United States – Ingestion of raw cow’s milk containing the H5N1 avian influenza virus can infect you and make you ill, but the same virus does not easily infect other people.
Low Airborne Transmission of H5N1 Bird Flu Virus
The University of Wisconsin-Madison scientists were able to infect mice and ferrets with the H5N1 bird flu virus when the virus was dropped directly into their nostrils, but airborne transmission of the virus was less likely. Disease transmission through the air is one of the primary causes of the disease’s rapid spread among individuals, as reported by HealthDay.
“This relatively low risk is good news since it means the virus is unlikely to easily infect others who aren’t exposed to raw infected milk,” said study leader Yoshihiro Kawaoka, a professor of pathobiological sciences at the University of Wisconsin-Madison.
He quickly pointed out that what has been discovered is how the virus affects the mice and ferrets, not humans. Such results in humans may not be similar to those in animals.
Infection Studies in Mice and Ferrets
While conducting their experiments, the researchers ascertained that mice could contract bird flu simply by consuming small amounts of raw milk that from an infected cow.
They then used ferrets to model how flu viruses could spread among people. This is because ferrets experience flu-like humans; the flu causes conditions such as fever, congestion, and sneezing in both animals and humans.
To check how effectively the bird flu virus could spread through the air with droplets, they put infected ferrets close to healthy ferrets. In this experiment, all four exposed ferrets remained healthy, and no virus was isolated from any of the animals during the experiment. On the cross-testing, though, one of the four reacted positively for H5N1 antibodies.
“That suggests that the exposed ferret was infected, indicating some level of airborne transmissibility but not a substantial level,” Kawaoka said in a university news release.
In another experiment, the researchers combined the bird flu virus with receptors that the human flu viruses generally interact with. Receptors are the hosts on which the virus hooks itself in a bid to penetrate the cells.
Human Receptor Interactions and Pandemic Potential
They also discovered that both H5N1 viruses interacted with both types of molecules, which showed that the bird flu virus is capable of infecting humans.
While that adaptability has produced only a scant number of human H5N1 cases, researchers pointed out that flu viruses that sparked human pandemics in 1957 and 1968 acquired that capacity after evolving the capacity to stick to receptors engaged by human flu viruses.
Last, it was identified that the virus reached the target organ—the milk glands and muscles of the infected mice, as well as horizontal transmission from mothers to pups, as reported by HealthDay.
Implications for Public Health
They mentioned that if the virus spreads widely among U. S. herds, these findings announced on July 8 in the journal Nature suggests that individuals are prone to diseases transmitted by consuming unpasterized milk and probably undercooked beef from affected cows.