CIDRAP reporters featured an article this afternoon regarding the potential for wastewater and retail milk sampling to monitor changes in the H5N1 genome in the U.S. milk supply:
These methods have some great advantages in that large numbers of herds can be pooled in the sampling process. The whole wastewater surveillance screening process has matured to successfully amplify and sequence SARS-CoV-2 variant RNA found at very low levels in sewage effluent substrates. The processes are now being adapted to influenza A and H5N1 in particular and can be adapted to retail or raw milk samples as well.
Time and date metadata will not be as precise as with single animal sampling; however, results will likely give both public health and veterinary specialists a much-narrowed field to search for both infected cattle and at-risk human contacts. More importantly, we’ll have a real-time look at the H5N1 genomic array in tested samples.
To fully implement this approach, state and federal specialists and private researchers, in collaborations with existing sewage surveillance and milk sampling networks, will need to build out and fund sampling and reporting strategies to best cover at risk areas. As with SARS-CoV-2 sampling, I’d expect this may start slowly, then build momentum if results show value in data collected.
This will be an excellent way to gain near real-time insights into genomic changes in the virus if it continues to circulate in dairy herds. It’s also possible that these bulk screening processes will assist in documenting declining prevalence should this virus burn itself out without extensive herd-level testing, as many in the dairy industry are counting on.
No matter what happens, we really have no choice but to monitor for incidence and zoonotic adaptive changes in this virus on a real-time basis. Fluids flow testing with genome sequencing is an exciting technological advance that allows us that opportunity.