Truly deadly virus should find the best balance between power spread and virulence. So, you want to meet a man has both power and spread of rabies virus H1N1 virulence super virus really is not a very easy thing.
Recent outbreaks of Ebola virus outbreak in West Africa are “plague the company,” the game also followed the fire up. In this game, you need to make your pathogens and kill people around the world, in order to achieve this, you need to make your ability to communicate with a certain pathogens and disease-causing ability, it is not only able to rapidly infect people around the world , and will not be people developed drug cleared.
In reality, we have to face the virus also has such properties. 2009, with Mexico as the source of an outbreak of H1N1 flu in less than a year swept the world, the reason why so soon be able to spread to the rest of the world, because of this flu virus can spread directly between people through the air, Coupled with modern developed transport, H1N1 may spread to the unprecedented rate of any place around the world for human habitation, high propagation efficiency. 2009 influenza outbreak caused about 2 billion people are infected, the death toll of about 10,000 to 20,000. If this outbreak of H1N1 in a virtual game, you can not win, because it’s too low virulence, even the successful infection of all human beings, can not kill them all. What if we replaced the virulence of the virus is particularly high, the results of what will happen?
In reality there is a nearly 100% virus kill the host, this is the rabies virus, the virus is generally spread through bites. If the person is infected with the rabies virus, dog bites or scratches, are susceptible to infection. Rabies virus can attack the central nervous system, the patient appeared cognitive impairment, confusion of consciousness, and exhibit crazy and aggressive tendencies, once symptoms appear, the patient is far from death. Rabies virus can thus become the closest man into a “zombie” virus.
There are more than 5.5 million people worldwide die of rabies each year, mostly in Asia and Africa, the vast majority of cases of human infection with rabies virus is caused by a dog in all infected persons, about 40 percent are children under 15 years of age, because children at higher risk of dog bites. About more than 1500 million people worldwide each year after being bitten by dogs receive rabies vaccination, this measure each year hundreds of thousands of lives could be saved, that is, in the absence of vaccination situation on Earth every year because of rabies the number of deaths should be in the hundreds of thousands of this magnitude.
This is not a small number, but compared to the rabies virus 100 percent fatality rate, this result is not bad. You know, on Earth there are 200 million people suffer from malaria each year, there are more than 60 million people have died; rotavirus annually cause more than 500,000 child deaths; 30 years of HIV was discovered, there are 36 million people died of AIDS, and these types of pathogens death rate is much lower than the rabies virus.
Rabies virus because 100 percent fatality rate, riding on a well-deserved “the first killer” throne, but it does not seem to regard it as an important threat, for obvious reasons, the decision by way of bites spread rabies virus The spread of power is not very high, so even if there is no protection of the vaccine, rabies virus is difficult to wreak havoc in the crowd.
2003 That memorable SARS so far, it was said, sars coronavirus virus is one of the most ferocious encounter since humans appeared, because it is both high infectivity and high mortality rate, then the SARS mortality How high do? It is estimated that the difference is not more than about 10%, about one percent of rabies virus. In almost H1N1 has spread considerable ability, the virus is lethal rate increased to 10%, that is a very terrible thing, if in accordance with the 2009 H1N1 infection to calculate the global two billion people, 10 percent will be 200 million people.
1997, Hong Kong was first discovered human infection h5n1 bird flu, which was first discovered in humans infected with avian influenza had only virus. After screening the patient and emergency isolation killed millions of chickens, the epidemic was quickly controlled. In subsequent years, H5N1 has also several times after another outbreak in Asia, each resulting in only a few people to dozens of deaths. By the end of 2013, H5N1 infected a total of 640 people, killed 384 people, the fatality rate in almost 60%. Early 2013, but the outbreak of the H7N9 bird flu, which is the second bird flu virus to infect humans, this bird flu virus mortality is estimated at between 20% -30%.
Compared SRAS coronavirus, the virulence of two avian influenza viruses have a lot of strong people so worried about the bird flu virus outbreaks reason is because it has a higher virulence. However, more people are worried about avian influenza virus through mutation, the ability to get through the air transmissible between humans directly.
Influenza viruses can be divided into alpha, beta and gamma three, including influenza A virus of the greatest threats to mankind. Influenza virus and the surface through which the hemagglutinin (HA) and neuraminidase (NA) of the composition is divided into different subtypes have now found at least 17 HA subtypes (H1 ~ H17), and 10 NA subtypes (N1 ~ N10), we usually see H1N1, H5N1 and H7N9, etc. is to use this way to distinguish the difference.
These influenza viruses to H1, H2 or H3 beginning is often called human influenza virus, because these flu viruses have been well adapted to the human respiratory mucosa cells, human cells infected with strong, able through the air In spread directly between people, so they can easily cause a global influenza pandemic.
And beginning with H4-H17 influenza virus, commonly known as bird flu virus, so called because they can be adapted to avian influenza viruses in cells, and human cells can not be infected. However, due to the massive concentration of breeding birds and other reasons, there are some avian influenza viruses have the opportunity to come into contact with and adapt to human cells, or possibly by recombination with human influenza viruses acquired the ability to infect human cells. Scientists have discovered that these can infect humans, bird flu virus, affinity for human cells to improve a little.
However, avian influenza virus infection of human cells compared to human influenza virus, or much worse, while at present it has not found the bird flu virus can be spread through the air directly between people. However, this is also the scientists most worried about, with 20% -60% mortality rate of the virus, once the ability to get airborne, the consequences could be disastrous.
Want the bird flu virus can spread through the air becomes not a difficult thing among people, in 2011 the United States and the Netherlands have both laboratory passaged through restructuring or adaptation methods in the lab has been able to air between ferrets mammals spread of H5N1 avian influenza virus directly, so that once the virus from the laboratory to flow out of the human race will be a huge threat, although these two studies published eventually come out, but the controversy has been to this day did not stop. In the study, scientists found that only takes a few mutations, we can gain the ability to make H5N1 among mammals spread through the air, regardless of the mutation or recombination, are likely to occur in nature.
This is a reminder to mankind, with the development of human society, human lifestyle changes as well as human life for the destruction of the environment, more and more new viruses have a chance to jump to humans from wild animals, these viruses in the first When exposed to a new host, often with strong virulence, SRAS is a warning. Meanwhile, the virus is constantly evolving, with new host of viruses and constantly co-evolution, a new virus for humans, it may be more adapted to the environment of human cells, thereby enhancing human appeal.
In general, the spread of the virus virulence is often weak and strong, and the spread of highly pathogenic viruses are often relatively weak force, both weak and strong, or both viruses in the evolution of the above have disadvantages. Truly deadly virus should find the best balance between power spread and virulence. So, you want to meet a man has both power and spread of rabies virus H1N1 virulence super virus really is not a very easy thing.