All viruses mutate. Researchers who analysed and tracked Sars-CoV-2 - the coronavirus that causes Covid-19 - have released findings about mutating strains of the virus, even before the Malaysian and Philippine health authorities announced they had seen patients with mutations of the virus.
Q How many variants of Sars-CoV-2 are there?
A The original strain found in China when Covid-19 first emerged in January was dubbed D614.
G614 - often referred to as the "G strain" - is a mutated variant which was prevalent across Europe and North America by May. This strain has been more virulent - infecting more people and found in more places - than the original one.
Researchers say there is another strain now, D614G, which is even more prevalent. This is the one the Malaysian health authorities on Sunday described as being 10 times more infectious. Some scientists claim the D614G variant has been circulating in South-east Asia as early as February.
Q Are the mutations deadlier?
A While the variants are more contagious, there is no evidence suggesting that they are more deadly than earlier versions. For example, multiple studies have shown the G strain to produce more of the virus in the human body than the D strain but it did not lead to higher hospitalisation rates.
Dr Bette Korber, a theoretical biologist and lead author of a study on D614G, said in an interview last month: "It is the dominant virus in the world. It took only about a month for that to happen and it is now the one we should be looking at."
Virologists at US-based Scripps Research, in a study published last month, found that viruses with the D614G mutation were far more infectious than the others.
But some scientists have argued that just because one strain travels farther, it does not necessarily mean it is more infectious. The quality of healthcare and the capacity to handle an outbreak should also be taken into consideration.
Q How to react to mutations?
A Changes in preventive measures to contain the spread of Covid-19 will not make a difference, whether the virus is more infectious or not, scientists said.
"The basic pillars of prevention and control of Covid-19 remain the same," Dr Sanjay Rampal, an epidemiologist with Universiti Malaya, said in an interview, adding that the authorities could instead improve capacity for screening, contact tracing and treatment.