It is time to take away swine passports! Put them on the no-fly list!
(...) The new H1N1 strain is based primarily on an unusual influenza virus that has been circulating widely in U.S. pigs since the mid-1990s. That "triple reassortant" flu is actually a combination of classical swine flu, a North American avian flu, and a strain of human flu. Somehow, a single pig became simultaneously infected with that virus and a pure swine flu strain found in pigs in Europe and Asia. The two strains swapped genetic material to produce the new H1N1 strain, which then began to infect humans.
By comparing the small genetic differences in flu samples from many patients, scientists estimate the pandemic strain was already circulating in people by November 2008. The earliest cases to be confirmed in people occurred in Mexico in March.
How did the two strains of swine flu mix?
That remains a mystery, and scientists will probably never know.
Relatively few pigs engage in intercontinental travel, and those that do are strictly quarantined.
But there are theories. One is that
a person in Asia became infected with the Eurasian swine flu, then traveled to North America and passed it along to a pig here that already had the triple reassortant virus. That would explain why the outbreak began in Mexico and the United States.
Another theory holds that
an infected North American pig traveled to Asia and passed along its virus to another pig with the Eurasian flu strain. That pig then infected a person, who brought the virus back to North America and spread it to other people. This would explain why H1N1 has seven out of eight genes in common with a flu sample taken from a Hong Kong pig in 2004. (...)
http://www.baltimoresun.com/health/sns-health-swine-flu-origins,0,5124822.storyIf you believe any of these theories, I have a flying pig I'd like to sell.
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
