Source丨21New Health21 original work
Author/Ji Yuanyuan
Editor/Xu Xu
Image/Figureworm
"The next pandemic that sweeps humans could be caused by a new strain of influenza created in animals, to which humans have little immunity." By analyzing nearly five decades of animal flu records, scientists in China and Australia came to this common conclusion.
The study, a collaboration between Fudan University and the University of Sydney, was recently published in the journal One Health. The collaborative research team between the two countries created a database of more than 70,000 animal influenza records from 1970 to 2016, providing an in-depth study of trends in these viruses in time and space. It provides a framework to detect and track animal virus outbreaks that are likely to occur in human populations.
Professor Michael Ward, one of the research team members and the University of Sydney's School of Veterinary Medicine, told the 21st Century Business Herald: "This provides a solid foundation for understanding how, when and where animal influenza viruses may evolve into pandemic pathogens. Humans are now recovering from the pandemic, but given the high mortality rates caused by some animal viruses, the flu virus that has erupted and dominated in humans threatens to dwarf the impact of the coronavirus. ”
The researchers concluded that bird flu could be the source of the next new pandemic strain. There are many subtypes of avian influenza, and birds are their natural hosts, increasing the likelihood that avian influenza will become zoonotic.
On March 26, the Guangdong Provincial Center for Disease Control and Prevention also released a prevention and control news, Zhongshan City reported a case of H3N8, the case is a female, 56 years old, previous multiple myeloma and other basic medical history, a history of exposure to live poultry before the onset, and a history of wild poultry activities around the home. The Chinese Center for Disease Control and Prevention reviewed and tested the samples of the cases, and the results were positive for H3N8 avian influenza virus nucleic acid.
Avian influenza is the largest animal influenza virus
Since March this year, there have been outbreaks of avian influenza in Europe, Japan and the United States, and an outbreak of avian influenza has also occurred in Argentina, the world's eighth largest exporter of poultry products. Meanwhile, in late February, Cambodian health authorities reported two cases of human infection caused by avian influenza A(H5N1) virus, with the second case being a household contact of the first case.
Cambodia's health ministry said symptoms of the H5N1 virus infection are similar to those of other flu, including cough, pain and fever, and in severe cases, patients can develop life-threatening pneumonia.
"Avian influenza is usually circulating in poultry, but concerns have recently emerged about various mammalian infections and the possibility that the virus is more likely to spread from person to person, warning residents not to come into contact with dead and sick birds." Cambodia's Ministry of Health said.
Avian influenza is a highly contagious infectious disease caused by avian influenza A viruses in poultry and wild birds. Due to the different antigenicity of hemagglutinin (HA) and neuraminidase (NA) of different avian influenza viruses, they can be divided into 15 H subtypes (H1~H15) and 9 N subtypes (N1~N9).
Human infection with highly pathogenic avian influenza is an acute respiratory infectious disease in humans caused by some strains of some subtypes of avian influenza A virus, such as H5N1 and H7N7. The mainland's Law on the Prevention and Control of Infectious Diseases classifies it as a Class B infectious disease, but implements Category A management, that is, once an epidemic occurs, preventive and control measures for Class A infectious diseases are taken.
On the question of the chance of bird flu being transmitted to humans, Professor Ward said: "The key is whether a subtype of bird flu will mutate to give the virus the ability to transmit from person to person. Of course, to become a pandemic, the first obstacle for the virus is to enter the mammals. It's a big jump for the virus to get from birds to mammals, and then if it spreads fairly well, it has a better chance of infecting humans. ”
"It's just a matter of probability. Viral jumping species are not uncommon, so it is likely that the virus will eventually jump to humans. Professor Ward said that when two different subtypes of influenza viruses infect the same host cell, their genetic material can mix to create a new virus that triggers a pandemic. For example, a bird virus that mutates in pigs before infecting humans could cause "viral outbreaks and global health crises."
An analysis of global events in the study found that avian influenza accounted for 79.6% of all animal reservoirs, followed by swine flu at 10.6%.
"H5N1 (avian influenza) is currently the largest animal influenza virus. It's been a big problem for the last 20 years, and it seems to have adapted to the environment and is developing quite well. Professor Ward said.
Influenza virus surveillance is inadequate
According to the World Health Organization, H5N1 has infected nearly 900 people since 2003, with a mortality rate of just under 52.5 percent. Since January 2022 in the United States, an outbreak of the H5N1 clade, known as 2.3.4.4b, has affected more than 58 million chickens, resulting in the death or culling of most chickens.
Professor Ward pointed out that some countries and regions have a relatively complete level of testing and relatively timely reporting. Asia, North America, and Europe are the regions most likely to report new influenza subtypes. Sweden has the largest diversity of subtypes, followed by the United States and China. While many countries on the continent have not recorded it, the available data show low diversity of subtypes.
On the one hand, there are many difficulties in implementing surveillance of animal viruses, and sampling wild populations, especially birds, is always difficult. On the other hand, the detection of non-wild animals, especially poultry, is also crucial. If a virus develops in some poultry, it can have an impact on trade and potentially human health, so countries are concerned about sharing this information.
"In places like South America and Africa, there are big black holes in animal flu surveillance. We just don't get a lot of reports, so it's hard to know what's going on. ”
Professor Ward said globally, inadequate animal flu surveillance and data sharing meant that health authorities were not prepared to detect new influenza strains or the capacity of the next viral pandemic.
Therefore, strengthening individuals for the prevention of avian influenza is of great significance. Some clinical experts told the 21st Century Business Herald that avian influenza is mainly transmitted through respiratory tract, and can also be infected through contact with infected poultry and their excrement, virus-contaminated environments (such as live poultry markets) and water sources, or direct contact with virus strains. Therefore, long-term personnel engaged in poultry breeding, trafficking, sales and slaughter have a high degree of infection, and it is recommended that personal protection work must be done during the period of employment. Specifically, the public needs to do the following four things in their daily lives:
First, practitioners engaged in breeding, slaughtering, processing, sales and their products should do a good job in personal protection. Wear masks, gloves, and protective clothing correctly.
Second, individuals should maintain good personal hygiene habits. Wash your hands frequently and ventilate more; Wash your hands before cooking and eating, and again after touching raw meat, poultry/eggs.
The third is to separate raw and cooked, cook and cook thoroughly. Do not use the same board knife to handle raw meat and cooked food, thoroughly clean the utensils that come into contact with raw meat, and avoid cross-contamination; Do not eat raw poultry and eggs, and do not slaughter and eat sick/dead poultry at home to ensure safety.
Fourth, frequent disinfection. Commonly used disinfectants, such as oxidants, dilute acids, bleaching powders and iodine agents; High temperature heating, 65 °C heating for 30 minutes or boiling (100 °C) for more than 2 minutes; Direct ultraviolet radiation.