Avian Influenza Outbreak in New Zealand and Worker Protection Guidelines

An outbreak of HPAI strain H7N6 was detected at an Otago egg farm in New Zealand

In December 2024, a high pathogenicity avian influenza (HPAI) virus, strain H7N6, was detected at an egg-producing farm in rural Otago, New Zealand (NZ). The virus likely originated from interactions with local waterfowl and wild birds. This was the first time that HPAI has been detected in NZ and another reminder that all poultry and egg producers need to be vigilant for signs of this disease in their flock.

The finding of HPAI led to immediate and strict biosecurity measures on the farm. Although it differed from the global H5N1 strain, Biosecurity NZ (part of the Ministry for Primary Industries – MPI) is working closely with the farm owner to manage and contain the outbreak. As a result, strict movement restrictions have been placed on poultry, poultry products, and equipment, with approximately 200,000 hens humanely culled.

The outbreak is believed to have resulted from hens being exposed to a low pathogenic virus from wild waterfowl, which then mutated to a highly pathogenic strain due to the mutation rate of influenza viruses. After depopulation, the affected sheds are cleaned and decontaminated and tested for freedom of AI before repopulation. Over 200 MPI staff are involved in the response, and while the risk to human health remains very low, Biosecurity NZ reassures that there are no concerns about food safety.

How poultry workers can be protected from AI (biosecurity guidelines)

Otago’s avian influenza (AI) outbreak and those that affected Australia in 2024 highlight the importance of strong biosecurity to prevent the spread of the disease.

AI, or ‘bird flu’, is a viral disease that primarily affects birds but can also spread to mammals, including humans. There are two main types: HPAI and low pathogenicity avian influenza (LPAI). While HPAI can cause severe illness and high mortality rates in birds, LPAI typically results in minimal signs but can mutate into the more infectious form, HPAI. Strains of HPAI, such as H5N1, have been circulating globally for years, often causing seasonal outbreaks in poultry, and usually belonging to H5 or H7 types.

Human infection with AI is rare but can occur, particularly when people are in close contact with infected animals. The virus can be acquired by humans through inhalation of contaminated particles, direct contact with infected animals or indirect contact with contaminated equipment or environments. It underscores the need for comprehensive biosecurity measures to protect the workers involved in managing such outbreaks and industries working closely with birds or wildlife.

The National Guidelines for Avian Influenza: Protecting People Who Work with Birds and Wildlife, recently developed by the Communicable Diseases Network Australia, are designed to provide employers and managers with essential information based on a site-specific work health and safety risk assessment.

These guidelines aim to protect workers, contractors, and volunteers exposed to birds or animals potentially infected with AI. They cover legislative provisions, how the virus spreads and its symptoms, how to prepare for an outbreak, worker health protection during outbreaks, and infection prevention measures such as hygiene and personal protective equipment.

Outbreaks like the one in Otago highlight the critical importance of following robust biosecurity measures and developing guidelines to prevent the spread of AI, protect the poultry industry and workers, and ensure the environment remains safeguarded during such incidents.