July 01, 2024

Understanding Bird Flu: Recent Outbreaks, Prevention, and Future Outlook

Bird flu, also known as avian influenza, poses significant threats to both poultry and humans. With recent outbreaks affecting numerous regions in Australia, it's crucial to understand its impact and how we can prevent its spread.

This article delves into the recent bird flu outbreak in Australia, its human implications, its preventive measures, and future outlook.

1. Recent Outbreak

The 2024 outbreak of highly pathogenic avian influenza in Australia is on our shores and strains of the bird flu have been found on eight farms in Victoria, and also these strains have been detected in New South Wales and Canberra.

Meanwhile, the first human case of H5N1 avian influenza in Australia has been reported as well. The case occurred in a child, who acquired the infection in India and was unwell in March 2024. The avian influenza virus was detected through further testing of positive influenza samples as part of Victoria’s enhanced surveillance system.

Impact of Outbreak: Local farmers face the harsh reality of Australia's biosecurity response to outbreaks of emergency animal diseases. In an effort to contain the disease, more than one million birds are set to be culled.

Affected Farms: The outbreak has impacted eight poultry farms in Victoria, which house egg-laying chickens and ducks raised for meat production. It began on an egg farm near Meredith in May, and has continued to spread in the region.

Suspected Source: It is currently believed that the disease spread from wild birds to domestic poultry, highlighting the challenges of managing avian influenza in areas where wild and domestic bird populations overlap.

2. Human Infections

Human infections with avian influenza viruses can happen when the virus gets into a person's eyes, nose or mouth, or is inhaled. This can happen when virus is in the air (in droplets, small aerosol particles, or possibly dust) and deposits on the mucous membranes of the eyes or a person breathes it in.

Transmission is also possible when a person touches something contaminated by viruses and then touches their mouth, eyes or nose. People who are in close and repeated contact with infected birds or heavily contaminated environments are also at risk for acquiring avian influenza.

The transmission of avian influenza from birds to humans is usually sporadic and happens in a specific context. However, due to ongoing circulation of various subtypes, outbreaks of avian influenza continue to be a global public health concern.

The spread patterns of high pathogenicity avian influenza (HPAI) have recently evolved from a historically known scenario to a new one. Both scenarios coexist in the current epidemiological situation.

Common Subtypes: Although avian (bird) influenza (flu) A viruses usually do not infect people, there have been some rare cases of human infection with these viruses. Illness in humans from avian influenza virus infections have ranged in severity from no symptoms or mild illness to severe disease that resulted in death.

The most common avian influenza viruses that have caused human infections include H5, H7, and H9 viruses, with Asian strains H5N1 and H7N9 being particularly notable.

3. Notable Statistics

H5N1: First identified in humans in Hong Kong in 1997, resulting in 18 infections and a 33% mortality rate. Subsequent outbreaks have occurred primarily in Asia and the Middle East, with occasional cases in other regions, including two cases in the United States (Colorado in 2022 and Texas in 2024).

The recently reported case in Victoria was in a child who returned to Australia from overseas in March 2024. The child experienced a severe infection but has since made a full recovery.

H7N9: This subtype caused an extensive outbreak in southeastern China starting in 2013. By 2017, nearly 800 cases were reported, with a significant mortality rate of about one-third. Worldwide, over 1500 human cases and at least 615 deaths have been reported.

Other Strains: Human infections with other strains, such as H5N6, H5N8, H7N3, H7N7, and H9N2, have been reported sporadically, with varying degrees of severity and transmission dynamics.

4. Symptoms and Impact

Birds: In wild birds, avian influenza infections are often asymptomatic, meaning they do not show noticeable signs of illness. However, in domestic poultry, the virus can cause highly lethal illnesses, leading to significant economic losses in the poultry industry.

Humans: The symptoms of avian influenza in humans can range from mild respiratory issues to severe pneumonia. Certain strains, such as H5N1, H5N6, and H7N9, have high case fatality rates, making them particularly concerning. Infected individuals may experience fever, cough, sore throat, muscle aches, and in severe cases, respiratory distress and multi-organ failure.

