The bird flu virus has lived in the innards of wild birds for centuries; there have been no signs of harm. However birds reared for their meat or as pets in human dwellings, fall sick and often die when exposed to this virus. Chickens and ducks are especially vulnerable. A bird virus is normally happy to live within the bodies of its normal host species, but can jump across and enter human bodies when there are plenty of them nearby. This is especially the case when a bird is terminally ill and close to death or freshly slaughtered. Interviews with people, especially children who have suffered from a bird flu attack, will generally establish that they have handled sick birds shortly before they fell ill.
Communities that live amongst animals including birds are in danger of a contagious virus outbreak. This has happened in Asia during the recent past. Communities in both rural areas and poor sections of cities share their dwellings with cattle. Chickens and ducks roam free, leaving children and adults exposed to their droppings. Handling living birds and cooking their fresh meat involves serious risk. Social habits are difficult to change and hence the threat of an epidemic in parts of Asia looms large. Poor nutrition can reduce immunity because the body has inadequate resources to produce white corpuscles in adequate numbers and of the right type. Malnutrition becomes a deadly threat when combined with close contact with domesticated animals. Children are especially vulnerable. This explains why some Asian children are vulnerable to encephalitis and rotavirus, though these diseases are virtually unknown in the West.