Post by DogGoneGood on Nov 9, 2009 16:54:35 GMT -5
H1N1 and dogs
November 6, 2009, By Jeff Grognet, D.V.M., ARTICLE, HEALTH
Even a year ago, people had no idea what H1N1 meant. It could have been a secret recipe for fried chicken. Now we know it as the virus that created the pandemic of swine flu. This virus and others have the ability to cross species. What we want to know is – do dogs play any role in housing these viruses, and are they at risk?
The transmissibility of flu viruses was exposed when avian flu was diagnosed in Southeast Asia. There were prophesies of a worldwide pandemic in 1997 after it spread from birds to people. This virus, called H5N1, and variants of the virus, were found in several Canadian flocks. Although the disease was diagnosed in some people, the worldwide epidemic never happened.
Names for influenza viruses are based on the H and N system. The letters refer to two proteins – hemagglutinin and neura-minidase – on the viral surface. Each influenza virus has these two proteins, but other factors determine its transmissibility and virulence.
In 2005, researchers identified a canine influenza virus that triggered a mild upper respiratory disease similar to kennel cough. Dubbed H3N8, canine influenza is considered dog specific and to date it has not infected people. A vaccine against this virus was recently introduced in the U.S.
Where did H3N8 come from? It has similarities to equine (horse) flu. In fact, when it was first isolated, one hypothesis was that dogs got it from eating horsemeat. This line of thinking is incorrect. Its origin was thought to be a mutated equine virus, but like any flu virus, you cannot pick it up by eating meat from an infected animal.
The recent outbreak of H1N1 was originally called swine flu because the virus’s genetic signature suggested it originated in pigs. Because it is actually a mix of human, pig and bird flu viruses, the swine flu moniker has been dropped, partly at the insistence of pork manufacturers. The official name for the virus is now influenza A/H1N1.
Most viruses infect just one species, or a limited number of species. Avian flu was an exception, infecting a multitude of birds as well as pigs, people and cats. However, H5N1 is not easily transmissible from birds to people, and person-to-person movement would be a rare event.
What stops flu viruses from spreading between species? Transmissibility is based on viral receptors, mainly found in the upper respiratory tract, that allow the virus to invade. If a species does not have the right receptors, the virus cannot infect.
Is a human with H1N1 a risk to dogs and other animals? We know the virus spreads between people rather quickly, but as of this writing, it has moved only into some pigs, turkeys, ferrets and one cat. The transmission has been from infected people to animals, not vice versa.
However, influenza viruses are constantly modifying themselves and their ability to infect other species could change. Authorities are monitoring these viruses along with instances of human exposure very closely.
For more information, visit canadianveterinarians.net.
(Originally appeared in our January 2010 issue. Click here to subscribe.)
Source: Dogs in Canada
November 6, 2009, By Jeff Grognet, D.V.M., ARTICLE, HEALTH
Even a year ago, people had no idea what H1N1 meant. It could have been a secret recipe for fried chicken. Now we know it as the virus that created the pandemic of swine flu. This virus and others have the ability to cross species. What we want to know is – do dogs play any role in housing these viruses, and are they at risk?
The transmissibility of flu viruses was exposed when avian flu was diagnosed in Southeast Asia. There were prophesies of a worldwide pandemic in 1997 after it spread from birds to people. This virus, called H5N1, and variants of the virus, were found in several Canadian flocks. Although the disease was diagnosed in some people, the worldwide epidemic never happened.
Names for influenza viruses are based on the H and N system. The letters refer to two proteins – hemagglutinin and neura-minidase – on the viral surface. Each influenza virus has these two proteins, but other factors determine its transmissibility and virulence.
In 2005, researchers identified a canine influenza virus that triggered a mild upper respiratory disease similar to kennel cough. Dubbed H3N8, canine influenza is considered dog specific and to date it has not infected people. A vaccine against this virus was recently introduced in the U.S.
Where did H3N8 come from? It has similarities to equine (horse) flu. In fact, when it was first isolated, one hypothesis was that dogs got it from eating horsemeat. This line of thinking is incorrect. Its origin was thought to be a mutated equine virus, but like any flu virus, you cannot pick it up by eating meat from an infected animal.
The recent outbreak of H1N1 was originally called swine flu because the virus’s genetic signature suggested it originated in pigs. Because it is actually a mix of human, pig and bird flu viruses, the swine flu moniker has been dropped, partly at the insistence of pork manufacturers. The official name for the virus is now influenza A/H1N1.
Most viruses infect just one species, or a limited number of species. Avian flu was an exception, infecting a multitude of birds as well as pigs, people and cats. However, H5N1 is not easily transmissible from birds to people, and person-to-person movement would be a rare event.
What stops flu viruses from spreading between species? Transmissibility is based on viral receptors, mainly found in the upper respiratory tract, that allow the virus to invade. If a species does not have the right receptors, the virus cannot infect.
Is a human with H1N1 a risk to dogs and other animals? We know the virus spreads between people rather quickly, but as of this writing, it has moved only into some pigs, turkeys, ferrets and one cat. The transmission has been from infected people to animals, not vice versa.
However, influenza viruses are constantly modifying themselves and their ability to infect other species could change. Authorities are monitoring these viruses along with instances of human exposure very closely.
For more information, visit canadianveterinarians.net.
A multi-published writer, Jeff Grognet, D.V.M., runs a veterinary practice in Qualicum Beach, B.C., along with his wife, Louise Janes, D.V.M.
(Originally appeared in our January 2010 issue. Click here to subscribe.)
Source: Dogs in Canada
