BEEINFORMED

Australia’s honey bees have recently undergone a nationwide health check, and the results are in. The National Virus Baseline Survey was launched in response to the detection of Varroa destructor in parts of the country. Its aim? To identify which viruses are already present in our hives, assess their distribution, and help detect any new virus introductions linked to the mite.

Words Shannon Holt, Bee Biosecurity Officer, DPIRD

Photography L.De Laeter

A total of 1,209 colonies were sampled across Australia for the following viruses:

• Slow Bee Paralysis Virus (SBPV)

• Acute Bee Paralysis Virus (ABPV)

• Deformed Wing Virus (DWV)

• Apis mellifera rhabdovirus 1 and 2 (AMR1/2)

• Black Queen Cell Virus (BQCV)

• Sacbrood Virus (SBV)

• Lake Sinai Virus 1 and 2 (LSV 1/2)

• Israeli Acute Paralysis Virus (IAPV)

• Kashmir Bee Virus (KBV)

What wasn’t found

One of the most reassuring findings was the absence of three exotic viruses considered high-risk to bee health:

• Deformed Wing Virus (DWV)

• Acute Bee Paralysis Virus (ABPV)

• Slow Bee Paralysis Virus (SBPV)

None of these were detected in any of the samples collected nationwide.

What was found

Three endemic viruses were found to be widespread and are more likely to be present in your hives:

• LSV 1 or 2: Detected in 84.1% of WA samples (National average: 83.9%)

• BQCV: Found in 79.2% of WA samples (National average: 94.8%)

• SBV: Present in 61.7% of WA samples (National average: 82.2%)

In contrast, IAPV was detected in only ~10% of WA samples. Its prevalence was notably lower in WA, NT, and SA, compared to:

• ~40% in NSW, VIC, and TAS

• ~70% in QLD

Interpreting the data

These figures reflect presence/absence results across samples (15 bees per sample). They do not indicate individual bee infection rates or viral loads. Many colonies with positive detections likely showed no visible symptoms.

Notable detections

Kashmir Bee Virus (KBV) was detected for the first time in Australia in a small number of hives in Victoria. Agriculture Victoria is working with potentially affected beekeepers to understand and manage any potential spread.

Apis mellifera rhabdovirus 1 and 2 (AMR1/2) were first detected in NSW during 2023–24 and have since been found in more locations. Mite analysis indicates a high prevalence of AMR1 in mite populations. As AMR viruses were only recently discovered in honey bees (within the last 7–8 years), their effects are less well understood compared to other viruses.

This survey provides a critical baseline for tracking changes in viral dynamics and informs future biosecurity and management strategies.

Photography

The Animal and Plant Health Agency (APHA), Crown Copyright

The high underlying prevalence of some viruses highlights the importance of:

• Maintaining strong colonies

• Practising good hygiene

• Staying informed about emerging threats

Thank you to the 29 WA beekeepers who participated in the survey. Beekeepers were selected in a targeted manner to ensure broad geographic coverage across the state and representation of different genetic stock.

Damaged wings due to deformed wing virus.