After a patient died of bird flu H5N1 infection last week, authorities in China have confirmed that his father, 52, is also infected. Both patients lived in Nanjing, Jiangsu province.

The father is said to have a fever and has been hospitalized. It is still not known how the father (or the son) became infected. The virus could either have got into him via a bird, or perhaps from his son. These two infections are an enigma for health experts as neither the son nor the father had any physical contact with birds – in fact, there have been no recent reports of H5N1 poultry outbreaks in the province.

There are more chickens, and poultry in general in China, than anywhere else in the world. The country also has tens of millions of backyard birds. It is known that areas where the population of backyard birds is high are especially vulnerable to the spread of H5N1 as it is more difficult to take precautionary measures effectively and swiftly in these areas. In many parts of the world people keep backyard birds to supplement their very limited supply of food – when faced with the prospect of going hungry they are much less likely to cooperate with the authorities.

H5N1 is a strain of the bird flu virus – the strain everyone is worried about because humans have no immunity against it, it is very virulent (strong and dangerous).

So far, a total of twenty-seven people in China have become infected with H5N1.

Scientists fear that the H5N1 bird flu virus strain will eventually mutate and become easily human transmissible. This has not happened yet. It is still extremely difficult for birds to infect humans, and even harder for a human to infect another human.

It is believed that one of the ways H5N1 could mutate would be by infecting a person who is sick with the normal human flu virus. The bird flu virus would then have the opportunity to exchange genetic information with the bird flu virus and acquire its ability to spread easily from human-to-human (become easily human transmissible). If this happened, we could be facing a serious, global flu pandemic.

If we can keep the number of outbreaks among birds down to a minimum, then the number of humans becoming infected is also low – giving the bird flu virus fewer opportunities to mutate.

Written by – Christian Nordqvist