Eurosurveillance: Strain-dependent H5N1 replication in bovine cells
A recent study on the European clade 2.3.4.4b influenza A(H5N1) viruses highlights the differences in how these viruses replicate in bovine cells and their thermal stability in whole and semi-skimmed milk. The study found notable variations in thermal inactivation and replication efficacy, which are crucial for understanding the safety of milk products. The study demonstrated that the thermal inactivation of the viruses varied significantly depending on the strain and the fat content of the milk. For instance, while all viruses were undetectable after treatment at 75°C for 30 minutes, residual infectious virus was detected after 30 minutes at 56°C in whole milk for three strains and in semi-skimmed milk for one strain. Some strains, such as H5N1-Chicken, retained infectivity in whole milk, while H5N1-Swan and H5N1-Pigeon were detectable in semi-skimmed milk. This suggests that whole milk may provide a more stable environment for certain influenza viruses compared to semi-skimmed milk. Overall, the study contributes valuable insights into the behavior of H5N1 viruses in dairy environments, emphasizing the need for effective control measures to mitigate risks associated with avian influenza in livestock.
