One key takeaway from the Covid pandemic was the importance of having fast and precise testing available at the point of care. This kind of testing can really make a difference in catching a virus before it spreads widely. Just a few years back, these effective tools were finally being utilized for patients in real-time.
Currently, a similar issue is being faced with the H5N1 avian flu in birds. The virus can infiltrate an entire flock before any bird shows signs of infection.
The traditional testing method, specifically the Polymerase Chain Reaction (PCR) test, which identifies genetic material from pathogens, takes several hours to yield results. By the time the results appear, the only viable option often becomes culling the entire flock.
In the U.S., there are over 1.5 billion chickens constantly moving on and off farms. The ongoing avian influenza outbreak, which has persisted since 2021, has affected more than 168 million birds.
Interestingly, many of the recent cases have been found in smaller backyard flocks and live bird markets. Genetic evidence points to repeated introductions of the virus from wild birds.
Typically, waterfowl and other birds carry these avian influenza viruses but often remain asymptomatic. This complicates efforts to control their spread among wildlife and, consequently, to domestic poultry.
Wild birds migrate in large numbers to the U.S. during the cooler autumn and winter months. As spring arrives, the risk of transmission increases.
Unfortunately, vaccinating wild birds against highly pathogenic avian influenza isn’t feasible, considering the estimated 50 billion of them. It would be almost impossible to catch enough individuals for effective vaccination.
Large poultry production facilities implement strict measures to limit exposure. Trucks must be cleaned thoroughly, and boots are disinfected upon entry and exit.
Inside, these facilities, often referred to as “barrier facilities,” keep birds healthy and safe from potential risks. On the other hand, homeowners with backyard flocks find it very challenging to avoid interactions with wild birds.
Influenza can spread through airborne droplets and contaminated surfaces. Backyard birds might get infected via water or food contaminated by wild birds.
When infected, more than 90% of chickens and turkeys succumb to the virus. Many times, affected birds can spread the virus for days before showing any symptoms, complicating control efforts. By the time birds exhibit signs, the infection might have already spread throughout the flock.
As a result, there’s a growing focus on vaccinating poultry against avian influenza before they can contract the virus. Dr. Jarra Jagne, a poultry veterinarian at Cornell, noted that various countries are using inactivated H5 vaccines, while U.S. firms are working on developing new solutions. The USDA is also providing grants to promote rapid advancements.
However, for vaccines to be profitable, they need to be cost-effective, particularly because chickens have a short lifespan (especially layers, which need to be vaccinated every two years) and low individual value.
Another significant challenge is that the antibody tests used in many countries to screen for highly pathogenic avian flu often cannot differentiate between sick and vaccinated birds. The National Chicken Council notes that the export market for chicken is worth over $5 billion annually, and some nations refuse imports from countries that vaccinate.
Yet, according to Dr. Laura Goodman, a molecular diagnostic expert, a new rapid test has been developed specifically for H5N1. This test can be performed before symptoms appear in chickens, making it valuable for use in barrier facilities or live bird markets.
If rapid testing becomes widely available, controlling H5N1 outbreaks should become significantly easier. This test can also help confirm that a flock remains uninfected, while traditional PCR tests can monitor for new emerging strains.
The overarching aim of introducing rapid molecular testing is not only to safeguard chickens, eggs, and economic interests but also because as the virus spreads and evolves, it poses a potential threat to broader species, including humans.
Alexander Travis VMD, Ph.D. chairs Cornell University’s Public and Ecosystem Health Department and plays a significant role in the School of Veterinary Medicine. He is involved with Tetmedical, Inc. Marc Siegel, MD, is also part of this discussion and holds a professorship in medicine at Langone Health in New York University.
