H5N1 VIRUS - SCI & TECH
News:
H5N1 kills 50 million birds, spreads to mammals
What's in the news?
● This
year, the world has been witnessing one of the worst-ever documented outbreaks
of the highly pathogenic avian influenza H5N1 killing millions of birds.
● The
virus, which is known to cause severe disease and death in birds, has also been
detected in mammalian species and also in humans.
Key takeaways:
● Uncontrolled
spread of the virus can be catastrophic to the already endangered bird species
globally, leading to the mass extinction of several species.
● This
has put health authorities on high alert regarding the implications of the
large outbreak on public health.
● Although
avian influenza has different subtypes, H5N1 is a highly pathogenic subtype
that causes mortality in birds.
● Since 2022, the virus has
infected over 100 million birds across the globe, resulting in the deaths of
over 50 million and culling of millions of poultry.
● Unlike
previous outbreaks of highly pathogenic subtypes of avian influenza, H5N1 is
heavily impacting wild bird species, including many which were on the verge of
extinction.
Impact:
● The
impact of H5N1 on wild bird populations has varied depending on several
factors, such as level of exposure, geographical locations and migratory
patterns of the affected species.
● High
mortality in wild birds due to the virus could lead to significant ecological
consequences, including vulnerability of predators and alterations in species
composition in affected ecosystems, and therefore a possible impact on
biodiversity not just limited to avian species.
● It
has raised concerns regarding the spread of the virus among critically
endangered avian populations.
● The highly contagious
H5N1 virus can also occasionally spillover from birds to animals through direct
or indirect contact with infected birds or their droppings.
● In
the recent months, a few sporadic cases of human H5N1 infections have also been
reported from Ecuador, Cambodia, and more recently in Chile.
● Given
the ongoing threat of an influenza pandemic, monitoring the spread in mammalian
populations is important in areas of close contact between humans and animals.
● However,
since the virus does not yet transmit efficiently among humans, the World
Health Organization (WHO) has assessed the risk of H5N1 to humans to be low.
Go back to basics:
H5N1/Bird Flu:
● Bird
flu or avian influenza is a disease caused by avian influenza Type A viruses found naturally in wild birds
worldwide.
● Avian
influenza, or bird flu, is a highly contagious viral infection that primarily
affects birds.
● It
can infect domestic poultry including
chickens, ducks, turkeys, pigs, cats, and tigers.
Does it spread to humans?
● Infrequently,
the virus can infect mammals from birds, a phenomenon called spillover, and rarely can spread between mammals.
● This
subtype has caused a number of human infections through close contact with
infected birds or contaminated environments, and is often fatal.
● Recent
reports of H5N1 spread between mammals raise concerns about its potential to
cause a human pandemic if it were to spill over and become transmissible among humans.
Types of avian influenza:
● Avian
Influenza type A viruses are classified based on two proteins on their surfaces
– Hemagglutinin(HA) and
Neuraminidase(NA).
● There
are about 18 HA subtypes and 11 NA subtypes.
● Several
combinations of these two proteins are possible e.g., H5N1, H7N2, H9N6, H17N10,
etc.
Symptoms:
● Virus
infections in humans have ranged from mild to severe influenza-like illness.
● Fever,
cough, sore throat, muscle aches, nausea, abdominal pain, diarrhea, vomiting
etc.
● Severe
respiratory illness (e.g., shortness of breath, difficulty breathing,
pneumonia, acute respiratory distress, viral pneumonia, respiratory failure).
● Neurologic
changes (altered mental status, seizures).
Prevention of spillovers:
● Vaccination
of poultry.
● Safe
disposal of dead birds.
● Wearing
personal protective equipment when handling birds.
● Quarantine
and culling of affected animals.
● Improved
surveillance and monitoring of H5N1 in birds and other animals.
● Molecular
surveillance of H5N1.
● Genome
sequencing can be employed to monitor the emergence of new subtypes, and keep a
close watch on mutations and virulence factors that may increase the ability to
infect humans.