Bird's Flu Threat Among Humans - Scientific Study Warns
Posted 2 months ago
Viruses have a clever way of invading human cells; they latch onto specific receptors on the cell's surface, like a key fitting into a lock. Sometimes, viruses that usually infect birds or animals leap to humans. How does this happen? It's all about tiny tweaks in the virus's proteins that allow them to connect with human cells. These changes, called mutations, are like nature's experiments, occasionally creating viruses that can cross species barriers.
A scientific study explores a significant concern: how flu viruses found in animals, like birds and cows, might adapt to infect humans more easily. This could potentially lead to human-to-human transmission. Specifically, the research focuses on the H5N1 flu virus, a subtype that mainly infects birds but has occasionally caused illness in humans. The researchers examined how small genetic changes in the virus might help it attach to and infect human cells, which could increase the risk of person-to-person spread.
Background
The H5N1 virus has been known since 1996 and is highly lethal to birds. In recent years, a highly pathogenic type of this virus 2.3.4.4b of this virus has started infecting mammals, including cows and, in rare cases, humans. In 2024, the first human case of H5N1 linked to dairy cows was reported in the United States, which raised concerns because the virus could mutate further and potentially spark a flu pandemic.
The virus infects cells using a protein called hemagglutinin (HA), which acts like a key to unlock specific receptors on cell surfaces so the virus can enter the cell to cause infection. Different species have different receptors, and the virus typically targets 'avian-type' receptors found in birds. However, the potential for the virus to adapt to recognize 'human-type' receptors is a serious concern.
Key Findings
The researchers identified a single mutation in the HA protein (changing one amino acid from glutamine to leucine) that allowed the virus to switch from targeting bird receptors to human receptors. This mutation significantly increased the virus's ability for attaching to human-type receptors in laboratory experiments, and adding another mutation made the binding even stronger.
To understand how this happens, scientists studied the 3D structure of the HA protein with and without the mutation. They discovered that the mutation changes the protein's shape, making it a better fit for human receptors.
Why This Matters
While the virus hasn't yet been able to spread between humans, these findings highlight how easily such a change could occur. Just one mutation in the right place might enable the virus to jump from animals to humans, increasing the risk of an outbreak.
What Should Be Done?
The study suggests closely monitoring flu viruses in animals, especially those in close contact with humans, like dairy cows or farm birds. Health authorities can identify potential threats early by monitoring genetic changes in these viruses and preparing vaccines or other measures to prevent a pandemic.