A new study from experts at the University of Pittsburgh School of Public Health and Emory University regarding infectious diseases in the U.S. reveals that avian influenza virus (H5N1) can survive on metal and rubber parts of commercial milking equipment for at least one hour, increasing the risk of transmission to humans and other animals.
The study highlights the higher risk of avian influenza exposure for dairy farm workers and indicates the need for more widespread use of personal protective equipment, including face shields, masks, and eye protection.
Automated milking equipment at Honbu Farm in Japan. (Photo: Dao Thanh Tung/TTXXVN).
“Dairy cows must be milked even when they are sick, and the duration of the virus’s presence in leftover milk on equipment is still unclear,” said Valerie Le Sage, the lead author of the study.
“What is concerning is that the virus in fresh milk can survive for several hours and has the potential to infect farm workers or spread from animal to animal.”
Clinical symptoms of avian influenza can range from mild fever and cough to difficulty breathing and pneumonia. This disease can be fatal.
Since March, when the avian influenza virus was first detected in dairy cows in the U.S., it has spread to other states and infected at least three people.
Although the Centers for Disease Control and Prevention (CDC) indicates that the current risk to the public remains low, the influenza virus can quickly adapt to spread from person to person.
To understand the potential for transmission from livestock to dairy farm workers, researchers examined the stability of infectious influenza virus particles in droplets of fresh milk on the metal and rubber components of commercial milking equipment.
In a laboratory environment simulating the humidity and temperature of outdoor milking stalls in Texas, H5N1 virus particles suspended in milk remained stable on metal and rubber for over an hour.
Meanwhile, H1N1 virus particles (swine flu), which behave similarly to H5N1 in the lab, remained infectious for at least three hours on rubber and at least one hour on stainless steel.
“Our data suggest that the surfaces of milking equipment can be contaminated for extended periods, increasing the likelihood of transmission from sick animals to humans,” Le Sage noted.
“These findings emphasize the importance of face shields, masks, and eye protection, as well as enhanced disinfection of equipment between cows to minimize risks for workers and reduce transmission among animals.”
