The discovery of a mutation of the pandemic H1N1 virus in Norway and some other countries is being assessed by the World Health Organization (WHO) for its significance to public health significance.

WHO was informed by the Norwegian Institute of Public Health of the H1N1 virus mutation detected in two patients, one of who died, while the other is severely ill.

According to the UN agency, apart from Norway, countries like Brazil, China, Japan, Mexico, Ukraine and the United States also detected the mutation sometime in early April.

The agency says this virus mutation continues to remain sensitive to anti-viral drugs - oseltamivir and zanamivir, the antiviral drugs.

As well, mutation occurrence is sporadic and spontaneous, with no links found between the infected patients infected, and the mutation does not appear to be spreading.

According to a WHO statement, thus far there have been 6,770 deaths worldwide due to the pandemic virus, with over 4,800 in the Americas.

Elsewhere, such as, Brazil, China, Japan, Mexico, Ukraine, and the United States, WHO says the same mutation has been found in both fatal and mild cases.