Avian influenza outbreaks can have heavy consequences for the poultry industry, the health of wild birds, farmer’s livelihoods as well as international trade.

Transmission: Human infections typically occur through inhalation or direct contact with secretions (saliva, mucous, or feces) from infected birds. Although human-to-human transmission is rare, the virus can potentially mutate, enabling it to spread more easily between people. This risk underscores the importance of vigilant surveillance and rapid response to outbreaks.

5. Preventive Measures

For Poultry Farmers:

Biosecurity: Implementing strict biosecurity measures is crucial to prevent contact between wild and domestic birds. This includes controlling access to poultry farms, using protective clothing, and disinfecting equipment and vehicles.

Surveillance: Regular monitoring of poultry health and rapid reporting of any signs of illness can help contain outbreaks before they spread. Farmers should be trained to recognise the symptoms of avian influenza and take immediate action if suspected cases arise.

For the General Public:

Personal Hygiene: Good hygiene practices, such as washing hands thoroughly with soap and water after handling birds or their products, can reduce the risk of infection.

Avoid Direct Contact: People should minimise direct contact with wild birds and observe caution around live poultry markets. Avoiding close contact with sick or dead birds is particularly important.

Vaccines and Medications:

Vaccination: Vaccines for poultry are available and widely used to control outbreaks in domestic bird populations. For humans, research is ongoing to develop effective vaccines against various avian influenza strains.

Antiviral Medications: Antiviral drugs can be prescribed to treat and prevent avian influenza in humans. These medications are most effective when administered early in the course of the illness.

Global Efforts and Regulations:

International Coordination: Global organisations like the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) work with countries to manage avian influenza outbreaks. This includes sharing information, coordinating research efforts, and providing technical assistance.

The World Health Organization’s Global Influenza Surveillance and Response System (GISRS) is a system fostering global confidence through effective collaboration and sharing of viruses, data and benefits based on a global public health model.

Regulations: Strict import controls, quarantine measures, and surveillance systems are in place to prevent the spread of avian influenza across borders. Countries must report outbreaks to international bodies to ensure a coordinated response.

6. Research and Future Outlook

Current Research:

Scientists are actively researching avian influenza to develop more effective vaccines for both poultry and humans. This includes exploring new vaccine technologies, such as mRNA vaccines, which have shown promise in other viral infections.

Research into antiviral treatments is also progressing, with the aim of finding more potent and targeted therapies against avian influenza viruses.

Enhanced diagnostic tools are being developed to enable rapid and accurate detection of avian influenza in both birds and humans, which is crucial for early intervention and control. For rapid diagnostic kits, positive results must be confirmed by molecular methods in areas where there are no outbreaks. In areas with outbreaks, both positive and negative results must be molecularly confirmed per APHIS’s Veterinary Services Guidance 12001.

Future Threats:

The potential for avian influenza viruses to mutate and acquire the ability to spread more easily between humans poses a significant risk of future pandemics. Continuous monitoring and research are essential to detect and respond to these threats promptly.

Climate change and changing agricultural practices may influence the patterns of avian influenza outbreaks, necessitating adaptive strategies for prevention and control.

7. Innovations in Prevention and Treatment

Genetic engineering and advanced vaccine technologies, such as viral vector and nucleic acid-based vaccines, hold promise for more robust prevention strategies against avian influenza.
Improved global surveillance systems, including real-time data sharing and predictive modeling, are being developed to enhance early detection and response capabilities. These systems can help identify emerging strains and track the spread of the virus more effectively.

8. Conclusion

Bird flu continues to be a significant concern globally, affecting both animal and human health. Understanding recent outbreaks, the nature of the virus, and implementing preventive measures are key to controlling its spread. Ongoing research and international cooperation will be essential in mitigating future threats and ensuring public health safety.

Stay informed, practice good hygiene, and support global efforts to combat this pervasive disease. By remaining vigilant and proactive, we can reduce the impact of avian influenza on our communities and protect both public health and the agricultural economy.