Finding out why H5N1 is hard to jump from person to person

The killer virus H5N1 prefers to reside in cells deep in the lungs, rather than the top part of the respiratory tract as with other flu strains, two recent studies found.

Human transmission - people of H5N1 probably won't happen (Photo: ecplanet) That may explain why human-to-human transmission of this avian influenza virus has so far not happened - and possibly will not happen in the future, Forbes.com announced yesterday.

Since 2003, the H5N1 virus has appeared in Asia, Europe, Africa and the Middle East, leading to the destruction of millions of domestic poultry. Although the infection is still limited among birds, the virus kills 103 people through bird-to-human transmission.

However, scientists fear that this killer virus could mutate into a different form, which can be transmitted more easily from person to person, and then a global pandemic flu pandemic could happen .

One of two studies published this week explored that possibility, made by scientists at the University of Wisconsin and University of Tokyo. The group found H5N1 very unlikely to reside in the upper respiratory tract. They penetrate the area much deeper, and are very flexible in the lungs - making the infected virus difficult to spread and be treated.

In contrast, ordinary human flu strains nest in upper respiratory cells. This means that, whenever people cough or sneeze, water droplets from this point will easily spread into the air, making it easy to spread people - people.

The findings by Japanese-American researchers were repeated by a Dutch research group, scheduled to be published in Science magazine tomorrow. The University of Rotterdam science group once again found that avian flu prefers to hide in cells deep in the lungs, and away from the upper respiratory tract.

Both mean that human transmission - people of H5N1 will most likely not happen, at least until now. However, any mutation can change that situation.

T. An