Mexico City  - The death toll from a spreading wave of influenza in Mexico has climbed to 81, Health Minister Jose Angel Cordova Villalobos said Saturday evening.

Twenty of the lethal infections have been definitively linked to the newly emerging strain of swine flu, he said. All told, 1,324 people have been admitted to hospital for examination.

In the United States, 11 non-lethal cases of a similar strain of influenza have been identified by the Centres for Disease Control, with tests pending on another 10 cases.

Washington/Geneva - The Geneva-based World Health Organization Saturday declared the outbreak of swine flu in Mexico and the United States a "public health emergency of international concern."At least 20 deaths in Mexico have been confirmed as swine flu, among a total of 60 deaths that have occurred there. Hundreds of more non-fatal cases have been reported, and schools, museums and other public places have been closed to prevent the spread.

In the United States, at least eight cases in Texas and California have been confirmed by the US Centres for Disease Control.

Washington - An illness that has affected abut 75 students at a private school in New York City is "likely" swine flu, said Thomas Frieden, the New York City health commissioner. The conclusion was reached after swabs were taken from nine students at St Francis Preparatory School in Queens on Friday.

The specimens were examined by the health department, which concluded they exhibited in Influenza A strain that was "likely" swine flu, Frieden said.

A confirmatory result was expected Sunday from the Centers for Disease Control in Atlanta, Georgia.

Tokyo - Japan began checking temperatures of passengers arriving from Mexico Saturday after a swine influenza outbreak killed more than 60 people in Mexico and infected at least eight in the United States. The Japanese government on Saturday began tightening health checks on travellers entering the country through Narita and Kansai airports directly from Mexico or via the United States.

Washington, Apr 25: People who are bony or lean are more likely to perceive an approaching sound as closer than it actually is, according to a new study.

Evolutionary psychologist John Neuhoff and colleagues at The College of Wooster in Ohio, who study "looming" sounds, said that such a connection between physical fitness and the brain''s auditory system may have evolved to help the weak get out of the way of approaching danger.

Washington, Apr 25: Scientists at University of Michigan, Ann Arbor, are developing a new technology, called histotripsy, to trim the interiors of aging prostates in the body.

Traditionally, researchers treated prostate growths by inserting a rigid instrument through the penis and scraping away cells lining the walnut-sized gland.

But, the new technology being developed by urologist William Roberts and a team at the University of Michigan, Ann Arbor, is a less invasive way to remove tissue using focused pulses of ultrasound.