Why do so many strains of bird flu originate in China?

I would assume that it is because their are more chickens, crammed in tight spaces, in China than the rest of the world. Their are over 1 billion Chinese people that need to be fed.

China eats more birds.

I think it is because there is a high density of birds in one place including at markets. They still sell live birds for people to take home to kill and eat. Some places kill the bird there for the customer. The birds are near various different breeds of birds so the virus has more opportunity to mutate, and also in tight proximity to humans. Think about it, most Americans never come into cntact with live birds or pigs for that matter, but imagine if the majority of us bought live chickens rather than packaged at the supermarket. So, more opportunity for the virus to jump and infect other birds and people and then it all just multiplies exponentially.

Those sound like guesses as to how it spreads. What I’m wondering is why it starts there. Anyone know?

It has to do with the proximity of livestock to humans. Many Chinese peasants still live with their livestock, even using their body heat for warmth in the winter months—much like European peasants did only a century ago. As one can imagine, this can make disease transference more likely, especially between swine and fowl.

@Jeruba Now that is an interesting question. I cannot answer it specifically, but what I do know is in the US we watch for wild birds that might have possibly contracted flu from Asian birds so it doesn’t infect our chicken population. Not all bird flus from chickens jump to wid birds, but I know there is at least one strain that does that we watch for and test. So, it makes me wonder if bird flu just has been on the continent of Asia for 100’s of years and we see it mutate and flare up sometimes and when it jumps to humans we become very aware of it, especially in modern day since we travel so much.

I’ll be following, hoping to see if someone knows the real answer. It seems like diseases come out of the tropics a lot, I don’t know that for a fact, but it seems that way. I think southern China is tropicalish. It still doesn’t specifically answer your question though. Plus, there are other tropical climates in other countries that we are not so focused on for flu. GQ.

They keep their fowl too close together in confined spaces.

Their animal cages are too small and stacked too high.

Since Fluther doesn’t allow for photo attachment, here is an article with a photo of chickens taken to market. This is typical of treatment I see of ducks in their country, as well.

The reproductive rate of chickens compounded by the phenomenal numbers allows for more spontaneous mutations of the birds and the pathogens to which they are hosts. The high density of the birds facilitates the spread of the pathogens. The high degree of contact between the birds and humans increases the likelihood that mtant forms of the pathogens will adapt to use humans as hosts as well. @Jeruba, I hope that helps to explain how and why there are so many pathogenic stains that arise in China.

All right, I’ll buy that, @Dr_Lawrence. But I’m still puzzling over why China specifically and repeatedly. I don’t think those conditions are unique to China. I see similar conditions in images of markets in Africa, Indonesia, and Mexico, just for example. So I get it that China presents an environment conducive to the mutation and spread of bird flu—but not why we don’t hear of other strains that start in other places with similar environments.

@jeruba Perhaps we will in the future or we may have failed to take notice of such events in other places. Population density in China may be much greater in the urban centres that it is in other places you mentioned.