A Flu By Any Other Name...
Influenza (flu) viruses have circulated in humans and animals (birds, pigs,
cats, dogs, horses, etc.) for centuries. Some will infect only one type of
animal. Others have more ability to move between species but may cause
different signs of illness in different animals.
These viruses are very
adaptive, they are able to mix with other influenza viruses and create new
viruses changing how well they spread and their ability to cause disease.
Influenza Type A
One strain of influenza virus is called Influenza A. It contains genetic materials
that it has picked up from influenza viruses infecting birds, pigs and people.
It circulates in susceptible pig herds and can cause high fever, lethargy and
respiratory symptoms (coughing and sneezing). Most influenza A viruses in pigs
are different from influenza A viruses that infect people. Most of the time,
these pig influenza viruses stay in pigs and these people influenza viruses
stay in people. Occasionally, influenza viruses can spread from people to pigs
and from pigs to people.
Sometimes people get confused
about what they should call influenza viruses in people and in pigs. To ensure
accurate naming, the World Health Organization (WHO), in collaboration with
several federal and international health organizations, announced a
standardized naming convention. Influenza viruses that normally circulate in
pigs and may infect humans will be referred to as “variant influenza viruses,”
designated by a “v.” “Variant” designates the virus as one that varies from
infecting only the species that is its usual host.
Proper H3N2 Virus Naming
U.S. Centers for Disease Control (CDC) officials say that when influenza A
(H3N2) viruses are found in swine, they should be called “swine influenza A
Another way of saying this
is “swine H3N2”. If human infections with these viruses occur, these viruses
are then called “variant” viruses as designated by the WHO because they are
infecting a different species and are called “influenza A (H3N2)v” or just
Calling a pig influenza
virus that contains genes from birds, pigs and people influenza viruses and
infects people, “swine flu” is misleading because it refers to the virus being
in pigs – swine H3N2.
When that virus crosses over
and infects people, the accurate way to refer to it is “variant H3N2” or
This new standardized naming
convention will allow the media to use more accurate terminology to communicate
to consumers and will help reinforce to consumers that you cannot get the flu
from eating or handling pork and pork products.