Eliminating avian influenza ‘risk points' in trucks and transport crates - Interpretive Summary

     

In 2016 and 2017, duck farmers in France faced the grim reality of having to depopulate their flocks due to avian influenza outbreaks. A study conducted at the time showed that the trucks and crates used for bird transport during this disease-control effort were often not decontaminated correctly.

In 2020 and 2021 came another wave of devastating avian influenza outbreaks—and a chance for French duck producers to see how well current decontamination protocols were working.

In a new study published in Poultry Science^® researchers with France’s ANSES - Ploufragan-Plouzané-Niort Laboratory report that while cleaning and disinfection (C&D) of transport trucks and crates during the 2021 outbreaks did eliminate traces of avian influenza on most surfaces, there’s more work to be done.

The scientists found that three quarters of crates and seven of the eight trucks sampled were positive for avian influenza (measured through detection of the viral genome) when they arrived at an abattoir. Encouragingly, they found that C&D procedures were reinforced more in 2021 compared with 2017, and workers were more likely to clean with detergent solution and warm water.

Overall, cleaning protocols were fairly consistent between abattoirs. Trucks were washed with a detergent solution, sprayed with a high-pressure washer and disinfected with a virucide (virus-killing) product. Crates were soaked or sprayed with detergent and disinfectant products.

This cleaning was consistent with each product manufacturer’s instructions for decontamination, yet the virus still snuck through. Twenty-eight percent of crates were still positive for avian influenza virus (AIV) after C&D. This surprised the researchers because up to 91 percent of the crates and vehicles had passed the initial checks for cleaning scores and microbiological counts.

“There is a knowledge gap concerning the correlation between the results obtained by direct detection of AIV genome from surface samples and the results of visual inspection and microbiologic counts on the same surfaces,” write the study authors.

Where should C&D protocols go from here?

Education may help. The researchers found that the truck drivers were most often the ones tasked with cleaning the truck’s cabin. While the abattoir provided cleaning products, drivers weren’t given cleaning instructions. In the end, only the driver’s foot mat was consistently cleaned and disinfected. The researchers found contamination most often in these truck cabins.

And there was one facility that could share some lessons. “This abattoir had a very long crate washing line, including a final disinfection step by immersion, and very strict separation between dirty and clean areas, which were on opposite sides of the building,” write the study authors.

The result? Zero contamination on cleaned crates.

Going forward, the researchers recommend that authorities monitor decontamination effectiveness through a combination of environmental sampling and AIV genome detection.

     

Strict cleaning protocols for vehicles, transport crates and truck cabins can control avian influenza.

Lengthy cleaning protocols may lead to slow-downs at abattoirs, but the trade off is less viral contamination between farms and slaughtering facilities.

Faster tools for detecting viral genomes are becoming more common as ways to catch contamination.

The full paper, titled “Avian influenza outbreaks: evaluating the efficacy of cleaning and disinfection of vehicles and transport crates” can be found in Poultry Science^® and online here.

DOI: 10.1016/j.psj.2021.101569