Testing a foundational piece of any strategy to combat avian influenza
The global poultry industry is currently grappling with a crisis of unprecedented scale. Highly pathogenic avian influenza (HPAI) has been wreaking havoc on poultry populations worldwide. There are a multiple of variants, but the one fuelling the current crisis is H5N1.
HPAI is a formidable adversary in the poultry world. Its ability to spread quickly and efficiently makes it a nightmare for farmers and health authorities alike. Within just 48 hours of the first bird showing symptoms, an entire flock of thousands can be wiped out. This rapid progression leaves little room for error in detection and response.
To date, H5N1 has affected more than 100 million birds since 2022, according to the CDC, causing billions of dollars in economic damage.
The threat extends beyond the immediate economic impact on poultry farmers. While HPAI doesn’t yet appear to spread easily between humans (though there have been at least 14 human cases in the US and at least 1 case where someone appears to have become infected without close animal contact), there have been almost 900 documented cases globally of human infection from poultry and cattle. Approximately half of these cases were fatal.
H5N1’s spread to cattle has increased the likelihood of human spillover, prompting the UK Health Security Agency in May to update the assessed risk of the virus attaining the ability to transmit efficiently between people. The report increased the risk from a remote chance (0-5%) to highly unlikely (10-20%) or unlikely (25-35%). The increasing potential for yet another deadly global pandemic adds an extra layer of urgency to the need for effective testing and containment strategies.
Testing is a foundational piece of any strategy to combat infectious disease — you can’t contain and prevent a disease that you can’t detect, after all. And, unfortunately, the current model for testing isn’t up to the challenge presented by H5N1.
Implementing a new model of testing that provides rapid, accurate results in the field is not just about protecting poultry flocks; it’s about safeguarding food security, protecting human health, and ensuring the resilience of the global poultry industry in the face of evolving pathogenic threats.”
Race against time
The standard means of testing for HPAI is the polymerase chain reaction (PCR) test, which we all came to know well during the Covid-19 pandemic. PCR diagnostics are extremely precise and have become the gold standard for detecting various pathogens, including HPAI. However, the process requires collecting samples from potentially infected birds and then carefully packaging and transporting these samples to a laboratory. These samples are often transported via mail, which is expensive, slow and high risk, given how dangerous the virus is to humans.
This entire process can take days or even weeks to return a result, with longer waiting times when testing facilities are overwhelmed during major outbreaks. In the context of HPAI’s rapid spread, such delays can be catastrophic, allowing the virus to decimate entire flocks and spread to neighboring farms before results are available.
There are alternatives, such as lateral flow tests (LFTs). Also known as antigen or instant tests, LFTs offer a faster alternative to PCR. They can provide results in as little as 10-15 minutes and don’t require sophisticated laboratory equipment. However, this speed comes at the cost of accuracy as LFTs are prone to producing false negatives. Because of this risky reality, LFTs are not commonly used for avian influenza.
For the most part, the USDA National Veterinary Services Laboratories (NVSL) and the National Animal Health Laboratory Network (NAHLN) have full control over testing for avian influenza, and it is all laboratory-based PCR testing.
Urgent demand for new testing model
Given its rapid spread, the devastation it wreaks on poultry operations and the danger of HPAI mutating to spread among humans, an ideal solution would provide precise results quickly in the field. Additionally, the ability to automatically transmit geotagged test data to relevant authorities would enable real-time tracking and rapid response to outbreaks, which is currently not available for centralised lab-based PCR tests.
Such a testing paradigm would offer numerous benefits to the poultry industry:
- Early detection: Rapid, accurate testing would allow farmers to identify infected birds at the earliest stages of the disease, before symptoms become apparent and the virus has a chance to spread widely.
- Targeted response: With precise information about which birds are infected, farmers could implement more targeted culling strategies, potentially reducing the overall number of birds lost to the disease.
- Outbreak containment: Quick identification of infected flocks would enable faster implementation of quarantine measures, reducing the risk of the virus spreading to neighbouring farms.
- Data-driven decision-making: Real-time transmission of test results to a centralised database would allow health authorities to track the spread of the virus more effectively, identifying hotspots and predicting potential outbreak trajectories.
- Reduced economic impact: By minimising the spread of HPAI, a rapid, precise testing strategy could help secure global trade, allaying fears about shipping infected birds and potentially saving billions of dollars in lost revenue.
Promising technologies
One technology that shows promise in meeting these needs is isothermal molecular nucleic acid amplification technology (NAAT). Like PCR, isothermal NAAT is a DNA/RNA amplification technology, but it maintains the sample at a constant temperature instead of cycling through temperature changes. Recent innovations in this technology have led to the development of rugged, portable, field-ready tests that can deliver precise and differentiated results, given the ability to spatially multiplex in approximately 30 minutes.
The devastating impact of HPAI on the global poultry industry serves as a stark reminder of the vulnerabilities in our current testing systems. As the threat of avian flu continues to loom large, the need for a new decentralised approach to poultry testing becomes increasingly critical. By embracing innovative technologies, the industry can take a significant step towards more effective disease management.
Implementing a new model of testing that provides rapid, accurate results in the field is not just about protecting poultry flocks; it’s about safeguarding food security, protecting human health, and ensuring the resilience of the global poultry industry in the face of evolving pathogenic threats. As we move forward, investment in and adoption of these advanced testing methods will be crucial in our ongoing battle against avian influenza and other potential poultry pandemics.
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