We hear that seven members of the same family in Kubu Sembelang, Indonesia, became infected with the H5N1 bird flu virus strain, all within a few days of each other. The World Health Organization (WHO) says it is possible that people infected people. However, the level of alert remains unchanged. Nobody can find an animal source for these human infections.
These seemingly ambiguous reports do nothing to alleviate anxiety levels for millions of readers around the world. Readers are immediately gripped with the thoughts: ?What is really going on? Has the virus mutated? What do we do? Why don’t they tell us more? Are we being told everything?’ Conspiracy theories abound. However, looking closely, the reports are not ambiguous or contradictory.
Let’s recap on exactly what has happened in Indonesia so far:
It all started when a woman infected with H5N1 shared a very small room with family members. The woman was very sick, coughing and sneezing a lot. Her nephew, 10, who was also in this small room, got infected. Then the nephew’s father got ill after spending a couple of days caring for his very sick son. Eventually seven family members got ill.
There have been cases of humans infecting other humans before. The WHO said, many months ago, that a human can catch bird flu from another human if there is prolonged and close physical contact – as would be the case when someone is caring for an infected person.
If all the seven members of this family were in close contact with each other, and subsequently infected each other – this is nothing new.
The H5N1 virus, in its current form, can only make a human sick if it manages to reach deep down in the lungs. It does not infect the upper-respiratory tract of a human, it infects the lower-respiratory tract. For a human to become infected and ill he/she must be exposed to a large, continuous cluster of H5N1. When an infected person coughs, tiny quantities of H5N1 are expelled, because it is so deep down in the lung. This makes it even more difficult for one human to infect another. The only way one human can infect another is by constantly coughing, really close to that other human, in close quarters, for a long time.
With family members all sharing a small room, it is easily possible that a sizeable cluster built up – enough to start infecting other family members. H5N1 already does that without having to mutate – transmit from human-to-human if conditions are right. What it cannot do is transmit from one human who sneezes in the supermarket to another who is walking by.
So, the infection of these family members is easily possible without H5N1 needing to mutate. In fact, if it had mutated we would have expected to see more infected people, perhaps neighbours and other people down the road – this has not happened. The only ones to become infected were the ones who shared this tiny room with an infected person who was coughing a lot.
What may raise some eyebrows is that even so, for all seven to become infected is surprising. Experts have said, even if a human is caring for another H5N1 infected person, and has close, prolonged physical contact, transmission is possible, but difficult.
What conclusions can we draw from the information so far?
— We know all the family members, if they did infect each other, did so in a small room – a situation which could lead to human-to-human infection without the virus having to mutate.
— Perhaps there is an animal source for all the seven. That source has not been found yet.
— It would be premature to say H5N1 has mutated – more people would have become infected in that area.
— It is possible H5N1 has mutated ever so slightly and that is why seven people were infected. But this is only speculation.
According to WHO, there is no evidence of ?efficient’ human-to-human transmission. Authorities in the area have to be thorough – turn every stone to find a possible animal source, keep checking all humans for further infection.
Written by: Christian Nordqvist
Editor: Medical News Today