Spillover of highly pathogenic avian H5N1 into the cattle population poses a risk to humans through the close contact with farm workers. High viral loads of influenza viruses in the unpasteurized milk of infected lactating cows has the potential to contaminate equipment within milking parlors and create fomites for transmission to dairy workers. Cattle H5N1 and human 2009 H1N1 pandemic influenza viruses were found to remain infectious on surfaces commonly found in milking equipment materials for a few hours. The data presented here provide a compelling case for the risk of contaminated surfaces generated during milking to facilitate transmission of H5N1 from cattle-to-cattle and to dairy farm workers.

The authors have declared no competing interest.

This project has been funded in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract No. 75N93021C00015 and an NIH award (UC7AI180311) from the National Institute of Allergy and Infectious Diseases (NIAID) supporting the Operations of The University of Pittsburgh Regional Biocontainment Laboratory (RBL) within the Center for Vaccine Research (CVR).

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