Respiratory viruses may spread via airborne dust

ISLAMABAD, August 24 (online): A study suggests that influenza viruses can spread through the air not only in droplets which a person who has the virus releases when they talk, cough, or sneeze but also on microscopic dust particles.

Seasonal flu outbreaks are responsible for the deaths of hundreds of thousands of people worldwide every year. In a pandemic, such as the1918 Spanish flu pandemic, millions can lose their lives.

In order to reduce transmission, scientists need to understand exactly how influenza viruses spread from person to person.

Experts have assumed that the droplets produced when a person with the virus breathes, talks, coughs, or sneezes are solely responsible for the airborne transmission of viruses.

But a new study suggests that dust, fibers, and other microscopic particles can also transmit influenza viruses through the air, with far-reaching implications for preventing and controlling outbreaks.

First, the scientists used a device called an aerodynamic particle sizer to sample the air from a cage containing a guinea pig.

The device revealed that the animal generated airborne particles ranging in size from 0.3 to 20 micrometers (or thousandths of a millimeter) in bursts of about 1,000 particles per second whenever it moved.

Healthy anesthetized animals exhaled only 0.10 to 0.18 particles per second, and anesthetized animals with influenza generated 0.5 particles per second.

This suggested that dust, rather than respiratory droplets, accounted for the vast majority of particulate matter released into the air while the animals were active.