Eyes on th Swine

We live in an age where the public believes someone, or thing, is always watching. Yet recently the Swine Flu has jumped into the human population. It made its first appearance in March and April, yet by late May officials were still trying to figure out where it came from.

The recent outbreaks of Swine Flu has tested systems that watch for human flu outbreaks, and proves a theory that pigs could be the “mixing vessels” of pandemic viruses. It has also pointed out how little progress has been made showing where and how such viruses evolve and predicting their transmissions to humans. Both would be great in preventing or warning of an approaching pandemic.

Though much funding and attention have been given to flu research, we are no closer to soundly finding animal diseases that could harm humans. For example in 2007 Jürgen A. Richt and his colleagues at the US Department of Agriculture’s National Animal Disease Center in Ames, Iowa found an H2N3 virus thought to have potential in going to humans; no one was interested. They put their findings in a scientific journal concluding with “it would be prudent to establish vigilant surveillance in pigs and in workers who have occupational exposure.”

When speaking of the disease, surveillance means doctors and diagnostic labs report every instance of certain pathogens found. Every human flu case is “reportable” to the Centers for Disease Control and Prevention. The CDCP tracks the incidence and movement of the illness. In both animals and humans voluntary lab testing only finds a small percentage of cases involving a doctor’s visit. Mandatory reporting and systemic sampling in swine herds are limited to a very small number of devastating illnesses.

Richt thinks veterinary labs could play a bigger part in animal screening by testing every sample for every pathogen. Richt says, “We need a better network to look in animal populations for emerging infectious agents with 21-st century technology.” A couple labs already have the technical ability to do this, says Richt. Microarray chips able to test pigs, cattle, and poultry could give small labs a large capacity to keep watch for microbial threats developing in livestock. Identifying animal flu strains is one thing, but finding whether or not they could pass to human is another thing altogether. “I'm a lot more pessimistic about being able to predict these things,” says Jeffery K. Taubenberger of the National Institute of Allergy and Infectious Diseases. He wrote a book about two swine branches of the H1N1 family tree. Both had a common H1N1-type ancestor, but they evolved differently, and little changes have let them transfer to different host species. Scientists looking for clear patterns about whether a virus is switching hosts have failed so far.

Because of this, no one can explain why avian H5N1 has infected about 400 people worldwide, but has, thus far, failed to totally adapt to humans. They also don’t know where the original pandemic virus from 1918 came from or where H1N1, its descendant, is going. H1N1 might fizzle out or learn to pass between people more easily. It could later return powerful or weak.
Taubenberger thinks that if we keep watch over an entire rural ecosystem, we might find some deeper insights as to why and how the flu virus evolves.

Money and research directed toward pandemic preparations have dramatically improved human flu surveillance and response systems. Unfortunately, without closer monitoring of animal sources of flu strain, human surveillance must remain the ultimate first line of defense.

Response
I found it quite interesting that so much goes on behind the scenes with viruses such as the flu. I never had thought about how these viruses develop and change to be able to transfer from animal to human. I had also never heard that the new H1N1 (Swine Flu) outbreak is a descendant of a 1918 pandemic. It’s weird to think that we may come into contact with a flu virus, and later be challenged by the same virus after it has developed and become much stronger.

http://www.scientificamerican.com/article.cfm?id=eyes-on-the-swine