Influenza Season and the Swine Flu H1N1:
While the typical influenza season is usually during the cold and dry months of Winter and early Spring months (Science Daily article on typical human flu); the current H1N1 flu (Swine or Pig Flu) has spread very rapidly during the months of April and May which are in fact warm in Mexico, current temperatures in Mexico City are in the 70-80's °F during this time of the year. A study by the Mount Sinai School of Medicine in New York City found that normal flu thrives in winter months because of the low humidity and low temperature.
The jury is still out on whether this influenza virus will thrive in the hot months only or if its effect will increment during the cold months of winter/early spring. This is a reason why the development of a vaccine is necessary: so that we can be prepared for it when we are the most vulnerable. It is still unclear if the colder weather will make the spread of this virus more aggressive.
Genetic Makeup of H1N1 Swine Influenza Virus:
The current H1N1 Influenza Virus has a genetic makeup that includes genes from three different virus that affect pigs, birds, and humans. It is now apparent that the predecessor to the current H1N1 pork flu had already been around in pigs for 10 years and just recently acquired the additional genes that have allowed it to become virulent in humans.
The H1N1 chimeric virus is mostly of swine origin, with 6 segments from pig virus, 1 from bird, and the last from human.
The pig flu virus can jump back and forth from Humans and Poricine species.
The H1N1 virus is first thought to have jumped from pigs to humans in Mexico, and it has been confirmed that once it made it to Canada, it infected pigs jumping from a human host. Humans that work in proximity with pigs are rarely infected with porcine-viruses, it is even more rare that a human infected with porcine virus infects another human (happens every 5 decades or so), but what was never documented is the virus of pig oringin jumping back to pigs.
Sources:
- Science Daily (2007) "Influenza Spreads Readily in the Winter Conditions"
- Yahoo News (May 2009) "Swine flu name change? Flu genes spell pig"
- Euronews (May 2009) "Human infects pigs in Canada"
