by Olddanb
Swine-flu outbreak linked to Smithfield Foods:
[Via Gristmill]
According to Mexican press accounts, thedeadly swine-flu outbreak now spreading into the U.S. is linked to large-scale hog operations in Mexico run by industrial-meat giant Smithfield Foods. WHO officials warned Saturday that the outbreak could reach pandemic levels.
[More]
I have not written anything on the flu epidemic because so many things are still changing. But I thought this article was possibly interesting. The details may change a lot in the next few days but it is a cautionary tale of how our methods for raising livestock could be very harmful to us.
It may take more time to get the location of ground zero figured out. Just because local source says that is what happened does not make it so. A little skepticism is warranted right now.
But, the circumstantial evidence is very intriguing. This huge pig operation is exactly where one might find the sort of epidemic flu we may be seeing begin its spread. The fact that the possible epicenter for a pandemic flu contains all the things needed for such a virus raises a strong case to be made. Further investigation will be warranted.
And the unique nature of the influenza virus makes it likely that, like Victor Frankenstein, we could create a monster made up of bits and pieces from a variety of sources that will have a tremendous impact on our lives. We would be the creators of our own calamity.
Influenza is an unusual sort of virus. Its genetic material is not a single piece of DNA; it is carried on 8 different RNA segments, almost like very small chromosomes.
And multiple influenza viruses can infect a single cell. So what can happen when multiple viruses infect a single cell? You get reassortment where new virus particles contain a mixture of segments from each of the different viruses.
So just as in the book by Mary Shelley, the new virus is made up of pieces from a variety of bits of genetic material. In this case, from different viruses.
Influenza viruses infect birds and humans. But generally, the influenza viruses for each species do not infect the other species very well. The worry about so called avian flu is that it would be a bird flu that could directly infect humans. Luckily this is not very easy to do.
Pigs hold a special place for influenza epidemics. They can actually be infected by both bird flu and human flu, as well as swine flu. So they have historically served as a wonderful reservoir for reassortment between bird, swine and human influenza viruses, resulting in a novel virus that can infect humans even though it contains genes from a bird virus.
When this happens, the new virus often can not be effectively fought off by our immune systems. If the new virus then can spread human to human, we get a pandemic.
So, the pig has historically been the animal that allows bird influenza to enter the human population, or at least some of the bird influenza genes. And, historically, Asia has been the hotbed of influenza outbreaks because it has been a one place in the world where large numbers of birds (such as ducks) have been raised in close proximity to pigs with large numbers of humans around.
But any place where there are lots of pigs plus lots of birds, with substantial human contact, is a potential breeding place for novel influenza viruses.
There have been large scale outbreaks of influenza in Mexican fowls before, some quite deadly.There are also apparently lots of ducks in Mexico that have been settling down in the huge fecal lagoons that are found at every large scale pig factory (read this old article from Rolling Stone to get an idea of what this is like). Almost a million pigs were produced at this plant in Mexico last year.
So, we have huge, relatively unclean factories with incredible numbers of pigs, large numbers of birds that have been known to carry avian flu viruses and lots of humans. A perfect incubator for a pandemic flu.
Here is a quote from a paper on influenza viruses:
Avian influenza viruses in wild aquatic birds are spread by fecal-oral transmission through the water supply (10); initial transmission of avian influenza viruses to mammals, including pigs and horses, probably also occurs by fecal contamination of water. Scholtissek has postulated that the use of fecal material from ducks for fish farming in Asia may contribute to transmission of avian influenza viruses to pigs (11). Another direct method of transfer is by feeding pigs untreated garbage or the carcasses of dead birds. Raising pigs under chicken houses and feeding them dead avian carcasses has been observed on rare occasions in the United States; H5N2 influenza virus was isolated from pigs living under chicken houses in Pennsylvania during the outbreak in 1982. Both pigs and poultry are commonly raised on the same commercial farms. From the perspective of the control of interspecies transmission of influenza, this is undesirable, for it may facilitate interspecies transmission of influenza viruses. After transmission to pigs, horses, or humans, the method of spread of influenza is mainly respiratory.
The bitting fly might be the vector that is involved, although I’m not so sure it would have much to do with a epidemic. This virus does not need blood to blood contact. It is spread human to human. This could just be a red herring.
So all it takes for an easy creation of a pandemic influenza virus is for there to be birds with influenza virus that pass it to the pigs. Throw in a sick employee and you have a ripe mix for reassortment of a deadly virus from bird, pig and human sources.
Following reassortment in the pigs, the virus can be spread a lot of ways. Perhaps contact between employees and the infected pigs. Or perhaps from the fecal lagoons where the virus could be released in a multitude of ways (i.e. release of fecal water, aerosolized by spraying, etc.) Someone breathes this in, gets sick and starts the spread.
It would be very ironic if a pandemic influenza virus was created due to the factory farming practices we have developed. In the end, Dr. Frankenstein died still fighting his creation. I hope that is not what lies ahead for us.
I’m hoping that the movie version is more descriptive. The one with Karloff, where the monster is fairly stupid and easily manipluated, dying in a huge conflagration while Dr. Frankenstein lives on … awaiting the inevitable sequel but with a wisdom borne of strife.
Technorati Tags: Science, Sustainability
