The type A Influenza virus
The flu virus - type A influenza virus- belongs to Orthomyxovirus family. Type A virus A causes pandemics, type B epidemics and sporadic cases while type C is very rare in humans. It contains RNA and it is wrapped making it a fragile virus in the environment. Its envelope has 2 glycoproteins; hemagglutinin (H) and neuraminidase (N). There are 16 types of hemagglutinin (H1-H16) and 9 different neuraminidase (N1-N9). It is stable under freezing and that is why a scientific team went to Spitsberg to get back samples from Norwegians died from flu in 1918 and buried in the permafrost in order to recover the important virus (the result was a total failure!)
Two kinds of events participate in the evolution of the virus.
Fast antigenic shifts : they are constant and small-scale. They occur every winter and the new strains cause epidemics.
Antigenic jumps cause major genetic changes. These events occur about every 10 years and result in pandemics.
Birds host all the 16 H and the 9 N while other animals host only some types. Pork can host human and avian viruses, which makes it an excellent intermediary. When a new virus appears, it may, in some cases, be transmitted to humans and cause a pandemic. This was the case of the H1N1 virus of the Spanish flu that happened in humans, whereas the younger generation, who known only the H3N8 viruses, had no immune defense against the new virus. We can read the phylogenetic analysis Worobeyen Michael et al. by following the link below.
The especialy large outbreak of this year is due to a mutation which occurred in the H3N2 genome, giving a better transmitted virus. As this mutation took place after the manufacture of the vaccine, this later was less effective.
Epithelial destruction, loss of ciliary function, mucus changes, local inflammation, bacterial infections.
The mortality rate depends on the strain and the patient’s immune status.
The Influenzae A virus: a biological weapon?
- North Korea
According to a defector from North Korea who confided to the British Secret Service, the country is working on the militarization of H5N1 (many researchers from Russian laboratories "Biopraparat" are working in North Korea. In Russia, they had already worked on the Spanish flu virus !
It is probable that China and Russia have similar programs. However, Iran, an ally of North Korea and closely linked to international terrorism, is working with one of the most populous Muslim country, Indonesia, in order to develop vaccines against avian flu: they have access to very dangerous H5N1 strains which are very common in Indonesia.
A variety of research can envisaged
- make frequent and repeated passages of the virus in animals or cell cultures to force it to mutate ;
- combine a virulent but low transmissible virus with a more transmissible from person to person virus. The virus could be stabilized by the addition of polyhydroxy compounds and spread by means of aerosols. Experiments have already been conducted in this direction.
Some consider that the flu virus is the most powerful weapon in the scale of bioterrorism. Actions must be taken urgently as, classification of the virus as "critical agent of bioterrorism" by the CDC, widespread vaccination, secure virology laboratories, increase antivirals production. Genetic analysis of monitoring should be increased. Doctors must learn to distinguish relatively similar clinical signs at the beginning of the flu and anthrax diseases.
Extensive immunological studies relative to the influenza immune response are expected to develop for more effective vaccines.
The influenza virus can be fatal, even among young people. It is well transmitted from human to human and can be easily aerosolized (large surface contamination).
Two scenarios were recently developed (CDCP FluAid software)
1- avian H5N1 virus compared to anthrax cause an equivalent mortality (2-9 dead for a 0.25% attack rate) under similar dispersion conditions than these of the letters containing Bacillus anthracis spores in 2001 in USA ;
2- for attack rates between 15 and 35% and mortality rates between 0.1 and 32%, the number of deaths could be up to 136 million.
Perhaps it would be wise for the CDC to class this virus in class A?
You can refer to excellent article by K. Iyer and S. Pola will be found on the following link: