Why the swine flu virus is a danger to humans
April 27, 2009 by Grace Ibay
Filed under Health
The new swine flu virus that broke out in Mexico is unique and potentially dangerous in one way. It is a virus that has a combination of gene segments from human, bird and swine viruses, and can potentially become infectious in humans that have no immunity to the new strain.
Influenza viruses can change its make-up in one of two ways: Antigenic drift is a series of mutations that cause the virus to gradually evolve over time. Antigenic shift is an abrupt change in the surface antigen proteins that suddenly creates a new subtype of the virus. In the history of influenza outbreaks, antigenic shift is the cause behind pandemics in 1918 (Spanish Flu), 1957 (Asian Flu) and 1968 (Hongkong Flu) because the populations have not developed antibody protection against the virus.
What’s especially unique about this new swine flu strain is that it’s a type A/ strain H1N1 and it hasn’t been previously detected in pigs. Lab tests showed that the H1N1 is susceptible to the antiviral drugs oseltamivir (Tamiflu) and zanamivir and the US government is prepared to use the drugs to treat and prevent infection with swine influenza virus.
The graphic below tracks the swine flu virus as it spread from Mexico to other countries. As of April 27, the USA reported 20 confirmed cases, Spain has confirms 1 case, Canada has 6 and Mexico has over 1,300 suspected cases with 62 deaths from swine flu infection.
In 2007, scientists reported two cases of H2N3 influenza virus in pigs that have two gene segments from birds mixed with gene segments from common swine influenza viruses. This made H2N3 strain infectious and highly transmissible between pigs. Lab tests also showed that H2N3 can infect ferrets and mice.
Image: Newscom
Grace,
Is the genetic combination of Bird, Swine, and Human Influenza a natural occurence?
Seth, unfortunately pigs are naturally occurring “mixing vessels” of influenza viruses. The surface of the skin cells inside the trachea of pigs have a molecule that can bind to molecules on the cell surfaces of human and avian flu viruses. If any two of avian, human and swine viruses are present at any one time in a pig, then it’s a convenient ‘petridish’ for reassortment of a new strain of virus. That’s what we have with the current outbreak.
Grace,
Do you think it’s possible this particular (mixed) viruses origin could have been a result of a “created” genetic modification of the flu virus?
thanks
I have heard rumours of this swine flu being introduced as a terrorist act instigated by the Middle East (some people say China and North Korea too). I think the best answer is always the obvious one. There are many pig farms in Mexico and pork is a popular meat there. Porcine vaccine and treatment are probably less stringent practices in Mexico than in the US. Grace’s earlier intelligent and thoughtful answer seems to me the obvious one. With the economic slump it is the worst timing for such a global outbreak, but I think odds are hugely in favour of coincidence in this case. Other serious flu strains have come and gone in recent years without much news coverage, not to mention the common strains that migrate to the US each year. There are always casualties. The timing was unfortunately ripe for a new news media frenzy, now that we are all WAY over hearing about the economy. I am in the tourist industry and I have seen a mild impact already due to this scare. I expect it to get a bit worse if the media finds something else to terrorize us with and a lot worse if they don’t. I think the really dangerous viral infection is the heavy dependence of the news media on advertising dollars and the consolidation of media ownership into large corporations. With those kind of friends, who needs terrorists?!
Is the real concern that as this flu circulates into the warmer regions of the world that a reassortment could occur and a more virulent strain could arise? I feel like this is why the WHO and CDC are tracking this so closely.
i think swine flu is coming from (pig) so, consuming the meat of pig is totally forbidden in any religoin . so i advice those people who are comsuming the meat of pig to stop.
mohamed Ahmed-ethiopia
E-mail:gataa2004@hotmail.com
Hashana, do you mean if this virus was artificially created in a lab? I don’t know and I don’t know that there’s a way to tell. Probably if one goes back to sequencing the virus, but I’m not an expert so I would not know the answer to that. As it is, the host (pig) is a very probable source, and a sick pig could have transferred the virus to other pigs nearby and to people coming in contact with the sick animal.
Yeah man..