More new facts are emerging in the quest to conquer the flu virus. Initially, the H1N1 virus appeared in 1918 as it spawned the most dangerous pandemic on record. This strain of virus in its weakened form returned every year for about 30 years until it reassorted its genetic structure and appeared as the Asian flu pandemic in 1957. This reassortment was due to a patient who was infected with both the H1N1 and H2N2 avian virus came up with a new immunological type of virus which resulted from the reassortment of the genes of those two viruses. This was the initial emergence of the new H2N2 virus. This pandemic in 1957 was not as widespread or severe as the one in 1918, “the Spanish influenza”.
Later, in 1968 the ” Hong Kong flu” emerged when a patient who had the seasonal H2N2 virus was also infected with the H3 avian, “bird” flu. This was not as severe as the 1918 flu either. Subsequently, the H3N2 and H1N1 combinations have appeared since the 70′s. The yearly flu vaccines target those two viruses and the influenza B virus. However, the H5N1 avian, “bird” flu started in 1997 and starting in Hong Kong caused 433 human cases with 262 fatalities.
The current H1N1″ so called -swine flue- started in 1998 in the U.S. It was first detected in pigs. This virus has the genetic make up of genes from the human, bird and swine flu viruses. Pigs can catch viral illness from humans and birds. This Spring this virus resurfaced in Mexico and is found to be highly transmissible and virulent. It spread from Mexico to California and by June it became a pandemic. It infects the young and pregnant women appear more vulnerable. The high mortality rate among the young appears to be due to the strong immune response the young people are able to mount,resulting in a “cytokine storm” which could be an immune response that devastates the host. Finally, the long awaited H1N1 vaccine has now arrived and will be available starting this week.