Understanding H5 bird flu in New Zealand: monitoring the spread and assessing risk

Bird flu risk in New Zealand

Through surveillance and testing, we assess the current level of risk from bird flu. Areas are labelled as low, medium, or high risk, based on a number of criteria. We explain how risk levels are determined on this page.

Currently:

• the risk level for all areas of New Zealand is low
• there is no evidence of mass mortality in wildlife
• there have been no detections in poultry.

It is not possible to predict when we might detect H5 bird flu spreading beyond individual wild birds in New Zealand.

Even if the virus isn't spreading here yet, we know it is likely to continue arriving, most likely with ocean-going or migratory wild birds. That's why we continue to ask New Zealanders to stay alert.

By continuing to prepare and maintaining good biosecurity habits, we can all help limit the impact of bird flu if it spreads here.

How bird flu risk levels are determined

MPI uses information about positive cases, such as where they are found and the species involved, alongside genomic sequencing carried out in our laboratory, to understand how the virus may be spreading. 

Based on this information, we determine one of 3 risk levels for an area – low, medium, or high.

Low risk

An area may be labelled low risk if there have been no recent bird flu detections in the area. It will remain low risk if H5 bird flu has been confirmed in individual wildlife but:

• surveillance and testing indicate isolated introductions
• there is no evidence of local establishment or ongoing transmission.

Medium risk

An area may be labelled medium risk if there have been recent bird flu detections and if evidence suggests there is limited local transmission occurring in wildlife. Evidence may include:

• 2 or more linked wildlife cases (by factors like location and species, or based on genome analysis)
• repeated detections in a similar location
• detection in species that do not leave New Zealand.

High risk

An area may be labelled high risk if there is ongoing transmission of bird flu in local populations. Evidence may include:

• multiple linked cases or clusters of cases (by factors like location and species, or based on genome analysis)
• an increasing number of detections
• spread across multiple locations, populations, or species.

Find out more

Our 'H5 bird flu risk levels' document has more information, including a map that shows the location of poultry farms.

H5 bird flu risk levels [PDF, 971 KB]

Monitoring bird flu in New Zealand

Our testing is focused on tracking the movement of bird flu. This helps support poultry industry decision-making, informs work to protect native wildlife, and is valuable information for anyone looking to make decisions about bird flu risk in their area.

MPI experts triage public notifications based on internationally recognised processes for assessing H5 bird flu.

Over the past 12 months, through surveillance and monitoring activities in wild birds, more than 2,500 wild birds and 12,500 commercial poultry birds were screened.  

International experience shows this approach will more quickly build an accurate picture of H5 bird flu than investigating single bird finds or species that are less likely to be of immediate concern.

H5 bird flu can only be confirmed through laboratory testing, which can require several tests.

The confirmed birds to date were found as part of our continuous surveillance programme that includes reports through the 0800 hotline, wildlife hospital notifications, zoos, and a national testing programme of waterfowl, along with poultry industry and vet notifications.

Find out more

Our 'Monitoring H5 bird flu' document includes a map that shows the location of birds that have been tested and where the virus has been confirmed.

Monitoring H5 bird flu [PDF, 1.5 MB]

H5 bird flu and migration

Because H5 bird flu is carried by wild birds, spread of the virus is often linked to migration patterns and pathways.

While we do not yet know exactly how migration will impact the spread of H5 bird flu in New Zealand, information about migration patterns may be useful for the poultry industry and bird owners when making decisions and to inform the work to protect native wildlife.

Migration is not the only way that H5 bird flu can spread, as we have seen with the positive detections of the virus in ocean-going sea birds here in New Zealand. While it may contribute to periods of higher and lower risk in different areas, it's important that people remain alert for H5 bird flu at all times of the year.

Find out more

Our ‘H5 bird flu and migration’ document includes information about seasonal bird observations, including species-specific migration pathways.

H5 bird flu and migration [PDF, 400 KB]