From Lisa Schnirring at CIDRAP, excerpt :
" The US Centers for Disease Control and Prevention (CDC) recently updated some of its background documents on swine-origin flu viruses in humans, based on the latest information it has learned about recently detected novel flu infections.
The CDC released the updated information, aimed at both the laypeople and medical audiences, on Jan 6. The information covers key facts about swine-origin variant viruses and infections involving the strains in humans, particularly the H3N2 type that has so far infected 12 people in five different states, most of them children.
Some of the patients had contact with swine, but other cases likely reflect limited human-to-human transmission, the CDC has said.
The new virus is a triple-reassortant that has acquired the M gene of the 2009 H1N1 virus. The CDC and many of its global partners are referring to the new strain as an H3N2 variant and are using the H3N2v abbreviation.
The CDC has said it's unclear why the number of detections in humans is increasing. It said factors could include better lab capacity to detect novel viruses, changed domestic and international novel flu virus reporting requirements, or a true increase in the number of cases from exposure to swine or through limited human-to-human transmission."