ALERT: Swine flu introdocues first intra-human transmissability

Health officials have seen mixes of bird, pig and human virus before, but never such an intercontinental combination with more than one pig virus in the mix. Scientists keep a close eye on flu viruses that emerge from pigs. The animals are considered particularly susceptible to both avian and human viruses and a likely place where the kind of genetic reassortment can take place that might lead to a new form of pandemic flu, said Dr. John Treanor, an infectious disease specialist at the University of Rochester Medical Center.

The virus may be something completely new, or it may have been around for a while but was only detected now because of improved lab testing and disease surveillance, CDC officials said.

The virus was first detected in two children in southern California — a 10-year-old boy in San Diego County and a 9-year-old girl in neighboring Imperial County.

SHOOT: This is scary.

clipped from news.yahoo.com "We certainly have 60 deaths that we can't be sure are from the same virus, but it is probable," said Health Secretary Jose Cordova. He called it a "new, different strain ... that originally came from pigs." Epidemiologists are particularly concerned because the only people killed so far were normally less-vulnerable young people and adults. It's possible that more vulnerable populations — infants and the aged — had been vaccinated against other strains, and that those vaccines may be providing some protection. The most notorious flu pandemic is thought to have killed at least 40 million people worldwide in 1918-19. Two other, less deadly flu pandemics struck in 1957 and 1968.