Episode 74 - Avian Flu

Avian Flu - Episode 74

On 22 May 2024, the World Health Organization (WHO) was notified of a laboratory-confirmed case of human infection with avian influenza A(H5N1) virus (clade 2.3.2.1a) by the International Health Regulations (IHR) National Focal Point (NFP) of Australia. This is the first confirmed human infection caused by avian influenza A(H5N1) virus detected and reported by Australia.

In 2024, Australia experienced significant challenges with avian influenza, primarily involving highly pathogenic avian influenza (HPAI) strains. The outbreaks were reported in Victoria, New South Wales, and the Australian Capital Territory, with H7N3 and H7N9 strains affecting egg farms in Victoria and H7N8 impacting poultry in NSW and the ACT.

Unusually, this outbreak occurred with 3 different strains at the same time as the first human contamination. We need to go 2 months without detection to be considered free of avian influenza.

Despite these outbreaks, Australia has managed to avoid the devastating H5N1 strain, which has caused widespread issues globally. This strain, first identified in China in 1996, has led to massive bird deaths and human infections across multiple continents. The H5N1 virus is highly pathogenic and can infect a variety of species, including wild birds and mammals. Human cases, though rare, have been reported, leading to severe illness and fatalities.

Australia's relative safety from H5N1 is attributed to its geographic isolation and stringent biosecurity measures. The country employs extensive surveillance and rapid response strategies to detect and manage avian influenza outbreaks. 

This includes testing migratory birds and domestic poultry, as well as imposing strict import controls to prevent the introduction of infected birds and poultry products.

Overall, while Australia has effectively contained current avian flu outbreaks, vigilance and robust biosecurity remain critical to prevent the introduction of more virulent strains like H5N1.

Preventing bird flu involves a combination of biosecurity measures, surveillance, vaccination, and public awareness. Here are some key strategies:

Biosecurity Measures

1. Restrict Access: Limit access to poultry farms and ensure that only essential personnel enter. Implement strict hygiene protocols, such as using disinfectant footbaths and protective clothing.
2. Quarantine New Birds: Isolate new or returning birds from the rest of the flock for at least 30 days to monitor for signs of illness.
3. Clean and Disinfect: Regularly clean and disinfect equipment, vehicles, and facilities to minimise the risk of contamination.

Surveillance

1. Monitoring: Regularly test domestic and wild birds for avian influenza viruses. Early detection helps in rapid response and containment of outbreaks.

Signs of disease usually appear in several or all birds in a flock, including:

• sudden death
• lethargy or reluctance to walk, eat or drink
• droopy appearance or ruffled feathers
• head or limb swelling
• bruising of the wattle, comb, feet or skin
• respiratory signs such as panting, nasal discharge or sneezing
• diarrhoea
• unusual head or neck posture, incoordination, inability to walk or stand
• unusual reduction in egg production.
•  

2. Reporting: Encourage farmers and bird owners to immediately report any signs of illness in their flocks to veterinary authorities.

Vaccination

1. Vaccination Programs: There is currently no approved Avain Flu Vacination in Australia, the USA or UK.

Public Awareness and Education

1. Educate Farmers and Bird Owners: Provide training on recognising symptoms of avian flu, proper biosecurity practices, and the importance of vaccination and surveillance.
2. Public Information Campaigns: Use media and public health campaigns to inform the public about the risks of avian influenza and preventive measures.

Import Controls

1. Regulate Imports: Strictly control the importation of birds and poultry products from regions affected by avian influenza to prevent the introduction of the virus.

Wildlife Management

1. Control Wild Bird Populations: Manage interactions between wild birds and domestic poultry, as wild birds can be carriers of avian influenza. Use netting or other barriers to prevent contact.

Response to Outbreaks

1. Rapid Response: In the event of an outbreak, implement rapid response measures, including culling infected and exposed birds, to contain the spread of the virus.
2. Movement Restrictions: Enforce movement restrictions on birds and poultry products within and between regions during outbreaks to limit the spread of the disease.

Avian Flu is fatal in chickens.

Currently, there is no vaccination against Avian Flu for use in Australia or USA, however, other countries are trialling them.

Inappropriate use of vaccination in poultry to try to prevent the spread of bird flu has become part of the problem and has serious human health implications, officials of the World Health Organization warned this week. “Vaccination can sometimes cause silent transmission of infection from asymptomatic birds. Mass vaccination programmes entail people tramping around the countryside from farm to farm and they can spread the disease with them. The first response must be culling,” said Peter Cordingley, WHO's spokesman in Manila.