Life-threatening viruses such as HIV, SARS, hepatitis and influenza, could soon be combatted in an unusual manner as researchers have demonstrated the effectiveness of plasma for inactivating and preventing the replication of adenoviruses.

When exposed to plasma - the fourth state of matter in addition to solids, liquids and gases - for a period of just 240 seconds, it was found that only one in a million viruses could still replicate - practically all were inactivated.

Fresh insight into how viruses such as SARS and flu can jump from one species to another may help scientists predict the emergence of diseases in future.

Researchers have shown that viruses are better able to infect species that are closely related to their typical target species than species that are distantly related.

Their results suggest that when diseases make the leap to a distant species - such as bird flu infecting humans - they may then spread easily in species closely related to the new victim, regardless of how closely related these are to the original target species.

As temperatures begin to cool, coughing and sneezing inevitably follow. So begins flu season in the United States and preventable deaths, says David Kimberlin, M.D., University of Alabama at Birmingham professor of pediatrics and president-elect of the Pediatric Infectious Diseases Society.

"Each year, an average of 24,000 people in the United States start the flu season alive and by the end of it have been killed by it; that is enormous," says Kimberlin, who co-directs the UAB Division of Pediatric Infectious Diseases.

Kimberlin says it is too early to forecast the extent of this flu season, but he cautions people to protect themselves.

Most of the time, being ill with the flu is little more than a nuisance. Other times, it can spark an exaggerated immune response and turn deadly. Researchers reporting in the journal Cell, a Cell Press publication, have now traced the origins of this severe immune response -- called a cytokine storm -- to its source.

Cytokines are the chemical signals that drive inflammation, and cytokine storms are thought to be the cause of many of the deaths attributed to the 1918 worldwide influenza pandemic and to the more recent outbreaks of swine and bird flu infection. The new study provides encouraging news by offering the foundations for a completely new kind of flu therapy.