Human death toll from bird flu rises as researchers worry.(News)

Egyptian authorities have reported their country's first human death from avian influenza--which, if confirmed, would mark Africa's first human fatality from the disease.

The 30-year-old woman from an area near Cairo developed symptoms and died following close contact with diseased poultry in her household flock, reported the World Health Organization (WHO). Further testing is underway at a laboratory collaborating with WHO to confirm the diagnosis; no signs of the illness have been found among the woman's family members and close contacts.

Meanwhile, 7 of 11 patients under investigation in Azerbaijan have tested positive for the H5N1 virus--5 of whom have now died from the infection, according to WHO. All but one of the patients lived in the small community of Daikyand, where a possible source of infection may have been numerous carcasses of dead swans, which may have been collected as a source of feathers. "In this community, the defeathering of birds is a task usually undertaken by adolescent girls and young women," WHO said in a statement, which noted that most of the country's human infections have occurred in females between the ages of 15 and 20 years.

Although most human cases of avian influenza have been linked to close contact with infected animals, there is growing concern among experts that the H5N1 virus could mutate to become more easily transmissible to humans, sparking a worldwide pandemic. Two new studies are now fueling this concern, suggesting not only that the virus has more human affinity than previously thought, but also that it may be undergoing genetic expansion.

Dutch researchers have found evidence that the virus attaches and replicates in the lower respiratory tract of ...