Coming back of Spanish flu

Spanish flu pandemic in 1918-1919 affected more than 500 million people in the whole world. The mortal virus took more than 400 million lives then. Since that time world flu epidemics (pandemics) recurred two times (in 1957 and 1968), however, unlike Spanish flu they were caused by a less mortal virus, since the number of victims was much less than during the pandemic 1918. The results of contemporary researches show that the virus of Spanish flu   was a typical avian flu virus which acquired an ability to propagate in human body and pass from human to human. Presently the issue of possible new bird flu epidemic is discussed at the highest levels. In scientists` opinion the following events should take place for the eruption of pandemic:
1.The avian flu virus should adjust to propagation in lower temperatures than the temperature of bird body. This has already happened. It has been proved by cases of infection of workers in poultry farms in some Asian countries.
The normal bird body temperature is about 420С, whereas the normal temperature of human body does not exceed 37,5 (inner temperature) or 340С (in nasopharynx ). It is obvious that the virus has acquired an ability to propagate in human body, however, only in lungs and trachea, but not in nasopharynx unlike regular flu virus.
2.   Mixing of the genetic material of human flu virus and bird flu virus must occur. According to scientists such a mixing could happen in pigs. The fact is that, the body cells of pigs could equally be affected by human flu and bird flu virus.  While propagating the viruses exchange part of genes, in the result of which new mutant species of viruses with totally new characteristics form. Examination of bodies died of Spanish flu showed that the virus of 1918 was a mutant virus which contained both human and bird flu components. These “mixed” variants of the flu virus are especially dangerous to people, because the recombination of the genetic material provides viruses with new proteins which are not familiar to immune system of human. Getting into human body such a virus starts to propagate without any hindrance within 1-2 weeks, which is enough to kill a human. The Spanish flu virus was a very uncommon one.  Modern researches and historic facts show that mainly young people died of Spanish flu, not children and old people (unlike the regular flu virus) despite the apparent immunosuppressive effect of some components of the virus. Patients affected by Spanish flu died of cardiopulmonary insufficiency associated with massive pneumonia and diffuse lesion of blood vessels of the whole body developing in a few days.
3. The virus should acquire an ability to pass from human to human. This last characteristics of the virus has not been fixated yet, since within the whole history of bird flu detection (the first epidemic among birds and cases of human infection were detected in 1997 in Hong Kong), there has not been any case of passing of the virus from human to human.  It is worth mentioning that if the virus acquires such ability, just one patient infected with mutant virus who would pass the ocean may provoke flu pandemic which would affect the whole world just within a few hours.
Despite all capabilities of modern medicine it would not be possible to prevent bird flu epidemic (in case the virus acquire all necessary characteristics). Presently all efforts to fight bird flu are arrowed at localization and suppression of the disease outbreak among birds.
Most professionals assert that in all probability the problem of Spanish flu recurrence is just a matter of time.