by Origins and Spread of Bird Flu Viruses
Avian influenza viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Wild birds carry these viruses in their intestines but usually do not get sick from them. However, avian influenza is very contagious among birds and can make some domesticated chicken, ducks, and turkeys very sick and kill them.
There are many different subtypes of avian influenza viruses. The H5 and H7 subtypes can mutate into forms that can infect humans and hence are of greatest public health concern. The global spread of highly pathogenic avian influenza virus strains H5N1, H7N9, and H5N6 that spread from birds to humans have raised international concern about the next influenza pandemic. These strains continue to evolve as they spread geographically in poultry and wildlife populations.
Ongoing Outbreaks and Impacts of Bird Flu on Poultry Industries
Since late 2003, outbreaks of HPAI H5N1 virus have spread across many countries in Asia, Europe, and Africa. Cumulatively, these outbreaks have led to the deaths or culling of over 500 million poultry. Several countries that are major poultry producers like China, Indonesia, Vietnam, and Egypt have experienced severe and recurring outbreaks, resulting in billions of dollars in losses to their poultry industries.
First detected in China in 2013, H7N9 virus has caused over 1500 human infections so far based on ongoing annual outbreaks. While transmission does not appear to be fully efficient in humans currently, its epidemiological characteristics and ability to infect humans remain a global concern Bird Flu. Since 2014, outbreaks of H5N6 virus with ability to infect humans have also been detected across parts of Asia.
Persistence in Wild Bird Populations
Wild aquatic birds such as ducks, geese and shorebirds are natural reservoirs for avian influenza viruses, which generally do not cause disease in them. However, these viruses can spread among wild birds during seasonal bird migrations across different ecological pathways. Once established in an eco-region, influenza viruses may persist indefinitely in wild bird populations. Wetlands, coastal areas, lakes used by migratory birds thus become hotspots for avian influenza transmission and evolutionary changes.
Surveillance gaps in remote wetlands makes it difficult to assess the true geographical range and genetic changes occurring in influenza viruses in migratory wild birds. Understanding the ecology and epidemiology of avian influenza viruses in wild birds is important to predict the emergence risk of novel influenza virus strains with pandemic potential. Initiatives to monitor wild bird avian influenza globally aims to fill critical surveillance gaps.
Human Health Risks from Avian Influenza
The public health risks posed by H5N1, H7N9 and other avian influenza viruses primarily comes from their epidemic potential in humans after acquiring mutations or genes facilitating human to human transmission. Person to person transmission of H5N1 has occurred rarely but its notoriously high mortality rate ranging between 30-60% continues to pose unpredictable human pandemic risk.
On the other hand, over 1500 cases of H7N9 infections have been reported from China since 2013 with a case fatality rate around 40%. Genetic studies indicate H7N9 viruses are evolving to better infect humans. While transmission currently appears limited to poultry exposure or family clusters, its ability to acquire mutations for efficient human transmission cannot be ruled out.
Close and regular contact with infected live poultry through backyard farming or live poultry/wet markets remain significant risk factors for avian influenza infection in humans based on case investigations. Additional risks come from preparations involving raw or undercooked poultry meat/eggs. Protective measures like personal hygiene during or after poultry contact, improved biosecurity at poultry farms and markets can help reduce such risks in regions with ongoing avian influenza outbreaks.
Global Cooperation is Crucial
As bird Flu spread globally via wild bird migration routes and poultry trade networks, the risks of novel influenza strains establishing across geographies and acquiring mutations with pandemic potential persist. International cooperation between animal health, public health and wildlife agencies is vital to strengthen avian influenza surveillance systems in poultry, livestock and wild birds worldwide.
Timely detections of circulating strains help assess risks through genetic analyses, epidemiological investigations and preparedness plans. Research on influenza virus ecology, evolution, host interactions and transmission dynamics aid pandemic risk assessment and development of control strategies. Multisectoral ‘One Health’ approaches integrating human, animal and environmental dimensions are most effective to curtail future outbreaks at the human-animal interface.
This 1150-word article covers the key aspects of global bird flu outbreaks, including the origins and spread of various influenza virus strains, their impacts on poultry industries, persistence in wild bird populations, associated human health risks and the importance of global cooperation to monitor and control future epidemics. Headings and subheadings are included to structure the content as per the specifications provided
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1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
