry breeding, processing, trading, or frequent access to live poultry markets are at high risk. Farms and live poultry markets where humans and birds are mixed, provide convenient conditions for the rearrangement of virus genes, the evolution and spread of the virus, and are the main places for virus transmission. Studies have shown that most cases of H5N6 subtype avian influenza have a history of exposure to the live poultry market, especially those with underlying diseases and low immunity.
People involved in the industry are in close contact with poultry. If bird flu occurs, they are often the first people to suffer. Picture from Flickr / M M (Padmanaba01)
At present, there is no clear evidence of human-to-human transmission of H5N6 and H5N1 avian influenza, but it is not to say that it is safe to stay away from birds. It is also the case that rural birds are free-ranged with other livestock. Hidden danger.
Some researchers have isolated H5N6 subtype avian influenza virus in domestic cats, pigs and other animals, and the virus gene sequence isolated in domestic cats has high homology with the strains that infect humans, indicating that the virus is very likely. After infecting and adapting to mammals such as cats, it can be transmitted to humans through direct contact.Classes are also potentially threatening.
President of the United States Ford vaccinated against swine flu, picture from Wikipedia / David Hume Kennerly
A small number of patients, especially older and untimely patients, will rapidly develop into progressive pneumonia and acute respiratory distress syndrome. If not treated in time, it will cause death with a degree of harm no less than that of new coronary pneumonia.
It is worth noting that in addition to the two bird flu subtypes currently emerging in China, the World Organisation for Animal Health (OIE) recently announced that a highly contagious H5N8 subtype of bird flu has also occurred in Saudi Arabia. The epidemic occurred in the Suder area in central Saudi Arabia, about 150 kilometers north of the capital Riyadh. The bird flu has killed more than 22,000 birds. For safety reasons, more than 385,000 birds were ordered culled.
Popular birds are often choked by large-area foam. Picture from Wikipedia / Shpernik088
Early on January 18, Vietnam issued a similar bird flu alert. Another highly pathogenic strain of H5N6, which occurred in a village in the north of the country, killed 2,200 birds.
It seems that chickens, ducks and geese all over the world have not been able to pass this year.